

Multiverse Collisions May Dot the Sky - digital55
https://www.quantamagazine.org/20141110-multiverse-collisions-may-dot-the-sky/

======
trhway
>The team concluded that a collision of two bubble universes would appear to
us as a disk on the CMB with a distinctive temperature profile.

we don't expect them to be real bubbles with real walls, don't we? Thus, once
the collision happened, the Universes get entangled, and, continuing the
expansions, the matter/space from each other should continue penetrating
deeper and deeper into each other (like 2 garbage trucks colliding in slow
motion). So it should be not just CMB temperature disk - looking at that
direction we'd be actually looking at matter/space from the other Universe.

~~~
ccvannorman
>like 2 garbage trucks colliding in slow motion

The best description of a QM interacting multiverse ever

------
aroberge
This suggestion glosses over a major point. In inflationary models, it is
often concluded that our _visible_ universe is a __tiny __fraction of the rest
of the "universe", where by "universe" one means something like a bubble
described in this article. I know of no model that would yield something where
our visible universe's CMB "boundary" would be close to the boundary of the
bubble.

If there is a collision between these bubbles, the imprint that would be left
on the CMB would almost certainly be outside our visible universe.

~~~
Florin_Andrei
Doesn't it depend on _when_ the collision happened?

~~~
aroberge
No, not really. During inflation, points separated by a finite distance
quickly see the distance between increase at a rate faster than the speed of
light in vacuum. (This is not a violation of special relativity that says that
information can not be transmitted faster than the speed of light.) So, if a
collision happened at any point outside of the visible universe, its influence
would have quickly been swept away from the edge of our visible universe. The
only way that there might have been some evidence left would be if the
collision had happened essentially exactly at what is currently the edge of
our visible universe. Statistically, this is extremely unlikely to say the
least.

------
zw123456
What if out universe was a matter universe and 14B yrs ago it collided with an
anti-matter universe and that was the big bang? An our universe was just a
little bigger than the other one? It seems like would explain a lot, like why
the universe is so empty.

