Inflaton, Mother of the Universe

quantalm writes "Forget the god particle, we're talking about the universe's particle mother. The theory of supersymmetry has rolled out two new ideas about the particle that puffed spacetime up from smaller than a proton to bigger than a soccer ball: it could be the 'unified particle' of Grand Unified Theories or a smaller-scale version that could be tested at the Large Hadron Collider at CERN."

Comments

unfortunately i do

[circletimessquare]

it was those quant assholes who got us into this mess

they used formulas extrapolating from cherry picked models to suggest that the economic universe could just go on inflating forever. big bang indeed

http://online.wsj.com/article/NA_WSJ_PUB:SB10001424052748704509704575019032416477138.html

Inflationary theory

[Kepesk]

I'm not saying that the inflationary phase of the universe is a false concept, but I've always thought that the way the theory came about is a bit sketchy.

Please correct me if I'm mistaken with any of this, but this is my understanding of its history. Earlier versions of the Big Bang theory did not include this rapid inflation in the earlier universe; the universe was said to expand at a more constant rate. However, when the Cosmic Microwave Background Radiation was first observed, there was no way to explain its irregularity based on that model. So physicists decided to plunk down a mysterious inflationary phase into their models of the early universe, a concept with no known cause or explanation, but which made the CMBR fit with the Big Bang theory. However, it's a concept that to this day they're still trying to reconcile with the rest of observed physics, as this article shows.

Could the theory be true? Sure. But if it is, it's because those physicists got lucky with their educated guess on the matter. Other theories with much more solid backing have in the past been roundly disproven.

Re:Inflationary theory

[Bigjeff5]

However, when the Cosmic Microwave Background Radiation was first observed, there was no way to explain its irregularity based on that model.

Actually you have that backwards, without inflation, the CMBR should be extremely irregular. There should be huge blotches of stuff all over. Think of a balloon filled with paint splattering on the floor - it doesn't create a fine coating all over the floor, it creates huge splatters here and there with huge gaps of nothing in between.

The CMBR, however, is extremely uniform. When you look at a picture of the CMBR, the variations in color are artificial (similar to the way the color nebulae from infra-red data) and represent extremely minute changes in radiation (you'll note there are no areas with no radiation, but there should be). The CMBR effectively shows a nice, even "coating" of radiation that covers the universe from one end to the other. This is disturbing, and cannot be explained by any physics we know of.

The only way to explain this is if the big bang wasn't an explosion (huge release, starts fast but decelerates quickly), but actually a controlled inflation - it had to start slow, accelerate, and then decelerate in order to produce the nice, even radiation we see. They had to accelerate the time-line of the Big Bang for a microsecond and then decelerate it immediately after in order to reproduce the uniformity seen in the CMBR. It's completely arbitrary, and has absolutely no grounding in physics, yet it's the only way to fit the physics we do know with the observations we see.

If you think you are disturbed by this, talk to a cosmologist or a physicist sometime. They absolutely hate having to change a model to fit observations without having any idea what is missing in their model to cause that change. It's like Dark Energy and Dark Matter, or the singularity of a Black Hole - cosmologists hate all of them. They use them, because it works, but they hate them all the same. They screw with their nice, neat physics.

Same thing with inflation - there is no known physical property that should cause inflation, yet inflation is the only way to explain the universe as it is now. It means there is something fundamental to the universe that we don't know or understand.

PS: Fun fact: if you tune an analog TV to an unused channel, something like 10% of the fuzz you see is caused by the CMBR.

Re:Inflationary theory

[PvtVoid]

However, inflation does more than just explain existing phenomena - it predicted a spectral index between 0.98 and 0.92, and COBE/WMAP bring it in at around 0.96.

Where on Earth did you ever get that idea? Inflation makes no such prediction. For example, Linde's "Hybrid" inflation model predicts a spectral index greater than 1.0, and is pretty much ruled out by WMAP. Similarly, so-called "Natural" inflation models can easily accomodate a spectral index as low as 0.7 or so. See for example this paper for a nice general review, and this paper specifically for the Natural Inflation case. Inflation does robustly predict adiabatic, superhorizon perturbations, and this is borne out by the data. This is powerful enough evidence without having to overstate the predictivity of the theory.

Re:Inflationary theory

[budgenator]

The universe was always as big as the whole universe, so how can it expand? How do we know we're not shrinking inside a fixed size universe?

Re:Brief(!) Explanation of Inflation

[bjorniac]

Ah, now you're into the fun stuff: Just about every physicist believes that general relativity will have to be modified by quantum mechanics at some stage and at least once you get to energy densities around the planck density (this value comes mostly from dimensional analysis - it's more of an order of magnitude thing). Since the standard big bang that results from GR has infinite density, we believe that corrections will happen before you get there - that quantum mechanical effects take place and that we can't trust GR when we get above the planck density. Therefore, since we don't have a proven quantum theory of gravity (there are some interesting, even heroic attempts but nothing anywhere near tested) we simply have to say that somewhere in the past, probably around the planck density, we don't have any good prediction for what's going on. So we can't just say that everything started in the same place (which was everywhere too - the joys of relativity :) ), as GR predicts.

Another outlook on this is that we know quantum mechanics will be seriously affecting matter at this stage too - the temporal heisenberg principle is between energy and time and hence there should be a large difference in energies (and hence temperatures) between nearby points, yet somehow they come out of this highly quantum mechanical phase into a classical phase in which they should be out of causal contact and yet somehow thermalize.