ELi5: How does the whole light year thing work? How does something happen a long time ago that we know of yet we can still see it and have to wait for it to happen again (like those exploding star things on tt)
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Light years are a measure of distance; how far something traveling at the speed of light would travel in a year. Because light is how we see, if something happens 1 light year away, it would take 1 year for the light to travel from where it happened to our eye. So if a star exploded 1000 light years away, the star would still be visible in the night sky here on earth for 1000 years even though it isn’t actually there anymore.
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