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Once all stars die you will be able to live very long off of the heat of dead stars as they slowly cool off to background temperature. And once those stars are

Once all stars die you will be able to live very long off of the heat of dead stars as they slowly cool off to background temperature. And once those stars are completely cold, you can start converting their mass into energy by dropping them into black holes, piece by piece. And once you dropped all matter you could into black holes you could live off merging black holes. And once you merged black holes you could live off of the black hole radiation until all black holes evaporate. But this would be if the Universe wasn't expanding at a growing rate. If the Universe is truly expanding at an ever accelerating pace there will come a Big Rip which will cause every fundamental particle to get further from all other particles at speeds faster than light. And then matter as we know it will cease to exist.

Waterluvian 4y ago
> faster than light How? From what frame?
- twawaaay 4y ago
  It is just a mental shortcut. Of course, things cannot be moving faster than light because speed addition cannot lead to relative speeds faster than light. What you will see is a slowing, red-shifting, darkening image of everything else as it speeds away from you asymptotically reaching speed of light until space between any two particles starts expanding so fast that no radiation can reach anything anymore and each particle forever lives in its own universe. Of course we don't know that because we really don't understand how the universe is built and this is just our faulty formulas extrapolated way more than we can reasonably support with our experimental data.
- wahern 4y ago
  > While objects within space cannot travel faster than light, this limitation does not apply to the effects of changes in the metric itself. Objects that recede beyond the cosmic event horizon will eventually become unobservable, as no new light from them will be capable of overcoming the universe's expansion, limiting the size of our observable universe. https://en.wikipedia.org/wiki/Expansion_of_the_universe https://en.wikipedia.org/wiki/Expansion_of_the_universe We can already observe this phenomenon happening at large scale. Our observable universe shrinks as galaxies effectively accelerate away from us faster than the speed of light (i.e. the space between us and them expands faster than the speed of light). Whether this phenomenon is inevitable at a local scale, especially an atomic scale, is unclear, AFAIU. See https://en.wikipedia.org/wiki/Big_Rip https://en.wikipedia.org/wiki/Big_Rip But in principle, IIUC, our own bodies are experiencing this effect right now. For now it's beyond miniscule, but slowly accelerating. This tiny local expansion and acceleration, summed over cosmic scales, is ostensibly how galaxies far enough apart can move away from each other faster than the speed of light. Fundamentally it's the continuation of the Big Bang.

Waterluvian 4y ago

> faster than light How? From what frame?

twawaaay 4y ago
It is just a mental shortcut. Of course, things cannot be moving faster than light because speed addition cannot lead to relative speeds faster than light. What you will see is a slowing, red-shifting, darkening image of everything else as it speeds away from you asymptotically reaching speed of light until space between any two particles starts expanding so fast that no radiation can reach anything anymore and each particle forever lives in its own universe. Of course we don't know that because we really don't understand how the universe is built and this is just our faulty formulas extrapolated way more than we can reasonably support with our experimental data.
wahern 4y ago
> While objects within space cannot travel faster than light, this limitation does not apply to the effects of changes in the metric itself. Objects that recede beyond the cosmic event horizon will eventually become unobservable, as no new light from them will be capable of overcoming the universe's expansion, limiting the size of our observable universe. https://en.wikipedia.org/wiki/Expansion_of_the_universe https://en.wikipedia.org/wiki/Expansion_of_the_universe We can already observe this phenomenon happening at large scale. Our observable universe shrinks as galaxies effectively accelerate away from us faster than the speed of light (i.e. the space between us and them expands faster than the speed of light). Whether this phenomenon is inevitable at a local scale, especially an atomic scale, is unclear, AFAIU. See https://en.wikipedia.org/wiki/Big_Rip https://en.wikipedia.org/wiki/Big_Rip But in principle, IIUC, our own bodies are experiencing this effect right now. For now it's beyond miniscule, but slowly accelerating. This tiny local expansion and acceleration, summed over cosmic scales, is ostensibly how galaxies far enough apart can move away from each other faster than the speed of light. Fundamentally it's the continuation of the Big Bang.