cosmic microwave background

[Saeros]

I'm not sure if this has been discussed on the forums yet, but i couldn't find anything when i searched the forum. Here are a couple of articles that I thought were interesting.

http://planetsave.com/
http://www.space.com/
http://www.nytimes.com/

here is a quote:

The evidence in question is said to lie in the haze of microwaves permeating the cosmos that was left over after the Big Bang. This light, and patterns within it, has granted scientists a picture of the earliest years of the universe.
However, a little over a month ago, a pair of physicists said they found something potentially even more extraordinary in this radiation — giant rings they said could be evidence of a universe that existed before the Big Bang roughly 13.7 billion years ago.

What does everybody think about that?

 

[Arbite]

Reminds me of an article I read earlier this year about how we can see spots were our universe may have collided with other universes in the CMB.

 

[SpaceYeti]

Sounds to me like reporters are blowing off-handed conjecture out of proportion. I doubt many serious cosmologists seriously except that this stuff is from before the big bang or from collisions with other universes. Firstly, "before the big bang" requires that time was constant from before the big bang to now (that it existed as it currently does). Secondly, the universe colliding claim requires a model of multiple universe which is more than sheer guesswork. It implies universes exist in a way that they can physically contact each other, which I'm not aware of a reason to think that.

The black hole collision seems the most likely cause, to me. However, I'm not a cosmologist.

 

[Vrecknidj]

1) Occam's Razor suggests we choose one universe over many.
2) Roger Penrose is known for bold claims.

That said, multiple universes might have more explanatory power than a single one. Further, it might be true.

Whether the CMB findings serve as evidence for this view remains to be seen.

 

[Agent Intellect]

Collisions with other universes is possible, but it's also possible that there are undiscovered forces that work on incredibly large scales in our universe that are undetectable at our size scale (the same way the strong nuclear force is too small to be detected at our size scale). It's also possible that people are seeing patterns where there are none. Just look at the full picture:

Spoiler

If you look long enough, you can probably find numerous other patterns that are otherwise meaningless.

That being said, it's also interesting that there is a directionality to the expansion of the universe (dark flow). While multiple universes is an interesting idea to think about and does have strong explaining power, I think it's just as likely, if not much more likely that our single universe is simply a lot stranger than we imagine, with as of yet undiscovered laws (and possibly even fundamental forces) and other phenomena.

 

[gcomeau]

1) Occam's Razor suggests we choose one universe over many.

No it doesn't. Don't confuse simplicity with parsimony, the razor is concerned with the latter. If a multiverse cosmology better accounts for observational data it would enjoy greater parsimony than a single universe model.

Not saying that is actually the case, just saying Occam's razor has nothing in particular to say on the subject of whether we should prefer one or the other in the absence of that evaluation being performed. Only if the two competing models performed exactly the same as each other in explaining available data would the razor then choose the single universe model as it made one less assumption than the multiverse model to produce the same results.

 

[SpaceYeti]

As is the case.

 

[gcomeau]

As is the case.

As what is the case?

I'm relatively confident the multi-verse models I'm aware of (not to be confused with the vague "maybe this is one universe bumping into another one" speculation the opening post mentioned) are not identical to single universe models in how they account for the observational data. I admit I haven't exactly been following developments very closely, not my field and it's been a while since I did any reading on it, but the last time I did I seem to recall people working on such models doing so because they thought they dealt with issues of flatness and dark energy better.

 

[Vrecknidj]

No it doesn't. Don't confuse simplicity with parsimony, the razor is concerned with the latter. If a multiverse cosmology better accounts for observational data it would enjoy greater parsimony than a single universe model.

Not saying that is actually the case, just saying Occam's razor has nothing in particular to say on the subject of whether we should prefer one or the other in the absence of that evaluation being performed. Only if the two competing models performed exactly the same as each other in explaining available data would the razor then choose the single universe model as it made one less assumption than the multiverse model to produce the same results.

Hence my use of the word "suggests."

Dave

 

[Vrecknidj]

No it doesn't. Don't confuse simplicity with parsimony, the razor is concerned with the latter. If a multiverse cosmology better accounts for observational data it would enjoy greater parsimony than a single universe model.

That's a HUGE "if" though. We have no evidence for other universes. Sure, we can create hypotheses "If there are other universes, and if they react with our universe in these ways, then we should notice this..." but, that's still a bold claim and the same things we notice that might suggest multiple universes could have a single-universe explanation as well.

Not saying that is actually the case, just saying Occam's razor has nothing in particular to say on the subject of whether we should prefer one or the other in the absence of that evaluation being performed.

And if the evaluation cannot be performed?

Only if the two competing models performed exactly the same as each other in explaining available data would the razor then choose the single universe model as it made one less assumption than the multiverse model to produce the same results.

All of this aside, I have no particular attachment to the Razor. It is merely a principle after all.

Thanks for reminding me of the need to not equivocate on "simplicity" though.

Dave