
Astrophysicists propose new twist on Big Bang - blazar
https://uwaterloo.ca/stories/waterloo-astrophysicists-propose-new-twist-big-bang?utm_source=social_organic&utm_medium=Facebook&utm_campaign=sciam_infographic
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trhway
>The researchers emphasize that this idea, though it may sound absurd, is
grounded firmly in the mathematics describing space and time. Specifically
they’ve used the tools of holography to “turn the big bang into a cosmic
mirage.”

embedding into higher dimension spaces (or in general - into more "richer"
structures) is a convenient mathematical tool and it works nice ... in
mathematics. To work in physics that higher dimension space must really exist.
Otherwsie, for all we know, out Universe can be just a 3d surface of a 4d nut
that a small 4d squirrel puppy is about to bite into.

~~~
collyw
Ignorant question here, but is it not the case that the normal laws of physics
don't apply at big bang time?

Do we expect the laws of mathematics to still apply?

Does anyone really have any clue about this stuff?

~~~
pawn
It's always been my understanding that the normal laws of physics don't work
at big bang time as well. One thing I've wondered about is how people are so
adamantly confident in the theory of the Big Bang in light of this. Is it
simply because they don't like the alternatives, because they've never been
heard an alternative, or is there a better reason?

~~~
Sharlin
NASA uses Newtonian mechanics to send spacecraft to the outer planets and
beyond. Everybody knows that Newtonian mechanics stop being accurate in
certain conditions, but that does not prevent it being an incredibly useful
model outside those conditions.

The best experimentally-verified cosmological models we have point to the fact
that the Universe was in a hot and dense state a few microseconds after a
specific point of time about 13.7 billion years ago. Extrapolating those few
microseconds back in time we get an unphysical result from our current models,
but that simply means those models are inaccurate if applied to the beginning
of time.

Contrary to the popular belief, The Big Bang model simply does not concern
itself with what happened at the exact moment of Big Bang; what it does is
describe the evolution of the Universe _after that_ , and does it well.

~~~
collyw
>Contrary to the popular belief, The Big Bang model simply does not concern
itself with what happened at the exact moment of Big Bang; what it does is
describe the evolution of the Universe after that, and does it well.

That sounds as much of a cop out as the answers religious people give.

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adinb
Original paper title: Out of the White Hole: A Holographic Origin for the Big
Bang

Arxive page (w/abstract):
[http://arxiv.org/abs/1309.1487](http://arxiv.org/abs/1309.1487)

Direct link to paper:
[http://arxiv.org/pdf/1309.1487v2](http://arxiv.org/pdf/1309.1487v2)

------
biot
This isn't a particularly new twist. The idea of our universe coming from a
black hole has been around for quite some time, as this 1998 article
discusses:

[http://martinelli.org/rexpansion/bhole.htm](http://martinelli.org/rexpansion/bhole.htm)

    
    
      "if we run time forwards, we can kind of visualize the beginning of
       our universe as a very rapid collapse (the inverse of "Inflation").
       A similar kind of event happens when a star (hot, spherical,
       massive, dense...) becomes so dense and massive it collapses in on
       itself and forms that mysterious black hole.  Here's an interesting
       question to explore... "Did our universe begin as a star that
       underwent a gravitational collapse?"  I.e., do we live in a black
       hole?"
    

Perhaps the novelty is a formal theory around the idea?

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GorgeRonde
This tends to confirm Lee Smolin's embryo-theory of cosmological natural
selection.

Source :
[http://en.m.wikipedia.org/wiki/Cosmological_natural_selectio...](http://en.m.wikipedia.org/wiki/Cosmological_natural_selection#Cosmological_natural_selection)

Cosmological natural selection Smolin's hypothesis of cosmological natural
selection, also called the fecund universes theory, suggests that a process
analogous to biological natural selection applies at the grandest of scales.
Smolin published the idea in 1992 and summarized it in a book aimed at a lay
audience called The Life of the Cosmos.

The theory surmises that a collapsing[clarification needed] black hole causes
the emergence of a new universe on the "other side", whose fundamental
constant parameters (masses of elementary particles, Planck constant,
elementary charge, and so forth) may differ slightly from those of the
universe where the black hole collapsed. Each universe thus gives rise to as
many new universes as it has black holes. The theory contains the evolutionary
ideas of "reproduction" and "mutation" of universes, and so is formally
analogous to models of population biology.

The resulting population of universes can be represented as a distribution of
a landscape of parameters where the height of the landscape is proportional to
the numbers of black holes that a universe with those parameters will have.
Applying reasoning borrowed from the study of fitness landscapes in population
biology, one can conclude that the population is dominated by universes whose
parameters drive the production of black holes to a local peak in the
landscape. This was the first use of the notion of a landscape of parameters
in physics.

Leonard Susskind, who later promoted a similar string theory landscape,
stated:

"I'm not sure why Smolin's idea didn't attract much attention. I actually
think it deserved far more than it got."

~~~
gizmo686
It seems like the proposed cosmological natural selection is fundamentally
different from biological natural selection in the sense that there is no
actual pruning. That is to say that given a universe all of its children will
survive and reproduce based solely on their laws of physics, independent of
what all the other universes do. This would mean that all possible universes
which could be reached through this mechanism will be reached, wheras in
evolution as it happens on Earth, most of the potential organisms never exist
because there ancestor got out-competed at some point.

------
joe_the_user
OK,

The thing about this popular article is it seems to imply that the universe
coming out of a black hole is different from it coming out from any kind of
singularity.

Well, reading the real article, it seems this popular article got things
garbled. The main problem they seem raise with the big bang is that it is a
"naked" singularity - there's no barrier between the world and the singular
point. So what they are doing is looking at a higher dimensional black hole
and finding a non-naked singularity that would generate approximately the same
effects as the big bang. There is still a singularity at work here, it is
simply that the singularity is not directly spewing matter out. "No naked
singularities" is a general principle I recall from scanning general
relativity articles.

------
thisjepisje
So how did this 4d universe come about? :D

------
calhoun137
I think this idea is almost certainly false, and it has it's genesis from a
mostly discredited psuedo-physics theory called the holographic universe[1].
But at least there is a testable prediction! In my opinion, the fact that they
offer a testable prediction merits a more thorough consideration of the
claims.

First of all, it has been well understood for multiple decades that the
General Relativity(GR) breaks down, and is no longer true, at mass/energy
scales that are present inside of a black hole. This is known because physical
quantities must be finite, but GR predicts the strength of a gravitational
field inside of a black hole is infinite. If string theory is true (and I
don't believe it is), then this would be a valid situation to apply it to,
since we know that there is unknown physics at play inside of a black hole.

Furthermore, the standard big bang cosmology is based on the idea that the
beginning of time is a "black hole in time", in the sense that as t->0, the
strength of the gravitational field diverges to infinity. Thus, it has been
well known for decades that GR is not a valid physical theory at very short
time scales after the beginning of time (this would be the epoch of
inflation[3]).

It is perhaps not apparent to the casual observer that this paper is based on
a very bizarre sect within string theory, known as the "Holographic Universe",
which according to Wikipedia "suggests that the entire universe can be seen as
a two-dimensional information structure "painted" on the cosmological
horizon". This is just a bunch of fancy words designed to blow smoke in your
eyes, and the entire theory is sort of a joke as far as most physicists I know
are concerned.

There are actually a number of strange cults within string theory, another one
that is good for a laugh is the Anthropic Princple[4]. This theory claims that
even though the 11 dimensional D-Brane that is folded into a Calubi-Yau
manifold upon which string theory is based predicts trillions of possible
universes, the universe we live in exists because it is the only possible one
we could live in:

"the conditions happen to be just right for the existence of (intelligent)
life on the earth at the present time. For if they were not just right, then
we should not have found ourselves to be here now, but somewhere else, at some
other appropriate time."

This kind of nonsense is why I left research in theoretical physics to purse
computer science and programming, which truly is the cutting edge of science.
There is a lot of valuable physics research going on in material science
departments(for example), but the string theory department needs to constantly
justify their funding by making extremely bold claims such as "what we
perceive as the Big Bang could be the three-dimensional “mirage” of a
collapsing star in a universe profoundly different than our own".

[1]
[http://en.wikipedia.org/wiki/Holographic_principle](http://en.wikipedia.org/wiki/Holographic_principle)

[2]
[http://en.wikipedia.org/wiki/D-brane](http://en.wikipedia.org/wiki/D-brane)

[3]
[http://en.wikipedia.org/wiki/Inflation_(cosmology)](http://en.wikipedia.org/wiki/Inflation_\(cosmology\))

[4]
[http://en.wikipedia.org/wiki/Anthropic_principle](http://en.wikipedia.org/wiki/Anthropic_principle)

~~~
arcticfox
As far as I know, none of what you say is as cut-and-dried as you make it
seem.

The Anthropic Principle is a common sense explanation to why our universe has
a paradoxically perfect ("fine-tuned" by 120 orders of magnitude off what we
would expect) cosmological constant that is just right for life and the
universe to exist. It's somewhat horrifying, but I haven't seen a better
explanation for fine-tuning. [1]

The holographic principle does not seem to be supported by a "very bizarre
sect". In fact, it seems to be one of the better explanations for the black
hole information paradox. [2]

Nima Arkani-Hamed dedicated a significant portion of his Messenger Lectures
[3] (same lectures where Feynman delivered his famous series) to the
principles that you dismiss out of hand as laughable above.

I'm a little depressed that the top comment is computer science > theoretical
physics. Theoretical physics predicts quantum scale behavior to 11-digit
accuracy. It's no joke.

[1]
[http://en.wikipedia.org/wiki/Cosmological_constant#Quantum_f...](http://en.wikipedia.org/wiki/Cosmological_constant#Quantum_field_theory)
[2]
[http://en.wikipedia.org/wiki/Black_hole_information_paradox](http://en.wikipedia.org/wiki/Black_hole_information_paradox)
[3] [http://www.cornell.edu/video/nima-arkani-hamed-quantum-
mecha...](http://www.cornell.edu/video/nima-arkani-hamed-quantum-mechanics-
and-spacetime)

