4 ms·
> Also, curious where the extra energy comes from to keep the 'vacuum energy' (zero point energy?) from going down - IIRC, its remained constant even though the
by consilient 4y ago
> Also, curious where the extra energy comes from to keep the 'vacuum energy' (zero point energy?) from going down - IIRC, its remained constant even though the universe is expanding
Energy is ill-defined in a global sense: it's the conserved quantity associated with time-translation symmetry, but there's no single choice of "time translation" that can be extended to all of spacetime.
- mech422 4y agoHmm...This goes beyond what PBS space-time taught me about it :-) My understanding was we have more space (eg space is expanding) but the 'vacuum energy' is staying constant.. If I understand what you're saying, that statement depends on the time frame you measure against ? edit: s/your/you're/
- consilient 4y agoNo, it's just not meaningful. The vacuum energy density is (likely) constant. The total energy of the universe is simply not a thing.
- mech422 4y agoHmm..ok - thank you. I'm gonna have to work on that more, atm I'm having a hard time comprehending how volume can increase without density decreasing. To google! Thanks!
- consilient 4y agoGoogle won't help you here. Popsci stuff is useless at best, and more often actively misleading. You need a GR textbook. An Introduction to General Relativity, Spacetime, and Geometry (https://fma.if.usp.br/~mlima/teaching/PGF5292_2021/Carroll_SG.pdf https://fma.if.usp.br/~mlima/teaching/PGF5292_2021/Carroll_S...) is relatively accessible.
- mech422 4y agooh! Thanks!