Learn Through English
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Learn Through English |
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Natural Science |
The Universe |
TERMS |
DEFINITIONS |
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Black Hole |
The remaining tiny core of a star larger than the sun, that used up all its fuel and exploded. What is left is so compact and dense that, although mountain-sized, it may outweigh our sun. The matter it's made from has been compressed so tightly that protons and electrons are forced together...which results in neutrons. It can be thought of as just one giant neutron! |
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Comet |
This is the remaining core of a sun-sized star that has exploded. It is very dense...a handful of its matter would weigh tons. |
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Galaxy |
A large cluster of stars, typically hundreds of billions of them. They occur in a variety of shapes; the commonest ones are spirals (like ours, the Milky Way), ellipsoids, and irregular shapes. |
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Neutron Star |
A collapsed star that is so dense nothing can escape its gravitational force, not even light...so it looks black. In actual fact, they would be hard to spot except for the radiation that is given off by matter falling into it. |
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Red Dwarf |
A large ball of gas, mostly hydrogen and helium, which burns by nuclear fusion. Larger, hotter ones may also contain shells of heavier elements that they have produced by fusion. |
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White Dwarf |
Either a star which has used up all its fuel and is cooling off...or a very small star that never got very hot in the first place. |
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Red Giant |
A house-sized or larger ball of ice, dust, and rock, large numbers of these orbit the sun out beyond Pluto. Every once in a while, perturbations in their orbits cause one to fall toward the sun; when it does, the heat warms it up and gasses boil off. This is the 'tail' we see in the sky. |
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Star |
Very large stars (much larger than the sun) will be extremely hot in their cores, but their outer layers are cool by comparison and appear red. Such large stars are either 'giants' or 'supergiants', depending on their size relative to the sun. |
B. If you want to learn a little more about stars, have a look at the following questions. Do you think you could answer them on your own? If you want to know the answers, click here.
1 |
What happens to a giant star when it runs out of fuel’? |
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2 |
Then the star core absorbs all the materials of the outer layers and when they hit the core... |
3 |
During this process the giant star becomes a... |
4 |
What is left behind after the explosion of a supernova? |
5 |
A pulsar is... |
6 |
A black hole is... |
After these exercises, go to more activities on the universe and our galaxy.