Quote:
Originally Posted by teh_mewse
Stars can burn for hundreds of millions to billions of years long..... the larger the mass of a star, the more brief and violent its life.
I'm fairly sure we can see, with telescopes, stars that are billions of light years away, and based on our observations we would expect them to be nearing their deaths. So, we can infer that the star we are seeing no longer exists, because we are seeing it billions of years ago.
But do all the examples of these stars require telescopes? Are there any stars that we can see in the night sky with our naked eye that no longer exist?
I see that there's people saying that people are answering the 'wrong' question, but I'll take a shot (at least it's interesting information, if I'm answering the 'wrong' question).
Betelguese: from the Wikipedia article: It is possible that Betelgeuse will become a supernova,[4][29] which will be the brightest ever recorded, outshining the Moon in the night sky.[29] Considering its size and age of 8.5 million years, old for its size class, it may explode within the next thousand years.[29] Since its rotational axis is not toward the Earth and also because of its 640 light year distance,[29] Betelgeuse's supernova will not cause a gamma ray burst in the direction of Earth large enough to damage its ecosystems.
If it will explode sometime within the next 1000 years, and 640 light years distance, there's about a 2/3 chance we are seeing light from Betelguese, but it no longer exists. Given the size of the galaxy, I think this is the best one can do (give a % chance that the star no longer exists, rather than *know* it doesn't)