VOYAGEA Journey of Learning Through Space

ISSUE 3 March 2005 £2.50

Great Puzzles and Competitions

THIS ISSUE: THE NIGHT SKY

GravityExperiments

Spectacular Imagesfrom theHubble Telescope

The Night Sky Part 2:CHOOSING THE RIGHT EQUIPMENT

The Discoveryof Pluto

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Voyage

1

CONTENTSTHE NIGHT SKY

22 On the Cover: Death of a Star

FEATURES and COMPETITIONS

Sci-Fi Focus - Smaller and Smaller 38

26 The Night Sky

Who’s who in Space 24

Great Puzzles and Competitions

Eye on the Sky 4

14 Huygens on Titan

Since its launch in 1990, the Hubble Space Telescope has been our looking glass through time and space. Thisphoto feature shows some of its most spectacular images.

After a seven-year hitch to Saturn with the Cassini spacecraft, the Huygens probe finally separated andheaded for a landing on the Titan moon. STEVEN CUTTS tells us how well it performed.

PLUSOrbital Mechanics 32 Did You Know 30Life on Mars 36 Re-Entry: Finding Pluto 44

Test your knowledge of space with: Get your entry in the next issue of VoyagePuzzle Page on page 12 Caption Competition on page 13Giant Wordsearch on page 31 Photo Competition on page 35

WIN A Die-Cast Space Shuttle Model in our great competition on PAGE 16

The 1960s Gerry Anderson puppet show has been turned into a great all-action movie. But it also has a link with the earlydays of the American Space Program. BRIAN LONGSTAFF shows us the connection.

Beginning Astronomy Part 2 - Last issue, we looked at how to get started in astronomy and what to look for in the sky.This time, DAVE BUTTERY looks at the equipment you can buy to study the sights.

Although Helen Sharman was the only astronaut to fly into space under the UK flag, Mike Foale has been the mostsuccessful British-born space explorer. ELAINE BAXTER tells us about him

8 100 Years of Relativity2005 sees the 100th anniversary of Einstein’s greatest theories. To celebrate his life and work,STEVEN CUTTS tells us about him.

18 Mr Pilbeam’s LabThe latest in our series of classroom experiments looks at gravity and gives you the chance to try out a wholerange of experiments to see how it works.

Editor:Mike Shayler

Production Assistant:Mary McGivern

Voyage Marketing:Suszann Parry

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A New Direction

Welcome to issue three of Voyage, the conclusion of it’s firstyear. And now that the magazine is established, we want to help itevolve into a valuable resource for students and schools. If youcan help, we’d like to hear from you.

• Educators (retired or active) who can expand upon the basiccurriculum with their knowledge of how it is taught

• Writers who can explain principles of space, such as how orbits work, why wehave seasons, why the planets spin and similar concepts

• Museums or attractions whose facilities offer outreach support• Guidance on resources for schools (books, websites, CD ROMS)• Anyone who would like to write about the benefits of space flight or the significant

breakthroughs (and their discoverers) in history• Schools who have conducted space related science projects and want to report

about it• Space related projects or clubs that schools and students can get involved in.

Please send your ideas to the Editor at voyage@bis-spaceflight.com or write to theBIS Headquarters

Mike ShaylerEditor

COMPETITION ENTRIESSend your answers for all competitions to:

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Entries Must Be In By 13 May 2005See the competitions for how to

mark up your entries

Don’t forget to include your name,age and address or school addressYou MUST get permission fromyour parent, guardian or teacher

before entering

ASTRO INFO SERVICE LIMITEDSCHOOL PRESENTATIONS 2005/2006

AT HOME IN SPACEJOURNEY ROUND THE SOLAR SYSTEM

ONE SMALL STEP

Packed with information, our shows includeaudience participation, slideshows, video,demonstrations, some real space hardware and alot of fun. Suitable for all ages, from 3 to 93!

To find out more and see some of the great comments aboutour shows, just log on to our website at:

www.astroinfoservice.co.ukand look under Presentations

or call us on 0121-422-8801

EYE ON THE SKY

4

The NeighboursThese two views of the MOON show justhow much detail Hubble can observe. TheMoon is too close to Earth for Hubble toget a complete picture of it, so the wholeMoon image shown here is taken from anEarth-based observatory. The ringedfeature is a 93 km wide impact cratercalled Copernicus and the larger imageshows Hubble’s close-up view of thatfeature, revealing the terraced walls of acrater that was formed from the impact ofa large meteor millions of years ago.When the meteor hit, it threw out a largespray of Moon material across thesurface, the kind of splash you would getfrom throwing a rock into sand

These four images of MARS were taken as theplanet went through its rotation. The visiblefeatures on Mars have changed since the firstrobot landings were made in the 1970s,because the frequent dust storms havecovered and uncovered many features of theplanet over the years.

Some of the familiar features can still be seen,however. At the top is the northern ice cap,small in size because the images were takenduring the northern summer. In the top rightimage, there is a small ring near the centre,which is the giant volcano Olympus Mons,and in the bottom right image, you can clearlysee the dark patch called Syrtis Major in thecentre and the large impact crater calledHellas at the bottom. This crater often fillswith frost and water ice clouds.

All the images show a busy atmosphere ofclouds and storms.

This view of the tilted planet URANUSclearly shows its faint ring system andseveral of its moons. The large orangespots on the planet itself are clouds whichcan circle the planet at up to 500 kph. Theimage has been colourised to make it easierto pick out the features, but the brightest ofthe clouds on the centre right is thebrightest cloud ever seen on the planet.

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EYE ON THE SKYAll the images on these pages are from the

Hubble website:

http://hubblesite.org

This view of JUPITER shows the stripycolouring of the planet and also the GreatRed Spot near the bottom. This is amassive storm about 25,000 km across andwas first spotted by astronomers in the17th Century, so the storm has been ragingfor over 300 years. It does change shapesize and colour, but winds in this stormcan reach speeds of 450 kph. ↓↓↓↓↓

↑↑↑↑↑ This double image of SATURN shows the planet with its ring systemedge-on. In the top image, you can only see the shadow of where theycross the planet. The large round shadow on the planet’s surface isfrom the orange moon Titan (top left), on which the ESA probe Huygenssuccessfully landed in January 2005. Several of the other moons appearas bright dots in these images.

↑↑↑↑↑ This double image of NEPTUNE shows the tremendouslyviolent stormy weather that affects the eighth planet. No one isquite sure exactly what drives the weather on Neptune becausethe Sun, which drives our own weather on Earth, is 900 timesdimmer out here. On Neptune, the wind can blow at over 1000kph and huge storms come and go frequently. When the Voyagerprobe arrived at Neptune in 1989, it observed a huge storm calledthe Great Dark Spot, but it has since disappeared.

This image of VENUS was taken with anultra-violet camera, and then colour-enhanced. The planet is covered by 30 kmthick sulphuric acid clouds and the ultra-violet camera can clearly show cloudformations, such as the horizontal ‘Y’-shaped cloud running across the middle.This formation has been seen before byprobes sent to observe the planet andmay give clues as to how the atmospherebehaves. →→→→→

EYE ON THE SKY

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Far, Far AwaySTAR CLUSTER →→→→→This amazing image is of a gigantic nebula called,rather blandly, NGC 3603. This image shows thelife-cycle of stars, from the giant gaseous pillars(the finger-like objects on the right and bottomright), through the starburst cluster of young andvery hot stars (the group of bright blue dots in thecentre) to the older blue supergiant star calledSher 25 (the single blue point surrounded by thering just left of and above the cluster). Sher 25 iscoming to the end of its life but is surrounded bynewer and developing stars.

←←←←← BANGThis image shows a pair of huge billowing gas and dust cloudserupting from a supermassive star called Eta Carinae. The star wasthe site of a giant outburst of light about 150 years ago, making itone of the brightest stars in the southern sky. But although itemitted as much visible light as a supernova, the star seems tohave survived the explosion, probably because it is so massive. Itis believed to give out about 5 million times more power than ourown sun and is about 100 times as massive.

STELLAR DANCE →→→→→Looking like a pair of evil galactic eyes, this image shows a close encounter between two spiral galaxies. The larger galaxy (NGC2207 on the left) is already changing the shape of the smaller one (IC 2163 on the right), its gravitational forces stretching out thematerial into long ribbons that extend thousands of light years off to the right of the image. Eventually, the two galaxies will mergeand become one - in a few billion years time.

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EYE ON THE SKY

←←←←← SPIRAL GALAXYThis magnificent image shows thespiral galaxy known as NGC 4414. Thecentre of the galaxy, as with mostspirals, is made up of mainly olderyellow and red stars, while the outerspiral arms are more blue from thecontinuing formation of younger stars.The arms are also very rich ininterstellar dust, which can be seen asstreaks and dark patches silhouettedagainst the starlight.

←←←←← HOURGLASSWhen the brightest stars get old, they get coolerand redder, increasing in size and energy outputand becoming known as Red Giants. Most of thecarbon and particles that help to form solarsystems like ours is produced by these RedGiants. When the giant has ejected most of itsouter matter, the ultra-violet light from the exposedcore of the star makes all the ejected materialglow, which is why you get nebulas like this onearound MyCn18. The one thing we haven’t figuredout yet is why they form such different shapes, likethe hourglass in this image.

TARANTULA →→→→→This is another nebula, called The Tarantula Nebula, in ourgalactic near-neighbour the Large Magellanic Cloud. Also inthe Cloud is a cluster of brilliant massive stars known asHodge 301. They can be seen in the bottom right corner of thisimage. Many of the stars in this starburst have exploded intosupernovae, blasting material out into the surrounding regionat great speed. This material is crashing into the TarantulaNebula and compressing the gases into the clouds andshapes you can see here. Hodge 301 has three red supergiantstars that are close to the end of their life and about to gosupernova (the three big orange spots), but Tarantulacontains gas globules and dust columns where new stars arebeing formed, so the cycle of stellar life goes on.

FEATURE

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It’s Einstein’s Yearby Steven Cutts

It’s “Einstein’s year” and if you didn’tknow that yet, you soon will do! Awhole host of media events havebeen planned to commemorate thehundredth anniversary of one specialyear in the Great Man’s life.

Early Years

Einstein was born in Ulm in 1879 toliberal Jewish parents and his early lifewas as marked by underachievementas his later life would be by genius. Bythe beginning of the 20th century,Einstein had managed to graduate froma Swiss University in Zurich butremained an unrecognised and underrated force.

Unable to obtain work as a careerscientist, he found a job at a smallpatents office in Switzerland. Withhindsight, such work might seem menialfor such a man, but Einstein, who wasat this time married with small children,would later reflect fondly on his time in

Albert Einstein (1879-1955)

E = MC2the patents office.Einstein found hisday job so easythat he had plentyof time toruminate aboutscience.

Great Theories

Then, in 1905,Einstein wroteand submitted 3new researchpapers and thesewere published inthe prestigiousGerman physicsjournal, Annalender Physik. Hadhe published justone of thesethree papers andnothing else in

his entire life, he would still be immortal.From time to time, an original copy ofone of these journals becomesavailable for auction and people bidludicrous sums of money to own it. Inthe history of physics, we call 1905 themiracle year.

It’s well known that Einstein oftenstruggled in high school. He also haddifficulty obtaining a place in University.As in adult life, the teenage Einsteinhad a habit of adopting unusualfashions and rebelling against authority.However, Einstein was eventuallyexposed to a formal Universityeducation in Zurich. Teachers in anyera have a habit of spotting thebrightest kid in the class but his geniushad yet to blossom and no-one inZurich spotted Albert.

The years that followed 1905 were filledwith both brilliance and political turmoil.By the 1930s, Einstein found himself

living in Nazi Germany and was forcedto leave Europe. Had he stayed, hewould almost certainly have been killed.

Holocaust

Nowadays, it’s common for Europeanintellectuals to rubbish America andexpress their despair that such a ‘vulgarand improper’ continent could havesurpassed their own. But it’s importantto remember that part of the reason thishappened is that within living memory,European institutions murdered orthreatened to murder tens of millions ofpeople.

Some of the most brilliant of thesepeople ran away to the States. Europe’sloss was America’s gain and Einsteintook up a chair in Princeton University,New Jersey.

Einstein soon became an internationalcelebrity! He was treated like a moviestar and found himself invited to thekind of social events that nowadays wewould associate with the likes of Sir BobGeldolf.

When I graduated from LondonUniversity with a degree in physics, Iimagined – perhaps immodestly – that Iunderstood about half of what Einsteinhad done. Most of the people cheeringEinstein in his own life time understoodnothing of what he had done. But theEinstein brand label had begun totranscend the world of physics andmoved into the realm of politics and themedia. His unusual route to the top, hisrejection of fascism and his refugeestatus from the Nazis all served to makehim an attractive icon for the liberalelite.

Inevitably, Einstein acquired his fairshare of enemies too. Quite apart fromthe Nazis there was an official anti

9

FEATUREEinstein society. Perhaps part of thereason for this was his own eccentricitybut envy must have played a part in theprocess too. After all, there are plenty ofPremiership footballers who don’t likeDavid Beckham.

Inspiration

Even today, the Einstein “brand label”remains a crowd pleaser. In the 1990s,Bill Gates promoted a new softwarepackage standing next to a plasticstatue of Albert. Others in the modernworld have looked at Einstein’s life andtried to read a parable for the rest of usto learn from. People take comfort fromthe academic set backs in his early life,his difficulty in obtaining a place atUniversity and the lack of earlyrecognition. If you’re struggling at highschool and your teachers have given upon you, don’t despair!

You might just be the next Einstein.

At this point, I feel inclined to cautionagainst such logic. Things that apply tothe greatest of us do not carryresonance for all of us. People like

Einstein only come along once acentury so the odds are this isn’t true.On the other hand, adolescence isn’t atime for giving up.

SCIENCE

As far as space travel is concerned,1905 is best remembered for Einstein’stheory of relativity.

Special relativity changes everything.Relativity makes it possible for men tofly to the stars and relativity makes itpossible for men to travel through time.

So what is it, what does it mean and

why do science fiction writers get soexcited about it?

Special Relativity

Here it is in a nut shell.

Special relativity is all about the speedof light.

The speed of light is 300 million metresper second. If you want to understandspecial relativity, remember that,because in special relativity the speedof light is always 300 million metres persecond. No matter who you are, orwhere you’re standing, it’s always thesame.

For Example

Supposing we stand by the side of themotorway and watch the cars drive by.A car drives by at 60 miles per hour.This is pretty fast, but at the same time,we see another car overtaking at 65miles per hour which is even faster.

Of course, if you were driving in theslow car, you’d see it very differently.The faster car drifts past you slowly,overtaking at a mere 5 miles per hour.

At least that’s what we’d expect in theordinary world. As a teenager, AlbertEinstein started to see it differently.Einstein dreamt that it might be possibleto travel at the speed of light.

At these kind of speeds, maybe thingswould look different.

“The most beautifulthing we canexperience is themysterious. It is thesource of all true artand science”

Albert Einstein

“The world is adangerous place, notbecause of those whodo evil, but becauseof those who look onand do nothing”

Albert Einstein

FEATURE

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Now supposing you were driving in acar at almost the speed of light whensuddenly you find yourself beingovertaken by a laser beam.

How would that look for the people atthe road side?

Firstly the passers by would needspecial equipment to judge your speed!Both you and the laser beam wouldwhizz by at fantastic speed, but they’dstill notice the laser beam drift past youvery slowly.

So how about the car driver? Whatwould you see? You’re driving at almostthe speed of light so you’d watch thelaser beam overtake you leisurely toyour right. Right?

Wrong! Einstein decided that the driverin the car would check his speedometer,glance to his right and watch the laserbeam whizz by at…

300 million metres per second.

Doing the Time Warp

Speed is distance divided time and yettwo observers (one by the road side andone in the car) have recorded twocompletely different speeds for the laserbeam relative to the speed of the car.How can this be?

If the relative speeds are clearlydifferent and yet the two observers haverecorded the same speed, what’schanged?

Einstein said - Time has slowed down.

Einstein argued that at extremely highspeeds, time would slow down. That’show the speed of light always looks thesame to any observer no matter howfast they’re going.

Travelling through Space

Now, supposing we set off on a missioninto outer space. We’re heading toanother star system so we need totravel at nearly the speed of light. Even

at these speeds, it would take nearly 5years to reach the nearest star, AlphaCentauri which is a good 4 and a halflight years away. After a brief stay atAlpha Centauri, the crew returns toEarth and lands back at CapeCanaveral about 10 years after they setoff.

This would be a major undertaking.You’re asking a crew of professionalastronauts to sacrifice a full 10 yearsout of their lives and their families backon Earth would miss them badly.

Peter Pan

But when the astronauts return to Earth,they have barely aged. Time haspassed so slowly in the space ship thatthe crew barely noticed the journey. Ineffect they have travelled not just to thestars but into the future.

Ever since Einstein came up with thisidea, science fiction writers haveproduced novels about time travel usingspeed of light travel.

In the Slow Lane

At the moment of course, no one can

travel that fast! The astronauts that wentto the Moon managed to gain about aquarter of a second of their lives (10days in space, top speed 11 kilometresper second) although I doubt in NeilArmstrong noticed the difference whenhe got back to Earth.

Similarly, very accurate atomic clockshave been flown in jet planes for a fewhours and then returned to theirairports. Identical clocks left on theground read a different time. The clockson the ground are ahead by a tinyfraction of a second, just as SpecialRelativity predicted.

There are two types of relativity. SpecialRelativity is about two objects travelling ata constant speed relative to each other.General relativity is much more difficultand concerns space ships that areaccelerating (changing speed) relative toeach other. When Einstein wanted towrite his General Theory of relativity hehad to take special maths lessons first.General relativity needs “4 Vectors”because in Einstein’s universe there are 4dimensions to consider; three dimensionsin space and one in time.

Einstein hadn’t exactly impressed his

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FEATURE

teachers at University. When one ofhis former tutors (Minlowski) finallyread Einstein’s theory of relativity, hewas amazed. “Imagine that! I wouldnever have expected such a smartthing from that fellow.”

Understanding the Rules

So what? you may say. Relativity is foregg heads. It will be many yearsbefore space ships can fly fast enoughto make time and interstellar travelpossible.

Maybe, but once you accept thetheory of relativity, a whole host ofother rules become apparent. Theserules changed our understanding ofphysics and enable modern engineersto build nuclear power, micro chipsand mobile phones. Unfortunately,they also made possible nuclearweapons.

The rules that apply in our everydaylives don’t apply at fantastically highspeeds and although no human beinghas travelled this fast yet, particleswithin atoms have done.

Relativity predicted that the mass of a

Computer artwork representing the distortion of time at speeds approaching thespeed of light. Detlev van Ravenswaay and the Science Photo Laboratory

Computer artwork illustrating the concept of warped space. This image showsEarth distorting the space around it through its mass and gravity. The greater themeasurement of mass and gravity from a body, the more the space around it isdistorted. Tony Craddock and the Science Photo Laboratory

particle would increase as it travelledfaster.

i.e. the faster you move, the heavieryou get. If a space ship tries to fly atthe speed of light, the mass of thespace ship increases enormously as itaccelerates. If it really could travel atthe speed of light, it would haveinfinite mass, which is impossible.That’s part of the reason why solidobjects can’t fly at the speed of light!Although the tiny (mass less) particlesthat make up light – photons - can.

“To imagine iseverything”

Albert Einstein

PUZZLE PAGE

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Find the astronomers. One pair of nameshas been matched to start you off

Johannes Hubble

Isaac Schiaparelli

Tycho Flamsteed

Nicolaus Halley

Galileo Newton

Clyde Brahe

William Copernicus

Percival Galilei

Edmond Tombaugh

Giovanni Kepler

Edwin Herschel

John Lowell

WORD PAIRS

GRID WORDCan you work out the answers to the clues below and fit them into the grid so that the answers spell out the word‘ASTRONOMY’ in the centre column? The clues are not in the same order as the grid.

CLUES:1. Planet nearest our sun

2. The first person to see Jupiter’smoons Io, Ganymede, Callisto andEuropa

3. Ours is called ‘The Milky Way’

4. Australis or Borealis?

5. This planet has a moon called Charon

6. Our sun is one

7. This word spells the same backwardsor forwards (called a ‘palindrome’)and means a system for detecting therange, direction or presence of things

8. We live on one called Earth

9. A gas or dust cloud in space

Which description matches the planet or body. One has been completed tostart you off.

Saturn The Red Planet

Jupiter The star in our Solar System

Pluto Fast moving planet nearest the Sun

Mars Titan and the Rings

Earth The Morning or Evening Star

Venus Our only natural satellite

Mercury Named after the ruler of the sea

Neptune The Blue Planet teeming with life

Uranus The little planet found in 1930

The Sun Chunks of rock

The Moon The Tilted Planet

Asteroid Belt The one with the Great Red Spot

In the grids below there are two sets of words. Can you match the first and lastnames of the famous astronomers or work out which planet in our solar system

is being described?

Puzzles by Miranda Line

A

S

T

R

O

N

O

M

Y

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CAPTION COMPETITIONTell us what you think these astronauts are thinking or saying. You can have more than one of themspeaking but please keep your answers short if you can — and nothing rude please!

In this photo are: (left to right) Scott Parazynski (NASA), Pedro Duque (ESA), and Curt Brown (NASA)

The best answers will be printed in the next issue and the one we consider the funniest will win.

THE PRIZEWe have 4 copies of the Voyager card game for the winner (see page 24, Issue 2).

Runners up will receive a copy of the next issue of Voyage.Please mark your entry Caption Competition 3 and send to the address on page 2.

LAST ISSUE

There were no winning entries to last issue’scompetition, so we are carrying the prize over to

this one, but with a new picture.

Remember, you can enter by post or email. Just putCaption Competition 3 in the subject line.

SPACE TODAY

14

HUYGENS on TITANby Steve CuttsLike many people, I expected the

Titan mission to fail. My gut feelingwas that the Huygens probe had a20% chance of sending back onephotograph before it blew to pieces.Flying to Titan was just tooambitious. The immense distancefrom Earth, the agonisingly lowtemperatures and the unavoidablyhigh risk nature of a surfacelanding all led me to believe that theTitan landing would end in disaster.I was wrong.

Right now, the Huygens probe looks likea wild success. The European SpaceAgency has a long way to go before itcan challenge NASA and the Russiansin the publicity stakes, but for a briefmoment on Titan they came close.Although some data has been lost andfog and cloud cover served to blur muchof the photography, enough materialcame back to solve many mysteries.

So why did we go to Titan?Titan is smaller than the Earth butbigger than our own Moon. All in all, it’sabout the same size as the planetMercury. Had cosmic history trodden adifferent path, a world the size of Titanmight well have ended up in orbitaround the Sun, in which case we’dquite happily refer to it as a fully fledgedplanet rather than a moon.

In the middle of the 20th century itbecame apparent that Titan had anunusual atmosphere. Earlyspectroscopic studies managed to pickup evidence of methane and otherhydrocarbons in the cloud cover. Thisdidn’t make sense because a planet (orin this case a moon) needs gravity toretain an atmosphere and the gravity onTitan isn’t enough to do this. Just aboutall the other moons around Saturn arerocky, airless bodies similar to our ownMoon. So why was Titan so different?

As the 20th century progressed, anotheridea emerged. It’s a fair bet that theatmosphere on Titan is similar to theEarth at the dawn of history. Scientistswere busy trying to recreate theseprimordial conditions in the laboratory

and had already succeeded inproducing primitive organic molecules.These molecules bear more than apassing resemblance to the chemicalsin our own bodies so maybe these reallywere the conditions in which lifeemerged millions of years ago. If thiswere true, Titan might represent animmense chemical laboratory, spewingout random organic molecules at afantastic pace. Astronomers began toimagine a world with a methaneatmosphere, organic rain, and an oceanthick with bleach.

In fact, Titan was so exciting that the

American space agency NASA decidedto divert it’s precious Voyager 1 probeaway from Saturn towards Titan. Thisdecision effectively represented an actof self sacrifice, since a visit to Titanmade it impossible for Voyager 1 toproceed to Uranus and Neptune.However, the enthusiasm to visit Titanwas so great that the abandonment oftwo entire systems was deemedworthwhile.

For a few hours in the early 1980s,Voyager 1 glimpsed a world shrouded incloud. No surface markings were visibleand it was clear that if we wanted tolook at the surface of Titan, we’d haveto go down there with a robotic probe.

Landing MissionThat’s why a robotic lander was addedto the Cassini orbiting robot. Theycalled it Huygens (after the astronomerwho first spotted Titan through atelescope) and the plan was for theAmerican Cassini probe to releaseHuygens as it approached Titan andthen change course to go on orbitingSaturn. It was one of the most daringadventures yet attempted in spacetravel. Given the abysmal performanceof the European Beagle 2 lander onMars, what hope was there forHuygens?

Well, at least some. The denseatmosphere had obscured the surfacefrom space but it would make a surfacelanding on Titan relatively easy. Anatmosphere enables a probe to bleedoff the fantastic kinetic energy of spaceflight without using fuel. In addition,Huygens could descend from the upperatmosphere to the surface slowly, usingparachutes, thus enabling a variety ofinstruments to analyse the cloud coveron the way down.

Power SupplyThe scientists who designed Huygensreckoned that they could keep theprobe airborne for several hours. But,as in all deep space missions, electricalsupply would be a problem andHuygens had to rely on a battery.

The first colour image of the surface of Titanshowing pebble-sized rocks through the haze.

15

SPACE TODAY

Batteries are a bad source of electricity,particularly on a mission into deepspace. Like the batteries in a lap top,the device could only supply Huygensfor a few hours and then shut down.Saturn (and Titan) is ten times furtherfrom the Sun than the Earth andsunlight intensity falls off according tothe inverse square law. The solarpanels would produce just 1% of theirpower output here on Earth, so thelander had to be charged up from thenuclear power plant on Cassini whilestill linked to the mother craft and thenreleased with all systems shut down toavoid consuming any electricity. Severaldays later, a tiny clock activated theHuygens lander, fifteen minutes beforeit hit the atmosphere. The battery thenhad to keep Huygens alive as itdescended to the surface.

This was a desperately high risk thing todo. Mission controllers are alwayslosing contact with deep space missionsand in this case, if they didn’t regaincontact in the first fifteen minutes, theproject would be a complete failure. Onthe other hand, if they could pull it off, itmight just be the most successfulscientific adventure of all time.

SuccessMuch to the relief of all involved, almosteverything went right. Even after sevenyears in space, the lander functionedperfectly. Unlike the ill-fated Beagle 2probe, it was designed to transmitduring the descent phase so that theairborne data could be retrieved, even if

the probe didn’t survive the landing.

There was a minor problem with one ofthe two radio channels and a couple ofhundred pictures were lost, but this isacceptable in a mission of thiscomplexity.

All the retrieved pictures are availableon the internet, including the ones seenhere. It has to be said that most of themwon’t mean very much to the laymanbut there’s an emerging mosaic imagefrom about 8000 metres that truly livesup to expectations.

Apart from the Earth, Titan is the onlyworld that we can divide into land andsea. Aerial shots show an area of lightland and a dark lake. There are hillsand valleys on the landed side of thepicture and the valleys are marked bywhat appear to berivers, with smallerrivers meeting up toform larger ones anddistinct estuariesleading out into theocean.

What does this mean?Liquid rain fall onTitan? Probably,although it may reflectfluid that oozes outfrom deep undergroundand then drains off intoa collection of streams.The Huygens probedoes appear to havelanded in the lake

A mosaic of Huygens images showing lighter coloured higher terrainand darker coloured lower areas

All images in this article courtesy ofESA/NASA/JPL/Arizona University

This group of imagesdetails a high ridge areashowing flowing channelsinto what appears to be amajor river

although conditions there were not asexpected.

Ever hopeful that Titan would turn out tobe a world with lakes and oceans, thedesign team had actually planned for a“splash down” (the probe could float!)although in the event, it seems to havecome down on a soft, possibly tarrysurface.

So what’s it made of? Well, if there isfluid on the surface of Titan, it can’t bewater. The surface temperature is-179OC so any water will be solid ice.However, a hydrocarbon (eg methaneor ethane) rain may fall every few years,cutting a path through the surroundinghills and valleys on its way to the sea.There, much of it evaporates, leaving anorganic semi-solid soup. The pebblesthat have been photographed aroundthe lander are probably solid water ice(snowballs).

As expected, an hour after landing, thebatteries went flat and the Hugyen’sprobe died with it.

Doubtless men will try to get to Titanagain but the immense distancesinvolved (a billion kilometres) and thelimitations of current day rockets meansthat it will be many years before theHuygens data can be bettered.

Voyage PRIZE COMPETITION

16

WIN A

This is an artist’s impressionof what we might do when we

go back to the Moon in thefuture. To win the

competition, all you have todo is answer the following

questions:

1. What year was the lastApollo flight to the Moon?

a) 1972b) 1982c) 1992

2. The picture shows a smalllander coming in to land.What was the name of theApollo 11 lander?

a) Spiderb) Columbiac) Eagle

3) Where on the Moon didApollo 11 land?

a) Sea of Tranquillityb) Sea of Crisesc) Ocean of Storms

Please mark your entryShuttle Competition andsend or email it to theaddress on page 2

ISSUE 2COMPETITION

Nobody correctly answered allthe questions in this

competition in issue 2, sowe’re carrying it over into this

issue.

17

DIE-CAST SPACE SHUTTLE MODEL

MR PILBEAM’S LABORATORY No. 2

18

You don’t need to book time onNASA’s Vomit Comet to experimentwith gravity. These experimentsgive you the chance to understandgravity yourselves. The first one(picture above) shows how to makea simple gravity simulator out ofbits and pieces. No dimensions aregiven, as everybody’s astronaut willbe different.

How to build it

You will need:a toy astronaut or action figurea wire coat hanger35 mm film pot (or equivalent)a screw eyea length of dowelwood or similar for the basemodelling material (eg papier mache)glue and paint

Tools needed (all should be used byadults or under adult supervision):junior hacksaw or wire cutters, woodglue; use of hand drill.

Method: All sizes depend on the size ofyour figure. Those given are for a 100mm action figure.

1. Cut your base to a suitable size. Inone end, drill a hole to take thesupport pillar (approx 250 mm).

2. Near the top of the pillar, drill a smallhole and screw in the screw eye.

3. Fit and glue the pillar into the base,and leave to set.

4. Cut approximately 400 mm from thewire coat hanger, and bend as

shown. If you put a little upside-downv-shaped kink in the middle to act asthe fulcrum, it should settle on thescrew eye and not fall off. Bend aloop in one end.

5. Cut another 100 mm of wire andbend to a hook shape that will slipthrough the loop on the arm. Crimpthis hook closed, so that it can’t slipout of the loop, but is free to swing.Attach your astronaut to the otherend of this wire (the hook on ours fitsbetween the astronaut and thebackpack). Check it swings freely.This system is needed to make surethe astronaut lands vertically on thebase.

6. Take the film pot, and bore holesthrough the lid and the base. Makethese holes slightly smaller than thewire to get a snug fit on the arm. Fillthe pot with Plasticene or somethingelse heavy, and place the armthrough the screw eye. Add thecounterweight, and adjust it until itjust balances the astronaut. Checkthat it swings feely up and down.

7. Use modelling materials to make thebase look like a planet of yourchoice.

Some words of wisdomThe simulator makes use of the theoryof moments. A moment is the turningeffect of a force, and is expressed inNewton-metres.

Our simulator is a system, with variousforces acting upon it. The mostimportant is gravity, which we need toneutralise for now. To do this, we need

to find the mass in grams of theastronaut. This is not likely to be much,so use a reasonably sensitive balance.

Now, measure the distance from theastronaut to the fulcrum in mm, andmultiply by the mass of the astronaut,then divide by 10,000. This will give themoment of the astronaut in newtonmetres (see notes at the end).

What’s going on?In a simple, balanced see-saw, theforces acting on the left- and right-handsides of the fulcrum are the same.These are known as balancingmoments. Moving the load at one endwill cause the see-saw to becomeunbalanced, so to regain balance, theload on the opposite side must either beincreased or its position changed. Thisis known as the principle of moments,and has the formula

force x distance, or Fd

Measure the available length of theother side of the support arm to thefulcrum. We need to make thecounterweight of sufficient mass so thatwhen you multiply its mass by itsdistance to the fulcrum, its moment isequal to the moment of the astronaut,so that the system is balanced.

In other words

Astronaut Fd=Counterweight Fd

Because we are dealing in grams andmillimetres, we’ll need to divide the

Issues of

Toy astronaut, firmlyattached to the hook. Thehook is freely attached tothe pivot arm.

Adjustable counterweight (aweighted 35mm film pot).This must be at the neutralbalance point when theastronaut is just touching thesurface.Indicator marks on the

support pillar.

19

MR PILBEAM’S LABORATORY No. 2

answer by 10,000.

For example, if the astronaut weighs50 g [F] and the distance [d] to thepivot is 15 cm, then the moment ofthe astronaut is F x d [15x50] /10,000= 0.075 newton metres. If thecounterweight weighs 100 g, then thedistance from the fulcrum needs tobe 7.5 cm in order to balance theastronaut.

Do this correctly, and your astronautshould be able to balance in a neutral(weightless) condition and at this point,the only forces acting on the astronautwill come from the environment(draughts etc). You can of course do allof this by trial and error, but it may takelonger.

Now we come to calibrating. You needto adjust the counterweight so that,when you lower it to touch the supportpillar, and then let go, the astronaut willhit the base, and bounce about 10mm.This can be taken as Earth standardgravity. Measure the distance of thecounterweight from the fulcrum andrecord it. The bounce doesn’t have tobe 10 mm, but space suits are heavy onEarth, and not very easy to jump aboutin, so even a jump of 10 mm is prettyspectacular for an astronaut only 100mm high.

To simulate how high an astronautmight bounce on Mars, we need toknow what Mars’ gravity is (it’sapproximately 38% of ours). To positionthe counterweight so that the astronautbounces the right amount, we need to

Gravitymove it farther from the fulcrum. To findthis distance, divide the distance of thecounterweight from the fulcrum by 0.38,and you will find that you have to moveit out to a distance of approximately 2.6times this measurement.

The following table gives you relativevalues of the planets in the SolarSystem. Use these values to adjust thesimulator to see how far the astronautcould jump.

Mercury: 0.38Venus: 0.9Moon: 0.17Mars: 0.38

Jupiter: 2.64Saturn: 1.16Uranus: 1.17Neptune: 1.2

Pluto: approx. 0.5

You can also research gravities of otherbodies, such as Phobos and Deimos,the moons of Mars. Can you use yoursimulator to give a meaningful result?Why are the gravities of Jupiter and theother gas giants similar to Earth’s,despite their being so much bigger?

Weightlessness Although astronauts in space are saidto be in zero gravity, this isn’t in fact so.Gravity never disappears entirely, it justgets weaker and weaker. If you movetwice as far from the centre of the Earthas you are now, gravity decreases to1/4 its surface value. Move three timesfarther out, and it decreases to 1/9 andso on, following the famous “inversesquare” law [see below]. At the height

the Shuttle orbits [amere 500 or sokilometres], gravityis still at 85% of itssurface value. Infact, if the Shuttlewere to stop movingrelative to the Earth,it would plummetlike a brick.

This is the realsecret. The Space

Shuttle is indeed falling, but its forwardmomentum means that as it falls, thecurve of the Earth falls away from underit at exactly the same rate, so that it cannever hit the Earth. Not only is theShuttle falling, but everything inside it isfalling, also at exactly the same rate. Soto the astronauts, the inside of theshuttle appears stationary, and they[plus anything else loose] seem to beweightless.

Weightlessness happens in a veryslight way in a lift as it starts down. Youaren’t attached to the lift, so for a splitsecond it leaves you behind, becauseyour own inertia means you start to fallslightly later than the lift. You thenalmost “float” for a very tiny length oftime inside, but falling at the same rateas the lift. Obviously, you don’t losecontact with the lift, unless it suddenlystarts to drop very fast.

So if you were to be caught in a rapidly

There will be another greatexperiment from Mr Pilbeam’s

Laboratory in the next issue. We’dlike to hear how your experimentswent, so if you want to send in aclass report, or pictures of yourspacecraft designs, we’ll put the

best ones in the magazine.

Mr Pilbeam’s Laboratory presentsa variety of interactive activitiesranging from the Victorian era to

the Space Age, includingpresentations on the phenomenaof reflection, the exploration of

Mars, rockets and robots.Although primarily aimed at ablechildren in Key Stages 2, 3 and 4,

the activities are suitable for awide range of audiences, includingspecial interest groups for adults

or children.

IF YOU WOULD LIKE MRPILBEAM’S LABORATORY TO

VISIT YOUR SCHOOL, CONTACTTREVOR SPROSTON AT

sproston@ntlworld.com

MR PILBEAM’S LABORATORY No. 2

20

falling lift, would you be able to saveyourself by jumping just before it hit thebottom?

Some experimentsThe effects of free fall can be shown invarious ways using simple householdjunk. Try some of the following and seewhat results you get. You might want tovideo some of these ideas, and playthem back at a slower speed

1. Take a 2 litre pop bottle, and poke asmall hole in it, about 60mm from thebottom. Fill it with water, but keep thehole covered. Stand it on a levelsurface [preferably outside], anduncover the hole. Observe the path

2. Get hold of a shoe box or similar,some string, and an action figure.Stand the shoebox on its end, andpoke a hole through the top. Tie thestring to the action figure and threadit through the hole from the inside.Pull on the string until the figure is atthe top of the box, then let go. Thefigure obviously falls down. Now holdthe box in the air by the string, let goand drop the box –what happens andwhy? You might want to decorate theinside of the box to make it look likea spacecraft, but that’s up to you.

3. This one is messy. You’ll need asmall water bomb balloon, a strongcardboard box, a weight, a pin andsome rubber bands.

Arrange the equipment as shown.The weight should stretch the rubberbands so that there is clear spacebetween the balloon and the point ofthe pin, but the weight shouldn’ttouch the bottom of the box. Carefullypick up the box, and let it fall. Whatshould happen is that the rubberbands, being in free fall, aren’taffected anymore by gravity, so theycontract and pull the pin up, so that itbursts the balloon. Very messy, butvery satisfying. Try it again with stringinstead of rubber bands. What doyou think will happen now?

4. The next idea dates back at least to1901, but is useful for illustrating thebehaviour of the Shuttle in orbit. To

of the water stream as it comes out.Why does the water come out?Essentially, because the water canescape, gravity is making it fall fasterthan the bottle (which can’t fall, as it’sstanding on something) so it runsout. Repeat the experiment, only thistime stand on a chair and drop thebottle without spinning it, while apartner watches the path of the waterstream. Do this several times. Whatdifference do you see, and why doyou think this happens?

Experiment 2.

Experiment 1.

Experiment 3.

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MR PILBEAM’S LABORATORY No. 2make this, you’ll need some basiccraft tools, a tube, some rubberbands, a little bit of wood and wire,and a couple of marbles. The originalengraving shows the mechanism:

You could use it as an inspiration foryour own device. Perhaps a schoolpiston trolley would provide thebusiness end.

If you do decide to design your own,the following diagram shows asimplified version.

Your dowel will need to move freelyin the tube, like a piston, but not be asloppy fit. Attach the rubber bands tothe dowel and to either side of theplastic tube. Now this is where youhave to be clever. You’re going tobend the wire so that it holds one

marble at the mouth of the gun,whilst the weight of the other marbleholds it in place. When you pull backthe plunger and let it go, it will hit thefirst marble, which will fly out of thetube, simultaneously [we hope!]allowing the second one to dropstraight down. If everything hasworked well, both marbles should hitthe ground at the same time. In asmall way, this is what’s happeningto the shuttle. If it was stationary, itwould drop, but its forwardmomentum keeps it going forwardsas fast as the Earth curves awaybeneath it, so that it never hits theground.

This diagram is intended as a guideonly. The trickiest part will be the littleframe to hold the marbles in place.You’ll need to make sure that the firstmarble doesn’t get blocked by thesecond one.

Send in your ideas if you come up witha better way, and I’ll include yourcredited plan on my website.

Videos and photos of some of theseexperiments are also available on theMr Pilbeam website:www.pilbeamslab.co.uk

Notes

newton [N]The newton is the SI unit of force.One newton is the force requiredto give a mass of 1 kilogram anacceleration of 1 metre per secondper second. It is named after theEnglish mathematician andphysicist Sir Isaac Newton (1642-1727).

Moment of a forceIn physics, this is the measure ofthe turning effect, or torque,produced by a force acting on abody. It is equal to the product ofthe force and the perpendiculardistance from its line of action tothe point, or pivot, about which thebody will turn. The turning forcearound the pivot is called themoment. Its unit is the newtonmetre.

The moment of a force can beworked out using the formula:moment = force applied ×perpendicular distance from thepivot. If the magnitude of the forceis F newtons and theperpendicular distance is d metresthen:moment = Fd

I am indebted to Dr Chris Welch ofKingston University, and to MrRoger Parsons for their invaluablehelp in preparing this article.

Experiment 4.

Piston held backunder tension

Piston released

22

ON THE COVER

DEATH OF A STAR

The brightest and heavieststars go through a spectaculardeath sequence when theycome to the end of their lives.After swelling up into brilliantsupergiant stars, they explode,blowing themselves apart in ahuge supernova.

A supernova shines brightly fora short time before it fadesaway. The outer layers of thestar are blasted off into spaceat great speed while the core ofthe star is often squashed bythe supernova explosion toform a Neutron Star

Neutron stars are very small,often only a few kilometresacross, but because the matterin a neutron star is squeezedvery tightly, they are alsoincredibly heavy. Just aspoonful of such materialwould weigh as much as MountEverest! With such aconcentration of mass, thegravity of a neutron star is verystrong.

Sometimes, this gravity canbecome too strong and the starshrinks even further until itvanishes and becomes a BlackHole. At the centre of the blackhole, the star that died iscrushed out of existence by thestrength of the gravity. Nothingcan get out of a black hole, butthey can be detected by the gasswirling around them, whichheats up as it disappears intothe black hole.

↑

23

SUPERNOVA 1987A

In February 1987, astronomershad the chance to see thissupernova in a small nearbygalaxy called the LargeMagellanic Cloud. The supernova(shown in this Hubble image bythe large arrow) is surrounded bythe rings of gas thrown off by thestar before it exploded and theremains of the exploded star arein the centre of the middle ring.

The material ejected into space bythis supernova is then recycled inother stars. Our own sun isprincipally made of hydrogen andhelium, but contains someadditional elements that wereejected by previous supernovaeand were incorporated into oursolar system during its formation.

Our sun is not big enough to gosupernova when it dies and willfollow a different cycle. When thesun’s hydrogen core is almostused up, it will start to collapseand get hotter. The sun willincrease in size with this increasein temperature, becoming a redgiant that will be big enough toengulf the inner planets of thesolar system. Eventually, the coreof the sun will become hotenough to start the fusion ofhelium into carbon and the corewill grow smaller and denser. Thesun will begin to contract andshrink to a fraction of its sizetoday. At this point, it will be whatis known as a White Dwarf andwill slowly cool off. But we don’thave to worry about this yetbecause it’s not expected tohappen for about another 4thousand million years!

Who’s Who in Space

24

Michael Foaleby Elaine Baxter

Michael Foale (PhD) was born toRAF Air Commodore Colin Foaleand his American wife Mary inLincolnshire, England on 6 January1957. Inspired at a young age by theidea of space flight, after spendingmost of his childhood anduniversity years in England, he laterused his dual nationality status tojoin NASA and was selected as a USastronaut. He is now a veteran ofsix space flights and is the currentholder of the US record for timespent in space having logged over374 days, including four spacewalks totalling almost 23 hours.

Foale considers Cambridge, Englandto be his hometown; and it was atQueen’s College in CambridgeUniversity that he completed anundergraduate degree in naturalsciences and a doctorate inastrophysics. During this time, heparticipated in scientific scuba divingprojects and gained his private pilot’slicence – skills that would laterbecome important for his astronauttraining. He also maintains interests inwind surfing and writing children’scomputer software.

Foale first moved to Houston inTexas to work on Space Shuttlenavigation problems at theMcDonnell Douglas AircraftCorporation. He then joinedNASA and was selected as anastronaut candidate in 1987,although it wasn’t until 1992 thathe made his first space flight,becoming the second Briton tojourney into space followingHelen Sharman’s trip to theRussian Mir space station in1991. Between space flights, hehas also worked as a payloadofficer at the Johnson SpaceCenter, flown the Shuttle AvionicsIntegration Laboratory simulatorto test flight software, anddeveloped crew rescue andintegrated operations for theInternational Space StationAlpha. He has served as Chief ofthe Astronaut Office Expedition

Corps and Assistant Director(Technical) of the Johnson SpaceCenter in Houston.

Foale’s early missions were on boardthe Space Shuttle: he served as aMission Specialist on missions STS-45and STS-56, which carried retrievableATLAS satellites studying the

atmosphere and solar interactions, andon STS-63, which was the first Shuttlerendezvous with the Russian SpaceStation Mir. This mission also includedFoale’s first EVA (extravehicular activityor spacewalk).

He then began training for his role in theShuttle-Mir programme – which involvedco-operation between the US andRussian manned space programmes,as preparation for the construction andoperation of the International SpaceStation. In preparation for his mission,Foale trained at the CosmonautTraining Centre in Star City, Russia andalso spent long hours learning Russian– a skill which later earned him greatrespect from his Russian colleagues.

Foale spent four and a half months onboard Mir, launching on the Shuttle’sSTS-84 mission on 5 May 1997 andreturning on STS-86 on 6 October of thesame year. His role initially involvedconducting science experiments, but helater found himself acting as a flightengineer helping to repair Mir after itsuffered a collision with a Progressunmanned re-supply ship. This collisionresulted in major damage to the spacestation’s Spektr module – whichcontained all of Foale’s personal

25

NASA Astronaut

belongings. He and one of his Russiancrewmates conducted a six hourspacewalk in order to inspect thedamage. His stay on board Mir wascertainly an eventful one, during whichhe and his colleagues narrowly escapeddeath, but he was at least able tocomplete several important scienceexperiments, and he became wellintegrated into the Russian crews onboard during his stay. During themission, he was able keep in contactwith his family, including his wifeRhonda and their two children Jennaand Ian, with the help of ham radioenthusiasts around the world.

His next role in space was that ofMission Specialist on the STS-103mission – an eight day mission onboard Shuttle Discovery to repair andupgrade systems on the Hubble SpaceTelescope. During an eight hour EVA,he helped to replace the telescope’smain computer and guidance sensor.

After three years on Earth, Foale’slatest challenge was as Expedition EightCommander on the International SpaceStation (with experienced Russiancolleague Alexander Kaleri) between 18October 2003 and 29 April 2004. Foaleand Kaleri were launched from andreturned to Kazakhstan aboard aRussian Soyuz vehicle, due to the

Mike Foale’s Space RecordMission Aboard Date Duration EVAsSTS-45 Shuttle 24 Mar - 2 Apr 1992 8 days 22 hours 0STS-56 Shuttle 8 Apr - 17 Apr 1993 9 days 6 hours 0STS-63 Shuttle 2 Feb - 11 Feb 1995 8 days 6 hours 4 hrs 39 minsNASA 5 Mir 15 May - 6 Oct 1997 144 days 14 hours 6 hrs 00 minsSTS-103 Shuttle 19 Dec - 27 Dec 1999 12 days 19 hours 8 hrs 10 mins

Expedition 8 ISS 18 Oct 2003 - 30 Apr 2004 194 days 18 hours 3 hrs 55 mins

Total Flight Time 378 days 15 hours 22 hrs 44 mins6 Missions 6000 Orbits 4 EVAs

unavailability of theSpace Shuttle fleetsince ShuttleColumbia had beendestroyed in anaccident.

Only twocrewmembers arecurrently allowedon board the ISSwhile the Shuttlefleet is grounded, inorder to limit theuse of essentialsupplies such aswater. Routinemaintenance andscientificexperiments took

up most of the crew’s time, asconstruction work on the Space Stationis also on hold until Shuttle flightsresume. Their six month stay included a

three hour EVA – to prepare for theupcoming launch of a new unmannedcargo ship, the European SpaceAgency’s ‘Jules Verne’ AutomatedTransfer Vehicle.

Michael Foale calls himself an ‘addictfor space flight’. He has been luckyenough to see many incredible things,and to fulfil a childhood dream of visitingspace. Through his involvement with theinternational space programme, he hasensured that even when his record fortime spent in space is broken, thisBritish astronaut will be remembered asone of the greatest contributors to theco-operative manned exploration ofspace.

Sources:http://news.bbc.co.ukhttp://www.nasa.gov“Waystation to the Stars” by Colin Foale

THE NIGHT SKY

26

This is the second in a series ofarticles designed to help newcomersenjoy the wonders of our magnificentnight sky. In the previous article, welooked at naked eye astronomy, and Ihope you have had the opportunity toview some of the spectacular objectsthat were around during the lateautumn/early winter. I also hope thatyou have begun to find your wayaround the sky, using the starhopping techniques that werementioned. This knowledge of thesky will become important when westart to use optical equipment.

Equipment ChoicesSo on to what this article is about,namely choosing and using your opticalequipment.

BinocularsConventional wisdom suggests that thefirst item of optical equipment youshould buy is a pair of binoculars, ratherthan a telescope. Well, not for the firsttime, I’m going to turn conventionalwisdom on it’s head and suggest thatbinoculars are not necessarily the bestchoice to begin with. Why, whenvirtually every book you can buy on thesubject says binoculars first?

2. The Right Stuff:By Dave Buttery, FRAS

easily purchase a decent beginnerstelescope made by a reputablemanufacturer for under £150, and evenunder £100! This places them in thesame price bracket as binoculars!

Secondly, binocular viewing is fine BUTit’s very hard to obtain a steady view formore that a minute or so (your armsmove, and the heavier the binoculars,the harder it is to hold them still).

Ah but the books say “lean on a wall orgate.” That’s fine (again for a shortwhile), providing there is oneconveniently placed and in the rightdirection for what you are looking at.Again the books say, “buy a tripod andmount for your binoculars.” Well, decentbinocular mounts and tripods, are NOTcheap! (those little ball and socketthings are really of little value) so onceyou have purchased your binoculars/tripods and mounts (or image stabilisedbinoculars) you will have spent morethan the cost of a good small telescope.

Thirdly, if you plan on sharing yourviewing experiences with others, onething you can’t do with unmountedbinoculars is pass them to your friendsor classmates and expect them to beable to find what you were looking at, asthey will be starting from scratch. I knowfrom personal experience that it can bevery hard, if not impossible, to guidesomeone with binoculars to an object inthe sky.

Finally, the biggest advance in amateurastronomy in recent years has been theintroduction of computerisedtelescopes. These ‘go to’ scopes asthey are called will find objects for you,but much more importantly, willcompensate for the Earth’s rotation bytracking in the opposite direction. Thismeans that objects remain in theviewfinder of a scope for long periods!Sadly this technology has not filteredthrough to the binocular market atanything approaching affordable pricesyet. Therefore, while I’m not at alldismissive of binoculars (I use minefrequently) I would advocate atelescope as your first purchase.

Buying BinocularsHowever before we leave binoculars, ifyou do decide to get some, a bit ofinformation may be helpful whenchoosing what to buy. Every binocularhas a two-number designation, such as6×30 or 8×50. The first number is themagnifying power or magnification, andthe second is the diameter of theobjective (front) lenses in millimetres –the aperture of each lens. But youshouldn’t assume that the higher thepower the better. Higher powers areindeed generally preferable, as theypenetrate light pollution more effectivelyand are especially desirable for doublestars, star clusters, and certain otherobjects such as the moons of Jupiter,but high power also narrows the field ofview (making it harder to find your wayamong the stars), and, worst of all,magnifies the dancing of the stars whenthe instrument is held in the hands. Forthis last reason, 10 power (10×) is themaximum usually recommended forhand-held binoculars.

With regard to aperture, the bigger theobjective lenses, the brighter the stars,and the fainter the object that can beseen. Here the astronomer shouldcompromise least. Most astronomicalobjects are hard to see not becausethey are small and need moremagnification, but because they arefaint and need more aperture. A pair of8×50s collects twice as much light asall-purpose 8×35s! Therefore the bestall-round beginning type forastronomical observations are 10x50.

TelescopesNow comes the interesting stuff! Thereare so many different telescopes on themarket from various manufacturers that

“ConventionalWisdom says buybinoculars first. Wethink you should buya telescope!”

There are a number of reasons I wouldsuggest a telescope as your primarypurchase. Firstly, price. In the recentpast decent telescopes were in the£500+ bracket and therefore binocularswere a better choice for beginners whomight lose interest after a while. This isno longer the case because you can

27

THE NIGHT SKYChoosing Equipment

at first glance the choice can be notonly confusing but overwhelming! WhatI am going to look at here are the sub£350 telescopes. This should helpremove some of the vast array of typesfrom our equation.

Before we go any further however, shunthe flimsy, semi-toy, “600 power!”department-store scopes that may havecaught your eye. The telescope youwant has to have two essentials: high-quality optics and a steady, smoothlyworking mount. You will not get thesetwo basic requirements from a toy storescope and not only will you have wastedyour money, but you will probably be sodisillusioned that you will pack up thehobby altogether! These days you canget a good make for the same price asthe ‘toy-store rubbish’.

Before we go any further I must stress Ihave no vested interest in any particularmanufacturer’s equipment (in fact I own4 telescopes by 3 different makers).There are a number of goodmanufacturers but the most commonlyadvertised in the magazines areCelestron & Meade (www.celestron.com& www.meade.com are themanufacturers websites). Each make awide variety of types of scope to meetall budgets, and with these products aswell as others like Orion, SkyWatcher,Intes, Bressier etc, quality is assured.

The choice of where you buy is up to

you, A reputable telescope dealer is mychoice, as you will get advice and helpshould anything go wrong, but qualityscopes by the above manufacturers canbe bought elsewhere, if you have theeye for a bargain (but are happy toaccept a low level of after sale service).Before Christmas 2004, ASDA wereselling nice little Meade scopes forunder £75 and even ALDI & LIDL havedecent telescopes from time to time. It’sthe manufacturer you need to look for!

Telescope TypesBroadly speaking there are two maintypes of scope: Reflecting andRefracting. All the other types you mayfind or read about are variants of thesetwo.

The ‘traditional’ scope is a refractor.You look through one end and see outof the other. These are cheaper thanReflectors at smaller apertures, but atsizes bigger than 3" their prices rocketdramatically. Apart from the lensmaterial and coatings, there are novariants of refractors.

Reflecting telescopes are what mostpeople think of when they think ofastronomy. You view the image via amirror and an eyepiece, so you look intothe side of the scope often near the top.There are a number of variants ofreflecting telescopes such as Maksutov-Cassegrain, Schmidt-Cassegrain, andSchmidt-Newtonian, but as these typesare beyond our budget of £350, we willlook at these another day.

Don’t forget portability andconvenience. Your first telescopeshouldn’t be so heavy that you can’ttake it outdoors, set it up, and take itdown reasonably easily. I use mysmaller scopes far more often than thelarger ones as they are more portable(and I have a van for my work).

RefractorsRefracting telescopes are the ‘generalpurpose scope’. If you want a telescopethat can be used for moderate stargazing (forget close up views of theplanets and galaxies, unless you wantto spend thousands) and bird watching

The two main tyopes of telescope: On the left isa Refractor and above is a Reflector

THE NIGHT SKY

28

etc, then your ONLY choice is aRefractor.

Refractors are fairly cheap if the lensdiameter (Aperture) is below 3" but getvery expensive beyond this. They aresimple scopes with very little to gowrong and require little or no setting up

couple of mirrors), they do require morecareful handling because if the twomirrors get out of alignment, you geteither a very poor image or no image atall (this is called collimation, keepingthe mirrors aligned). Also you shouldnot let anything fall down the tube(forbid the thought) as not only can itdamage the primary mirror, but if it’s a‘bit of paper’, it’s a devil of a job to get itout. One thought to finish this section.You can often see 3" or smallerreflectors for sale, but personally Iwouldn’t touch a reflector smaller than4" as refractors are great small scopesand require far less maintenance.

We’ll look at the various mount optionsnext time, as they are a subject thatrequires a lot of explanation, but beforewe finish, two things have to be saidabout astronomy through a telescope orbinoculars concerning the two brightestobjects in the sky; The Moon and Sun.

These are the two most obviousastronomical objects, the two easiest tosee, and the two most problematical tothe beginner. Firstly, let’s deal with theSun. NEVER look at the sun throughANY optical aid directly or you will goblind! Simple as that, no ifs or buts! Butthe Sun is great to see if its image isprojected on to card (we’ll look in detailat this another time) or viewed througha solar filter. These are cheap (under£20), easy to make or fit, and give

100% protection. They fit over the mainlens of a refractor, or the open end of areflector, but please don’t buy modelsthat go over the eyepiece, as they areextremely dangerous if even slightlydamaged (and you may not knowthere’s a problem before it’s too late).

The Moon is a favourite object of manyastronomers. It’s easy to find, easy tosee, and even through the most modestof scopes the detail you can view isbreathtaking! But don’t make themistake of viewing it at a full Moon,because it is dazzlingly bright. If youwant to view a full Moon use a neutraldensity or Moon filter to prevent youreyes from being damaged. However,the best time to view the Moon is beforeor after it’s full phase, when you canlook along what is called the terminator(the line between night and day) andsee the craters truly come alive! Theshadow’s in and around the cratersshow their depth and detail inspectacular fashion and there’s adifferent view every night! In fact youcan spend a lifetime studying the Moon,

– you just point and look! Keep the lensclean and protected and you’ll haveyears of trouble free viewing. You lookin one end and see out of the other, butto make life a bit easier you can use aStar Diagonal (below) which turns theimage 90° to make for more comfortableviewing, particularly when viewingimages high overhead (unless you likelying on your back), although this doesrotate the image as well.

ReflectorsMost people associate this type ofscope with astronomy, and with goodreason! They are only useful for stargazing. Trying to view a bird through areflecting scope is possible, but believeme it’s very complicated! You look intothe scope at right angles to the tube, asthe image is reflected from the bottomof the tube using the scope’s primarymirror, via a smaller secondary mirror tothe eye. The secondary mirror issuspended in the middle of the tube onwhat is referred to as ‘the spider’(anything from two to four small rods).

While for value for money you can’tbeat a basic reflector (they are quitecheap up to 6" or even 8" depending onthe mount as all they are is a pipe and a

A comparison of the maintelescope types. In aRefractor (top) you look inone end and see out theother. In a Reflector(bottom), you look throughthe side and the image isreflected off the mirrors

A Star Diagonal.

Inside a Reflector Telescope

Filters to protectyour eyes. (left) aMoon Filter (farleft) different Sunfilters for differentscopes

29

THE NIGHT SKY

and never get bored.

What’s in the sky this Spring?Before we finish, let’s just check what’saround in the sky in late winter/earlyspring.

Well, lots actually; it’s a great time forobservations. From March onwards, thegreat winter constellations (Orion,Taurus and Gemini) are beginning toset in the west by mid evening, but thespring ones (Leo, Bootes and Virgo) arehigh in the southern sky.

Dave Buttery is a Fellow of theRoyal Astronomical Society and amember of many Astronomicaland Educational groups.

He is the senior partner in AURIGAAstronomy, an astronomicaleducation service for schools,which helps teachers with theastronomical components of theNational Curriculum via his mobileplanetarium ‘The Auriga StarDome’.

For further details on what Davecan offer your school, call

01909 531507 or visit AURIGAAstronomy’s website

www.auriga-astronomy.com

Planet watching is ok, but limited.Venus, which has dominated the sky forover a year, is now around the far sideof the Sun, so is not visible. Mars isbrightening in the morning sky in theconstellation of Capricornius and Jupiteris visible all night long blazing away inVirgo (if you have a scope look for thepinpricks of light beside it; these are it’sinner (Galilean) moons). Saturn remainsbright in Gemini, but is only visible inthe early evening, as Gemini sets early.The Beehive cluster M44 in Cancer (aninverted Y) between Gemini and Leo isa great object to view through a scope.There are few other phenomena to viewand the only meteor showers are faint,so concentrate on looking at the starsand seeing their beautiful colours.

Instrument images courtesy www.starizona.comStar maps created using ‘Starry Night’

“NEVER look at theSun directly throughany optical aid oryou will go blind!”

The Beehive cluster M44 in the constellation ofCancer (see chart on the left)

Corvus

A view of the Moon’s terminator between dayand night, showing the detail of the craters

Cancer

M44

Gemini

Auriga

Canis Minor

Monoceros

OrionTaurus

SW

Canes Venatici

Leo

Come BerenicesBootes

Sextans

VirgoCrater Hydra

DID YOU KNOW ABOUT..?

30

TIME AND SPACE

SUNLIGHTEven the light from our own sun takes a while toreach us. The sun is over 150,000,000 km away,so its light takes more than 8 minutes to gethere. If you could turn the sun off instantly like alight bulb, it would still be 8 minutes before itwent dark on Earth.

SPEED OF LIGHTLight travels at 300,000 kilometres per second. Thatworks out as roughly:

18,000,000 km per minute1,000,000,000 km per hour26,000,000,000 km per day181,500,000,000 km per week726,000,000,000 km per month9,500,000,000,000 km per year.

That’s 9.5 million million kilometres in one year,called a Light Year

GALACTIC SUBURBOur sun and the stars that make up the constellations are just part of a grouping of starsknown as a Galaxy. Our Galaxy is estimated to be about 100,000 light years across, soeven light would take 100,000 years to get from one side to the other. When you considerthat there are over 100,000 million stars in our galaxy alone and that there are countlessother galaxies in our universe, the odds that there is life out there somewhere seem betterthan we might think. Whether we will ever be able to ‘boldly go and explore strange newworlds’ is a different matter.

BEST SPEEDThose numbers seem difficult to comprehend, so let’ssee how fast we can go. In order to escape Earth orbitand head off into space, a spacecraft has to reach atleast 40,000 kilometres per hour. At that speed, thespacecraft would be able to cover:

960,000 km per day7,000,000 km per week27,000,000 km per month349,000,000 km per year

At that rate, it would take us over 27,000 years tocover a Light Year

A GALAXY FAR, FAR AWAYWhen you realise that the nearest star system to oursis over 4 light years away, you can see why we haven’tgone there yet! It would take us 117,000 years to reachit in the fastest spacecraft we have at the moment

LOOKING BACK IN TIMEBecause of the huge distances involved, wheneveryou look up at the stars, you are actually looking backin time. The light from the nearest star system to ourshas taken over 4 years to reach us, so today we areseeing what that system was like over 4 years ago.There are many star systems that are so far away thatwe are only now seeing what they were like at the timethe dinosaurs walked on Earth and there are systemseven further away than that.

31

GIANT WORDSEARCH - CONSTELLATIONS

Hidden in this grid are the names of many of the constellations you can see in the night sky, some with theirlatin names and some with their more familiar ones. Mixed in with these are a few stars and the names ofsome of our famous astronomers. Words in the grid can run backwards, forwards, up, down and diagonally.Answers on Page 42/43

E L B B U H S I L A E R O B A N O R O C

T A G E V D H T E A B U R S A M A J O R

N R D H I R G A H I C K T E I N I M E G

C A P E G A S U S E R E X N Y L A S S R

O A W R M C H R L P U P R S T B U E E E

P S N S T O E U Y O X L A T E R R L C A

E R O C I S R S R I S E I R A A I A S T

R Y I H E O C D A S S R E R P H G H I B

N M R E E R U C N S I N I P A E A T P E

I E O L R L L U B A I S I L A L I U Q A

C L W B E N E D U C T S L O T H E U N R

U O E T A R S E E O S E R U T P U R O X

S T B O O T E S T I Y M A G A L I L E O

A P C E N N T L M A U R T H E L E G I R

L S N A T X E S O V A P S U N G Y C N I

S U E S R E P E R A T O S T H E N E S U

S N E G Y U H S N E P R E S A G I T T A

Andromeda Crux Kepler PtolemyAquila Draco Lacerta RigelAries Equuleus Leo SagittaAristotle Eratosthenes Lynx SerpensAuriga Galileo Lyra SextansBootes Gemini Newton TaurusBrahe Great Bear Orion ThalesCancer Halley Pavo Ursa MinorCassiopeia Hercules Pegasus VegaComa Berenices Herschel PerseusCopernicus Hubble PiscesCorona Borealis Huygens Plough

Puzzle by Mike Wilson of Free Spirit Writers

WORD LIST

HOW IT WORKS

32

Orbital MechanicsEvery object ever discovered thatisn’t resting (‘gravitationally bound’)on the surface of another, biggerbody, is moving relative to everythingelse that exists. And every solidobject, star and gas cloud, no matterhow lightweight, has a gravitationalpull swinging the tracks of otherfreely moving objects towards andaround it.

An orbit is simply the path an objecttraces through space, Orbital Mechanicsis the study of the paths things follow inspace, and how orbiting bodies affectone another’s future paths. It coversmore than how natural objects in space(meteors and moons to planets, galaxiesand whole galactic clusters) have theircourses altered by other objects’ gravityfields.

It started as part of the science ofastronomy, with early observers’ tryingto understand and explain the ways theysaw other planets’ moons orbiting, orcomets taking unusual, sometimeschanging paths around the Sun. But alifetime ago it began to become part ofpractical engineering, and now it’s vitalto every space mission and the mosteffective way of getting about the solarsystem.

The best space travel power supplywe’ve got, for now, is the gravity ofplanets and stars – or of the sun. It’salways there, needs no fuel, can be usedany number of times, and always workswhen it’s needed. But to use it, aspaceprobe or ship needs to be already

in space, in its own independent orbit.Since we have to start on Earth,unfortunately, we have to use hugeamounts of rocket power to get anythinginto space at all. But once we have aspaceprobe into an orbit of its own, itson board rocket engine can work reallyeffectively.

As it happens, the rocket is quite goodfor changing an orbit quickly, convertingits fuel’s stored energy into kineticenergy (changed orbital speed). Butrockets are nothing like so good as aplanet’s or even a modest moon’s gravityand rockets and a strong local gravityfield can work together in a moreefficient and flexible way than either onealone. They do it by putting a subtle twiston what happens whenever a small,natural object’s orbit passes closer than

usual to a farlarger one.

If, picking anexample close tohome, a smallasteroid (down tothe bus size andfew dozen tonsmass we mightprefer to call a bigmeteor) crossesthe Moon’s path,the pull of theMoon’s gravity willchange its course.It can’t switch itspath through aright angleinstantaneously,

but it drags against the body’s inertiafrom following its original orbit and overtime, these forces between them put thebody on a constantly-changing path – acurve. All orbits, natural or artificial arealways curves and since gravity’s pullincreases as it nears the Moon’s centreof gravity, while the smaller object’sinertia remains the same, the curve itfollows tightens too.

A body’s gravity always pulls directlytowards its centre of gravity, tighteningthe curve of an orbit it swings aroundthat centre, or simply towards it – and italways accelerates the object it pulls.But depending on the details of theencounter, its acceleration can add to orbe a brake against the orbital speed aclose-passing object already has.

It will still be in an orbit. All objects inspace are always in orbits. They can’t beanywhere else. Its new orbit may meetthe Moon’s surface at some point and ifso, the collision’s energy will be freed inthe asteroid and about the same mass ofMoon’s surface, turning them from coolminerals into white hot gases andplasma in a time the asteroid would havetaken moving through its own length,and leaving the shape of that bit of Moonchanged by expanding into as muchspace, as fast as possible.

It can become really interesting, though,if the rock’s changing orbit misses theMoon and carries on, back out intospace. If this does happen its orbit willhave been twisted or swung around andits speed so altered that for practical

by Gary Walters

A concept image of a mission to Mars, with the spacecraft firing itsengines to change its orbital speed and bring the craft into the correctorbital path to circle the planet.

33

HOW IT WORKSpurposes it’s a completely new orbit itwas never in before.

A spaceprobe making a close pass to amoon or planet will be swung around itas a natural meteor or asteroid wouldbe. But with steering corrections in mid-course, a spacecraft can be sent pastthe planet so precisely that its orbit willbe changed exactly the way its missioncalls for. Even better, this kind ofclosest-approach is just where using arocket engine gets the best results.Because the rocket’s fuel, like all therest of the spacecraft, has swappedpotential energy for kinetic energy,following its orbit down into a stronggravity field, it can split this extra energy50/50 with the craft when it leaves it asexhaust gas. Then, since its mass hasgone, gravity can’t convert this kineticenergy back into potential energy and sothe spacecraft keeps it, besides theordinary chemical (or nuclear, or ion-electric…) energy from its used fuel.

Closest approach is also the placewhere a light touch of artificialpropulsion can get a whole, wide rangeof results. The far stronger, natural forceof gravity is pulling an orbit through moredramatic direction changes, quicker thanat any other time. Slight nudges inposition, heading or speed make bigdifferences where gravity is mostpowerfully altering all three moment tomoment. It will amplify small, rocket-powered speed and direction shifts,multiplying them up so probes likeGalileo and Cassini can explore wholeminiature solar systems of moons likeJupiter’s and Saturn’s. By simply eking-out a few tanks full of fuel throughintelligently prepared encounters withtheir close approach gravity and lettingnature do most of the work, such probescan sweep around these moons in aseries of long loops, cruising betweeneach target.

This ‘gravitational slingshot’ approach,making the best of rocket power bysaving it for when it will get mostadvantage from working with gravityrather than against it, has been the onemost used in human (and robot) solarsystem exploration so far. In fact it’s theonly one that’s been used, since theeasiest orbits between planets (andmoons) were calculated so long agobecause these transfer orbits are reallyworst-possible-case gravity slingshots;desperate measures taken because theyhave to begin at a standstill and as far

down in a gravity field as you can get.

When human space travel has to start atthe wrong end ofthe gravityslingshot onEarth’s surface,anything naturallyoff Earth, in anorbit where it maybe useful, could bevital to the projectbeing practical oraffordable at all.And if Martianexploration goesahead in the nearfuture, it may bebecause it can usematerials thatnatural OrbitalMechanics has leftin place, alreadytravelling betweenthe orbits of Marsand Earth.

The Amorasteroids (namedafter the first oneseen) orbitbetween Earth and Mars. There areestimated to be hundreds, from dozensof metres’ size to Ganymed, a 32 kmnugget of nickel iron mixed with silicaterocks, and Eros, the largest, and the firstasteroid to be surveyed and landed onby a spaceprobe (2002, NEAR-Shoemaker). Their orbits stay outside,but often come close to, Earth’s orbit,but sometimes reach out well beyondMars – although since they’re affectedby Earth’s, Jupiter’s and Mars’s gravity,they have some of the Solar system’smore changeable orbits. They may soonbe part of the most interestingcombination of natural and artificialorbital mechanics so far.

Mars Cycler craft (or stations), recently

The gravity of the planet in the centre pulls on the comet passing close byand alters its trajectory on to a new orbit (blue path). The planet’s moon,on its own circular orbit, would also have a small effect on the path of thecomet if it was close by.

proposed by Buzz Aldrin, and others,would be permanently orbitinghabitations making regular cycles oforbits from Earth to Mars and back.Amor asteroids are already close to theorbits Earth-Mars cyclers would use, butmost importantly, they already haveabout the orbital energy a cyclerspacecraft would need. So in a nearfuture, this could be the first case ofspace materials being a better andsimpler option than materials sent fromEarth. It would also be the point at whichorbital mechanics changed from beingone essential tool for planning andnavigating surveys through the Solarsystem to being the deciding factor inwhich should be next step in the humanexploration of Space.

The influence of Gravity. Earth’s gravity keeps our Moon in orbit around us, whilethe gravity of the Sun keeps us on our own yearly path

Planet

Moon Comet

Earth Sun

Moon

34

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Over 600 places labelled on the Hugg-A-Planet, Earth. A real globe but soft. Helpschildren learn about caring for PlanetEarth. 12" in diameter.

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35

PHOTO COMPETITION - WHAT IS ITCan you work out what this object is floating above the Earth?

The winning answer will be printed in the next issue of Voyage.

LAST ISSUE:Nobody correctly guessed that this image was ofour Sun, taken from the Skylab space station usinga special camera. The prizes have to be won, sosee what you can come up with this issue.Remember, you can enter by email.

The winner of the competition will receive twoautographed Data Cards; one of Ed Gibson andone of Jack Lousma, both former Skylabastronauts

THE PRIZESigned copies of Ed Gibson AND Jack Lousma’s Data Cards.Runners up will receive a copy of the next issue of Voyage.Please mark your entry Photo Competition 3 and send to the address on page 2

FUTURE SPACE

36

Life on Marsby Steven Cutts

Is there life on Mars? That’s been ahot topic for as long as we’ve viewedthe Red Planet and the answers arehard to come by. An entire fleet of thevery latest robots has now descendedon Mars, intent on great discoveries.And yet, if there is life on Mars, howwill we recognise it?

In looking for carbon based life forms onMars aren’t we guilty of planetarychauvinism? Why should life on anotherworld bear any resemblance to life onEarth? When we look for signs ofchlorophyll or DNA on Mars, surely we’remerely projecting our own expectationson to another planet. Isn’t this like earlyEuropean explorers arriving in a distantforeign land and writing off the locals asuncivilised because they didn’t speakEnglish?

These are difficult questions to answer,but there’s no question that Earth basedscientists are prejudiced and do expectalien life to resemble our own because, inso far as we can second guess thenature of alien life at all, we can only fallback on our knowledge of fundamentalphysics and chemistry.

As a starting point, let us assume that thelaws of both physics and chemistry arethe same throughout theuniverse. The evidence tosupport this view is actuallyquite strong. What is thereabout the environment here onEarth that may have helpedthis planet to create life?

Firstly, we know that the Earthhad as much gravity millions ofyears ago as it has now. Whenthe world was young, volcanicactivity was probably far morecommon and we know thatvolcanoes emit gases into theatmosphere. This gascombined with other chemicalsin the fledgling atmosphereincluding carbon dioxide,sulphur dioxide, methane andwater vapour. The stronggravitational field of the Earthhelped our planet cling to a

dense atmosphere and in turn, the highsurface pressures permitted theexistence of liquid water over vast areasof land.

And it is water, more than anything elsethat served as the cradle of life on thisplanet. It’s not unreasonable to suggestthat water might do the same on anotherworld too. If you compare all the differentliquids yet identified, it turns out thatwater will act as a solvent to morechemicals than any other liquid. It wasthe same million of years ago and afantastic number of chemicals becamedissolved in the world’s oceans. Butmodern life consists of complex organicchemicals. Where could these havecome from?

This issue remained a mystery for thefirst half of the 20th century. Then, in the

1950s, a group of American scientistsperformed a remarkable series ofexperiments in which they tried torecreate the early environment on Earth.At first sight, their synthetic planet wasrather crude, essentially a glass flask halffilled with water. Above it, a small pocketof gas contained carbon dioxide,methane and sulphur dioxide. Next, anelectrical spark was repeatedlytransmitted through the “atmosphere” andsometimes the flask was also exposed toultraviolet light. A few days later the flaskwas opened and its contents examined.To the amazement of many scientists atthe time, the fluid contained thousands oforganic molecules, including amino acidsand other essential building blocks ofmodern life. That such a crudeenvironment could give rise to such a richmixture of organic chemicals so quicklyshocked the scientific world and to thisday, this is the model used to explain theorigins of life on Earth.

The world’s oceans contained the waterand above it the primordial atmospherewas shaken by lightning storms. Fromfurther out in space, ultra violet lightflooded down to further stimulate thisvast chemical laboratory and over many

millions of years the oceansbecame filled with vastamounts of organic molecules.Eventually, some of thesemolecules formed the basicbuilding blocks of life.

It still takes a leap of theimagination to see how suchinert chemicals could suddenlytransform themselves intoliving cells but at least some ofthe material required has beenaccounted for. If it still seemschauvinistic to assume otherworlds can only have createdlife the same way, it’s worthgiving some thought to thenature of organic chemistry.

Organic molecules are basedon the carbon atom. Carbon isa truly magic atom capable oflinking itself to other carbon

In areas like this on Earth where there is water and hot springs, conditionsare ideal for the growth of life, as can be seen in the different colours ofthe bacteria colonies in the water

37

FUTURE SPACE

atoms and in doing so producingmolecules of all shapes and sizes. If wewere to produce one example (i.e. justone molecule) of each organic moleculethat it is possible to make, the total massof such a collection would be larger thanthe planet Earth! But if we gaze acrossthe periodic table, it’s difficult to find anyother atom that is capable of establishingsuch complex chemistry and it’s evenharder to imagine a living creature notrequiring extremely complex molecules toexist. Silicon is occasionally put forwardas a possible competitor to carbon and itmay well be that silicon life forms haveevolved somewhere. Even so, siliconpales into insignificance in comparison tocarbon.

So, we’re looking for a planet with liquidwater on its surface and a carbon basedchemistry to its life forms. Liquid waterrequires a minimum atmospheric density.On the surface of the Earth, water canexist as a liquid between 0 and 100degrees centigrade. On top of MountEverest, the atmosphere is much thinnerand this means that water will boil at lukewarm temperatures. Celebrating yourascent to the summit of Everest with areally hot cup of tea has always been outof the question. If an alien planet has athinner atmosphere than our own, it’s stillpossible for water to exist on the surfacebut only at lower temperatures. If lifereally did appear in the Earth’s oceans itprobably appeared at the equator. Justabout all chemical reactions areaccelerated by heat and excessive heatwill break up even the staunchest oforganic chemicals (our own bodies aremade of organic chemicals – we can all

burn!) but equally aworld with liquidwater existing onlyat 0 to 10 degreescentigrade wouldstruggle to createthe right mix ofchemicals. Bunsenburners havealways been goodfor speeding upchemical reactionsin a test tube andthe primordialversion of thisplanet was oneheck of a big test

tube. Similarly, our own bodies are keptat 37 degrees centigrade becauseeverything happens much quicker likethat!

So where does this leave the rest of thesolar system? Venus has an atmospherebut this is much too hot for any complexchemicals to remain intact for any lengthof time. Mars has an extremely thinatmosphere but a warm day would still beas cold as the poles on Earth. It’spossible for life to exist on the polar icecaps of this planet but if our theoriesabout evolution are correct, these lifeforms evolved slowly in the comfortablenursery of the equatorial regions. It wasonly then, over a period of many millionsof years that more sturdy creaturesgradually evolved that could survive andflourish in the artic niche. Starting fromscratch at such low temperatures wouldbe very difficult.

Its been suggested that Jupiter mighthave an atmosphere that could supportsome sort of exotic alien life, but theproblem is that Jupiter simply doesn’thave a surface. It’s just one vastatmosphere and that atmosphere is soturbulent that even if life did begin at acertain altitude, the fledging organismswould soon be swept up into the freezingstratosphere or down towards the hyperdense, super heated core. Nothing couldsurvive such a journey.

So what does all this mean for Mars?The odds are – and I’m expressing apersonal opinion here – there is no life onMars. The current batch of robotic probeshave been sent to exclude the possibility

of life on Mars, not to confirm it.

And yet, all that may be about to change.Human beings are covered in micro-organisms. Most of these tiny creaturesstay with us from the cradle to the graveand when we die, it is this bacteria thatreturns our bodies to the Earth. As soonas the first people arrive on Mars, thesebugs will make it outside the spacecraftand into the soil. Will any of themsurvive? They certainly will and it’shappened already. In the 1960s, NASAlanded a series of robotic probes on theMoon and one of these was found by thecrew of Apollo 14 when they landedwithin walking distance of the device. Itwas too heavy to bring back but theastronauts managed to salvage thecamera and return it to Earth. It wasanalysed in detail and it soon became

When this martian meteorite was first studied, it was thought that theobjects in this image were proof of microscopic life on Mars

apparent that the probe had takenbacteria with it and that some hadactually survived several years on thesurface of the probe. Some species haddied and none of them had flourished butthe fact that micro-organisms from Earthcould survive in the lunar environment forany length of time at all was more thanastonishing.

Mars is a far more hospitable cultureenvironment than the Moon. Theextremes of temperatures are far lesssevere, the soil is more inviting and theremay well be traces of water. Just as lifeon Earth began with bacteria, so too, willlife on Mars. What follows will be moresophisticated and some time soon therewill be life on Mars. It will be human lifeby the look of things.

It might be that the first life forms to take holdon Mars could be micro-organisms like these,carried there by human visitors

SCI-FI FOCUS

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Smaller and Smallerby Mat Irvine

The idea of wanting to makeyourself smaller and smaller, sothat you might even become toosmall to see, is hardy new – and itdid not begin with television andmovies.

After all, there is the very famousbook, Gulliver’s Travels by JonathanSwift in which Gulliver – besidesmeeting a race of people far largerthan himself called theBrobdingnagians – met another racethat were far smaller than himselfcalled the Lilliputians. The book hadsuch an impact on its readers thatboth words have passed into theEnglish language – especially ‘Lilliput’for referring to anything ‘small’.

Gulliver and Alice

Gulliver didn’t attempt to try and makehimself smaller to match the Lilliputians,and in fact their smaller size did notseem to affect them when it came tocapturing Gulliver and tying him down,although they did have the strength ofnumbers. This perhaps did not apply toAlice from Alice in Wonderland, whomanaged to make herself both largerand smaller with the help of convenientbottles marked ‘Drink Me’.

These stories made no attempt toexplain why some people were larger orsmaller, or for that matter how exactlyAlice managed to change size so easily,(it was making other characters in thestory giddy). However, when filmsbegan to be made that involved makingthings – and especially people –smaller, some ‘device’ had to beinvented that could conveniently explainhow this change was taking place.

Invariably this is was in the form of a‘highly sophisticated and scientific ray’and it was sufficient to say this hadproperties that would ‘shrink’ the bodydown to a small size, and would(hopefully?) be able to return it back toit’s normal size. Fortunately you didn’thave to delve too deeply as exactly howthis actually worked!

Fantastic Voyage

The classic movie that involvesminiaturisation is Fantastic Voyage from1966, in which the submarine Proteuswith her five-person crew is miniaturiseddown to the size of a blood cell and

injected into the bloodstream of ascientist in a coma. The objective wasto destroy a blood clot in the brain of thescientist so he could recover and revealthe secrets that could save the world!As a movie it wasn’t that bad, but therewas still no real explanation as to howone could shrink a human body – letalone a mechanical device such as theProteus – down to the size of a humanbody cell, because on the face of it, youcan’t.

Admittedly people come in all shapesand sizes. Some will grow to over twometres in height, while others stayunder one, but we are all roughly withinthe same size range. This is mainly

In the 1966 movie Fantastic Voyage, submarine ‘Proteus’ waits under the miniaturisation ray device.When its crew was on board, they were all shrunk down to the size of a blood cell and injected intothe patient. 20th Century Fox

“There was noexplanation abouthow to shrink down ahuman body, becauseon the face of it, youcan’t”

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because if we weren’t roughly betweenone and two meters, the whole structureof our bodies would have to change –and we wouldn’t then be human.

Little and Large

After all, there are creatures that are farsmaller than us and others far larger,but none of them look humanoid. If youreduced the human shape down muchless than one metre in height, youwould start to find that our bones andmuscles would be proportionally far toobig and powerful and would likely pullthe body apart. Consequently, youwould have to develop far thinner bonesand far less powerful muscles, whichwould certainly change your look.

On top of this your metabolism – theway your body works – doesn’tdecrease proportionally to your size. Infact it goes up! Watch a mousebreathing and compare it to an elephant(assuming you can find a convenientone…) and you will see that themouse’s breathing and its heartbeatsare far faster than the elephant.

It’s also a reason why, ingeneral, the smaller a creatureis the shorter its lifespan – andelephants do tend to out-livemice. So, if we were the size ofmouse, besides dying of heatexhaustion through all thatexcess metabolism, you would

probably only live two or three years atmost!

Of course there are creatures evensmaller than mice – most insects are farsmaller. Gnats and midges are so small

that they are difficult to see with the eyeat all – they only reveal their presencewhen they bite you! But these are stillmuch, much larger than even thelargest white cell in the human body, soeven a gnat-sized scientist would havebeen no use for the Fantastic Voyagejourney.

However although miniaturisation ofhumans is great in science fictionstories and movies, when it comes tothe actual idea of miniaturisation ‘forreal’, fortunately we humans don’t haveto be involved at all. Not only that, butyou would not start with devices ormachines like the Proteus, which arehuman scale and then miniaturised, youwould build them already at thisminiscule size. The idea of some highlysophisticated ‘miniaturisation ray’

Two potential uses fornanotechnology (left) a microsyringe injected into thebloodstream to deliver medicine orextract samples directly from thered blood cells. (right) a micro-submarine that could be used torepair defective tissue or find anddestroy tumour cells.

Coneyl Jay and the Science Photo Library

“One company isworking on a ‘SmartCapsule’ which wouldcontain operatinginstruments and acamera”

A computer concept of a medical nanorobot at work, injecting a curative orinhibiting drug into a group of cancer cells.

Roger Harris and the Science Photo Library

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doesn’t come into it. It’s less fun, butmore practical…

Nanotechnology

This science was first called ‘micro-robotics’, but more recently it hasgenerally become known as‘nanotechnology’. ‘Nano’ is derived fromthe Greek for ‘dwarf’, so it purely means‘technology on a very small scale’, andit can involve any technological orengineering procedure that works atvery small sizes.

These days it is already possible tomake miniature machines that are smallenough to pass through the widesthuman blood vessels. They were notaround in 1966 when Fantastic Voyagewas made, otherwise maybe thescientists in the movie would have usedthem instead.

Engineers and scientists at TohokuUniversity in Japan have also built a tinymachine that is eight millimetres longand one millimetre in diameter thatcould bore its way into tumours in thebody, spinning by means of a magneticfield. It could heat up to destroy thetumour, or a hollow version coulddeliver drugs to a precise spot.

The Olympus Company is working on a‘Smart Capsule’ which containsoperating instruments and a camera.The current size would enable it totravel ‘only’ through your intestines, notblood vessels, but they are working onthat!

Electron Microscope

There is another invention that hasmade this possible – the electronmicroscope. One advantage theProteus crew would have had is thatthey could actually see what they werelooking for (although their eyes wouldby then have been smaller than thewavelength of light, so how they couldsee is yet another one of thosequestions best left unasked…).

With nanotechnology, the scientists and

doctors are still fullsize, so trying tomanipulate cells(let alonemolecules andatoms), becomessomewhat difficultif you cannotactually see them.But the electronmicroscope allowsyou to see this at a‘nano’ level, andhas also allowedmechanicaldevices – cogsand wheels – toactually be built,using very preciselasers to ‘etch’ outthe parts.

The Body HelpingItself

As the explorationof this branch oftechnology

The arrow shows a tiny micro-cog in the palm of this hand. Such cogs are onlypossible thanks to the precision of lasers

David Parker and the Science Photo Library

→→→→→

Computer artwork depicting the possibility of using nanorobots to repairDNA, the body’s genetic code. When this code becomes damaged, it canlead to a number of illnesses and diseases, including cancerVictor Habbick Visions and the Science Photo Library

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develops, it is very likely that‘nanotechnology’ will become the notionof manipulating the cells, or evenatoms, of the body itself rather thanbuilding specific miniature machines.This would be to such an extent thatthese ‘machines’ ( if this is still the rightword for them) would be manufacturedout of the raw material of life.

It is after all only what the body is doingall the time. In effect, the body is onemass of ‘nanotechnology’ on a cell-sized level, keeping your body workingnormally. Cells are constantly repairingthemselves and their contents;manufacturing new ones and repellinginvading cells.

Maybe nanotechnology will solelybecome the term for ‘helping the bodyto help itself’, but this idea of artificiallymoving body cells around and makingnew ones at this tiny level has alsobought in a term which itself has led tomuch discussion – and not a littleconsternation – the term ‘grey goo’!

Grey Goo

The term is now usually associated witha speech the Prince of Wales made in

July 2004 when he voiced concern thatfurther research into nanotechnologycould produce a medical disaster in thestyle that the drug thalidomide causedin the 1960s.

However, the term was first used nearly20 years before, way back in 1986,when the idea of micro-robotics was juststarting development. It was voiced byscientist Eric Drexler in his book ‘TheEngines of Creation’, wondering at thattime if the uncontrolled development oftiny nanotechnology robots – he thencalled them ‘nanobots’ – could get outof control. Everything could then beconverted into ‘grey goo’ in the sense oftaking over a specific niche in natureand, frankly, not being very useful orinteresting, rather like a ‘robotic weed’(although he also pointed out that theyneed not be ‘grey’ or ‘gooey’!)

As with most far-reaching statements,some people come down on one side,some on the other, though it is fair tosay that the vast majority of scientistsdon’t agree with the idea of ‘grey goo’.

In all, it would seem thatnanotechnology, initially in the form ofthese micro-robots and then maybe

Computer artwork of a nanotechnology camera system inside the body. Each unit provides part ofthe picture, like the compound image of an insect’s eye. These are then transmitted to the receiverand reconstructed into a whole image. The small size of the cameras would allow them to viewanywhere in the body without needing an operation. Roger Harris and the Science Photo Library

Stories – books, TV and film –where miniaturisation plays animportant part:

Gulliver’s Travels - Jonathan Swift(novel and a TV series)

Alice’s Adventures in Wonderland- Lewis Carroll (novel and severalTV series)

The Borrowers - Mary Norton(novel; TV series and movie)

The Incredible Shrinking Man(movie 1957)

Fantastic Voyage - movie 1966(and Isaac Asimov novelisation,1966)

Fantastic Voyage II : DestinationBrain - Isaac Asimov (novel 1988)

Innerspace (movie 1987)

Honey, I Shrunk the Kids (movie1989)

Land of the Giants (Irwin Allen TVseries)

purely the manipulation of the bodycells themselves, is here to stay.

Eventually it will be possible to destroysuch blood clots in the brain of acomatose patient from the inside of hisbody, though it has to be said, it isextremely unlikely to be from aminiaturised sub with five crew as inFantastic Voyage. Perhaps not the stuffof big-screen movies, but in it’s ownway, equally exciting.

“Nanotechnologymay come to mean‘helping the bodyto help itself’.”

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SOLUTIONS

A U R O R A

S T A R

P L A N E T

R A D A R

G A L I L E O

N E B U L A

P L U T O

M E R C U R Y

G A L A X Y

GRID WORD PAGE 12

THE ANSWERS TO THECLUES ARE:

1. Mercury2. Galileo3. Galaxy4. Aurora5. Pluto6. Star7. Radar8. Planet9. Nebula

Fit the words into the grid asshown and you can make theword ASTRONOMY readingdown the middle

WORD PAIRSThe correct pairings are shown below. How many did you get right?

Johannes Kepler

Isaac Newton

Tycho Brahe

Nicolaus Copernicus

Galileo Galilei

Clyde Tombaugh

William Herschel

Percival Lowell

Edmond Halley

Giovanni Schiaparelli

Edwin Hubble

John Flamsteed

Saturn Titan and the Rings

Jupiter The one with the Great Red Spot

Pluto The little planet found in 1930

Mars The Red Planet

Earth The Blue Planet teeming with life

Venus The Morning or Evening Star

Mercury Fast moving planet nearest the Sun

Neptune Named after the ruler of the sea

Uranus The Tilted Planet

The Sun The star in our Solar System

The Moon Our only natural satellite

Asteroid Belt Chunks of Rock

Big BangCurrent belief is that the universe started with a ‘big bang’about 14 billion years ago. To give you an idea of how longthat is, imagine all the events in the universe condensedinto one day. Earth wouldn’t be around until late afternoonand the whole of human history would only take up the lasttwo seconds of the day!

Put the Clocks ForwardThe Earth’s day, which is the time it takes to spin acomplete revolution about its axis, is 24 hours long. But theinfluence of our Moon is slowing us down and is graduallymaking the day longer. Eventually, we might have to makeclocks that have 25 hours on them - in about another 200million years!

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SOLUTIONS

UNLUCKY 1335 years ago on April 11, 1970, NASA launched Apollo 13 to the Moon. The mission suffered an in-flight explosion but thecrew survived and were returned safely to Earth. But if you ever thought the number 13 was unlucky, spare a thought for thethree astronauts of Apollo 13 - James Lovell, Fred Haise and Jack Swigert:

• Launch time was 13:13 hours local time from the Kennedy Space Center in Florida• The launch pad was 39A (which is also 3 x 13)• The explosion in the spacecraft took place on April 13• The original Command Module pilot Ken Mattingly was grounded and replaced by Swigert because he was thought to have

caught German Measles (German Measles has 13 letters)• The first names of the crew, Jack, Fred and James have a total of 13 letters

These ‘13s’ weren’t the only thing to happen to the mission:• One of the five main engines of their rocket failed during launch but they made it into orbit ok. They thought that this was

the piece of bad luck that they were expecting on this mission, but they were wrong.• Jim Lovell’s wife Marilyn lost her wedding ring down the plug hole of the shower the day before the launch• The crew was supposed to have flown Apollo 14 but were changed when the original Apollo 13 crew needed more training

time. Lovell thought he would get to walk on the Moon sooner, but he never landed at all.

GIANT WORD SEARCH PAGE 31

E L B B U H S I L A E R O B A N O R O C

T A G E V D H T E A B U R S A M A J O R

N R D H I R G A H I C K T E I N I M E G

C A P E G A S U S E R E X N Y L A S S R

O A W R M C H R L P U P R S T B U E E E

P S N S T O E U Y O X L A T E R R L C A

E R O C I S R S R I S E I R A A I A S T

R Y I H E O C D A S S R E R P H G H I B

N M R E E R U C N S I N I P A E A T P E

I E O L R L L U B A I S I L A L I U Q A

C L W B E N E D U C T S L O T H E U N R

U O E T A R S E E O S E R U T P U R O X

S T B O O T E S T I Y M A G A L I L E O

A P C E N N T L M A U R T H E L E G I R

L S N A T X E S O V A P S U N G Y C N I

S U E S R E P E R A T O S T H E N E S U

S N E G Y U H S N E P R E S A G I T T A

RE-ENTRY: A look back at significant moments in space history

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Seventy-five years ago, onFebruary 18, 1930, Americanastronomer Clyde Tombaughended a long search to discovera suspected ninth planet in oursolar system by finding the littleworld we call Pluto.

Hunt the PlanetThe search for Pluto began twenty-five years earlier, beforeTombaugh was even born. PercivalLowell, another Americanastronomer, had been studying theknown outer planets Uranus andNeptune and calculated thatsomething was disturbing the orbitof Uranus. He reasoned that itmust be the influence of anotherplanet and the search for it began.When Tombaugh joined the staff ofthe Lowell Observatory in Flagstaffin Arizona, he took up the search.

The Maths was Wrong

The calculations that the searchwas based upon were actuallywrong, but it wasn’t until much laterthat this was known. Pluto is fartoo small to have a noticable effecton the two bigger planets, butamazingly, a careful search of thesky by Tombaugh turned up Plutoanyway. He had painstakingly

FINDING PLUTO

studied images of the stars for overten months and suddenly noticedthat one tiny dot among thethousands had moved quite adistance from one picture to thenext. This was too far and too fastto be anything other than a planet,and Pluto was discovered.

Clyde Tombaugh

Tombaugh was born on February4, 1906 and built his first telescopeat the age of 20 with only limitedknowledge of how to do it. He soonlearned and built many morethroughout his life. He used one ofthem, a nine-inch telescope, tomake detailed drawings of themarkings he had observed on Marsand Jupiter and in 1928 he sent

these drawings in to the LowellObservatory. They were impressedwith the detailed and carefulobservation he had shown andinvited him to the Observatory towork.

Tombaugh had never had anyformal science education andtaught himself geometry andtrigonometry and learned about thestars through his home madetelescopes. It wasn’t until 1932,two years after he made history bydiscovering Pluto, that he couldfinally afford to go to college andgain his qualifications.

Tombaugh died in January 1997,just two weeks short of his 91stbirthday.

Little WandererPluto is the smallest planet in our solar system, abouttwo-thirds the size of our Moon. It takes about 248years to go around the Sun and it’s the only planet inour solar system that we’ve never sent a spacecraft to.It’s very difficult to see even with the biggest Earth-based telescopes and not even the Hubble SpaceTelescope has been able to give us a really clearpicture yet. Trying to view Pluto from Earth is a bit liketrying to read the print on a golf ball from about thirtymiles away!

MythologyPluto was named after the Roman god of the underworld,probably because it is so far from the sun that it is inperpetual darkness.

In mythology, Pluto assisted his brothers Jupiter andNeptune to defeat their father, Saturn. They shared theworld, with Jupiter choosing the earth and the heavens,Neptune ruling the sea and Pluto receiving the lower worldto rule over the shades of the dead. These shades wereferried to him across the river Styx by the boatman Charon,which is why Pluto’s only moon was given that name.

WHERE TO GO

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This map of the UK is going to build into a guide to all the places that you can go to experience space and sciencedisplays, shows or interactive days out. It only has a few entries at the moment, so we’d like your help to fill it up. Ifyou or your school have been to a science centre near you, tell us about it and we’ll add it to the map.

If you are a space or science centre, we want to let people know you are there, so send us some details about yourcentre to let schools and students know what you do. We will be featuring different centres in future issues.

Aberdeen: Satrosphere01224 640340 www.satrosphere.net

Edinburgh: Royal Observatory0131 668 8405 www.roe.ac.uk/vc

Newcastle: Discovery Museum0121 232 6789 www.twmuseums.org.uk/discovery

Halifax: Eureka! the Museum for Children01422 330 069 www.eureka.org.uk

Leicester: National Space Centre0870 607 7223 www.spacecentre.co.uk

Norwich: Inspire01603 612612

www.science-project.org/inspire

Hailsham: Observatory Science Centre01323 832731 www.the-observatory.org

London: London Planetarium0870 400 3010 www.london-planetarium.com

Weymouth: Discovery01305 789 007www.discoverdiscovery.co.uk

Bristol: At-Bristol0845 345 1235www.at-bristol.org.uk

Glasgow: Glasgow Science Centre0141 420 5000 www.gsc.org.uk

Cardiff: Techniquest02920 475 475 www.techniquest.org

Oxford: Curioxity01865 247004 www.oxtrust.org.uk/curioxity

Birmingham:Thinktank at Millennium Point0121 202 2222 www.thinktank.ac

Macclesfield: Jodrell Bank01477 571 339 www.jb.man.ac.uk/scicen

Armagh: Armagh Planetarium028 3752 3689wwwarmaghplanet.com