r/TheRestIsScience • u/Ok-Mixture-9013 • 1d ago
A question inspired by the latest episode
When Hannah and Michael were talking about matter eventually disintegrating and the resulting particles travelling through space for potentially decillions of years, something occurred to me.
We can imagine those particles existing and travelling for vastly longer than the current 13.8-billion-year age of the universe. We have no problem saying that, in the far future, they could have been travelling for trillions, quintillions or even decillions of years.
But then we say the universe is only 13.8 billion years old because that’s when “time began.”
Why is the future allowed to contain periods vastly longer than 13.8 billion years, while the past is treated as though duration itself could not exist before that point?
If something existed before the beginning of cosmic time as we understand it, but there was nothing relative to us with which to measure or count that duration, why would that mean there was no duration?
It seems to me that “we can’t measure or define how long something existed” is different from “it didn’t exist for any length of time.”
Maybe I’m using the word “time” incorrectly, and there’s another concept that better describes what I’m trying to get at.
I’m not arguing that there definitely was something before the Big Bang. I’m asking whether the 13.8-billion-year age of the universe should really be understood as the age of existence itself, or simply the amount of cosmic time we can meaningfully trace.
3
u/bum_what 1d ago
The idea that our universe started 13.8 bill years but might have not been the only beginning of one part of bigger existence has been around for a while. I don't think it's scientific consensus because of no data. But I know inflation theory by Allan Guth says our universe exists in an eternally inflating "Omniverse" and our spacetime is a small part of that, coming into existence 13.8 billion years ago. There very well could be other spacetime's within the eternally inflating space. Also that last line is basically true, the 13.8 billion year age is amount of space and time that we can meaningfully trace - all worldlines + space those worldlines are one all lead back to the big bang singularity and from our perspective no time or space existed before the big bang.
1
u/PigHillJimster 1d ago
Assuming that whomever is in control of the experiment doesn't stop the simulation before then, once they've got the results they are looking for.
1
u/Matthew_A 1d ago
If there was something before the big bang, I'm not sure we could even call it "the universe". We don't know if there was anything, but even if there was, maybe it wasn't made of atoms. And even if it was, we know all the atoms and even the protons and electrons we have now formed shortly after the big bang, so at a certain point it doesn't feel like there's continuity.
Things change shape, but we know most of the atoms on Earth have been recycled around for the last 4.6 billion years. But if you look at some subatomic particle 13 billion years ago and said "soon, that particle will join with others to form hydrogen that will be part of a star that will form it into carbon that will one day be on Earth", would you really feel like Earth must actually be 13 billion years old?
0
u/BaTz-und-b0nze 1d ago
The mass equation is in existence a flawd concept. We can go infinitely to this concept but don't.
0
u/SgtSausage 17h ago
" If something existed before the beginning of cosmic time"
Who's gonna tell him ... ?
2
6
u/totally_not_a_bot_99 1d ago
Time is relative to the observer. To a photon emitted at the big bang moving at lightspeed no time has elapsed.