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“Far better is it to dare mighty things, to win glorious triumphs, even though checkered by failure than to rank with those poor spirits who neither enjoy much nor suffer much, because they live in a gray twilight that knows not victory nor defeat.” – Theodore Roosevelt
Modeling the Solar SystemGeocentric Model aka Ptolemaic Model
Ancient Greeks• Earth is at the center of the Universe.• The Earth stood still & never moved.• Stars are on a separate sphere orbiting the
Earth
was named after the philosopher Claudius Ptolemy who lived circa 90 to 168 A.D.
• 7 objects moved differently in the sky known as the “wanderers” or planetai. Sun, Moon, Mercury, Venus, Mars, Jupiter & Saturn
Ptolemy» Designed an updated model of the
geocentric model.» The planets orbit in circles around the
Earth & also travel in circles on the orbit.
Both the Earth moving (spinning) and gravity affect the wind. But the primary cause of the wind is temperature differences, not the moving of the Earth or gravity.
Heliocentric Model
Nicholas Copernicus» Earth revolves around the Sun.» Moon revolves around the Earth.» Earth rotates on an axis.» Planets revolved around the Sun.» Planets have circular orbits.
If the Earth suddenly stopped spinning, everything not attached would go flying off to the east, parallel to the surface of the Earth. The speed would depend upon your latitude. Only the people at the poles would be safe. You wouldn't go flying off into space because the 1000 mph maximum (at the equator) isn't enough to overcome gravity, which would still be present. If you survived, the resulting six month day and six month night would probably take care of you pretty quick.
Tycho Brahe & Johannes KeplerTycho Brahe & Johannes Kepler Brahe charted the motions of Brahe charted the motions of
celestial bodies before telescopes.celestial bodies before telescopes. Mathematician Kepler used Brahe’s Mathematician Kepler used Brahe’s
data to form the Laws of Planetary data to form the Laws of Planetary Motion:Motion:
1. The path of a planet around the 1. The path of a planet around the Sun is an Sun is an ellipseellipse..
Tycho Brahe died of a ruptured bladder because he refused to excuse himself at a banquet as it would have been rude.
Tycho had his nose cut off in a duel. He wore a gold and silver prosthetic nose
2. A planet will travel faster when it is closer to the Sun & cover a greater distance than when it is farther away.
3. The more distant the planet’s orbit is from the Sun, the longer it takes to make a single revolution.
Revolutionary PeriodsMercury = 88 Earth daysEarth = 365.25 daysJupiter = 11.86 Earth yearsPluto = 248 Earth years
Nebula Theory: Formation of the Solar System
1. More than 4.6 billion years ago, the solar system was a cloud (nebula) fragment of gas, ice, & dust.
The Sun shifts it's magnetic field every 11 years, and it has already happened for this solar cycle. The Earth's magnetic field flip is much more erratic and has happened approximately 25 times in the last 5 million years. It's been about 740,000 years since the last flip, however, so we're long overdue. There is evidence that we may be heading towards a reversal (the dipole magnetic field is weakening and the higher order terms are increasing), but we can't predict when it would happen. Depending upon how quickly the field reversal happens, it could cause problems for things like electric power lines and oil pipelines, and if the field goes to near zero, it might cause a higher background radiation at the ground, but there is no evidence that previous reversals have had any major biological effect. The forces due to the interaction of the solar and terrestrial magnetic fields are only very small perturbations.
2. Gradually, this cloud fragment contracted into a large, tightly packed, spinning disk. The disk’s center was so hot & dense that nuclear fusion reaction occur forming the Sun.
Planetary objects and satellites do not, as a rule, blow up. If the Moon did, you could expect large chunks of it to hit the Earth at pretty high speeds. Very messy. After a while, the survivors might see a very pretty ring of debris about the Earth.
Parachutes use air resistance to slow down a descent. Since there is no air on the Moon, they would be completely ineffective. The parachute would fall at the same rate as a rock.
3. The rest of the material in the disk cools enough to clump into scattered solids.
A new star is born in our galaxy every 18 days
Scientists believe that we can only see about 5% of the matter in the Universe. The rest is made up of invisible matter (called Dark Matter) and a mysterious form of energy known as Dark Energy.
It is estimated that within the entire Universe there are more than a trillion galaxies (the Milky Way itself contains 100 billion stars). This means that there are probably about 100 (to the 22nd power) stars in the entire cosmos.
Our sun is a second or possibly 3rd generation star
4. Finally, these clumps collided & combined to become the planets, dwarf planets, comets, asteroids, etc.
»» The planets all orbit on the same plane called the ecliptic.
»» The 8 planets occasionally line up in a straight line.
Astronomers have discovered more than 150 planets outside our solar system, ranging from 100 to 1,000 times Earth's mass.
Gravity and the Solar SystemGalileo
» Believed that objects fall to the Earth at the same rate despite the object’s weight.
»Air resistance slows down falling objects.
The Earth and the Moon eventually will be "locked" together with each only having one side constantly facing the other. (Right now the same side of the Moon faces the Earth, but all sides of the Earth see the Moon. In the future this will not be true!) Life on Earth will be quite different then, but this won't occur for billions of years yet. When it does occur, the Moon's orbit will be 50% larger than it is now, and a month will be about 50 days.
The Sun consumes about 600 million tons of hydrogen per second. (That's 6 x 108tons.) This would mean the Sun consumes the mass of the Earth in about 70,000 years.
The sun emits enough energy to melt a bridge of ice 2 miles wide, 1 mile thick, and extending the entire way from the Earth to the Sun, in one second.
Sir Isaac NewtonLaw of Universal
Gravitation
»» Gravity is a force generated between two objects.
»» Gravity depends on the mass of each object & the distance between them.
Sun contains all of the naturally occuring elements, although some are very, very rare. The Sun is mostly hydrogen (90%), and helium (9%). Everything else is only 1% of the Sun.
Most of the visible light from the Sun comes just from the fact that it is hot. The surface (what we see) is about 5800 Kelvin. The center is over 15,000,000 Kelvin.
F = m1 x m2Gr 2
F is gravitational force
m is the mass of an objectr is the distance between the 2 masses
G is the Gravitational Constant
G= 6.673 x 10 -11
r
m2
m1
Gravity Equation
Albert Einstein Theory of General Relativity
»» Matter tells space how to curve.
»» Curved space tells matter how to move.
» » Everything moves in the straightest possible line in curved space-time.
Gravitational time dilation has been experimentally measured using atomic clocks on airplanes. The clocks aboard the airplanes were slightly faster with respect to clocks on the ground. The effect is significant enough that the Global Positioning System’s satellites need to have their clocks corrected.
• I do not believe that civilization will be wiped out in a war fought with the atomic bomb. Perhaps two-thirds of the people of the earth will be killed.
• I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones.
• Insanity: doing the same thing over and over again and expecting different results.
• Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.
----------Albert Einstein
The Planets & their MoonsDistances in the Solar SystemDistances in the Solar System
Astronomical UnitsAstronomical Units Distances in space are millions of Distances in space are millions of
miles/kilometers in the solar system.miles/kilometers in the solar system. One astronomical units (AU) is the One astronomical units (AU) is the
distance between the Earth & the Sun.distance between the Earth & the Sun.
1 AU = 93 million miles = 150 million km1 AU = 93 million miles = 150 million km
Terrestrial Planets
Mercury• .39 AU from the Sun
• Named after the Roman messenger god (Hermes)
• Covered in craters & cliffs, similar to the Moon.
• No true atmosphere; trace amounts of sodium & potassium.
• As cold as -170oC in the dark & as hot as 425oC in the light.
The sun's rays are about seven times as strong on Mercury as they are on the Earth.
Mercury is the most iron rich planet in the Solar System with an iron core like Earth.
Earth and moon from Messenger (on it’s way to Mercury)
Venus• .72 AU from the Sun • Named after the Roman
goddess of love & beauty (Aphrodite)
• Thick atmosphere of CO2 which causes a severe greenhouse effect producing temperatures well over 400oC. (Hottest planet)
• Air pressure is 90 times greater than the Earth’s.
• Similar to Earth’s size.Venus is known as Earths' twin sister because of its similar size and proximity to each other.
Its atmosphere is made up mostly of carbon dioxide. It has clouds made of sulfuric acid!
Has retrograde rotation (rotates backwards) Takes longer to rotate than to revolve around the
Sun. (Day is longer than its year.) Covered with inactive volcanoes. 3rd brightest object in Earth’s sky.
Earth• 1.0 AU from the Sun• Also known as Gaia, Terra,
or Home.• More than 70% of Earth’s
surface is covered in water.• Only planet known to have
life in existence.• Has a natural satellite
(Moon/Luna.)
At this moment, the earth is in the middle of the Pliocene-Quaternary glaciation which began ~2.58 mya. We are in an interglacial period which started btw 10k and 15k years ago and my last ~50k years before global glaciations begins again.
The pressure at the centre of the Earth is 27,000 tons per square inch.
The Sun is 330,330 times larger than Earth. Earth spins at ~1100 mph, revolves around the sun a
~67,000 mph, moves (with the solar system) around the Milky Way at ~45,000 mph, the Milky Way hurtles through space at ~500,000 to 660,000 miles per hour.
Mars• 1.5 AU from the Sun• Named after the Roman
god of war (Ares)• Iron oxide (rust) in the soil
gives it a reddish color.• Polar ice caps made
mostly of frozen CO2 (dry ice) & some water.
• Mars is half the size of the Earth.
• Global dust storms.• Ranges from -125oC at
night & 20oC during the day.
Mars is red because it is covered in iron oxide (rust).
In 1996 NASA, while studying the ALH 84001 meteorite of Martian origin found in Antarctica in 1984, announced that fossilized micro-organisms from Mars might be present in it.
• Olympus Mons, the largest volcano in the solar system is on Mars.
• Thin Martian atmosphere of Nitrogen & CO2
• Mars has two small moons (Phobos and Deimos) that came from the asteroid belt.Phobos
DeimosPhobos, is moving closer and closer to Mars. Scientists think that one day it will crash into Mars.
Deimos rises and sets twice a day.
Jupiter
Saturn (- rings)
UranusNeptune
Earth, Venus, Mars, Mercury, the Moon...Earth, Venus, Mars, Mercury, the Moon...
Jovian Planets
Jupiter• 5.2 AU from the Sun• Named after the Roman king
of the gods. (Zeus)• Completely made of
Hydrogen & Helium gas (gas giant)
• Largest of the solar planets.• Swirling bands of rotating
clouds in the upper atmosphere.
About 1300 Earths would fit inside Jupiter - and the Sun could hold about 1000 Jupiters.
Jupiter's core is non-metal, but due to the immense pressure inside Jupiter, the core has become a metal. This metal is liquid metallic hydrogen.
Jupiter acts as a huge vacuum cleaner, attracting and absorbing comets and meteors. Some estimates say that without Jupiter’s gravitational influence the number of massive projectiles hitting Earth would be 10,000 times greater.
• Large rotating hurricane called the Great Red Spot. (2 Earth sizes)
• 4 faint rings in orbit.• 2.5 times greater in mass than all of the other
planets combined.• Has at least 63 natural satellites, 4 largest are
known as the Galilean Moons.
Jupiter is so big that twice the mass of the rest of our Solar System's planets combined would still not be enough to equal its mass.
The Great Red Spot has been observed for over 300 years!
Ganymede
»» Largest moon in the solar system (bigger than Mercury, but less mass.)
» » Covered with a crust of rock & ice that is heavily cratered.
» » Thin atmosphere of Oxygen.
Callisto
»» 3rd largest moon in the solar system
» » Most heavily cratered object in the solar system.
» » Thin atmosphere of CO2.
Europa
»» Covered in a shell of ice
»» A deep ocean beneath the ice shell.
» » Thin atmosphere of Oxygen.
Europa orbits Jupiter every 3.5 days and is phase locked -- just like Earth's Moon -- so that the same side of Europa faces Jupiter at all times.
However, because Europa's orbit is eccentric (i.e. an oval not a circle) when it is close to Jupiter the tide is much higher than when it is far from Jupiter. Thus tidal forces raise and lower the sea beneath the ice, causing constant motion and likely causing the cracks we see in images of Europa's surface from visiting robotic probes.
This "tidal heating" causes Europa to be warmer than it would otherwise be at its average distance of about 780,000,000 km (485,000,000 miles) from the sun, more than five times as far as the distance from the Earth to the sun. The warmth of Europa's liquid ocean could prove critical to the survival of simple organisms within the ocean, if they exist.
Io
»» About the size of the Earth’s Moon.
» » Most volcanically active body in the solar system. Erupts sulfur.
» » Thin atmosphere of Sulfur dioxide.
»» No craters. Why?
Saturn 9.6 AU from the SunNamed after the Roman god of agriculture.
(Cronos) Made of Hydrogen & Helium (gas giant) Flattened poles from spinning very fast. Less dense than water.
If you put Saturn in water it would float
• Most elaborate system of rings (rock & ice debris)
• 14 or more rings.• 56 or more natural satellites.
Mimas Titan Dione
One of Saturn's moons - Rhea, appears to have a system of rings itself!
Titan
»» 2nd largest moon in the solar system.
»» Has a thick, dense atmosphere mostly of Nitrogen & some methane.
»» Surface is “squishy” & has lakes of liquid hydrocarbons.
Saturn's moon Titan has hundreds of times more oil and natural gas than all the known reserves on Earth.
Uranus• 19.2 AU from the Sun• Named after the Greek god of the sky.• Gas giant made of Hydrogen, Helium &
methane.• Rotates on its side.• System of rings.• 27 or more moons.
Uranus was originally named Georgium Sidus or “George’s Star”.
On Uranus, each pole gets around 42 years of continuous sunlight, followed by 42 years of darkness.
Even though Neptune is further from the sun, Uranus is the coldest planet in the solar system.
Neptune• 30.1 AU from the Sun
• Named after the Roman god of the sea (Poseidon)
• Gas giant made of Hydrogen, Helium, & methane. (the methane makes it blue)
• Near-supersonic & dynamic storms.
• Faint ring system.
• 13 known moons
Neptune is so far away that it took the space probe Voyager 2, 12 years to reach it.
Neptune is the stormiest planet. The winds there can blow up to 1,240 miles per hour, that is three times as fast as Earth's Hurricanes.
Triton
»» Icy, rocky surface.
»» Coldest body in the solar system (- 37oC)
»» Icy volcanoes & geysers erupting Nitrogen, dust & methane
Dwarf Planets
Ceres• 2.7 AU from the Sun• Largest object in the asteroid belt (950km in
diameter.)• Classified an asteroid for over 150 years.• It is believed to have a rocky core, icy water
mantle, & a thin, dusty crust.
Pluto• 39.4 AU from the Sun• Named after the Roman god of the underworld
(Hades)• Second largest dwarf planet in the solar
system.• Pluto’s companion, Charon , is half the size &
doesn’t orbit around Pluto.• Pluto & Charon are small enough to fit inside
the United States.
Pluto is smaller than the Earth's moon.
Some astronomers believe that Pluto was once a moon of Neptune but it somehow escaped into its own orbit.
Technically, Pluto's name is now 134340 after being declassified as a planet.
Eris• 67.7 AU from the Sun• Largest known dwarf planet in the solar
system with a diameter of 2400km.• At least one moon, Dysnomia.
Other Possible Dwarf Planets Orcus Sedna Charon Possibly 43 others
Other Solar ObjectsComets
– Large chunks of frozen gases, rock & dust orbiting the Sun. (Dirty snowball)
1. Nucleus – main portion of the comet
2. Coma – thawed gases & dust form a bright cloud surrounding the nucleus.
3. Tail – solar winds push away the gases of the coma forming a blue ion tail & a yellowish-white dust tail.
If one were to capture and bottle a comet's 10,000 mile vapor trail, the amount of vapor actually present in the bottle would take up less than 1 cubic inch of space.
Nucleus
Coma
Dust Tail
Ion Tail
A comet is a dirty snowball hurtling through space
Mark Twain was born a year that Halley’s Comet was visable. He died the next time it came by Earth
Famous Comets Halley’s Comet
» » Most famous comet
» » Returns roughly every 76 years.
Halley's comet is known to have appeared in 1066 - the year which began the Norman Conquest - and is shown on the Bayeux Tapestry. Apart from heralding the Battle of Hastings, comets are also said to have accompanied the deaths of Attila the Hun (453 AD), Emperor Valentinian (455 AD) and Charlemagne (814 AD) - not to mention the Fire of London (1666) and the birth of Napoleon (1769).
"Delavan's Comet of 1914, whose path was not accurately determined. ...is not expected to return for perhaps 24 million years."
Comet Hale-Bopp
» » Comet discovered by amateur astronomers.
» » Last seen Spring of 1997.
It was visible to the naked eye for a record 18 months, twice as long as the previous record holder, the Great Comet of 1811.
It will next return to the inner solar system around the year 4385.
The comet’s orbit was ~4,200 years but it passed close enough to Jupiter to change it’s orbit. It is now ~2,533 years
Comet Shoemaker-Levy 9
» » Broke into several pieces and collided with Jupiter in 1994.
» » They created several dark marks in the atmosphere that eventually disappeared.
The comets that pass close to the Sun originally came from one of two places: either the Oort Cloud or the Kuiper Belt. You can think of the Oort Cloud as a giant spherical shell surrounding the Sun that's filled with about 1 million million comets (a 1 followed by 12 zeros).
Asteroids– Large chunks of rock material left over from
the formation of the solar system.– Most asteroids are found in the asteroid belt
between Mars & Jupiter.
If an asteroid hit the Earth, the effect would be similar to gathering ALL the worlds’ nuclear weapons together, and detonating them.
Carbonaceous or C-type Asteroids: More than 75 percent of asteroids fall into this category.
There are hundreds of thousands of asteroids orbiting the Sun. A few of them are larger than 200 kilometers (125 miles) in diameter, but the majority of them are about the size of a pebble.
Meteoroids, Meteors, & Meteorites– Meteoroids are pieces of rock & dust left
behind by orbiting comets.– Small meteoroids that burn up in the Earth’s
atmosphere are called meteors or “shooting stars.”
– Larger meteoroids that don’t burn up in the atmosphere and hit the Earth are called meteorites.
