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38 Cards in this Set
- Front
- Back
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Name 3 other things that orbit the sun
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Dwarf planets
Comets Dust |
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Name difference between stars and planets
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Stars - huge, very hot and far away, give out light
Planets - smaller, much closer and reflect sunlight |
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When did the solar system form?
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5,000 million years ago
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How did the solar system form?
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A cloud started to squeeze and it's particles got closer to one another and then gravity locked in and pulled in everything so close that it collapsed on itself
At the centre the particles formed a protostar that got so hot that nuclear fusion began and it became the sun |
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What are comets made of?
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Rock dust and ice
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How many stars are there?
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Thousands of millions
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How many galaxies are there in the universe?
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Thousand of millions
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What is a light year?
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The distance that light travels through a vacuum in a year
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What is the speed of light?
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300 000 km/s
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How old is the earth, sun and universe?
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Earth - 5000 million years
Sun - 5000 million years Universe - 14 000 million years old |
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Name the two factors that can help us identify how far away a star is
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Parallax
Brightness |
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What is parallax?
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When something appears to move when you look at it from different places
Astronomers take pictures of the sky six months apart - the bigger the movement the closer it is |
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What is red shift?
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When the wavelength of light changes as a galaxy is moving away - the redder it is the quicker it's moving away
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Evidence that the universe is expanding
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Redshift shows the more distant the galaxy the further it moves away from us
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Why does the universe expand?
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The matter and energy of the universe was compressed in a small space and then it exploded and started expanding
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How may the universe end
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If there enough mass the universe will stop expanding and begin contracting - the Big Crunch
If there's not enough mass it could expand forever |
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Evidence of a changing earth?
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Rocks are eroded yet made again by lava from volcanoes.
Fossils deep in rock |
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What happens in the rock cycle?
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Particles erode from existing rock
Washed into the sea and settle as sediment Crushed together to make sedentary rocks Can be pushed to the surface or pushed down into heat and pressure Eventually rise to the surface and are eroded again |
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What was Wegners theory?
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There had been a supercontinent called Pangaea which broke due to continental drift - explained why the coastlines fit and matching layers of rocks and similar fossils
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Why was Wegner's Theory not accepted?
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He was a meteorologist
Couldn't explain how the drifting happened Movement wasn't detectable |
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What is the structure of the earth?
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Crust (oceanic and continental)
Mantle Liquid outer core Solid inner core (nickel and iron) |
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Volcanoes and mountains form at
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Plate boundaries
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Mountains are formed by
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Plates crashing into one another
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How are the Himalayas formed?
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India is crashing into the Eurasian plate
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You record seismic waves with
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Seismographs
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When there's an earthquake, wave motions are produced which travel on the surface and inside the earth, seismologists measure...
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The time it takes the shock waves to reach each seismograph
Which parts don't receive the shock waves |
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What are the two seismic waves?
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P waves (longitudinal waves)
S waves (transverse waves) |
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Properties of P-waves
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Travel through solid and LIQUID
Faster than S waves Longitudinal |
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Properties of S-waves
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Travel through solids only
Slower than p-waves Transverse |
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How do seismic waves show the structure of earth
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P-waves change direction halfway through - sudden change in properties from mantle to core
S-waves not detected in core - outer core is liquid P-waves travel quicker through inner core - it's solid |
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What is a wave
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A disturbance caused by a vibrating source which transfer energy
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What is the amplitude?
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The distance from the rest position the the crest or trough- shows the amount of energy
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What is the wave length
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The length of a full cycle of the wave
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What is frequency
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The number of waves passing a certain point per second
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Distance =
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Speed x time
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What are transverse waves? (E.g EM waves)
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Waves where the vibrations are at 90 degree to the direction of travel of the wave
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What are longitudinal waves?(e.g sound)
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Waves where vibrations are along the same direction as the wave is travelling
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Wave speed(m/s) =
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Frequency (Hz) x wavelength (m)
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