Wh y Do the Stars
Wh y t o D he Stars
Shine?
What makes up our galaxy? What is the Milky Way? What is the solar system?
Shine?
You can find the answers to these and other questions about the planets and stars in Why Do the Stars Shine?
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Why do the stars shine?
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What is the Milky Way?
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Contents Questions about the stars . . . . . . . . . . 4 Questions about the solar system . . 10 It’s a fact. . . . . . . . . . . . . . . . . . . . . . . . 12 Can you believe it? . . . . . . . . . . . . . . 20 Who found out? . . . . . . . . . . . . . . . . . 26 Glossary. . . . . . . . . . . . . . . . . . . . . . . . 30 Find the answers . . . . . . . . . . . . . . . . 33
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Questions about the stars Q: Why do the stars shine?
A: Stars are balls of hot gas. They are a very
long way away, so they look like sparkling points of light. A star begins to shine when it gets very hot in the middle and releases energy, producing heat and light.
Q: What is the galaxy?
A: The galaxy is all the stars we can see
in the sky – every constellation and all the star clusters we can see through telescopes. There are 200 billion stars in the galaxy. 4 why do the stars shine.indd 4
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Star clusters
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Q: What is the Milky Way?
A: The Milky Way is the name of the
galaxy that we live in. We call our galaxy the ‘Milky Way’ because from Earth it looks like a wide, white road leading into space.
Q: WseehentheandMilkywhereWay?can you A: The best time to see the Milky
Way is on a clear winter night. The best place to see it is in the country, far away from bright lights. The closer you are to the equator, the more you can see.
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More about stars
• Stars are not ‘star’ shaped. • Stars are bigger than planets. • Our Sun is a star. • Stars are born, live for billions of years and then die. • They change size as they use up their gas. • A star dies when all the gas inside it is used up.
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Questions about the solar system
Q: What is the solar system? A: The solar system
is made up of the Sun together with the eight planets, comets and small asteroids that orbit around it. At the edge of the solar system there are millions of ice balls.
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Q: WMoonherecome did the from?
A: The Moon was made
millions of years ago. We do not know for sure how it was made, but most scientists think that a small planet crashed into the Earth. The collision blasted huge pieces of the Earth’s surface into space. These pieces of Earth came together in an orbit around the Earth and became the Moon. 11 why do the stars shine.indd 11
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Gravity holds the planets, asteroids and comets in their paths around the Sun.
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Ju p
The biggest planet in the solar system is Jupiter. It is so big that all the other planets could fit inside it.
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> Speedway The Sun, Earth and the rest of the solar system travel around the Milky Way at up to 900,000 kilometres per hour (km/h). Earth goes around the Sun at about 107,000 km/h.
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> Halley’s Comet Halley’s Comet is the most famous comet. It is named after Edmund Halley, who saw the comet in 1758. People last saw it in 1986.
Halley’s Comet
A comet is made of dust, ice and gases. It is like a dirty snowball with a tail.
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Mars
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> The red planet Mars is often called ‘the red planet’ because it looks red. The Romans named the planet Mars after their god of war because red is the colour of blood and fire.
> Moon size The Moon has the same surface area as the continent of Africa.
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> The names of planets Most of the planets are named after Roman gods. Venus has the name of the goddess of love and beauty because it is the brightest planet. Mercury has the name of the messenger god because it moves fast across the sky.
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A supernova
> Supernova A supernova is a star that destroys itself in a huge explosion. They are very bright and you can see them in the sky in the daytime.
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Can you
it? believe
Mars Observer
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Disaster!
The Mars Observer cost a billion dollars, but it only took one photo. It blew up in 1993 before it reached Mars.
Comet Halle-Bopp
When Comet Halle-Bopp was near the Sun for a year, it put 8 tonnes of water into space every second.
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Time travel
On 21 December 1968 Apollo 8 travelled to the Moon. It took only three days.
The Moon
The Apollo spacecraft
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A black hole
Black holes
When a huge star collapses, it creates an area of intense gravity – a black hole. A black hole eats up everything that comes near it, including light.
on
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Energy from the Sun
In one second the Sun sends out more energy than people have used in all history.
Always moving
You are moving at about 107,000 kilometres per hour all the time. That’s how fast the Earth is travelling around the Sun.
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Who
found out? Earth's orbit:
Nicolaus Copernicus Nicolaus Copernicus (1473–1543) was a Polish mathematician and astronomer. In 1514 he said that the Earth turned on its axis and moved around the Sun in one complete year. People did not believe him, but Galileo and other astronomers later helped to show that his idea was correct.
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Supernova:
Tycho Brahe Tycho Brahe (1546–1601) was a Danish astronomer. In 1572 he saw a new star that was as bright as Venus. It was the brightest supernova for 500 years. People were very surprised by his discovery because they thought that stars never changed.
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Invisible darkness:
Dr Vera Cooper Rubin Dr Vera Cooper Rubin (1928–) is an American astronomer. She discovered that galaxies are surrounded by clouds of invisible dark matter. Astronomers still do not know what it is.
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Discovering planets:
Carolyn Shoemaker Carolyn Shoemaker (1929– ) is also an American astronomer. She has discovered more planets than anyone else. She has found more than 800 asteroids and 32 comets and codiscovered Comet Shoemaker-Levy 9. In 1992 this comet travelled too near to Jupiter and broke into 21 pieces.
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Glossary English–English asteroids: small, planetary bodies astronomer: a scientist who studies stars, planets and space axis: the line around which a rotating body turns black hole: a region in space with extremely strong gravity that eats up everything that comes near blast: explode and throw things out in many directions collision: two moving objects hit one another violently comets: objects moving across the sky with bright tails of light constellation: any pattern into which stars are grouped and named equator: a line around the middle of the Earth, an equal distance between the North Pole and the South Pole orbit: to move in a curved path around a planet or other body in space planets: large round masses of rock and metal (for example, Earth), or of gas (for example, Jupiter), which move around a star 30 why do the stars shine.indd 30
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English–Norwegian
engelsk–norsk ordliste:
axis: akse billion: milliard blast: sprenge blow up: eksplodere, sprenge change size: forandre størrelse constellation: stjernebilde crash into: kollidere med dark matter: mørkt stoff disaster: katastrofe goddess: gudinne gravity: tyngdepunkt invisible: usynlig 31 why do the stars shine.indd 31
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messenger: budbringer Milky Way: Melkeveien orbit: bevege seg i bane rundt probe: giver, sensor release energy: avgi energi scientist: forsker sparkling: funklende, blinkende speedway: her: fartsbane star cluster: klynge/gruppe med stjerner surface: overflate
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Find the
Answers 1. What makes a star shine? 2. List three facts about the Milky Way. 3. List at least three facts about stars. © CAPPELEN DAMM AS, Cambridge University Press og Denise Ryan & Associates 2011 ISBN 978-82-02-34865-6 (gjelder hele boksen med Level 7-bøker) Materialet i denne publikasjonen er omfattet av åndsverklovens bestemmelser. Uten særskilt avtale med Cappelen Damm AS er enhver eksemplarframstilling og tilgjengeliggjøring bare tillatt i den utstrekning det er hjemlet i lov eller tillatt gjennom avtale med Kopinor, interesseorgan for rettighetshavere til åndsverk. Utnyttelse i strid med lov eller avtale kan medføre erstatningsansvar og inndragning, og kan straffes med bøter eller fengsel. Original konsept: Cambridge University Press og Denise Ryan & Associates 2010 Redaksjon Cambridge University Press: Jean Glasberg, Hilary Ratcliff og Claire Lawrence Redaktør Cappelen Damm AS: Toril Lindberg Tekst: Michael McMahon
4. List the eight planets in the solar system. 5. What more is the solar system made up of? 6. Describe a comet. 7. What is a supernova? 8. What is a black hole? 9. What do you know about Copernicus? 10. What is Carolyn Shoemaker known for?
Fotoliste: Alle bilder tilhører og er gjengitt med tillatelse fra NASA foruten disse: s2 og s6: Shaun Lowe; s5n: Manfred Konrad; s26, s27, s28 og s29: Photolibrary Design: Framnes Tekst & Bilde AS Trykking/innbinding: Korotan, Ljubjana 2011 www.cdu.no
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