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Asked by aliceschofy to Carol, Ellie, John, Philip, Rebecca on 25 Jun 2012.
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John Welford answered on 25 Jun 2012:
Because they are a great big ball of fire – like our sun! I don’t know much about how stars work, but it blows my mind to think that the stars we see in the night sky may not even exist any more. The light that we see has travelled so far to get here that the stars themselves may have burned out many years ago!
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Eleanor Turpin answered on 25 Jun 2012:
Stars are not really on fire, but they are great big balls of a very, very hot gas, called a plasma. Inside of stars there is mainly hydrogen and helium (the lightest two elements). Becuase the hydrogen and helium atoms are so hot they have lots of kinetic energy and crash into each other really fast. When they hit each other at these high temperartures (5500 C in our Sun) some of the kinetic energy gets turned into light energy that is emitted from the star – and that light energy is what causes them to shine.
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Philip Glasson answered on 27 Jun 2012:
Beacase they’re hot!!
Hot atoms have lots of excess energy to throw off some of their electrons.
When theses electrons re-collide with the atoms.
BANG! light comes out
Stars have lots of atoms, (lots of gas)
and lots of heat (from nuclear reactions & gravitational pressure)Lots of atom + lots of heat = lots of light.
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Carol White answered on 27 Jun 2012:
Not all stars shine! Some small stars (called protostars) don’t actually shine because they’re not hot or big enough.
Why are all stars white?
Well they’re not…The hottest start are actually blue! Then they get cooler through the colours of white, yellow, orange and then red. For example, the sun is yellow and it’s definitely a star! They might all seem white but they’re really not…
Comments
Philip commented on :
I think Carol won this one ! 😉
charliereynolds commented on :
yeah i think that too.