Astronomy / Space Is the universe expanding faster than the speed of light?

[NoahRyan]

Current theory states the universe is 14 billion years old and 46 billion light years radius. Does this mean expansion is occurring faster than the speed of light? Does this contradict relativity? Does it mean it is impossible for light to travel to the other side of the universe? (barring wormholes or other FTL travel).
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[Steve]

Any budding Stephen Hawkings got the answers here?

 

[tvrobyn]

Current theory states the universe is 14 billion years old and 46 billion light years radius. Does this mean expansion is occurring faster than the speed of light? Does this contradict relativity? Does it mean it is impossible for light to travel to the other side of the universe? (barring wormholes or other FTL travel).

Short answer... No. Lightspeed is a constant 'c', and as such using Einsteinian laws remains the same throughout the multiverse. If you were to sit at any point at our galaxys edge with a sufficiently powerful telescope you would see clear across to the other edge- barring of course nebulae, anomolies which blur or distort vision, and gravitational bending .
Hope that helps.
also there is a theory that cosmic expansion is powered by 'dark' energy, which brings up other ideas and theories. Have you seen the NASA warpship? The theory is that it moves by 'warping' space using amounts of energy, like when you place a toy in the sink and drop small amounts of detergent into the water behind it. And in a cool way it looks like the Vulcan starships from Enterprise.

 

[tvrobyn]

I'm such a geek! LOL

 

[Steve]

I seem to remember reading somewhere that in the first split second after the Big Bang, the universe expanded at many times the speed of light. So it looks like the speed of light cannot be exceeded, except when it did. :S

 

[tvrobyn]

I seem to remember reading somewhere that in the first split second after the Big Bang, the universe expanded at many times the speed of light. So it looks like the speed of light cannot be exceeded, except when it did. :S

In that instance gravitational forces caused the big bang, and at that instant gravity didn't abound everywhere in the baby universe, just lots of intense heat.

 

[Steve]

In that instance gravitational forces caused the big bang, and at that instant gravity didn't abound everywhere in the baby universe, just lots of intense heat.

Yeah, but did it expand faster than the speed of light? That's what the OP was getting at. That things can move faster than c.

 

[tvrobyn]

Yeah, but did it expand faster than the speed of light? That's what the OP was getting at. That things can move faster than c.

The current theory says that yeah that's true. Then gravity abounded and slowed everything right down.
The theory is that gravitational TWISTING caused the big bang. Stephen Baxters Ring series has some great ideas as does The Time Ships by the same author. Schrodingers cat and Schrodingers kittens by Matthew Gribbin I think would be a good read for anybody.
Theres another theory that says Time,Space and THOUGHT are unified. Kind of like 'the Force', basically you can go as fast and as far as you'd like. We just have to learn to build THAT engine...

 

[SuperG]

Short answer... No. Lightspeed is a constant 'c', and as such using Einsteinian laws remains the same throughout the multiverse. If you were to sit at any point at our galaxys edge with a sufficiently powerful telescope you would see clear across to the other edge- barring of course nebulae, anomolies which blur or distort vision, and gravitational bending .
Hope that helps.
also there is a theory that cosmic expansion is powered by 'dark' energy, which brings up other ideas and theories. Have you seen the NASA warpship? The theory is that it moves by 'warping' space using amounts of energy, like when you place a toy in the sink and drop small amounts of detergent into the water behind it. And in a cool way it looks like the Vulcan starships from Enterprise.

My short answer.

Lightspeed is a constant in fabrick of space time.

But what is expanding. Expansion of the fabrick of space time? Wich doesn't brake the constant.

But knowings so means that if expansion from the two oposit sides off the universe is at a level that lighspeed can't compensate that. So asume that Light never reach the other border. But that also not true. Light goes from galacy to galacy. Where between the expansion is a fraction of the total expansion. so the distance get shorter so the expanding factor to.
To a point wenn the left over distance doesn't expand the rate of C. Wenn reach that cross overpoint then border is reachable.

But I wonder does it expand at that speed.
But then there this the expansion accelleration.

 

[Eckhart]

I have certainly listened via the tubes to Stanford Physics Professors (Leonard Susskind in particular) that yes indeed, parts of the Universe are moving away from hereabouts faster than the speed of light due to the expansion of the space between.

I would certainly recommend the Stanford University YouTube channel.

Brady Harans deepskyvideos channel may also be of interest.

 

[Giskard]

Star Gazing Live mentioned that indeed the universe IS expanding faster than the speed of light. But as someone else mentioned, it's space-time that is expanding at that rate (picture 'inflation) - the galaxies themselves are not actually flying apart from each other faster than light (because that would violate Einstein's theory).

 

[Magma]

Recent studies have mapped all of the galaxies around us and their relative positions and found that their distribution is completely even. So either we happen to be coincidentally at the centre of the entire universe, or the entire universe is evenly distributed. Given that the latter is the most likely probability, it means that the universe must have no edge and therefore is of infinite size, was always infinite in size since the beginning of the Big Bang, and yet is somehow expanding. The distance between galaxies is expanding, and between some galaxies this expansion may appear to exceed the speed of light, but the galaxies are not locally travelling at relativistic speeds so no laws are violated.

I can thoroughly recommend looking at http://scaleofuniverse.com/ to get an idea of the silly scale of thought this is all working at.

"There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened." - Douglas Adams, The Hitchhiker's Guide to the Galaxy

 

[Cmdr Andy B]

slap me if i'm being silly but if Gal A is moving this way < at .99 c and galaxy B is moving that way > at .99 c doesn't that mean that they are moving away from each other at 1.98 c but neither is exceeding light-speed?

apply that to the universe and the western edge is moving at .99c away from the center while the eastern edge is moving away at .99c from the center. therefore the western edge is moving away from the eastern edge at 1.98c and as above is still not exceeding the speed of light.

 

[Magma]

Galaxy A and galaxy B can be stationary, and the space between them expands faster than the speed of light. Welcome to the wonderful world of astrophysics.

 

[Bikky]

My short answer.

Lightspeed is a constant in fabrick of space time.

False

Well if you look at the idea of impossible to travel at the speed of light?

What is the speed of light? It's certainly not constant, as it's proven that gravity will affect its speed and can even warp it.

If you don't think this is the case, why can you not see the centre of a black hole? Because gravity is too strong for light to escape.

Therefore light Isn't the fastest thing. In the Immortal words of Terry Pratchett, "Darkness was there first" so maybe its impossible to reach the speed of dark.

But back to the original, It would mean ED style space travel in the future is possible with an Event Horizon style ship engine. Probably named after that PONR on a black hole. The event horison is the last line where you can escape the gravity well.

 

[Geraldine]

Interesting discussion, but it appears it was started by a spam bot. Not the first time this has happened Anyways, since you are all so involved in it, I left the original post in place minus the spam nonsense and sadly, "NoahRyan" will be unable to reply to your posts from now on.

 

[Davidtq]

Being the luddite I am, the speed of light in a vacuum being a magical speed limit has never sat well with me.

Nor have I found the arguments of super-luminal travel resulting in time travel to be particularly persuasive.

Im also almost certain that a degree of controlled time travel is a possibility.

3 major scientific heresies in one post. Fortunately I can just be written off as simple and uneducated.

 

[Magma]

Im also almost certain that a degree of controlled time travel is a possibility.

It is more than a possibility, it is practically mandatory. I am currently travelling through time roughly at a fairly controlled rate of one second per second.

 

[Davidtq]

It is more than a possibility, it is practically mandatory. I am currently travelling through time roughly at a fairly controlled rate of one second per second.

Well you see my futureself vistied me at 18 and told me that I invented a time travel machine at age 40 and that pizza was the key.

I was quite peeved actually because damn had I put on weight...

 

[JKF]

Two galaxies, each at opposite sides of the universe, moving away from each other at 10000 miles per second.

A civilisation in Galaxy A sends a ship in the opposite direction from Galaxy B.
A civilisation in Galaxy B sends a ship in the opposite direction from Galaxy A.

Both ships eventually attain a speed of 185000 miles per second relative to their respective point of origin. So neither ship has broken their own law of relativity; each ship, from point of origin, has not exceeded the speed of light.

But...

The Galaxy A ship is travelling away from Galaxy B at 195000 miles per second.
The Galaxy B ship is doing likewise.
So from opposing galaxies the ships are travelling faster than the speed of light, yet no law has been broken.

And, the Galaxy A ship is travelling away from the Galaxy B ship at 380000 miles per second; let's hope Einstien isn't on one of those ships

On top of that, if we are between Galaxy A and Galaxy B, and we'd sent a ship to each of them, would our ships not be able to travel with their ships or would our ships be 5000 miles per second slower?