Lightspeed Travel Simulation

December 29, 2005 10:52 PM

What would Tübingen look like if you traveled through it at the speed of light?
posted by feathermeat (33 comments total)

What would happen if you played a game of billiards at the speed of light?
posted by Rothko at 11:10 PM on December 29, 2005

I should probably go to bed. I could've sworn this post was about traveling through a turducken at the speed of light.
posted by Gator at 11:11 PM on December 29, 2005

'K, Gator and I are on the same wavelength, and a strange one at that.
posted by moonbird at 11:15 PM on December 29, 2005

Wow. C sure is slower than I thought.
posted by sourwookie at 11:35 PM on December 29, 2005

This happened to me once. I think what they're trying to say is that if you eat enough mushrooms, you too can travel at the speed of light. It works pretty well. And even though they do some crazy math, I can assure ya, it isn't required. Don't let it discourage.
posted by panoptican at 11:38 PM on December 29, 2005

Unrelated to my previous comment, because it's a different comment: this is pretty cool.
posted by panoptican at 11:41 PM on December 29, 2005

What other cities should be experienced very quickly?
posted by longsleeves at 11:56 PM on December 29, 2005

Who would have guessed — kinda looks like a giant Tübe.
posted by rob511 at 11:57 PM on December 29, 2005

Wouldn't it be completely dark, since photons don't have time to reflect off of things, then enter your eye when you are moving as fast as them?

Well maybe a few photons that would be coming directly head on at you, but that's about it right?
posted by parallax7d at 12:51 AM on December 30, 2005

Hey, where's the blue shift? (And red shift, for the things that are behind you.) This isn't right at all.

I don't know what would happen AT lightspeed (it couldn't be good for you), but this video is as you approach lightspeed. The main interesting feature it demonstrates is that your field of view becomes wider as you go faster, where you can eventually see stuff that's actually behind you. You "catch up" to photons coming from an angle behind you.

I don't think things would be any darker as you approach lightspeed; in fact the total rate of photons whacking you in the front would be higher, offset by a lower number of photons whacking you from behind. Imagine riding a motorcycle through the rain. You get much wetter in front (excepting the muddy stripe up your back from the cast off water from the rear wheel).

The feature they miss is that the blue shift should be strongest in the center of your forward view, dropping to neutral for objects perpendicular to your path, then red shifted for objects behind you. Wait. Now I'm not sure where the neutral point would be. But light from the front would definitely be blueshifted, and light from the rear would be redshifted.

It would also be interesting to see yourself approach a mirror at close to lightspeed. Your (bluer, sped up) reflection would arrive at the same place in the reflected scene that you were at a while before. It would be like a visual echo of your arrival.
posted by surlycat at 1:27 AM on December 30, 2005 [1 favorite]

Sorry if this is a dumb question, surlycat, but what are "blue shift" and "red shift"? I tried googling, but I got frustrated after about a million results for some video game.

Do "blue shift" and "red shift" refer to literal color changes? If so--why does that happen?
posted by feathermeat at 1:58 AM on December 30, 2005

No, parallax7d, because light travels at the speed of light relative to any observer regardless of the observer's own speed.

Freaky, I know.
posted by spazzm at 2:16 AM on December 30, 2005

Wow, Light Speed is a lot slower than I thought.
posted by Jeff_Larson at 2:51 AM on December 30, 2005

Red shift. Wikipedia is your friend for stuff like this.

It is to light what doppler effect is to sound (how, for example, a car horn drops in pitch as it speeds past).
posted by Goofyy at 3:29 AM on December 30, 2005

Wasn't this in a documentary?
posted by taursir at 4:54 AM on December 30, 2005

Redshifted light wouldn't necessarily be redder, but the name makes sense because red shift makes the observed wavelength of the light longer, and red light has longer wavelengths than other visible light, As you picked up speed looking behind you, blue light (from the point of view of the emitter of the light) would get shifted to first green, then yellow, red, infra-red, and eventually into wavelengths so low you couldn't see it.

Red shift is more talked about than blue shift because red shift is what astronomers observe in all the light that reaches us from the stars, and it's a kind of cosmic speedometer. If the light from a star or galaxy is only redshifted a little, it's only receding from us at a small fraction of the speed of light. If it's really redshifted, then it's whizzing away at tremendous speed (and turns out to be much further away as well).

Blue shift would turn visible light into fairly obnoxious x-rays then eventually gamma rays and cosmic rays as you picked up speed. That's one of the reasons I said that traveling at the speed of light couldn't be good for you -- you'd have to approach the speed of light and get blasted with radiation. Also, though, your mass would tend towards infinity, so the amount of energy you'd have to expend to reach lightspeed would also tend towards infinity.

They should do the video from the point of view of someone watching you pedal by at nearly lightspeed. As you approached, you'd be bluer, then normal color, then redder as you rode off. You'd also be flattened front-to-back, like a pancake whizzing past vertically.

The best book on Relativity is Relativity, by Albert Einstein. It's pretty easy reading, honest.
posted by surlycat at 5:15 AM on December 30, 2005 [1 favorite]

You'd also be flattened front-to-back, like a pancake whizzing past vertically.

You forget riddled with radiation sickness, like you said. ;)
posted by Jimbob at 5:30 AM on December 30, 2005

If it takes a couple of seconds to travel down a small road, light in Tübingen must either be really slow, or the architecture there must be of pretty impressive dimensions.
posted by uncle harold at 6:19 AM on December 30, 2005

This subject was also covered with similar detail in Episode 8 of Carl Sagan's Cosmos titled: Travels in Space and Time
posted by clunkyrobot at 7:31 AM on December 30, 2005

Metafilter: like being flattened front-to-back, like a radioactive pancake whizzing past vertically.
posted by blue_beetle at 8:18 AM on December 30, 2005

MetaFilter: Traveling through a turducken at the speed of light.
posted by Gator at 8:19 AM on December 30, 2005

What Uncle Harold said. That must be some looooong street.

Also Surly, great catch on the blue shift thing.
posted by storybored at 8:21 AM on December 30, 2005

You'd also be flattened front-to-back, like a pancake whizzing past vertically.

Not so. Length contraction is invisible. (flash) [via] [mentioned]
posted by squarehead at 8:40 AM on December 30, 2005

I'd worry more about turducken traveling through me at the speed of light.
posted by alumshubby at 8:53 AM on December 30, 2005

Blue shift would turn visible light into fairly obnoxious x-rays then eventually gamma rays and cosmic rays as you picked up speed.

Actually, cosmic rays are high-energy charged particles moving at relativistic speeds. The worst and rarest are things like carbon and iron moving at 90% C. Our local old cyclotron just got another lease on life doing materials research for the Mars program simulating these events.
posted by KirkJobSluder at 9:07 AM on December 30, 2005

I'd worry more about turducken traveling through me at the speed of light.

New! From White Castle!
posted by hangashore at 10:15 AM on December 30, 2005

I suspect it would be rather blurrier.
posted by shmegegge at 1:48 PM on December 30, 2005

And faster!
posted by nobody at 4:08 PM on December 30, 2005

This is possibly the coolest thing I've ever seen on MetaFilter. BTW, I had the same initial impression as some others here: sure seems ... slow. The accompanying text explains that it's not a series of frames from different places along the journey, it's a series of frames taken in the same place on each successive lap. Knowing this actually makes the video cooler. There's a nifty animation on the site as well that demonstrates how you can take images of things that are behind you (with a camera facing forward) when traveling at nearly light speed.

The video is really the least interesting part of this. Read the explanation. Great, great post.
posted by zanni at 5:34 PM on December 30, 2005

Thanks for the clarification, zanni. I completely missed those two explanatory links on the page. (I think my skimming brain assumed they were referring to the video effects methods, not to the near lightspeed travel effects).
posted by nobody at 9:32 PM on December 30, 2005

light travels at the speed of light relative to any observer

Nah, it's more fun to think that if your turned on your headlights it would ball up in front like loose toilet paper.
posted by CynicalKnight at 10:11 PM on December 30, 2005

In the simulation we reduce the speed of light in "virtual Tübingen" to 30 kilometers per hour: We can then ride a bike through the city at nearly the speed of light.

The second video involves turning corners at 90% the speed of light ie about 27km/h. You can see practically all of Tubingen apart from where you are going, it seems.
posted by apodo at 2:59 AM on December 31, 2005

Cool.
posted by Smedleyman at 4:44 AM on December 31, 2005