Human Understanding of both Earth and Space has Changed Over Time

Unit E: Topic One

1.1 Early Views About the Cosmos

http://www.youtube.com/watch?v=Wx-QNISuJWA&feature=related

Tracking Cosmological Events

• Very special annual events in ancient times were solstices and equinoxes.

Earth’s Rotation and Seasons

Earth’s rotation and the why seasons happen

Solstice

• Solstice – represents the shortest and longest periods of daylight– Winter solstice: shortest period of daylight • Dec. 21st in the Northern Hemisphere

– Summer solstice: longest period of daylight• June 21st in the Northern Hemisphere

Equinox

• Equinox – Represents periods of equal day and night– Autumnal equinox: occurs in the fall• September 22nd in the Northern Hemisphere

– Vernal equinox: occurs in the spring• March 21st in the Northern Hemisphere

• http://www.youtube.com/watch?v=rkWW4mA8Xs0&feature=related

Geocentric vs. Heliocentric

• These two models of how the planets moved in space evolved over time.

• The role of observation guided scientific understanding of space.

Geocentric

• Proposed by Aristotle• Assisted by the geometry of

Pythagoras and Euclid• Planets revolved around Earth• The stars stayed stationary as if

glued to a ceiling• This was agreed upon for about

2000yrs.• This model couldn’t explain why

some planets seemed to reverse direction (retrograde motion)

Heliocentric

• Proposed by Copernicus• Later on, Galileo and Kepler

determined that the revolution around the sun was an elliptical pattern, not circular.

Ellipses

• Complete the QuickLAB on drawing ellipses

• Bill NyeOuter Space

1.2 Discovery Through Technology

The Astronomer’s Tools

• Quadrant: Measures a star’s height above the horizon

• Astrolabe: Measures a star’s angle above the horizon and could predict future star positions

• Cross-staff: Measures the angle between the moon and any given star

• Telescope: Allowed scientists to get even closer to the night sky

The Immensity of Distance and Time in Space

• 1. Astronomical Unit (AU) is used for measuring distances inside our solar system (aka “local distances”)

• 1 AU = 149 599 000km (the distance from the center of the Earth to the center of the sun)

The Immensity of Distance and Time in Space

• 2. Light-Year (LY) is used for distances beyond the solar system, out to stars and galaxies.

• LY = 300,000 km/sec (the distance light travels in one second)

• Keep in mind that a light year is a distance, not a time.

• If you wanted to wind a piece of string 1 light-year long, you would have enough string to wrap it around 236 million times.

Math Problem

• After the sun, the next nearest star to Earth, Alpha Centauri, is 4.2 light-years away. How many kilometers is this?

• Answer: 300,000km x 60 sec x 60 min x 24 hr x 365 days x 4.2 ly sec min hr day year

= 3.97 x 10 km13

Take a Walk Through the Solar System

Outside activity

1.3 The Distribution of Matter in Space

What is a star?

• Hot, glowing ball of gas that gives off light energy

• Stars vary greatly in their characteristics• They can be compared by their surface

temperature and their brightness (luminosity)• Our sun has a mass 300,000 times greater

than earth.• See next picture

Hertzsprung-Russel Diagram

• In the 1920s, two scientists, Ejnar Hertzsprung and Henry Norris Russel, began comparing the surface temperature of stars with the stars’ brightness (luminosity). When they plotted their data, they discovered that the distribution of star temperature and brightness is not random. Instead, the “Hertzsprung-Russel diagram” shows the stars fall into several distinct groupings. Part of this pattern has since been accounted for by the current theory of how stars evolve and change over very long periods of time.

The Birth of a Star

Watch it!

• http://vimeo.com/33756895

• http://videos.howstuffworks.com/science/birth-of-a-star-videos-playlist.htm#video-40907

Draw the picture in your notes

InfoBIT

• Our sun is a very average star in the middle part of its life. How average is it? Stand 1 m away from the wall. This distance represents the Sun’s diameter. At this scale, the diameter of the largest star now known would be 2300m (2.3 km).

What are Black Holes?

• Black Hole animation • Journey to a Black Hole

• http://www.youtube.com/watch?v=3pAnRKD4raY

• Vsauce

Star Groups

• Constellations – groupings of stars we see as patterns in the night sky.

• There are 88 recognized constellations by the International Astronomical Union

• Unofficially recognized groupings are called asterisms.

• The most common asterism is the big dipper – it is part of the constellation Ursa Major but it is not a constellation itself.

• http://www.youtube.com/watch?v=QXeEAQtC75g

• The Universe: The Constellations

Galaxies

• A grouping of millions or billions of stars, gas, and dust.

• They are held together by gravity

• Our galaxy is the Milky Way

• Can be classified as spiral, elliptical or irregular

1.4 Our Solar Neighbourhood

http://www.youtube.com/watch?v=fmxi3HvK2Js&feature=related9 minutes The Solar System: A Brief Glance

Protoplanet Hypothesis

• The theory of how solar systems are formed

The Sun

• Made up of mainly Hydrogen and Helium• 110 times wider than Earth• Surface temperature = 5500ºC• Core temperature = 15 000 000ºC• Releases a steady flow of charged particles that flow out in every direction, this is called solar wind.

• Bill NyeThe Sun

The Planets

• Each has its own unique features and characteristics. • Divided into inner planets (terrestrial) and outer

planets (Jovian).• Inner – tend to be smaller and rockier, close to sun• Outer – large and gaseous, far away from sun

• http://www.youtube.com/watch?v=IC3fRNFIgkQ&feature=r

• http://www.youtube.com/watch?v=waS56I_y57I&feature=related songs

• http://www.dailymotion.com/video/x6p7wa_15-why-isn-t-pluto-a-planet-any-mor_tech

• Elatedwhy pluto is no longer a planet

Organize significant information on the Planet Information Sheet

Bill NyeThe Planets

Why Do Planets Move in an Orbit?

• Answer: Universal Gravitation• Explanation: There is a gravitational force between all

objects that pulls them together. When no forces act on an object, it will move in a straight line at a constant speed. Since the sun has gravity to pull the planets inwards, they move in an elliptical orbit.

Other Bodies in the Solar System

• Asteroids– Between the orbits of Mars and Jupiter lies a

narrow belt of small, rocky or metallic bodies traveling in space.

– They range in size from a few meters to hundreds of kilometers

– Origin of asteroids: scientists are uncertain

Other Bodies in the Solar System

• Comets– Made of dust and ice that travels through space– When they get close to the sun, they heat up and

gases are released.– As the comets move, the streaming gases are visible

as a “tail”– Comets usually stay in the outer edges of the solar

system, but sometimes they’re thrown into the inner solar system and regularly rotate around the sun.

Other Bodies in the Solar System

• Meteoroids– Small pieces of rock flying through space

• Meteor– When a meteoroid is pulled into our atmosphere,

atmospheric friction causes it to light up– These are shooting stars

• Meteorite– If the meteor lasts long enough to hit earth, it is

called a meteorite Two impact cratersleft by a meteoritein Quebec

• Bill NyeComets and Meteors

1.5 Describing the Position of Objects in Space

http://www.youtube.com/watch?v=OR8EQ0DWpPw&feature=related

Intro to Solar Orientation [Solar Schoolhouse]

Where in the sky is it?

• In history, how did they measure locations of celestial bodies in the sky?

• In order for scientists to understand the sky and what was going on, they had to observe, measure and calculate.

• To document the location of an object, scientists use altitude, azimuth and altitude-azimuth coordinates.

Altitude

• Altitude gives you the “how far above the horizon it is”.

• Stars straight up will be at 90º• Points on the horizon will be at 0º• Stars half way up the sky will be at 45º• Zenith refers to the highest point directly overhead

Azimuth

• Azimuth determines which compass direction it can be found at in the sky.

• Stars in the north will have an azimuth of 0º• East = 90º• South = 180º• West = 270º

Estimating Positions in Space

Determining the Motion of Objects in Space

• Planet means “wanderer” in ancient Greek• Read page 404 in Science In Action 9

Celestial equator is directlyabove the Earth’s Equator

Using the Information

• Because astronomers understand the nature and geometry of elliptical orbits, as well as of celestial motion, they now understand the paths of planets and their moons.

• This allows the timing of solar and lunar eclipses to be predicted.

• Some enthusiasts make it a hobby to plan trips wherever they can around the world to witness eclipses

Solar Eclipse

• When the moon passes between the Sun and the earth.

• A shadow is cast on the earth.

• http://www.youtube.com/watch?v=taLnPflkoZo

Lunar Eclipse

• When the earth passes between the moon and the sun.

• A shadow is cast on the moon.

• http://www.youtube.com/watch?v=fWNKQ9jGmiM

PAT Style QuestionsUse the following information to answer the next question.

Any was given a list of notes on early theories of celestial bodies (sun, moon, and planets)A. Earth centeredB. Sun centeredC. Proposed in the 1500sD. Proposed 2000 years agoE. Proposed by AristotleF. Proposed by Copernicus

1. The notes above related to the “heliocentric” model of planetary motion are labeledA. A C FB. B C FC. A D ED. B C E

PAT Style Questions

1. Throughout time, people have created stories and proposed theories about space. The aboriginal people are knon for their legends that dealt with

A. Descriptions of planetsB. The formation of star constellationsC. Predictions about cometsD. Explanations of star travel

PAT Style QuestionsUse the following information to answer the next question.

Four scientists and their contribution to the study of space are listed below.1. Kepler proposed that the planets revolve around the sun in an elliptical

orbit.2. Aristotle proposed that Earth is in the center and all the planets revolve

around the Earth.3. Galileo used the telescope to confirm the sun-centered model of planetary

motion.4. Copernicus proposed the “heliocentric” model of planetary motion

Numerical Response 5. Listed from the earliest contribution to the most recent contribution, the

order is ______, _______, _______, and _______

PAT Style QuestionsUse the following information to answer the next question.

Four characteristics of a certain type of star are given below.• Contain extremely high-density materials• Has a strong gravitational pull• Light cannot escape from its pull of gravity• Difficult to detect

1. The type of star that these characteristics describe is a A. White dwarfB. Nebula C. Black holeD. Supernova

PAT Style QuestionsUse the following information to answer the next question.

I The formation of stars is called constellationII Stars start out as an accumulation of dust and gases called a nebulaIII The Milky Way is another name for an exploding starIV Galaxies can be classified as spiral, elliptical, or irregular

Numerical Response

1. Place the number 1 in the blank if the statement is true and the number 2 if it is false.

_______ _______ _______ _______I II III IV

PAT Style Questions

Use the following information to answer the next question.

A star is a burning ball of gases that has different stages in its life cycle. Four of these stages are given below.

1. Neutron Star2. Nebulae3. Supernova4. Red Giant

5. Listed in order from the earliest stage in a star’s life to the last stage, the stages are ______, ______, ______, ______

PAT Style Questions

1. The second largest planet with rings in our solar system is

A. UranusB. JupiterC. SaturnD. Neptune

PAT Style QuestionsUse the following information to answer the next question.

Calvin is setting up a model of the solar system. He positions a cardboard sun at one end of a school hallway and Pluto at the other end, 20m away.

Calvin knows that Pluto is 39.5 AU (astronomical units) from the sun and Jupiter is 5.27 AU from the sun.

Numerical Response

1. In order to make this model to scale, how many meters from the cardboard sun should Calvin place Jupiter? (Record your answer to two decimal places) __________________

PAT Style Questions

1. A total solar eclipse was observed across the Antarctic on November 23, 2003. This meant that the sun, Earth, and moon were in what alignment?

A. The sun was between Earth and the moon.B. The moon was between the sun and Earth.C. Earth was between the moon and the sunD. Earth was between the moon and the sun, but

the moon was lower and the sun was higher.

PAT Style Questions

1. Jen read in an astronomy book that every 33 years, Earth passes through the Leonid stream resulting in a shower of “shooting stars” visible on earth. This shower is actually

A. The tail end of a cometB. A cluster of brightly lit starsC. Many meteors entering the atmosphereD. An explosion of a supernova

Review Questions1. What name is given to the compass direction when we are trying to locate an object in

the night sky?2. Define altitude.3. What is the point directly overhead called?4. Explain what the ecliptic is.5. Why did the Greeks call the planets wanderers?6. Why must two coordinates, azimuth and altitude, be given to specify the location of an

object in the night sky?7. The table below has two incorrect entries.

a) Identify each error and correct it to something possible.b) Explain why each of the two entries is incorrect.

8. Is it ever possible to specify the location of an object in the sky knowing only the altitude? Explain your answer.

9. Imagine two friends, one in Calgary and the other in Edmonton, observing the same body in space. Describe how their coordinates would be different for the same object.

10. Does the rotation of the Earth affect azimuth and altitude measurements of the stars? Explain why or why not.

a) What can be done to ensure someone using your measurements would be able to find the object you located?

Topic 1 Quiz

Date: