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Q & A: history and fate of stars

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Most recent answer: 02/08/2012
Q:
Hi first i like to say i really like your website, it has many answers that help me. I have a question about stars, if we see stars million light years away then how is it that some of these stars have died and still produce light. If they are dead then the light we see at night is just an image of what once was? When will this light finally reach its end or does it just keep going on for infinity and traveling until it hits something where it either gets absorded or bounces back off into space. If this is the case will the big dipper and all the other constellations one day not exsist and if so what lifetime does anyone expect that to be. I understand this is a hand full but I am trying to really find out how all of this works. I am very intrested in science and want to be very smart at it and have a good foundation on all aspects of science.
- Ray (age 15)
Brownsville, Texas, USA
A:
That's a nice set of questions.

"If they are dead then the light we see at night is just an image of what once was?"
Yes, that's true for some distant stars.

"When will this light finally reach its end or does it just keep going on for infinity and traveling until it hits something where it either gets absorded or bounces back off into space."
If we understand things correctly, the light just keeps traveling until it gets absorbed by some other star or planet or dust or something.

"will the big dipper and all the other constellations one day not exsist"
Yes, none of the stars we now see will continue forever as active stars. They use up their nuclear fuel after a while.

"what lifetime does anyone expect that to be." It varies between stars but typically is something in the range of roughly 10 billion years.

Mike W.

(published on 02/08/2012)

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