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I was reading a column today from an ongoing article that ended a couple of years ago. It was explaining the basics of the expansion of the universe. In the article, it adresses the question "are there galaxies that are moving away from us faster than the speed of light?" they answer, that yes, the distance between us and those galaxies is growing at a faster rate than the speed of light. If that statement is true, how is it that we would be able to observe these galxies if the distance between is us growing more quickly than the light can cover it?
The space itself has increased in scale. The galaxy is not moving faster than light. Light can still pass through the space, but the expansion causes red shifting of the light as it moves through.
But there is no experimental proof of an expansion of space. This is a major problem in my opinion.
Expansion of space is a parameter that is being adjusted according to the observation of redshift. So it is a free parameter.
You can't use redshift vs distance (or time) to say it is in agreement with the theory of expansion of space...
The expansion of space as a parameter is defined by the redshifts vs distances of clusters of galaxies.
A parameter may be a variable in space and time.
Why would space grow/expand?
What is made of to expand?
Could it generate itself?
Is it possible that light get redshifted by yet to be discovered phenomenon?
Like for example: the photon looses small amount of energy as it passes through empty space (or quantum vacuum)?
I wish scientists would rid their vocabulary of the term proof. All too often far too many of them use it in inappropriate ways. If I had it my way you'd have to have a license to use that term.
It's actually mathematicians and lawyers who misuse the word.
Etymologically it derived from the latin probare, to test (e.g. with a probe!) . Experiment is indeed proof (as with proof spirit, and proof-tested gun barrels), and exceptio probat regulum makes sense.
NASA Finds Direct Proof of Dark Matter (...)"A universe that's dominated by dark stuff seems preposterous, so we wanted to test whether there were any basic flaws in our thinking," said Doug Clowe of the University of Arizona at Tucson, and leader of the study. "These results are direct proof that dark matter exists." ect proof that dark matter exists."
proof - a : the cogency of evidence that compels acceptance by the mind of a truth or a fact b : the process or an instance of establishing the validity of a statement especially by derivation from other statements in accordance with principles of reasoning etc.
It's expansion means that there is simply more of it being created as time progresses.
You mean to say that space is something that it is being created?
What do you mean by "more of it"? You mean that in the past it was less of "it"?
In the article, it adresses the question "are there galaxies that are moving away from us faster than the speed of light?" they answer, that yes, the distance between us and those galaxies is growing at a faster rate than the speed of light. If that statement is true, how is it that we would be able to observe these galxies if the distance between is us growing more quickly than the light can cover it?
1. Expansion of the universe.Is expansion of the universe the outward moving of mass and energy from the centre of the universe (if there are such things) or does this mean that every little 'bit' of space is growing including the space between elementary particles (if considered as 'static')
but any premise of not being able to see things means they must be traveling away fromHowever if ALL space is expanding (using the balloon theory) then we could surely measure this looking at subatomic particles.
3. Regardless of expansion, if the relative velocities are less than double the speed of light we would get some form of observation.. and theres no point saying things cant go faster than the speed of light.. if I travel 2/3c in one direction and something traveled 2/3c the opposite then our relative velocity would be greater than the speed of light (4/3c) but then neither of us ARE travelling faster than light, and a signal fired from him would eventually reach me
That's not how velocities add in SR.
However if ALL space is expanding (using the balloon theory) then we could surely measure this looking at subatomic particles.
Quote from: PhractalityThat's not how velocities add in SR. Itís unclear from what he wrote who was doing the measuring/observing of the motion. Thatís why I ignored it. He very well could have meant that as measured in frame S there is an object moving in the Ėx direction with speed v = -2c/3 as measured in S and one moving in the +x direction with speed v = 2c/3 as measured in S and the relative speed of one body with respect to the other is 4c/3 as measured in S. Since no body is moving FTL then thereís no conflict with relativity.
While the distance between the two, in S, is growing at a rate of 4/3 c, that is not a velocity as velocity is defined in SR or in GR.
Sorry I framed my questions badly, as I was interested in the same thing with my own thoughts..