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The extra energy comes from the increase in gravitational potential energy between objects. The accelerating increase in this potential energy implies the total
by mjfl 3y ago
The extra energy comes from the increase in gravitational potential energy between objects. The accelerating increase in this potential energy implies the total energy of the universe is increasing. I’m not talking about harvesting dark energy directly.
- antod 3y agoI'm no physicist, but isn't the gravitational potential energy between two objects inversely proportional to the distance between them?
- mjfl 3y agoit is, in the negative direction though. So increasing the distance increases the potential energy by making -1/r closer to zero.
- antod 3y agoHeh, I had to go off and read some stuff to get my head around what "negative" potential energy would even mean (high school physics was decades ago). So... the negative is just a convention to represent work done against the "field", and positive is work done by the field? ie more of a vector than actually being negative energy? I think I get that bit now. So now I'm wondering if that still applies to an expanding universe vs eg a rocket leaving earth. If things aren't moving further apart by work (ie force x distance) being done against their gravitational fields so much as space time expanding, is there an increase in potential energy? And then if objects are moving apart faster than escape velocity, could that still be seen as increasing potential energy? I think I'm confusing myself further...