Kevin's Watch

Nathan, it breaks my heart that you know so much about this stuff, but are so confused about free will.

Ooooh, I can't believe... Ooooh! Just... Oooooh!

Nice One!

--A

Hey, any astronomers here? Here's the next question:

If something like the Hubble Telescope can see a galaxy 15 billion lightyears away, that means they're seeing the galaxy as it existed 15 billion years ago. But isn't that WAY too soon after the Big Bang for there to have been galaxies?? It's gotta take billions of years for a galaxy to form, wouldn't you think? How far away is the farthest galaxy we've seen, and what's the current estimate on the age of the universe?

NASA's Wilkinson Microwave Anisotropy Probe (WMAP) project estimates the age of the universe to be:

(13.7 ± 0.2) × 109 years.

That is, the universe is about 13.7 billion years old, with an uncertainty of 200 million years. However, this age is based on the assumption that the project's underlying model is correct; other methods of estimating the age of the universe could give different ages.

en.wikipedia.org/wiki/Age_of_the_universe

The oldest galaxy yet found was discovered in 2004 by scientists at Caltech using the Hubble Space Telescope and the Keck telescopes. This protogalaxy, imaged when the universe was about 750 million years old, contains only about 1 million stars. It is visible from this vast distance thanks to gravitational lensing due to the Abell 2218 cluster. The great mass of this galaxy cluster bends and focuses the light passing through it, acting as a natural lens in space. (See [1].) This galaxy was displaced by galaxy Abell 1835 IR1916 as the most distant galaxy ever seen by humans.

The existence of such old protogalaxies suggests that they must have grown in the so-called "Dark Ages" (before the first generation of stars) from anisotropic irregularities present during the era of recombination, some 300,000 years after the Big Bang. Such irregularities of the right scale were observed using the Wilkinson Microwave Anisotropy Probe (WMAP) in 2003.

en.wikipedia.org/wiki/Galaxies

The following recent news on CNN reports the age of the universe at 13.7 billion years.

The big bang's 'smoking gun'

(AP) -- By the faint cosmic glow of the oldest known light, physicists say they have found evidence that the universe grew to astounding proportions in less than the blink of an eye.

In that trillionth of a second after the big bang, the universe expanded from the size of a marble to a volume larger than all of observable space through a process known as inflation. At the same time, the seeds were planted for the formation of stars, galaxies, planets and every other object in the universe.

Interesting article that. Saw one on the NatGeo site too.

--A

Tell me if I'm understanding this idea correctly.

The visible universe is a 13.7 billion lightyear sphere with the earth at its center. This does not mean that the universe is a 13.7 b/ly sphere with the earth at its center, merely that that's the limit of our current ability to observe. That sphere could be a tiny sphere anywhere inside of a humongously bigger sphere, which has the site of the Big Bang as its center.

Meh?

Sounds good to me, man...except that my understanding is that the Big Bang didn't happen at "one" place you could point to, but that it happened "everywhere" - at all points of space, because it was space itself that burst into existence. Yeah, the "visible" universe could be just a miniscule part of an incomprehensibly larger cosmos, if you accept the inflationary model. I mean, it could be really, really huge - maybe even bigger than the human ego, if that's possible.

Matrixman wrote:maybe even bigger than the human ego, if that's possible.

You watch your language! I'll wash your mouth out with soap, young man!! "Bigger than the human ego," indeed!!!! *hmph*

Ah, that's it - the radiation being used to measure is not the furthest extent we can see, it's the ever-present cosmic microwave background, found at a consistent temperature of 2.7 Kelvin. This is a spectrum of black-body radiation produced from the earliest possible time that such radiation was not immediately lost in interactions with matter, when that universe was around 400,000 years old. This radiation is what is looked at, and the pattern of it - specifically the first acoustic peak - can be used to determine the size of the universe at the time te peak was formed. The time the light would have taken to travel this distance is used to estimate the age of the universe.

It all comes from current big-bang theory, which is consistent with the temperature and frequency range of the background radiation.

Fist and Faith wrote:Tell me if I'm understanding this idea correctly. The visible universe is a 13.7 billion lightyear sphere with the earth at its center.

Maybe. Maybe not.

If we believe that light is subject to Doppler (and we do) and we stipulate that motion is relative (and we do) then light information from very distant objects (which are moving very rapidly away from us) may be travelling at far less than C.

Matrixman wrote:Sounds good to me, man...except that my understanding is that the Big Bang didn't happen at "one" place you could point to, but that it happened "everywhere"

One of the neat things about big bang theory is that, i you postulate an explosion at point X, which causes particles to travel away from X in a distribution of directions and speeds, then, from the point of view of any of those particles, it seems that all the other particles are moving away from them, and that the farther the other particles are away, the faster they are moving away. Just as if each particle was at point X.

So you don't even need to postulate warping of the fabric of space to create the phenomenon that all objects feel as if they are at the center.

The question is: if the universe is finite, then your particle/planet may or may not be at the edge. If you were at the edge, you could observe that you were. Since we cannot see any such thing, either we are in the middlish part of the universe, or the universe is infinite and has no edge.

Maybe the edge in one direction is 13.8 b/ly away, just out of our ability to see. And maybe the edge in the opposite direction is a google ly away. So we're not really near the center of this finite universe, but we have no way of knowing that.

No?

explain please. what was here before the big bang? how did we get something from nothing?

sgtnull wrote:explain please. what was here before the big bang? how did we get something from nothing?

But where did God come from?

Here's that Hawking quote again:

Hawking wrote:Hubble's observations suggested that there was a time, called the big bang, when the universe was infinitesimally small and infinitely dense. Under such conditions all the laws of science, and therefore all ability to predict the future, would break down. If there were events earlier than this time, then they could not affect what happens at the present time. Their existence can be ignored because it would have no observational consequences. One may say that time had a beginning at the big bang, in the sense that earlier times simply would not be defined.

What this is saying is, because of the nature of the Big Bang, we have no way of knowing what existed before the prior to it. Or if, indeed, anything existed. All evidence pf pre-BB was destroyed by BB.


Here's a question. If we could pull it off, and if the universe is finite, could we send a ship to the edge, turn around, and watch the Big Bang take place? After all, we're seeing galaxies as they existed millions or billions of years ago, and Trelaine saw what earth was like hundreds of years ago.

Lore: it seems that God and the big bang are just as credible, since we can not explain either?

Fist: if we had the tech it would be possible, of course that is if speed of light is possible.

I was under the impression that topics in the Loresraat could be discussed freely from a secular/scientific point of view, and that the Close was where the merits of science vs. theological views of the world could be debated.

Matrixman wrote:I was under the impression that topics in the Loresraat could be discussed freely from a secular/scientific point of view, and that the Close was where the merits of science vs. theological views of the world could be debated.

As was I. I was hoping to put an end to it before it got going.

sgtnull wrote:Lore: it seems that God and the big bang are just as credible, since we can not explain either?

That's not my point. You suggested that the theory of the big bang was flawed because of the 'something from nothing' factor. My view is that that the same can be applied to God. I mean there had to be a point where he came to exist.