All right, so nothing is supposed to be able to travel faster than light, right?
Supposedly, when the Big Bang occurred, the universe expanded from a singularity (with zero radius) to a larger size several (thousand?, million?) light-years in diameter. All of this occurred in a fraction of a second. Explanations?
“I don’t want to achieve immortality through my work… I want to achieve it through not dying.”
– Woody Allen
Where did you hear that? Sure, the monoblock got a lot bigger in the first seconds, but I never heard anyone say light-years bigger.
Last I heard (and I fully expect to be corrected by the real physicists on the board) the inflationary period ended with the Universe being about the size of a grapefruit. As if size were a valid concept in the early stages of the Universe.
IIRC, the inflation theory was proposed specifically to avoid problems with special relativity. The universe is too uniform, which meant the various parts had to be in contact with each other when they should have been relativistically separated. So physicists cooked up the inflation theory to allow the parts to mingle long enough to establish the proper uniformity and then inflate to create the proper size that we find today.
I’m probably talking through my hat about this next bit but the universe didn’t just suddenly get larger – it inflated. The distinction is that inflation wasn’t an event that took place in space and time – it was that the nature of space and time changed. Something like that. Next time I see Stephen Hawking I’ll ask him again.
Relativistically,
pluto
If man was meant to fly faster than the speed of sound he would have been born with 50,000 pounds of thrust.
I would LOVE to be a physicist! In my next life I will definately take those courses. Imagine, if your theories don’t match observed reality YOU GET TO CHANGE REALITY! Superstrings, inflationary events, whatever you need to get your equations to balance YOU CAN CREATE! Beyond cool…
Dr: Have you considered accountancy?
Livin’ on Tums, Vitamin E and Rogaine
If man was meant to fly faster than the speed of sound he would have been born with 50,000 pounds of thrust.
I knew I had heard this somewhere, so I spent a little time surfing and found out where I heard it from.
In the early 1980s, Alan Guth, a professor at MIT, suggested a new epoch should be added, known as the inflationary epoch, lasting between 10^-35 and 10^-24 seconds after the beginning of the universe.
One characteristic of his inflationary epoch was as follows:
Here’s a link to a page describing his book.
http://www.bkstore.com/mit/fac/guth.html
It seems to be widely accepted in the scientific community. It does in fact propose the universe expanded at speeds greater than the speed of light. I just couldn’t find anything describing how this occurs. Anybody???
John Moffat theorizes the speed of light was faster at the beginning of the universe. And has slowed down to the speed it is today. Speed of Light May Not be Constant
The problem is that the universe is so smooth and regular. This homogeneity had to date back to the very early universe. Even when the universe was so much smaller, there is a problem that points far distant, even then, from each other somehow had to (excuse the anthropmorhisizing) “know” what each other’s average temperature and density was. It was this equalization of temperature and density of the early universe that was somehow communicated at a speed faster than light.
However, I have a guess. First, dismiss the idea that the Big Bang was like some cartoon bomb exploding outward into a pre-existing void. Time and space and the other 6 or 7 dimensions were created/expanded/inflated from some quantum fluctuation into our friendly mipsman-loving universe that we know. But at some kind of boundary condition to the space time continuum (hate to say it but “the edge of the universe”), there is no requirement that any physical laws need hold especially the speed of light. So a point at one end of the universe need only communicate its temperature and density to the edge and the edge could instantly communicate and equalize those conditions to all points in contact with the edge. The smoothing process could cover the universe at faster than the speed of light. I thought of this based on a lab experiment I did at UCLA. They have a great cosmology lab. (Just kidding, it was an engineeering lab.)
The limit of the speed of light applies to matter/energy/particles/waves in the universe. In the inflationary theory, the universe itself expands. Think of the analogy of a pond, with waves travelling at a fixed speed. The pond itself suddenly gets larger, faster than the waves themselves travel. How? I don’t know.
The problem with the uniformity of the universe is that when you look at very great distances in opposite directions, the universe is very uniform. The universe isn’t old enough for light or anything to haev got from one side of the universe to the other, so there is no reason to expect such uniformity.
It is too clear, and so it is hard to see.
I have a related question: It’s believed that the universe is expanding today because distant galaxies exhibit a severe red-shift, meaning they’re flying away from us so fast, their light has been stretched out and they appear more red than they really are.
Has anyone detected a galaxy that is blue-shifted, coming toward us at high speed?
And if all galaxies suddenly become blue-shifted, does that mean the sky is falling?
Those who do not learn from the past are condemned to relive it. Georges Santayana
Zen is on the right track. ‘C’ as a speed limit, applies to matter/information/etc. moving through the Universe. There is no rule saying the Universe itself cannot move faster.
Stephen
Stephen’s Website
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Energy moves at the speed of light. Why? It has no mass and it is the nature of energy to move at the speed of light.
Matter cannot move at or beyond the speed of light. Why? It has mass and infinite energy is needed to accelerate something massive to the speed of light.
Space has no mass. Therefore, it seems to me that space can “move” or “expand” at any speed it needs to to maintain the integrity of the universe. It could even stop or change direction instantaneously because it has no mass and therefore no inertia. And any matter occupying that space is simply carried along. Since that matter is moving with space and not through it. the laws of motion do not apply to the mass.
Am I even close to being right? Where’s Undead Dude when you need him?
Those who do not learn from the past are condemned to relive it. Georges Santayana
By the way, there’s nothing stopping matter from going faster than light. It’s just very unlikely. Light speed is an average, not an absolute.
When you’re talking something as small as the unviverse was back then (according to theory) it would have been very easy for mass to go faster than the speed of light for a very short amount of time, for a very short distance. And 10E-34 is a very short amount of time.
Not only that but you get to cancel out a pi with a 3! Boy, the mathematicians hate it when cosmologists do that.
A bit of an inside joke but when I went to university our Astrophyics professor cancelled a pi with a 3 to which a math student exclaimed “You CANNOT do that!”.
What more could you expect from somebody who lets people kick him to the head?
Well, back when they taught just the simple-minded part of physics to engineers, we used to figure that there was something called the Physics Supply Store out there somewhere, where you went to obtain things like ideal gases. That’s probably where all those theory patches and whatever are procured also.
As an engineering student, I never got an account with that place, because I always kept running into reality on the bench, and it never let me use any of those rubber concepts used in cosmology. Cosmology’s kind of neat, though, in how it masquerades as a science and yet seems just to flex with faith in the face of empirics, as it rambles along, ignoring falsifiability.
Ray
jab1 – IIRC, there are blue shifted galaxies, but they have to be nearby (since red shift grows with distance). Galaxies move in relation to each other besides their motion due to the expansion of the universe and a few of them happen to be moving toward our galaxy.
Caveat – this is one of those arcane “facts” stuck in my mind somewhere and I honestly can’t remember whether it was stars or galaxies they were talking about. I know that is not a trivial point. There are certainly blue-shifted objects of some kind out there, but I’m not sure if even nearby galaxies aren’t so far away that they’re all red-shifted.
If man was meant to fly faster than the speed of sound he would have been born with 5000 pounds of thrust.
3 as an approximation of pi?..5???..As a mathematician, I must say…What’s wrong with you people??? 
Mathematicians, always whining. Hey! Listen up!
There is a finite chance that at any time pi = 3 or 5 for that matter.
And the limit of 2 + 3 = 6 as 3 approaches 4.
We can do it cause we’re physicists. Quantum mechanics allows it. And besides, the theory seems to work so why quibble over some trivial .1415926535897932384626…
In QM things dissappear and reappear all the time on their own, electrons go backward in time whenever they feel like it and know the state of the rest of the universe AND WHEN WE’RE KNEE-DEEP IN QUARKS WE’RE NOT GONNA START WORRYING WHETHER THE MATHEMATICIANS LIKE US CANCELLING PI WITH A 3!
Uhhh… I just had 4 physics midterms in 8 days so don’t mind me… but don’t piss me off either or I’ll integrate you from here to infinity like this (snaps fingers).