New Theory Suggests Start of Universe

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

[Physicist]

Is this what's known in scientific circles as the fudge factor?

It's what's known as the extinction function, and it has plagued astrophysics for a hundred years. For example, one of the most important measurements in astrophysics is the measurement of Cepheid variable stars, which have a strong correlation between the period of their variation and their intrisnic brightness. This makes them a "standard candle": if you know how long a Cepheid's period is, and you know how bright it appears to your telescope, you should be able to tell how far away it is.

The only problem is that between here and the distant star, the universe is not exactly transparent. There are molecular clouds that block some of the light from the star, making it appear dimmer--and therefore farther away--than it actually is. This wreaked havoc with galactic distance measurements in the first half of the 20th century, until people learned how to measure the extinction function and correct for it.

In the case of the very earliest stars, the extinction function doesn't affect our distance measurement. (We do that by looking at the redshift.) What it does do is affect our ability to count the earliest stars, and measure their brightness. The universe was a much thicker, murkier place back then, so it's not surprising if we've been underestimating the amount of activity.

[Arthur McGowan]

If you are looking at something you can't see, how do you know?

[VadeRetro]

If there was no "before", then what are the leading non-religious based hypotheses as to how it began?

I see that Physicist has arrived, so if I were smart I'd shut up now.

OK, I'm not that smart. That I can recall from reading the layman's treatments of cosmological stuff, you have the quantum hiccup idea and the multiverse idea. The former says that the universe is a quantum fluctuation with zero total energy. The latter says that some part of a meta-universe sort of collapsed and popped out into our Big Bang to form our universe.

[elfman2]

That I can recall from reading the layman's treatments of cosmological stuff, you have the quantum hiccup idea and the multiverse idea. The former says that the universe is a quantum fluctuation with zero total energy. The latter says that some part of a meta-universe sort of collapsed and popped out into our Big Bang to form our universe.

That's interesting. I think I remember reading a sci fi story many years ago that had us in a 3rd big bang after a series of expansions and contractions. Nevertheless, they're all appear inadequate in addressing the something from nothing paradox.

[JoJo the Clown]

Physicist, would you care to take a stab at answering my question above? What is the explanation for how a singularity becomes a non-uniform universe?

[abandon]

What accounts for the variation in the universe...

Quantum Mechaincs? It introduces randomness into the universe.

[Physicist]

What accounts for the variation in the universe,

Believe it or not, acoustics. I'm sure you've heard that there's no sound in space, but that's because the universe is so rarefied. That didn't used to be the case; sound waves were the main energy transport in the early universe. The result is that you get a characteristic spectrum of density fluctuations. You can see in the following plot just how well the observed fluctuations match the theoretical acoustic spectrum:

and what accounts for the fact that the universe is mostly empty?

Gravitational collapse. The denser areas collapsed into stars, galaxies (and even larger structures), which sucked the matter out of the less dense areas.

I've run a few simulations of such cosmological structure formation using the National Scalable Cluster Project supercomputers here at Penn, using parallel code written by Prof. Paul Bode.

• This animated .gif shows the mass density of a simulated portion of the universe 100 light-years across. Black is lowest density, followed by blue, green yellow, red, and finally white as highest density. Later images show later times, when more structure forms due to gravitational attraction. As the movie plays, the universe ages from 50 million to 12.5 billion years. During this time, our simulation volume actually expands by a factor of 40, but this expansion isn't shown.
• Here is another such universe, showing more resolution (WARNING: 7 MB).
• Here is the first frame of that universe, and here is the last frame.

It's an interesting research topic.

[Pres Raygun]

I took special relativity in college, but not general relativity. Consequently, I have some unanswered question about the expansion of space. How can one distinguish between an object's velocity (movement relative to space) from space itself expanding? Similarily, general relativity accounts for gravity due to space curving, but curving relative to what, meta-space?

[Physicist]

I see that Physicist has arrived, so if I were smart I'd shut up now.

Don't clam up on my account; you're doing fine, and I'm way too busy to field all of the questions today.

[Jay W]

What's beyond space?

A brick wall.

What's beyond the brick wall? It's bricks all the way beyond....

;-)

[Godfollow]

"The whole universe was contained in the Big Bang."

I am no scientist, I am an artist, nevertheless I enjoy thinking on these things and hearing others thoughts and observations. In my way of thinking, if all dimensional space is contained at some "point" along with all the matter of the universe just before the big bang (and is expanding as matter expands) then where was that "point" contained? i.e., what was the field or backdrop for that "point"? Was it nothing? If so, I cannot wrap my mind around nothing where something existed.

I have heard that there are perhaps as many as ten dimensions which make up our universe, of which only three are perceived by our senses, and a forth may be inferred or mathematically shown. This is intriguing but has no other meaning for me other than, that the other dimensions make up what I believe is the spiritual realm.

I do read the Bible, and I believe in God and that He is the mind behind the great expanse of our universe. And not until death will we see the multidimensional reality of our existence. I also believe that the mind that is not prepared to see the face of God, will be forever after separated from His presence. A place where perhaps God called something out of nothing, a place of “outer darkness” as described by Jesus in the book of Matthew chapter 22 verse 13.

[VadeRetro]

Encouraging to hear I'm not making too big a mess of it. I love the stuff you reposted in #47 as a response to the "Information never arises without direction" mantra of the Intelligent Design crowd. The basic forces of physics are direction enough to create lots of complexity, and thus information, at the expense of turning some useable energy into entropy.

[callisto]

This is an artist's impression of how the very early universe (less than 1 billion years old) might have looked when it went through a voracious onset of star formation, converting primordial hydrogen into myriad stars at an unprecedented rate. Back then the sky would have looked markedly different from the sea of quiescent galaxies around us today. The sky is ablaze with primeval starburst galaxies; giant elliptical and spiral galaxies have yet to form. Within the starburst galaxies, bright knots of hot blue stars come and go like bursting fireworks shells. Regions of new starbirth glow intensely red under a torrent of ultraviolet radiation. The most massive stars self-detonate as supernovas, which explode across the sky like a string of firecrackers. A foreground starburst galaxy at lower right is sculpted with hot bubbles from supernova explosions and torrential stellar winds. Unlike today there is very little dust in these galaxies, because the heavier elements have not yet been cooked up through nucleosynthesis in stars. Recent analysis of Hubble Space Telescope deep sky images supports the theory that the first stars in the universe appeared in an abrupt eruption of star formation, rather than at a gradual pace. Painting Credit: Adolf Schaller for STScI

[VadeRetro]

How can one distinguish between an object's velocity (movement relative to space) from space itself expanding?

I think a clue was the way red-shift correlates with distance. Either we're really at the center of the universe and the whole thing is moving away from us or the whole blob is expanding and diffusing. The former position looks attractive to some people but there's a lack of corroborating evidence that our corner of the universe is that special.

Similarily, general relativity accounts for gravity due to space curving, but curving relative to what, meta-space?

You can see the curvature of space when dense foreground objects lens galaxies behind them, or the sun subtly shifts the apparent position (as seen from earth) of a star behind it. Thus, you can say "curving relative to less-curved space." At any rate, this action of mass on space is well documented now.

[Physicist]

If you are looking at something you can't see, how do you know?

The answer to your question is, almost by definition, as broad as empirical science itself.

[callisto]

An interesting article from today relating to the Big Bang from ScienceDaily .

Sun Is Mostly Iron, Not Hydrogen, Professor Says

Manuel says the solar system was born catastrophically out of a supernova -- a theory that goes against the widely-held belief among astrophysicists that the sun and planets were formed 4.5 billion years ago in a relatively ambiguous cloud of interstellar dust.

Iron and the heavy element known as xenon are at the center of Manuel's efforts to change the way people think about the solar system's origins.

Manuel believes a supernova rocked our area of the Milky Way galaxy some five billion years ago, giving birth to all the heavenly bodies that populate the solar system. Analyses of meteorites reveal that all primordial helium is accompanied by "strange xenon," he says, adding that both helium and strange xenon came from the outer layer of the supernova that created the solar system. Helium and strange xenon are also seen together in Jupiter.

More

[VadeRetro]

It is sort of counter-intuitive. Your "point imbedded in what?" question is the early version of "What's outside the universe?" Like "What was before the beginning of time?", these questions are almost paradoxical, hard to even visualize. Either there was always something in some form, somewhere (and my mind has trouble with that) or something somewhere somehow came from nothing (and my mind has trouble with that). For you, God is an answer, but I just find myself asking "Where'd HE come from, then?"

[Physicist]

Consequently, I have some unanswered question about the expansion of space. How can one distinguish between an object's velocity (movement relative to space) from space itself expanding?

You can't, for the same reason that you can't tell the difference between acceleration due to gravity when you're sitting in a chair at home, and acceleration from a rocket, when you're sitting in the pilot's seat. This is known as the "equivalence principle", and there are different formulations of it. It's a big topic.

Similarily, general relativity accounts for gravity due to space curving, but curving relative to what, meta-space?

Have you ever played the game "Asteroids"? If you move your ship past the left-hand edge of the screen, it appears on the right-hand edge; if you move your ship past the top of the screen, it appears on the bottom. The space in which the ship moves, therefore, is shaped like the surface of a doughnut. (Take a rubber sheet and connect the left-hand side to the right-hand side, and you get a tube. Bend the tube around so that the top edge mates with the bottom edge, and you have a doughnut.)

Now, when you're playing the game, where is the doughnut? In what space does the doughnut exist?

[Joe Hadenuf]

Stephen Hawking: He claims that as the physicists on the cutting edge of cosmic theory get closer and closer to the so-called "beginning of time" and look further into the evasive "singularity" theories the more convinced they become that everything is too nice and neat to be purely accidental.

Just like our own planet Earth. We get half a day of daylight, the other half night, to sleep. Water we need to survive falls from the sky. We throw seeds in the ground and up comes the food we need to exist. Its all to perfect to be an accident. Way to perfect.

[Pres Raygun]

Thanks for the reply. I'm not doubting Big Bang Cosmology just trying to understand it better. Your answer to the first question is not completely satisfying. If the Big Bang was an explosion from a single point in space rather than expansion of space, then the observed increasing red-shift with distance would be expected, provided that the pieces continued to accelerate throughout the history of the universe. If this were the case, we would appear to be at the center of the explosion even if we were not.

Regarding the second question, I understand the overwhelming evidence supporting the curvature of space, but any curvature must be relative to some other geometry. I was just wondering how general relativity deals with this other geometry.