nivek
As Above So Below
Could Parallel Universes Be Physically Real?
We can imagine a very large number of possible outcomes that could have resulted from the conditions our Universe was born with. The fact that all 10^90 particles contained within our Universe unfolded with the interactions they experienced and the outcomes that they arrived at over the past 13.8 billion years led to all the intricacies of our experiences, including our very existence. It is possible, if there were enough chances, that this could occur many times, leading to a scenario that we think of as "infinite parallel Universes" that contain all possible outcomes, including the roads our Universe didn't travel.
Jaime Salcido/simulations by the EAGLE Collaboration
You've likely imagined it before: another Universe out there, just like this one, where all the random events and chances that brought about our reality exactly as it is played out just the same. Except right now, when you made one fateful decision in this Universe, you took an alternate path in this other Universe. These two Universes, which ran parallel to one another for so long, suddenly diverge.
Perhaps our Universe, with the version of events we're familiar with, isn't the only one out there. Perhaps there are other Universes, perhaps even with different versions of ourselves, different histories and alternate outcomes from what we've experienced. This isn't just fiction, but one of the most exciting possibilities brought up by theoretical physics. Here's what the science says about whether parallel Universes might actually be real.
On a logarithmic scale, the Universe nearby has the solar system and our Milky Way galaxy. But far beyond are all the other galaxies in the Universe, the large-scale cosmic web, and eventually the moments immediately following the Big Bang itself. Although we cannot observe farther than this cosmic horizon which is presently a distance of 46.1 billion light-years away, there will be more Universe to reveal itself to us in the future. The observable Universe contains 2 trillion galaxies today, but as time goes on, more Universe will become observable to us, perhaps revealing some cosmic truths that are obscure to us today. - Wikipedia user Pablo Carlos Budassi
As vast as our Universe might be, the part that we can see, access, affect, or be affected by is finite and quantifiable. Including photons and neutrinos, it contains some 1090 particles, clumped and clustered together into approximately two trillion galaxies, with perhaps another two-to-three trillion galaxies that will reveal themselves to us as the Universe continues to expand.
Each such galaxy comes with around a trillion stars inside it (on average), and these galaxies clump together in an enormous, cosmos-spanning web that extends for 46 billion light-years away from us in all directions. But, despite what our intuition might tell us, that doesn’t mean we’re at the center of a finite Universe. In fact, the full suite of evidence indicates something quite to the contrary.
The reason the Universe appears finite in size to us — the reason we can’t see anything that’s more than a specific distance away — isn’t because the Universe is actually finite in size, but is rather because the Universe has only existed in its present state for a finite amount of time.
If you learn nothing else about the Big Bang, it should be this: the Universe was not constant in space or in time, but rather has evolved from a more uniform, hotter, denser state to a clumpier, cooler and more diffuse state today. As we go to earlier and earlier times, the Universe appears smoother and with fewer, less-evolved galaxies; as we look to later times, the galaxies are larger and more massive, consisting of older stars, with greater distances separating galaxies, groups, and clusters from one another.
This has given us a rich Universe, containing many relics from our shared cosmic history, including:
But this in no way means that there isn’t more Universe out there beyond the portion that’s accessible to us. In fact, there's both observational and theoretical arguments that point to the existence of much more Universe beyond what we see: perhaps even infinitely more.
(much more on the link)
.
We can imagine a very large number of possible outcomes that could have resulted from the conditions our Universe was born with. The fact that all 10^90 particles contained within our Universe unfolded with the interactions they experienced and the outcomes that they arrived at over the past 13.8 billion years led to all the intricacies of our experiences, including our very existence. It is possible, if there were enough chances, that this could occur many times, leading to a scenario that we think of as "infinite parallel Universes" that contain all possible outcomes, including the roads our Universe didn't travel.
Jaime Salcido/simulations by the EAGLE Collaboration
You've likely imagined it before: another Universe out there, just like this one, where all the random events and chances that brought about our reality exactly as it is played out just the same. Except right now, when you made one fateful decision in this Universe, you took an alternate path in this other Universe. These two Universes, which ran parallel to one another for so long, suddenly diverge.
Perhaps our Universe, with the version of events we're familiar with, isn't the only one out there. Perhaps there are other Universes, perhaps even with different versions of ourselves, different histories and alternate outcomes from what we've experienced. This isn't just fiction, but one of the most exciting possibilities brought up by theoretical physics. Here's what the science says about whether parallel Universes might actually be real.
On a logarithmic scale, the Universe nearby has the solar system and our Milky Way galaxy. But far beyond are all the other galaxies in the Universe, the large-scale cosmic web, and eventually the moments immediately following the Big Bang itself. Although we cannot observe farther than this cosmic horizon which is presently a distance of 46.1 billion light-years away, there will be more Universe to reveal itself to us in the future. The observable Universe contains 2 trillion galaxies today, but as time goes on, more Universe will become observable to us, perhaps revealing some cosmic truths that are obscure to us today. - Wikipedia user Pablo Carlos Budassi
As vast as our Universe might be, the part that we can see, access, affect, or be affected by is finite and quantifiable. Including photons and neutrinos, it contains some 1090 particles, clumped and clustered together into approximately two trillion galaxies, with perhaps another two-to-three trillion galaxies that will reveal themselves to us as the Universe continues to expand.
Each such galaxy comes with around a trillion stars inside it (on average), and these galaxies clump together in an enormous, cosmos-spanning web that extends for 46 billion light-years away from us in all directions. But, despite what our intuition might tell us, that doesn’t mean we’re at the center of a finite Universe. In fact, the full suite of evidence indicates something quite to the contrary.
The reason the Universe appears finite in size to us — the reason we can’t see anything that’s more than a specific distance away — isn’t because the Universe is actually finite in size, but is rather because the Universe has only existed in its present state for a finite amount of time.
If you learn nothing else about the Big Bang, it should be this: the Universe was not constant in space or in time, but rather has evolved from a more uniform, hotter, denser state to a clumpier, cooler and more diffuse state today. As we go to earlier and earlier times, the Universe appears smoother and with fewer, less-evolved galaxies; as we look to later times, the galaxies are larger and more massive, consisting of older stars, with greater distances separating galaxies, groups, and clusters from one another.
This has given us a rich Universe, containing many relics from our shared cosmic history, including:
- many generations of stars,
- an ultra-cold background of leftover radiation,
- galaxies that appear to recede away from us ever-more-rapidly the more distant they are,
- with a fundamental limit to how far back we can see.
But this in no way means that there isn’t more Universe out there beyond the portion that’s accessible to us. In fact, there's both observational and theoretical arguments that point to the existence of much more Universe beyond what we see: perhaps even infinitely more.
(much more on the link)
.