What Defines a Different Universe?

[PhyHunter]

Are there Parallel Universes ?

 

[PhyHunter]

And how can they affect our universe ?

 

[jedishrfu]

Parallel universes are speculative physics. We have no way currently of knowing whether or not they exist. There are also several theories that describe different types of parallel universes and how they fit into mainstream physics:

http://en.wikipedia.org/wiki/Multiverse

By definition, a universe contains everything there is so by extension parallel universes are in reality added structure to the existing all encompassing universe that everything and everyone lives in.

 

[pnorm91]

I had an interesting discussion about this with my grandfather a couple of weeks ago. I think where a lot of us get hung up is the string theory interpretation of "alternate universes" where everytime some event occurs, the universe splits and forms a separate universe where the opposite decision was made. This is an interesting theory, but that is all it is.

I just recently had this thought, however; We are a very small planet, in a small galaxy in a vast universe. we have little knowledge of many things outside our galaxy, let alone things that might exist outside the range of what we know. about 13 billion light years in any direction is as far as light has traveled since the universe began. however, this light is continually expanding, and always will. which leads me to believe, that beyond our universe, there has to be additional space that we are taking up with our expansion. So, what I'm thinking is that there is a posibility of other universes existing out in space. these universes would be in addition to ours, not parallel universes that couldn't be seen. So it wouldn't be universes where I exist but didnt marry my wife, or didnt go to college, or didnt have a baby, they would be universes just like ours where millions, billions, maybe even trillions of other unique, individual beings exist. although with our current technology (and likely none in the near or probably even distant future) we would never be able to see them, but theoretically, if they existed we could if the technology existed.

Of course I've not founded any of this in anything other than speculation, but its a fun thought.

 

[yup790]

Yes

As far as I know there are three versions of parallel universes.

Firstly is the infinite universe. This means that there are infinite numbers of observable universes. Each is like its own universe. This also implies that there are repeats of this world within our own universe.

Secondly there are multiple big bangs. Each big bang creates its own universe with its own equations and constants. Some would be so inhospitable that atoms couldn't be made and others could be really hospitable and life and chemistry would be really interesting. Others would be just like ours.

Lastly, there is the many worlds interpretation of quantum mechanics. This means that every option on every level creates a new universe.

 

[1MileCrash]

So, what I'm thinking is that there is a posibility of other universes existing out in space. these universes would be in addition to ours, not parallel universes that couldn't be seen.

That doesn't make any sense. How are you defining 'a universe?' What makes something in space a "different universe?"