Origin of the Universe

[Schneibster]

OK, here's a second apparently controversial topic.

The current most popular model of cosmology is ΛCDM, pronounced "lambda cee dee em." This stands for the lambda in Einstein's field equation,
G[μν] + g[μν]Λ = (8πG/c⁴)T[μν]
and for Cold Dark Matter.

The lambda is the cosmological constant. Einstein originally left this out, but de Sitter proved that this led to a continuously expanding universe. Since the cosmology of the day was Fred Hoyle's static model, Einstein put in lambda to account for the fact we don't live in a de Sitter space. Of course, next thing along is Hubble proves the universe is expanding, and not long after Peebles and Dicke predicted the CMBR, which was discovered by Penzias and Wilson. We've studied the CMBR intensely; and we know much of what it has to tell us. Here it is:

The universe as we know it started with an event called the "Big Bang." This event, however, did not create the space and time of our universe. Those existed before. The Big Bang was when the universe was filled with matter and energy; but that was long (in terms of how much happened- actually it's only about 10^-46 second, but that's a long time in these terms, we'll see why shortly) after the inception of our universe. In fact, at the time of the Big Bang the very farthest thing that can affect anything we can see, today-- the "edge of the visible universe--" was 40 billion light years away. Today it's nearly 150 billion light years, almost four times larger. However, at the inception of the universe, that space 40 billion light years across was the size of a pea. And immediately before that it was part of a spaceless, timeless überverse.

What happened was, there was a minute vacuum fluctuation in the überverse. This is the parent spacetime of ours; in this spacetime, however, neither space nor time exist as we know them. Instead, they are small, just like the other six dimensions (and just like the other six dimensions are today, too). The überverse has no size; it can only be treated semi-consistently externally by assuming it is of zero size. However, it also contains all of everything; it is therefore infinite, internally. Both of these mean "I don't know" in different ways in appropriate kinds of math. And by all of everything I mean that all possible universes, a number on the close order of 10^300, or a googol cubed, exist, with all possible laws of physics. We're in this one because it has chemistry, and because it has three large space and one large time dimensions which happen to be the dimensions of gravity, and because it has the correct mix and strengths of forces created by the six small dimensions. These things allow things like us to evolve. And bear in mind that the physics are guaranteed to be uniform for 40 billion light years when the Big Bang goes off, and to be uniform for 150 billion light years today, more than ten times the thirteen billion light years we can see to the edge of the universe. No wonder we think physics is uniform over the whole universe; it is, all of it we can see anyway, and ten times farther than that!

Now, I said at first the universe only started to expand from a vacuum fluctuation in the überverse; I didn't say why. The reason is because although it's got no space or time, the überverse does have lambda. Yes, that same lambda from Einstein's GR field equations. That cosmological constant. The thing is, though, it's a fluctuating value, and it's uncertain, and I mean Heisenberg uncertain. Now, when this value is negative, spacetime expands; that's clear from its association with g[μν]. And when its absolute value is large, spacetime expands exponentially. So a fluctuation occurs, with the right large negative value and the spacetime in that "place" in the überverse, whatever that means, undergoes huge exponential expansion. But again, this is unstable; large negative values of lambda decay by quantum tunnelling into small negative values. But when space expanded, more space had to have lambda. And the thing is, since lambda is a property and not a substance, it can increase to cover how much space is expanded into existence. But when lambda decays, it turns into energy. And the amount of lambda that got made when our "determinable universe" expanded from the size of a pea to 40 billion light years across was enormous. So it made an enormous amount of energy; this was the Big Bang.

We can see the huge holes in the universe created by the "bursting bubbles" of two nearby centers of expansion, tens of billions of light years across. Enormous expanses of nothing, or anyway as "nothing" as there can be in our universe. Our minute clusters of galaxies left like clusters of foam around these gigantic voids. We can also see the "echoes" of more "nearby" universes to ours, as distortions in the CMBR.

And here come the models: they've got a model now that creates voids where we have voids, and froth where we have froth, and even a Virgo cluster where we have a Virgo cluster, with an M87 where we have an M87. The last I checked they expected to replicate the Milky Way in its correct location. They don't expect to be able to get finer than that any time soon.

So you see when people deride models, I know they have no idea what they're talking about.

And we really do know where the universe came from.

I don't see where the problems are. This seems to me pretty much an incontrovertible chain of evidence.

[Schneibster]

From there we have the creation of galaxies in the "froth" surrounding the bubbles of nothing, by gravity and dark matter. As I've said, we can simulate this well enough to give us a universe that looks like ours.

The larger of these nascent galaxies, like ours, first develop active nuclei, and become quasars; then when the black holes at their centers have swept out their neighborhoods, they quiet down to spirals and barred spirals like the Milky Way, M31 in Andromeda, and M33 in Triangulum, all members of our Local Group.

During the period when their nuclei are evolving, stars are too. The first generation of stars would be almost entirely hydrogen and helium, with a tiny admixture of lithium. After several billion years, most or all of them will have burned out, gone nova, supernova, and so forth. Many of these events result in the creation by nuclear burning of heavier elements, what astrophysicists call "metals." Supernovae can even make elements heavier than iron, at the bottom of the packing fraction curve. So the second generation of stars will have more metals in it; and the third more yet. The third generation is our Sun's generation. We call stars with metal content like our Sun's "Population I stars," and stars with metal content like second-generation stars "Population II stars." We have never actually seen a first-generation star (actually, I might have seen an article that they found one in Triangulum, but if so, it's the only one ever and it's not even in our galaxy). If we did we would designate it, almost completely free of metals, "Population III."

By the time we get to the third generation of stars, the protostellar nebulae are pretty dirty. They're not just hydrogen and helium; there are lots and lots of heavier elements, all the way up to uranium. The details of planetary coalescence are being studied in planetary nurseries all over the sky; and again, here the computer models come. We can see how planetesimals are formed, and we can see how they combine to form a planet, and we can see how most of the metals stay in the inner planets and when the sun ignites its nuclear fusion, its T-Tauri wind blows away most of the light elements from the inner planets, and concentrate them on the outer planets and in the Oort cloud. We strongly suspect that a Jupiter is required to protect the inner planets from late bombardment.

So that also covers the origin of the Earth, and all the things that lead up to it.

And again, I just don't see where the chain of evidence is broken.

[Schneibster]

Is there anybody here who doubts dark matter or dark energy, or any of the recent results with WMAP and COBE?

For that matter is there anybody here who even knows what those are?

And everybody understands the Hubble Space Telescope has achieved its mission with flying colors and done a bunch more stuff that its original planners never envisioned, right? And that that mission was to determine the value of the Hubble Constant, the increment in speed of recession we see varying with distance.

I keep meeting these "religious people" who think the universe is like a thousand miles across with cellophane across the top, like a terrarium or something.

[Schneibster]

So folks here understand that all the visible matter in the universe is concentrated in a sort of "froth" around huge empty holes tens of billions of light years across, right? That our local group, a few tens of millions of light years across, with three big galaxies (Milky Way, M31 in Andromeda, and M33 in Triangulum) and maybe a hundred little irregular ones, is part of the Virgo Supercluster, perhaps ten billion light years thick and twenty or thirty billion light years wide, between two of these huge voids, right?

We truly live on spit in the ocean of night. The simile is irresistible. We exist on a thin film of froth on the edges of enormous empty spaces. That is the geometry of the universe. The filamentarians won.

[Schneibster]

And we're all clear on how stars burn nuclear material into more and more complex nuclei, and how then when they go supernova they have enough energy to make elements that are beyond the bottom of the packing fraction curve, right? So everything lighter than iron is more plentiful than everything heavier?