Question:
Is it true that the stars we see may already be burned out? And if you were
up close to a star, would it be as bright as it is on Earth?
Replies:
Well, there are all sorts of different stars in the sky, some of them much
bigger and brighter than our Sun (if we were as close to them as we are to
our Sun), and some of them much smaller and dimmer. The big bright ones are
the ones that die first (usually in a big explosion). Since our galaxy is
only about 100,000 light-years across, very few of the regular stars we can
see would have blown up in the time it takes for their light to reach us.
Even the short-lived ones live for millions of years. You would have to go
to the next galaxy to start to see a significant fraction of stars that have
died even though we still see their light. All this of course is assuming
that our calculations about the life-times of stars are correct.
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