Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Gordian Knot on 19/12/2011 15:37:30
-
I have been seeing some reports that state that at the farthest distances that we can see, space is moving faster than the speed of light. It has also been said that at the very beginning of the Big Bang, space expanded faster than the speed of light.
Supposedly, anything within "space", is limited by the speed of light. Space itself is the only exception. Am I understanding this information correctly? Is this accepted theory, i.e. most cosmologists would agree? Or otherwise.
And the big Q. Any theories as to why space can travel faster than light?
-
Space is classically empty. A nuthin :)
You want to define it as a 'density'? You gotta fetch an aether. You gotta an aether you ain't main stream.
QM is another color of the horse.
So there..
-
I haven't a clue what stream I am in, I just know I'm swimming upstream. Against a really strong current.
That being said, the information I quoted were not my words, they were the words of cosmologists. Michio Kaku for one. You can debate with him whether he is main stream or not.
I am also confused by your statement that space is empty. It was my understanding that modern theory suggested that "empty space" was actually full of dark energy.
How 'bout throwing a guy a life preserver!
-
I have been seeing some reports that state that at the farthest distances that we can see, space is moving faster than the speed of light. It has also been said that at the very beginning of the Big Bang, space expanded faster than the speed of light.
Supposedly, anything within "space", is limited by the speed of light. Space itself is the only exception. Am I understanding this information correctly? Is this accepted theory, i.e. most cosmologists would agree?
Yes, that's the mainstream theory. Imagine that you're driving a car over a huge sheet of rubber. You mark your starting spot, and zoom off at top speed, then mark your finishing spot. If the rubber hasn't stretched, the distance between them agrees with what you would calculate from your speedometer multiplied by the time it took you.
Now imagine someone is stretching this sheet out as you move. The distance between your start and end will be larger than it was in the previous case. This means that you appear to have moved further then you would calculate from your speedometer, even though at any instant in time you know that your speedometer is accurately measuring how fast you're moving over the sheet right beneath your car. The thing is that if the entire sheet stretches, the endpoints of your trip can move apart faster than your car can drive over the sheet.
This is similar to how points can move apart faster than light in space. Imagine light like the car: it has a speedometer that measures how fast it goes over the region of space it's currently occupying, and that is always constant for light in a vacuum. But if space is stretching then the endpoints of its trip can be moving apart faster than the speed of light.
-
JP, are you a popular science author. If not, perhaps you should be. If you are, please point me towards some of your books.
-
Sorry GK, Space is a weird thing.
It's either 'empty' as in creating no resistance or friction, but on another level full with 'bosons' of different kinds, or 'energy'. If we assume that there is one ultimate fluffiness, then 'energy' should be it, possibly :) But 'energy' is also a description of transformations, so maybe 'bosons' is better? Or 'fields' perhaps, as another description?
But the space we all see normally and, well, see? isn't there for us at all. So when 'space' grow :) it 's sort of contradictory. Something not 'there' but 'growing', or 'expanding'. The reasoning behind the expansion seems to be that we have this 'energy', and from a very small plane that 'energy' that makes up the 'space' we see then isn't the whole story. It's in a equilibrium for us macroscopically, but when zooming in on 'space' the idea is that you can have energies that's below the 'space' we see, as well as above. Those 'negative energies' as they are 'under our visible space' macroscopically can then be all kind of things. They can, as i understand it, be responsible for a expansion, they can also become what we call Higgs field. The 'expansion' here being some sort of transfer from our normal 'positive energy' into the 'room time geometry', which makes some weird sense to me although I don't understand why we won't notice such a constant, and accelerating, transformation from one 'quantity' energy to a 'hidden' becoming our expanding SpaceTime.
The one thing I see as important is that there is no densities macroscopically in a vacuum. The only thing it can express is 'gravity' that then becomes its 'metric' creating the 3D shape as I see it. Maybe 'distance' as a some property of its own too? I'm not sure there.
-
I have been seeing some reports that state that at the farthest distances that we can see, space is moving faster than the speed of light. It has also been said that at the very beginning of the Big Bang, space expanded faster than the speed of light.
Supposedly, anything within "space", is limited by the speed of light. Space itself is the only exception. Am I understanding this information correctly? Is this accepted theory, i.e. most cosmologists would agree? Or otherwise.
And the big Q. Any theories as to why space can travel faster than light?
As I understand cosmology correctly, it is meaningless to speak of the motion of space. What is meaningful is that space is being created. And since light travels in space and things further away from our galaxy travel faster than things near our galaxy, eventually observers in our galaxy will observer the speed of light increasing with distance. But there is no observer near the light itself who'd measure anything but c.
Best wishes
Pete
-
As I understand cosmology correctly, it is meaningless to speak of the motion of space. What is meaningful is that space is being created. And since light travels in space and things further away from our galaxy travel faster than things near our galaxy, eventually observers in our galaxy will observer the speed of light increasing with distance. But there is no observer near the light itself who'd measure anything but c.
"eventually observers in our galaxy will observer the speed of light increasing with distance."
Is that true? It seems more likely to me that 'time' will adjust in such a way that c will remain constant.
-
Thank you all for your responses. Muchly appreciated!
Yor-On, what kind of particle are you? You know, proton, electron, yoron? :)
PMB, you said that "observers in our galaxy will observe the speed of light increasing with distance. But there is no observer near the light itself who'd measure anything but c".
Are you suggesting that though we see space as faster than the speed of light at great distances, that a hypothetical someone at that far distance will observe the area around them as the normal speed of light?
That would seem to suggest that what we see very far away is an illusion of space moving faster than c. Yes? No? Maybe?????
Another comment that is causing me confusion. You mention that space is being created. It was my understanding that nothing in the universe is created or destroyed, it just changes form. Of course, this gets us back to that whole is-space-a-whole-lot-of-nuthin question. Which only makes it more confusing, as you would seem to be suggesting that "nothing" is being created.
-
:)
Yeah, if it is 'created' and if it is 'fluffy', and if the SpaceTime 'box' has a closed lid then we need to rearrange the 'energies' to fit the new fluffiness. And then we also should see the consequences somewhere. And if it is so then the Big Bang should have been the ultimate enormous rearrangement of fluffinesses. I admit that I might express this in mucho too complicated manner, but if considering 'sheepies comb', a well known expression in TNS circles, we find that this rearrangement either is totally wrong, or else, explains it all. Which one to choose?
Don't ask me, ask someone that knows..
God?