"The Universe" on the History Channel

[jluetjen]

Originally Posted by Rick Lee

It was just the reversal of the Big Crunch. The previous universe's expansion ran out of steam, slowed and then reversed itself, pulling all matter back to a central point. Time went backwards and eventually, all matter was concentrated to infinite density. Then it exploded and started the universe we have now. It will eventually repeat itself.

Actually, I believe that measurements now suggest that there will not be any "big crunch", but rather that our existing universe will continue to expand and cool forever. I posted a summary of this research on this thread. So it looks like you can religate the bang-crunch-bang theory to the same dust-bin as the flat earth and the sun-centered universe.

[Superman]

Impossible, John. That would force folks to consider what might have caused the Universe. Hard to respect that question and still deny the existence of God. Not impossible, as we will likely see, but difficult to do.

[jluetjen]

I'll just let that go Superman since I'm not looking to start any fights. I can't speak for others though...

[kstar]

Originally Posted by Superman

Impossible, John. That would force folks to consider what might have caused the Universe. Hard to respect that question and still deny the existence of God. Not impossible, as we will likely see, but difficult to do.

The universe as we know it may just be one of many other constructs in a "multiverse". This is where some scientific hypotheses are headed, FWIW.

Best,

Kurt

[sjf911]

What about the "Big Rip".

http://www.space.com/scienceastronomy/big_rip_030306.html

[Moneyguy1]

Just to set the record straight: Black holes are not "big" They are massive, but in size they are a singularity; a point; infinitely small. The event horizon is another matter. Gravity seems to be the one overall influence on the independent parts of the universe (solar systems, galaxies, etc). The best description of the thing called "timespace" (the fabric of the universe) is not that difficult to conceive, since time and space do not exist independent of each other.

[ckissick]

Originally Posted by frogger

Just dug this up.


Scientists Claim To Break Speed-of-Light Barrier
By Maia Weinstock
Staff Writer
posted: 06:06 pm ET
19 July 2000

This "faster than the speed of light" thing is not accepted as a true speed, as discussed below, from Wikipedia:

"It has long been known theoretically that it is possible for the "group velocity" of light to exceed c. One recent experiment made the group velocity of laser beams travel for extremely short distances through caesium atoms at 300 times c. In 2002, at the Université de Moncton, physicist Alain Haché made history by sending pulses at a group velocity of three times light speed over a long distance for the first time, transmitted through a 120-metre cable made from a coaxial photonic crystal.[7] However, it is not possible to use this technique to transfer information faster than c: the velocity of information transfer depends on the front velocity (the speed at which the first rise of a pulse above zero moves forward) and the product of the group velocity and the front velocity is equal to the square of the normal speed of light in the material.

Exceeding the group velocity of light in this manner is comparable to exceeding the speed of sound by arranging people distantly spaced in a line, and asking them all to shout "I'm here!", one after another with short intervals, each one timing it by looking at their own wristwatch so they don't have to wait until they hear the previous person shouting. Another example can be seen when watching ocean waves washing up on shore. With a narrow enough angle between the wave and the shoreline, the breakers travel along the waves' length much faster than the waves' movement inland."

[SlowToady]

http://science.slashdot.org/article.pl?sid=07/08/16/1621233

Although, I admit, my post was a bit mis-leading, albeit unintentionally. I didn't read the article carefully enough at first, and after a second reading, I found out that the researchers used a computer simulation to figure this. Oh well, still interesting but...

On the subject of Black Holes, a black hole was just found that is ~1 billion light years across. Also on SlashDot.

Also, that German guy who said he broke the speed of light, I read a bit about that and it seems the consensus of other scientists is that this claim has been made before, and it stems from a mis-understanding of the data and what is happening. So, in all likelyhood, c has not been breached.

Originally Posted by }{arlequin

link?

[nota]

the only faster then light thing happening I know of is the universe itself
the space itself is expanding
farther away from each point
and things at very very great distance look to be moving away faster then ''C"
but arenot really moving that fast , just space is getting bigger

the universe is not only stranger then you conceive
it is stranger then you can conceive

[jluetjen]

Huh??? What the 'ell are you talking about? I'm not aware of any observed object moving away at speeds faster then the speed of light. The furthest observations made have been of the Cosmic Microwave Background Radiation (CMB or "CMBR"), which has a redshift of 1089. The furthest galaxy has an unvarified redshift of 10, with the furthest quasar with a redshift of 6.04. In all cases, I don't believe that anything has been observed to be receeding at a speed greater then C, although this observation I guess is possible given the fact that space itself is expanding.

Do you have some sort of a reference to an object that has been observed to be receeding at a speed > C?

[frogger]

My bank account.

[SlowToady]

Mmmm, you're married...

Originally Posted by frogger

My bank account.

[Superman]

There seems to be some misunderstanding here. Black holes have size. Objects at the edge of the observable Universe are travelling near the speed of light, but we have no evidence that any are moving faster than light. Indeed, we have no conclusive evidence that anything has or can move faster than light. And....

perhaps I am trying to start a fight. Depending on your definiton of "fight." I'm interested in discussing stuff John, and any input you have is fair game. You may have been considering my assertion that a number of folks are going to be very slow to accept a scientific theory that gives the Universe a "birth." That's my expectation, and it seems to be coming to pass. When a person takes the position that there is no influence on the Universe from the outside, and that the only mechanisms we need to recognize are the laws of physics, then it becomes challenging to pose that everything in the Universe is subject to causation except......the Universe.......with just one fascinating theoretical exception. The exception is that the Universe had no cause. No beginning. No birth. Even then, assuming a Universe that was never born and never dies, we still have a (some would say) weak theory that the Universe is the only uncaused cause. That (some say) weak method of negating the presence of a cause of the Universe falls apart if we find out that there was a time when the Universe as we know it did not exist, and a moment later when it did. I'm not suggesting you defend any particular position, but if you are inclined then please do.

[frogger]

Why not keep an open mind and see where the chips fall? That's the ideal scientific approach. I only see a fight in terms of accepting the evidence supporting a particular hypothesis.

[sjf911]

The most distant observable objects are not moving through space any faster than we are. Rather, the intervening space is expanding and creating a "relative" motion or speed. Objects beyond the observable limit may well be traveling at relative speeds greater than C but not violating C.

[ckissick]

Originally Posted by sjf911

The most distant observable objects are not moving through space any faster than we are. Rather, the intervening space is expanding and creating a "relative" motion or speed. Objects beyond the observable limit may well be traveling at relative speeds greater than C but not violating C.

Exactly. As always, the best way to visualize this is with a balloon. Blow it up to a small size, and draw a few dots on it. Now blow it up larger, to twice the size. As it grows in size, the dots get farther apart from each other.

If you are an ant standing on one dot and observing the closest dot to you, X units of distance away, it moved away to a distance of 2X when the balloon doubled in size. Another dot that started out 2X from you would then have moved away to a distance of 4X. The first dot moved 1X from you, but the second dot moved 2X from you. And they moved over the same time period, so the more distant dot appeared to move faster. In fact, they are all moving at the same speed, as measured from a common reference frame.

On the scale of the universe, the most distant objects appear to be receding at a speed greater than c.

[scottmandue]

Originally Posted by frogger

Why not keep an open mind and see where the chips fall? That's the ideal scientific approach. I only see a fight in terms of accepting the evidence supporting a particular hypothesis.

NOW THATS JUST CRAZY TALK!!!

On a side note NOVA on PBS is running a series on the big bang/origins of earth/origins of life... do you suppose they are trying to compete with the History channel?

CAGE MATCH! HC Vs PBS!!!

[jluetjen]

Originally Posted by ckissick

On the scale of the universe, the most distant objects appear to be receding at a speed greater than c.

I understand that theoretically this is possible, but you are stating it as an observable reality. Could you please produce a reference to something that appears to be receding at a speed greater then c? A picture better yet!

[Superman]

Relativity is certainly confusing. It also seems to defy certain beliefs about physics. For example. imagine objects A, B and C are aligned.

A---------------------B-----------------------C

Imagine that object B is receding from Object A at 60% of the speed of light. Imagine object C is receding from Object B at 70% of the speed of light. And so, one might conclude that Object C is receding from Object A at a rate in excess of the speed of light. But......that's not the case. In reality, Object A and Object C are receding from each other at about 80% of the speed of light. That's from the perspective of both C and A.

It HAS to be this way. Particularly if, as Einstein said, things like mass and speed are observer-dependent. If not, then when we notice quazars directly over the North Pole receding at nearly the speed of light, and quazars directly over the South Pole doing the same thing, we'd conclude that those quazars are receding from each other at nearly twice the speed of light. And we'd be wrong. At least, from the perspective of the quazars.

My personal belief is that reports of stuff travelling faster than light.......are misinterpretations.

[ckissick]

Originally Posted by jluetjen

I understand that theoretically this is possible, but you are stating it as an observable reality. Could you please produce a reference to something that appears to be receding at a speed greater then c? A picture better yet!

It's not happening theoretically, it's happening in reality, and it's an observable reality. But nothing is moving faster than c, it just looks like it. The expansion of the universe is what makes possible the perception that objects are moving at faster than c. With the balloon analogy, the ant sees the neighboring dots moving away, and on a balloon, they are. But the balloon is also expanding. On the scale of the universe, when Einstein's theories come into play, it's the expansion of the universe that matters.

Read the link below, and notice the second paragraph that says,

"Because it is the metric defining distance that is changing rather than objects moving in space, this expansion (and the resultant movement apart of objects) is not restricted by the speed of light upper bound that results from special relativity."

http://en.wikipedia.org/wiki/Universe_expansion

So, you ask, if some distant part of the universe appears to be racing away from us at faster than c, then how can the light reach us? This is where it gets complicated, and I don't have room to explain it here. Also, I have no idea how to answer such a question.