2.3M views · Jun 15, 2020 · 18:30 · 2 HN recommenders · 5 mentions · discussed 2020–2023
PBS Space Time explains Roger Penrose's conformal cyclic cosmology, in which the far future of our universe becomes the big bang of the next. It explores what could come after the universe ends.
Why Hacker News points people here: HN recommends it as a clearer explanation of Penrose's cyclic cosmology than comment threads can give.
“It's explained in this PBS Space Time episode much better”HN comment, 2020
“It's explained in this PBS Space Time episode much better”
Explains conformal cyclic cosmology better than the comment.
According to CCC and to my understanding, it is sort of the case. The universe has undergone a "scale change" which marks the beginning of a new Epoch. It's explained in this PBS Space Time episode much better: this video
“I'd recommend learning a bit about what we think could come 'after' this period”
Explores what might come after the universe's end.
This dramatic visualization of the timeline for the rest of the universe is well worth a watch to get a feel for what we believe the future of the universe to look like [TIMELAPSE OF THE FUTURE: A Journey to the End of Time] link However, when you get to the end (which is perhaps a little depressing!), I'd recommend learning a bit about what we think could come 'after' this period, where the universe has become so isotropic and homogenous no clocks or measuring systems of any kind can be developed so the universe loses any sense of size or energy – it's been proposed that this creates opportunity for a new universe to exist [What Happens After the Universe Ends?] this video These are fields of study right on the edge of what's testable by science so it's more fun to think about than it is to have certainty (although Penrose has, debatably, claimed evidence for echos of previous universes visible in the CMB!).
“when all particles are moving at speed of light, time becomes meaningless”
Explains Penrose's cyclic cosmology idea.
Argument was a bit more complicated. Basically when all particles are moving at speed of light, time becomes meaningless and you can consider space to be infinitely small. I.e. identical conditions to Big Bang this video
“There was a PBS Space Time episode about a year ago”
Covers the recent Penrose idea.
There was a PBS Space Time episode about a year ago that covered what I think is the same recent Penrose idea that you have mentioned [1]. [1] this video
“In conformal cyclic cosmology (CCC for short), the heat death of universe looks a lot like big bang.”
Explains conformal cyclic cosmology.
In conformal cyclic cosmology (CCC for short), the heat death of universe looks a lot like big bang. Essentially once all matter is reduced to photons (and massless particles) there is nothing to track time (or space), light can be understood as being everywhere all at once, thus causing huge amount of energy and with very little entropy. [PBS Spacetime on CCC] this video
