Discussion in 'Techforge' started by The Night Funky, Aug 9, 2019.
Like tears in the rain.
well sort of - if the star is 20 light years away (for argument's sake) then we are seeing what was happening 20 years ago.
I read about this recently. This idea that there's some sort of universal "present" isn't really sustainable. The universe consists of spacetime - not just time - so saying 20 light years away is accurate. Saying 20 years ago is not.
whoa....now my mind is blown! Thus nothing of value was lost. My "senior moments" are becoming an increasingly common event lately.
Only to the extent that we are used to understanding 'away' as 'away from here, and now', but don't bother to add 'from here and now' to 'ago". Do that and you're fine.
Yes, it's very counterintuitive, but the "present" is a local phenomenon. It loses meaning as distance from the observer increases.
It is possible under Special Relativity to create a situation where an event in one person's future is in another person's past, but paradoxes can't ensue because causality is maintained. In other words, I can get to what might be said to be in your past, but only if it's in a way that ensures I can't affect your past.
I can get to one year ago from your perspective, but only if I also wind up at least one light year away from your perspective. Then there's nothing I can do in your past that would change your present.
So, if the notions of future and past are dependent on our relative states of motion, is there really an absolute future or past? It appears that no, there isn't.
One of the first things that a spacefaring civilization ala Trek would have to do is come up with a map of the galaxy which reflects the position of the known stars and planets at the same point in time (one could call it Universal Standard Time, or Stardate). Because if it takes you 9 months to travel to a star 20 lightyears away, and you're aiming for where the star was 20 years ago, you'll either miss it or quite possibly smack into it. Neither of which is what you'd want.
So, the distance is 20 light years, but the light from the star is now (real time) because whatever telescope their using can see it that far away, in real time? Something like that?
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