- #1
Byron Forbes
- 47
- 17
- TL;DR Summary
- Speed of gravity thought experiment
Thought experiment - the sun suddenly disappears.
Light stops after 8 mins and, according to LIGO and Albert, so will gravity.
The light part is easy to understand - the photons are already in flight so they get here 8 mins later.
But what about the gravity? Assuming that the gravity did indeed last for 8 mins then how would it do so? Would it last at the same magnitude for the entire 8 mins and then cease completely or would it drop off gradually?
But most importantly, how would it last at all? If it did, wouldn't it mean there was something between the sun and Earth that was coupling them even before the sun disappeared? Otherwise, how could the gravity possibly be sustained?
Light stops after 8 mins and, according to LIGO and Albert, so will gravity.
The light part is easy to understand - the photons are already in flight so they get here 8 mins later.
But what about the gravity? Assuming that the gravity did indeed last for 8 mins then how would it do so? Would it last at the same magnitude for the entire 8 mins and then cease completely or would it drop off gradually?
But most importantly, how would it last at all? If it did, wouldn't it mean there was something between the sun and Earth that was coupling them even before the sun disappeared? Otherwise, how could the gravity possibly be sustained?