If galaxies on the otherside of the universe appear to be moving away at 1/2 speed of light -are we to them?

Question

In otherwords do we appear to be moving away at 1/2 the speed of light?

Answer 1

Hi Itsverystrange

It is actually true that distant galaxies can (and are) travelling away from us at apparently greater than the speed of light. Any galaxies outside our Hubble volume (r = c/H) are apparently receding from us at greater than c - this is why they're outside our past light cone.

There's no conflict with special relativity here because SRT is a strictly local theory. The coordinate system itself is doing the expanding, the galaxies aren't moving with respect to their local coordinates.

Hope this helps!
The Chicken

Answer 2

Yes, and in fact, interestingly, we predict that eventually, some galaxies will be moving away from us at a speed -great than the speed of light-! This is still okay, because it's simply the space between us that is expanding, the galaxy isn't really "travelling" faster than light. We'll know this because (if I've got my head striaght on this) the light from distant galaxies will just go out. Eventually, only the other stars in our galaxy will be visible.

Answer 3

...the galaxies aren't moving with respect to their local coordinates? The galaxies are moving, they are being carried away in an expanding Universe. At a smaller scale, they move along a valley in space that is warped by the gravity in the Local Supercluster, the gravity of the "Great Attractor". The Milky way is orbiting other galaxies in the Virgo cluster at a speed of thousands of kilometers per second. We are moving, aren't we?

Answer 4

Yes, we would appear to be moving away from them at 1/2 the speed of light. It is all related to the Hubble Constant.

Answer 5

This would in fact be true. This is one of the few rules from classical mechanics that does not change as a result of the theory of special relativity. If an object is travelling at a stated velocity with respect to another object, then the initial object can be seen as travelling the same absolute velocity (but in the opposite direction) with respect to the other object.

One needs to realize, however, that this does not mean that the speeds of each galaxy relative to another reference frame in the middle will sum to one half the speed of light. That is to say that each galaxy could appear to be travelling something more like .35c away from a stationary reference frame in the middle of the two galaxies.

Further, I must point out that the galaxies will never appear to be going faster than the speed of light and it will never come to pass that only the stars in our own galaxy will be visible. This violates Einstein's Theory of Relativity. If the two galaxies were to reach .95c in opposite directions of that stationary reference frame in the middle, then they would appear to be going around .99c in relation to each other as opposed to 1.9c. I know I went beyond the scope of the question, but I felt I needed to clear some things up.

EDIT: Just wanted to say thanks to the Chicken for pointing out the changing nature of space itself.

Answer 6

Yes, relative to their position. Just like if you see someone speed away in a car at 60 km/h, to the person in the car it seems as if YOU are moving away at 60 km/h. It's all relative to the observer's point of view.

Answer 7

yes we do. Somehow we don't realise that speed. Soon, as we are speeding up, we will almost reach the speed of light and once upon a time rules of Relativity will apply to us...wait and watch

Answer 8

hi, (ANS) ok!! convinced! it is a very complicated question and that i dont imagine your going to get any definitive (incorrect or properly!) solutions to this one. Why? because any answer will proceed to be in the relms of concept. **As I understand the idea of the tremendous bang, the universe become made out of a singularity experience which occurred 2 hundred billion years in the past. From that instantaneous (enormous bang) all time, matter, area & gravity all started and all the matter in our universe began to enhance outwards in all instructions collectively. As products interior of our universe holiday faraway from us on the speed of sunshine, its no longer the speed of the person-friendly itself that alterations besides the undeniable fact that the gap of the item and consequently the gap the person-friendly has to holiday to achieve us (when we see the item). consequently the added away the item "the older the person-friendly" is because its had to holiday thus far. note: the speed of the person-friendly continues to be a consistent cost. So No! products dont strengthen in p.c. as they bypass faraway from us. they only keep on transferring away on an same consistent p.c., yet as they bypass away we are seing them as older & older. the person-friendly from those products or different galaxies is tens of millions of years previous, going decrease back in time. to be able to summerise this, products we can nevertheless see on the sting of our observable universe through techniques like radio telescopes or with the Hubble deep area telescope. we are watching products created tens of millions & tens of millions of years in the past, of direction some products have receeded a lot that their person-friendly bearly registers with our instrutments because they're so distant & so historic. previous those limits even scientists won't be able to say what takes position out in the primal void, its a organic secret.

Answer 9

Yes.

Answer 10

You would assume so. hmmm yep