New Theory Suggests Start of Universe

AP via Yahoo! ^ | January 8, 2002 | Paul Recer

[Scully]

I don't like it. So you can call me "Captain Crunch" because I want things to start over again. And again.

Me too! Let's hope we find that "missing mass" soon.

[Karl_Lembke]

bump

[JoJo the Clown]

plain talk, no it isn't. Explosions normally spew out debris non-uniformly because of (a) non-uniformity in the original explosing mass, and/or (b) differences in the surrounding environment that affect the path of the exploding mass. But that wouln't apply to a singularity, which by definition, would be homogenous and without an "environment."

[Doctor Stochastic]

The human mind isn't large enough for such a notion.

Speaking for yourself, of course. The expansion isn't very hard to describe. What's important is that expansions (and curvatures) of a manifold can be detected locally. (Result due to Gauss) The surface of a sphere has no center (or corners). If the sphere is expanding, points will move away from each other.

[JoJo the Clown]

Sorry, that doesn't answer my question. The issue IS how a singularity can become a universe that is in fact, non-uniform, without resorting to an explanation that requires an external influence on the distribution of matter from the singularity. Quantum mechanics does NOT explain the resulting non-uniformity. No one has ever adequately explained how non-uniformity can result, but I gave you a shot. I thought I would let you take a stab at it anyway.

[Physicist]

Quantum mechanics does NOT explain the resulting non-uniformity.

Yes, It Does!

Let's assume a totally uniform distribution of energy. With a high enough energy density, particles will be pulled out of the vacuum. This is an intrinsically random process; the particles will not appear simultaneously on the points of a lattice^*, but will have a random distribution. Random distributions by nature have areas of differing density. As in the distribution of cancer cases in the U.S., the dense lumps don't require a cause. Any resulting lumps will be amplified by the effect of gravitational collapse.

---

^*Moreover, even if the particles did appear on the points of a lattice, there may still be a "handle" upon which gravity could act, because you cannot have a lattice that is free of multipole moments to all orders. The resulting non-uniformities may be of regular size, shape and spacing, but they'd exist. It all comes back to the fact that a particle, by definition, is itself a localized (read: non-uniform) concentration of energy.

[waterstraat]

Here's my question. Assuming that the farthest thing away from us is 14 billion light years distant, and the universe is 15 billion years old, then how fast do stars and other matter have to travel to get that far away? If this object that's 14 billion ly away from us is 7 billion light years from the originating point of the Big Bang, then that matter had to travel at almost half the speed of light to get there. Of course, I'm assuming that this is the maximum distance of any object from us, and I'm not sure that's the case I got news for you. There are stars 14 billion years away from us in all directions, so it is 14 billion years away, not 7.

Furthermore, those stars that are 14 billion years away, are traveling at near the speed of light, so therefore, they are not 14 billion years away, they are 29 billion years away, making a current diameter of 58 billion light years.

The stars that we see that are 14 billion years away, were 14 billion years away, 14 billion years ago. They are now 29 billion years away.

Lastly, what we see that existed 14 billion years ago, is long gone, they no longer exist. No star lasts 29 billion years, or for that matter, no star lasts even 14 billion years. Everything we see out there, has long since burned out.

[waterstraat]

I was trying to give you a three dimensional visualization of a multidimensional expanding space-time. Why objects appear to be moving faster as the distance from us increases.

Check out the National Geographic Map of the Universe. First published around june of 1983 or so, it is an excellent 3 dimensional map of the total universe. It is so good, even a preschooler(mine did) can understand and visualize the entire universe, and where we are in it, and where all the known galaxies are, and so forth.

[RadioAstronomer]

I have that map. :)

[plain talk]

I am no phyicist but I know that neither you or I know the structure of this so called singularity and whether IT was homogenous or not at a sub-atomic level prior to the big bang. The concept of the big bang producing an explosion where matter was not spread uniformly is perfectly consistent with what we have observed and makes complete sense. The particles flying out of the big bang explosion could have had different velcoities so that any initial uniformity quickly degraded into non-uniformity etc Not sure why you are homing in on this particular point anyway.

[AndrewC]

The particles flying out of the big bang explosion could have had different velcoities so that any initial uniformity quickly degraded into non-uniformity

You both might want to read the following Inflation for Beginners. It addresses the complexity/uniformity problem.

excerpt: The theory said that inflation should have left behind an expanded version of these fluctuations, in the form of irregularities in the distribution of matter and energy in the Universe. These density perturbations would have left an imprint on the background radiation at the time matter and radiation decoupled (about 300,000 years after the Big Bang), producing exactly the kind of nonuniformity in the background radiation that has now been seen, initially by COBE and later by other instruments. After decoupling, the density fluctuations grew to become the large scale structure of the Universe revealed today by the distribution of galaxies. This means that the COBE observations are actually giving us information about what was happening in the Universe when it was less than 10^-20 of a second old.

No other theory can explain both why the Universe is so uniform overall, and yet contains exactly the kind of "ripples" represented by the distribution of galaxies through space and by the variations in the background radiation.

[Old Professer]

Speaking for yourself, of course. The expansion isn't very hard to describe. What's important is that expansions (and curvatures) of a manifold can be detected locally. (Result due to Gauss) The surface of a sphere has no center (or corners). If the sphere is expanding, points will move away from each other.

I was hoping someone would say this; what you propose then, is a topographical universe with no core or center whatsoever, right?

Is it then hollow?

[Old Professer]

*Moreover, even if the particles did appear on the points of a lattice, there may still be a "handle" upon which gravity could act, because you cannot have a lattice that is free of multipole moments to all orders. The resulting non-uniformities may be of regular size, shape and spacing, but they'd exist. It all comes back to the fact that a particle, by definition, is itself a localized (read: non-uniform) concentration of energy.

By this definition there is no uniformity; it must all be an illusion.

[Physicist]

By this definition there is no uniformity; it must all be an illusion.

The gauge theories of particle physics suggest that there is a "natural" scale of order the Planck length. It is entirely possible that the objects we take to be pointlike are actually extended somehow over a scale equal to the Planck scale. (Many "theories of everything" such as superstring theories exploit this.) Back when the radius of the universe was of this order, I could imagine a state of true and perfect uniformity.

[waterstraat]

I have that map. :)

Which version? It has been updated at least once, with different galaxies and clusters and Quasars on the updated one. Write to Nat'l Geographic and get a new updated copy with different items added. A great map!

[Doctor Stochastic]

Is it then hollow?

No.

[longshadow]

cosmic density fluctuation bttt & lurking placemarker

[RadioAstronomer]

Cool!! :) Thanks for the tip.

[Hajman]

The gauge theories of particle physics suggest that there is a "natural" scale of order the Planck length. It is entirely possible that the objects we take to be pointlike are actually extended somehow over a scale equal to the Planck scale. (Many "theories of everything" such as superstring theories exploit this.) Back when the radius of the universe was of this order, I could imagine a state of true and perfect uniformity.

Would you happen to be speaking of supersymmetry?

-The Hajman-

[Hajman]

Old Professer: Is it then hollow?

No.

Actually, it depends on how you look at it. Some theories have a tendancy to look at our space as three space on a four space hyperplane, in which case the universe would in fact be hollow.

-The Hajman-