'Big Freeze', not 'Big Bang', says pop science site

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'Big Freeze', not 'Big Bang', says pop science site

Postby Princess Marzipan » Thu Aug 23, 2012 4:55 am UTC

Via io9, a gawker partner/subsidiary/something.
http://io9.com/5936949/new-theory-unive ... big-freeze

Spoiler:
A group of theoretical physicists at the University of Melbourne and RMIT University have proposed a new theory on the origin of the universe that could overturn the Big Bang model. This new idea, which piggybacks off the nascent field of quantum graphity, suggests that the early universe went through a dramatic transformation, or phase shift, in a manner similar to how a liquid turns to a solid. To prove their theory, however, the researchers will have to find the crack in the ice.
According to lead researcher James Quach, the early universe can be compared to a liquid — a state of matter that has no definable form. As it cools, it "crystallizes" into the three spatial and one time dimension that characterizes our universe today. It's the cooling of the universe, says Quach, that gives it its structure. Consequently, Quach and his team are making the case that the start of the universe should not be modeled as a Big Bang, but rather like a Big Freeze — akin to water transforming into ice.

A driving force behind Quach's work is his contention that the Big Bang theory is inadequate. Speaking to the Sydney Morning Herald, Quach had this to say:

The biggest problem with the big bang model is the bang itself. At the bang, physics breaks down. The model cannot make any predictions at what occurs at the big bang. You can't use any of the mathematics [or] any of the theories."

This is where quantum graphity could come to the rescue. Writing in Space, Natalie Wolchover explains how the theory fits in:

The notion that space and time are emergent properties that suddenly materialized out of an amorphous state was first put forth by physicists at Canada's Perimeter Institute in 2006. Called "quantum graphity," the theory holds that the four-dimensional geometry of space-time discovered by Albert Einstein is not fundamental; instead, space-time is more like a lattice constructed of discrete space-time building blocks, just like matter looks continuous, but is actually made of building blocks called atoms.

According to this theory — which is still a kind of holy grail of physics — space is made of indivisible chunks that function much like pixels do on a computer screen. Consequently, in order for this theory to be proved right, the researchers will have to demonstrate that these building blocks truly exist.

Again, the states-of-matter analogy could help. When liquids turn to ice, they crystallize and form cracks. What Quach and his team need to do now is find the cosmological equivalent of these "cracks," or defects.

And indeed, they believe this might be possible. According to Quach, light and other particles might bend or reflect off such defects — an effect that could be measured. Looking ahead to this possibility, the team has already performed some calculations and are claiming that the math looks right. The key now will be in setting up the appropriate experiment. As Wolchover notes, the team needs to figure out the average distance between cracks: "It isn't known whether they are microscopic, or light-years apart."

The next step for the researchers, therefore, will be in figuring out if they need to use a telescope or a microscope.

The entire study will appear in an upcoming issue of Physical Review D.
Hey, people who know things about things: on a scale of total crap to mind-blowing insight, where does this fall, in your estimations?
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Re: 'Big Freeze', not 'Big Bang', says pop science site

Postby poxic » Thu Aug 23, 2012 5:06 am UTC

Sounds like different ways to describe the same thing, sort of. Big Bang describes a massively hot event which then cools, allowing particles to form. Big Freeze is just describing the cooling rather than the hot banging thing. Er.

It might be more complicated than that (I are an arts grad). Also, the gravity atoms they're discussing sound like loop quantum gravity, a concept that's been around for a bit. It sounds neat but there's no evidence yet, I think.
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Re: 'Big Freeze', not 'Big Bang', says pop science site

Postby Charlie! » Thu Aug 23, 2012 5:23 am UTC

Sounds like science journalism of articles written by other science journalists. It's usually bad enough looking at the world through one layer of fuzzy marshmallow.

But yes, this is about what loop quantum gravity predicts as a consequence of a big bang (not a replacement). And the thing it predicts is like domains in steel - "cracks in ice" isn't a very good analogy.
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Re: 'Big Freeze', not 'Big Bang', says pop science site

Postby PM 2Ring » Thu Aug 23, 2012 5:47 am UTC

poxic wrote:Sounds like different ways to describe the same thing, sort of. Big Bang describes a massively hot event which then cools, allowing particles to form. Big Freeze is just describing the cooling rather than the hot banging thing. Er.


Yep. Standard Big Bang theory doesn't attempt to explain how the universe happened to be in its initial state; after all, it's a bit difficult to posit causal explanations for the state of the universe at t=0, unless you invoke causes that operate backwards in time, or some sort of meta-universe that gave birth to our spacetime.

So Standard Big Bang theory describes the various phase changes that occurred as the early universe cooled down and thus it's quite reasonable to talk about it as a Big Freeze. IIRC, Novikov was one of the first cosmologists to popularise this sort of terminology. OTOH, the universe became less dense as it cooled, but stuff normally becomes more dense when it freezes, water being one of the few exceptions to this rule. But the image of a Big Freeze nicely captures how various symmetries were broken as the primeval universe cooled, just like liquid water loses some of its symmetry when it crystallizes into ice. Symmetry breaking is an important feature in any theory of the early universe, but it's especially so in Quantum Loop Gravity, which is particularly interested in symmetry breaking as applied to the geometric properties of spacetime itself.


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