Gravitational waves - finally, The topic cover Big bang, inflation and the CMB Options

[TheAnt]

Ripples in the CMB finally show the effect of the cosmic inflation, a holy grail of cosmology and one achievement for the scientists involved.
In a double score it also give further support for the idea of inflation and gravity waves in the first moment after the big bang.

New Daily story

[Vultur]

Cool!

(Now they just need to actually get one of the gravitational wave detectors to register one...)

So this cosmic inflation thing... never been too clear on it... this is something that happened immediately after the Big Bang, rather than an alternative to Big Bang theory, right?

One news article I saw about this was going on about multiverse stuff... is that related to inflation at all?

[centsworth_II]

My recollection from having read Alan Guth's great book, "The Inflationary Universe," is that the idea for inflation was spurred by the fact that the universe we see could not have arisen from the Big Bang as originally proposed. Inflation was needed to explain differences in the composition and distribution of matter in our current universe as well as its apparent size.

Edit: Another great book by George Smoot, "Wrinkles in time," describes events paving the way for the pioneering (COBE) mission to map the cosmic microwave background.

As far as I know, inflation as used in the Big Bang theory for the creation of our universe does not automatically imply the creation of multiple universes, but can imply that our own universe is much much larger than we can ever hope to see.

Disclaimer: I have no in depth knowledge in this area.

[Gerald]

Inflation is mainly needed to explain the flatness of space-time, and the evenness of the cosmic microwave background (CMB), with only sublte features.

If the universe started (almost) from a singularity, it should have expanded like a surface of a ball (but one dimension higher, called a 3-sphere). Such a surface should be curved. But the curvature of the observable universe is below the limits of measurement, meaning it's almost flat. Hence we can observe only a tiny fraction of the universe; most of the universe is and has been receding faster than light, hence is not observable. A phase of fast expansion (inflation) in the very early universe is a possible explanation.

A slowly expanding universe should contract locally by gravity, and hence show clear large-scale heterogeneities, including features of the CMB, but it doesn't. This can be explained by inflation.

But these two arguments are just plausibilities. Gravitational waves, caused by the acceleration of mass/energy, and recorded in the CMB, provide direct evidence for cosmic inflation.

Multiverse theories are not feasible to evidence by observation; they refere to hypothetical universes outside our space-time, and try to work around an answer why our universe has exactly the properties (constants, laws of nature) it has; hence multiverse theories are off-topic in this forum.

[TheAnt]

So this cosmic inflation thing... never been too clear on it... this is something that happened immediately after the Big Bang, rather than an alternative to Big Bang theory, right?

One news article I saw about this was going on about multiverse stuff... is that related to inflation at all?

Yes inflation is a bit of add-on to the Big bang theory, and not one alternative, one can view it as a refinement of the original theory.

One way of viewing the inflation phase is to imagine that the natural laws as we know them today still not had settled with the values we're use to have during that extremely short moment.
In fact, more than one research group have been looking for changes in these laws at very distant objects, but found none.

So whatever it was that happened in that very short timespan, 10 -32 second it appear to be limited that that very brief time. (Tried to use <sup> formatting but did not work in preview)

The speculation of what might happen if the natural laws were just a bit different comes as a consequence of that yet that has led to quite some fuzzy thinking with disputable logic.
So as Gerald pointed out this is not a matter that fit within the scope for this forum. Rather one for speculative Science fiction!

[Vultur]

OK, thank you!

So there is still thought to have been a Big Bang immediately before the inflationary epoch, rather than the inflation being a new model for the Big Bang itself? Is that correct?

[Gerald]

In the strict sense, yes.

The sequence of the first 10 seconds after the Big Bang is thought to have been about as follows:

• 0 - 10e-43 s: Planck epoch, causality needed to come into existence, all four forces of the standard model of particle physics unified,
• 10e-43 s - 10e-36 s: grand unified (GUT) epoch, separation (symmetrie breaking) of gravity from the three remaining forces still unified (strong/weak nuclear force, and electromagnetism),
• 10e-36 s - 10e-32 s: inflation, exponentially accelerating expansion of the universe,
• 10e-36 s / 10e-32 s - 10e-12 s: electroweak epoch, separation of the strong interaction, leaving weak interaction and electromagnetism unified to the electroweak interaction,
• 10e-12 s - 10e-6 s: quark epoch, quark-gluon plasma, all four fundamental forces separated
• 10e-6 s - 1 s: hadron epoch, quarks (bound by gluons) form hadrons, e.g. protons and neutrons, hadron - anti-hadron formation and -annihilation,
• 1 s - 10 s: lepton epoch, lepton - anti-lepton formation and -annihilation, electrons are leptons.

This is followed by a few minutes of nucleosyntheses, then 380,000 years plasma of atomic nuclei (mostly protons, some helium nuclei, few lithium), electrons, photons (photon epoch). After this the universe has cooled down to allow atoms to form, and to become transparent; the radiation of the end of the photon epoch is now redshifted to the CMB by ongoing expansion of the universe.

[Vultur]

Ah - thank you again!

[TheAnt]

@Vultur Yes and no, the original Big bang theory dealt with the idea of something like a primordial seed that went unstable and exploded.

Our current thinking rather deals with the idea of a giant quantum event.

Perhaps you know that a pair consisting of a particle and one antiparticle can spawn into existence seemingly from nothing.
Only to immediately annihilate each other.
This is something that often happen quietly right under our noses without us even noticing, but the most violent stellar explosions called pair-instability supernova are thought to be powered by the creation of electron-anti electron pairs.

The Big bang as we think of it now is somewhat like the same kind of event creating a pair of particles, one normal and the other the anti-particle, only scaled up to one immense scale.

That's the reason there's been a number of studies looking for anti matter both in our own galaxy as well as in the very distance cosmos.
When none were found there's been many papers written dealing with this matter antimatter asymmetry.
And the creation and study of anti hydrogen also deals with this to some part.
Some are attempting to see if it might be just a little bit different, which would explain the event would be lopsided favouring matter over antimatter.

As one amateur only trying to keep up with the discussion on these matters, I have a feeling that we have not heard the last word yet on this.

[dvandorn]

How to say this correctly, here...

One of the things that really fascinates me about cosmology is how we have a somewhat self-consistent mathematical model for the Big Bang which postulates "the fabric of spacetime" inflating at speeds far faster than C, and how it can be flat or curved, locally bent, even completely ingested into gravitational point sources. And yet we have no description or model, really, of exactly what the "fabric of spacetime" actually is, the mechanisms by which it can inflate, be distorted by mass, etc. We have macro- and micro-models of "reality" that don't mesh, either conceptually or mathematically, and the abyss that lies between must be where these mechanisms are hiding from our view.

Physics, as far as it has progressed in the past century or so, is now to the point where it can ask basic, cogent questions. But it's not yet to the point where they can be answered.

An exciting time to be alive, eh?

-the other Doug

[djellison]

How to say this correctly, here...

If you have to ask that question - why are you posting it?

[MarsInMyLifetime]

It is an interesting conundrum, Doug. I am no cosmologist, but one thought exercise I use to try to imagine inflation is simply working my way through the unfolding of a point into a line, into a plane, into a cube, and finally into a tessaract. In the final event, volume increases 8 times in a single unfolding, the process of which has no sequence or flow--it's just there. At this point, adding one more dimension gets me from point to vast volume in a single conceptual leap.

Although this is only an imperfect analog, it helps me get away from the explosion viewpoint (matter being flung out from a "center of everything") to inflation perspective (physics coming into existence as dimensions unfold). At least it gives me a sensible springboard to think about foam, strings, and branes (of which I have so few--I'm just a little bear).

The genius of Salvador Dali's painting, Corpus Hypercubus, is that it depicts this human perspective of transcendent physics in common memes. And yet it is but a Cargo Cult representation of the technology that we do not comprehend behind the growing manifestations of this universe that has visited us.

[TheAnt]

And yet we have no description or model, really, of exactly what the "fabric of spacetime" actually is, the mechanisms by which it can inflate, be distorted by mass, etc........

An exciting time to be alive, eh?

-the other Doug

I agree we live in a really exciting time.

But I have to say that we've made some inroads into understanding parts of this 'fabric of spacetime even in understanding it mathematically, the Casimir effect for example were predicted already in 1947, but it took many decades before it could be directly proven.

So I do have the impression that we have even been given some answers, even though I agree that a comprehensible theory seem to be quite distant.

And MarsInMyLifetime did provide a concept for us amateurs on how we could envision inflation also. 'The bottom line for the cause might be that Aristotle were right: Nature abhors a vacuum.

[Doug M.]

So, looking at the image: http://regmedia.co.uk/2014/03/17/gravity_waves.jpg

Is it just me, or does that look kinda like an interference pattern?


Doug M.

[AndyG]

Multiverse theories are not feasible to evidence by observation...

...Everett's Many Worlds Interpretation offers a possible solution to observable quantum effects, however.

Andy