Other than Planets, name three things that orbit the Sun
-Dwarf Planets -Asteroids -Comets
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Approximately how old is the Solar System?
5,000 million years old
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What is the source of the Sun's energy?
Nuclear Fusion - Hydrogen Atoms fuse together to form helium because of the High Gravity
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What are comets made of?
Balls of rock, dust and ice
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Roughly how many stars make up the Milky Way?
Thousands of millions of stars
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What is a light year?
The distance that light travels through a vacuum in one year
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Briefly Describe parallax and how it's used to measure the distance between the distance of nearby stars
Astronomers take pictures of the sky six months apart when the earth is at opposite sides of its orbit and compare the stars with the background
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Explain why we see stars and galaxies as they were in the past
It takes time for light from the stars and galaxies to reach us
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What is red shift?
When a galaxy is moving away from us the wavelength of the light from it changes - the light becomes redder. This is called red shift
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Evidence of Expanding Universe?
-Big bang theory -Red shift
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Name the process that wears mountains down
Erosion
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Describe Wegener's theory of continental drift
His idea was that the Earth's continents were once joined together, but gradually moved apart over millions of years. It offered an explanation of the existence of similar fossils and rocks on continents that are far apart from each other.
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3 Reasons why his Idea was rejected at first
-Wegener wasn't a 'proper' geologist -There were other simpler ideas for the same evidence -No-one could provide a good explanation of how whole continents could move apart
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how fast are sea-floors spreading?
A few cm per year
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What causes tectonic plates to drift?
Convection Currents in the mantle, caused by heating in the core and mantle, cause the plates to drift
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Where do most earthquakes and volcanoes occur?
Near the edges of tectonic plates
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How are the Himalayas being formed?
India is crashing into the Eurasian plate
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The 2 types of seismic waves
1)P-Waves (travels through solids and liquids) 2)S-waves (pass through solids only)
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Other cards in this set
Card 2
Front
-Dwarf Planets -Asteroids -Comets
Back
Other than Planets, name three things that orbit the Sun
Card 3
Front
5,000 million years old
Back
Card 4
Front
Nuclear Fusion - Hydrogen Atoms fuse together to form helium because of the High Gravity
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