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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They’re a measurement of distance. A light years is how fast light would take to travel in a year. Do some crazy math and you arrive at a distance of 5.88 trillion miles/9,461,000,000,000 kilometres. Light will take time to reach us, that’s why it’s referred to as the speed of information and causality. It’ll take 4 yrs to reach Proxima Centauri. The light that left it on Jan 1,2019 was seen on Jan 1,2023.(Well, not exactly but just an example.)
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