What would the world look like during extreme time dilation?

[cosmicalstorm]

I've been thinking about this subject for a while, im not sure exactly how to formulate the question but I'll give it a try.

From what I understand time slows down a lot once you get close enough to c, according to the Wiki entry on Time Dilation the slowdown at extreme velocities would be so great for the traveller that it would be possible to cross billions of lightyears in a human lifetime.

But what would the rest of the universe look like to somebody moving at this speed?

Since so much time is passing by for everbody else, would not the universe look like one of those time travel animations where everything else is moving extremly fast?

In essence, provided the speed was great enough (99%-99.99% of C or even more*) would'nt you be able to actually see the galaxies swirling round and round, planets shooting through their orbits in a blur, supernovas appearing and disappearing in the every second and so on?

Or am I missing something completely, does anyone know enough about this subject to straigthen this out for me?

*Im aware of the immense difficulties involved in reaching these kinds of speeds.

[Junghalli]

One thing you'll notice at high relativistic speeds is the stars in front of the ship would appear heavily blueshifted, while the ones in back would appear heavily redshifted. I imagine at high enough speeds they might be redshifted and blueshifted right out of the visual spectrum, so the sky looks totally dark to the naked eye, but I'm not sure how fast you'd have to go for this to happen, or exactly how fast you'd have to go for the red/blueshifting to be perciptible to the human eye, for that matter.

[Surlethe]

Since so much time is passing by for everbody else, would not the universe look like one of those time travel animations where everything else is moving extremly fast?

In essence, provided the speed was great enough (99%-99.99% of C or even more*) would'nt you be able to actually see the galaxies swirling round and round, planets shooting through their orbits in a blur, supernovas appearing and disappearing in the every second and so on?

No. Time dilation is a "both-ways" proposition: when you're traveling relative to the universe, it sees you slow down -- but from your perspective, the universe is traveling relative to you with exactly the same speed, so it actually seems slowed down to you, not sped up.

It's like a bad "In Soviet Russia" joke.

[cosmicalstorm]

Thats what I get for trying to apply logic to relativity

[Ryan Thunder]

Since so much time is passing by for everbody else, would not the universe look like one of those time travel animations where everything else is moving extremly fast?

In essence, provided the speed was great enough (99%-99.99% of C or even more*) would'nt you be able to actually see the galaxies swirling round and round, planets shooting through their orbits in a blur, supernovas appearing and disappearing in the every second and so on?

No. Time dilation is a "both-ways" proposition: when you're traveling relative to the universe, it sees you slow down -- but from your perspective, the universe is traveling relative to you with exactly the same speed, so it actually seems slowed down to you, not sped up.

It's like a bad "In Soviet Russia" joke.

Augh. I hate Relativity. Not only does it stick a gigantic wrench in any interstellar sci-fi I might write, but it breaks my brain, too...

[Sriad]

Since so much time is passing by for everbody else, would not the universe look like one of those time travel animations where everything else is moving extremly fast?

In essence, provided the speed was great enough (99%-99.99% of C or even more*) would'nt you be able to actually see the galaxies swirling round and round, planets shooting through their orbits in a blur, supernovas appearing and disappearing in the every second and so on?

No. Time dilation is a "both-ways" proposition: when you're traveling relative to the universe, it sees you slow down -- but from your perspective, the universe is traveling relative to you with exactly the same speed, so it actually seems slowed down to you, not sped up.

It's like a bad "In Soviet Russia" joke.

This is... well, it's exactly half right.

The universe in the direction of your travel would be extremely blueshifted and crowded into a small area in front of the ship; exactly how small depends on the speed/degree of time dilation. The blueshifted picture would be moving as much faster as you'd expect: if time on the ship is going by at 1/1000 the relative resting rate,

A simple thought experiment shows why this is the case.

Superman is flying at .9999995 C (giving a relativity factor of almost exactly 1000) toward a globular cluster 10,000 LY from Earth.

-From his perspective it will take ten years to get there.

-One could say there are ten thousand years' worth of light-information "in transit" from the cluster to Earth.

During the first (subjective) year, he will plow through the light it took the globular cluster destination ~1,000 years to emit, and which will fall on Earth over the next 1,000 years. Superman saw 1,000 years of (extremely blue-shifted) time go by in the globular cluster while only one seemed to pass for him. For the entire journey, he is absorbing light radiating from his direction of travel 1,000 times faster than if he were at rest relative to it.

On the OTHER HAND:

When Superman looks back toward Earth for 1,000 subjective seconds, only 1 second's light (Earth POV) catches up with him. The Earth is extremely red-shifted and time appears to be passing 1,000 times more slowly.

[Sriad]

That's what happens when one doesn't properly proof-read.

The bit before the thought experiment should read "if time on the ship is going by at 1/1000 the relative resting rate, [the blueshifted view will be going 1,000 times faster.]" or something like that.

[Surlethe]

Your thought experiment seems sound. I want to think about it some more, but it looks like I was wrong.

[Kuroneko]

One should distinguish between what an observer sees and what the observer measures. Both the origin and the destination will be dilated relative to the ship; time dilation is symmetrical. However, visual effects are not. Similarly, length contraction is also not visually seen because the light registered at any given instant has not been emitted at the same time; visually, objects look rotated rather than contracted (although with some angular distortion due to aberration). The measured length contraction will be apparent only after the observer compensates for the different emission times of the observed photons. It's the same with time dilation.

In general, a spacetime diagram would clear this up. Suppose there are two objects at rest relative to one another in some inertial frame; then we can represent them in the (t,x) plane as lines of x = 0 and x = D, where D is the distance between them. Another object traveling between them, starting from (t,x) = (0,0) has the worldline x = vt, where v>0 is its velocity as fraction of lightspeed. Light signals have slopes ±1, so on the journey between (0,0) to (D/v,D), the object sees light signals from x = 0 (slope 1) emitted from coordinate time interval [0,D(1/v-1)], with a much larger interval for signals from x = D (slope -1).

At γ≫1, Superman would start observing light from 10,000yrs ago at the start of his journey to 10,000yrs in the future (in the rest frame) at the end, meaning he's see about 20,000yrs of information in just 10 years. For γ = 1000., a ±90° field of view from the forward direction would be compressed to just ±acos(v/c) = ±0.0573°.

[Ender]

Your thought experiment seems sound. I want to think about it some more, but it looks like I was wrong.

In truth, you are both wrong. For extreme time dilation everything would be blueshifted to such a high energy state that you would rather rapidly receive a lethal dose of radiation, and thus wouldn't see anything.

[Ryan Thunder]

Your thought experiment seems sound. I want to think about it some more, but it looks like I was wrong.

In truth, you are both wrong. For extreme time dilation everything would be blueshifted to such a high energy state that you would rather rapidly receive a lethal dose of radiation, and thus wouldn't see anything.

Thought it might be like that when I read it, but didn't want to say it.

One thing I hadn't thought of, though; since radiation gets blueshifted, does this mean that I can (theoretically) reduce the ionizing effects of radiation by traveling rapidly away from its source?

[FireNexus]

Wouldn't you still have to worry about the blueshifted CMBR still, though?

[Oskuro]

For extreme time dilation everything would be blueshifted to such a high energy state that you would rather rapidly receive a lethal dose of radiation, and thus wouldn't see anything.

Don't be such a spoilsport, the example uses Superman after all.