does the past still exist ?

robfosters said:
Isn't sound a bit like this? By the time you hear a sound it's already in the past because the instance of that sound production has passed but the sound has travelled and still exists, but is also in the past.
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Same with light though. You just see if faster than you hear sounds. (Meaning that light travels from the point of origin faster than sound does.)

The past nolonger exists in the present, but it exists as something that happened in that there is evidence of it.
 
[TFU] Thegoon84;29781440 said:
And if the past really does still exist, will the BBC still blame Jezza Corbyn for it!!!!! HMMMMMMMMMMMMMMMMMMMMMMM
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Corbyn is proof that the past still exists in the present.
 
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Not read thread, but if I haven't forgotten all my GR...

moon man said:
just wondering if the past still exists...
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Depends what you mean by "exist". ;)

The main pitfall people fall into is around simultaneity. Einstein's relativity tells us that simultaneity is NOT universal. I might say two things happened at exactly the same moment, but some other observer (in a different frame of reference) might disagree and say one happened after the other.

So one observer's "past" event might well be the present or future for another. Wikipedia has some nice graphics on this https://en.wikipedia.org/wiki/Relativity_of_simultaneity

Therefore it makes no sense to talk about THE past (there isn't ONE), only the past as seen from your frame of reference (YOUR view of the past).

moon man said:
just wondering if the past still exists or is it instantly gone and only exists in memory...
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Since time appears to be unidirectional, the OP is correct that "the past is gone". There's no way to reach or communicate with spacetime that's in your past.* As above, you have a version of events that you call the past, and so does every other observer, but they might be different.

moon man said:
...as the light has to travel from objects we see and our brains have to process this then we never see the present
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You always live in your present, but the light you're receiving will have been emitted in the past, so yes I suppose this is true in that you never "see" the present.

* There are solutions to GR that permit time travel, but most people think they're "bugs" in the maths and will go away when we have better theories. See https://en.wikipedia.org/wiki/Closed_timelike_curve
 
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