Excursions at the Speed of Light

D4C5CE writes "S/F fans can finally find out what you really get to see at relativistic velocity, and tourists are one step closer to "doing Europe in a day" in these amazing Space Time Travel simulations of the Theoretical Astrophysics & Computational Physics department at the Institute for Astronomy and Astrophysics Tübingen. They put you in a driver's seat that both Armstrong the Astronaut and Armstrong the Cyclist would equally enjoy, in simulators built to ride a bike at the speed of light."

Sounds like a wonderful experience...

[booyabazooka]

What it's like to ride a bike at the speed of light. I'd imagine, then, you would just sit down on the bike, and then get off, since to you, the trip would be instantaneous.

Re:G forces

[Anonymous Coward]

Except for the problem of the air pushing against you at that speed.

Re:G forces

[fm6]

It's a little sad that most people still don't understand the difference between speed and acceleration. When I first read about the Scientific Revolution as a kid, the writer spent a lot of time sneering at medieval scholars who stubornly stuck to Aristotle's physics [answers.com] despite all the experimental evidence showing that it was wrong. But as far as most people are concerned (including the script writers on Star Trek) Aristotle has never been debunked.

Re:Sounds like a wonderful experience...

[cryptoz]

That's wrong...Time would pass normally for you. You would think at a slower speed (the same speed you're moving) so you wouldn't notice a difference. When you got off the bike, however, much more time would have passed for everyone else than you.

All this is, of course, assuming Einstein was right (and I think some experiment somewhere proved these effects to be correct)

How long?

[OverflowingBitBucket]

Those curved buildings are kinda cool, but how long would those buildings even be in your field of vision if you were blasting past them at the speed of light? I don't think your brain would get a chance to process that kind of detail before it blurred into the image from the next microsecond, which would probably be completely different. I'd say it'd all be a messy blur.

Looking backwards would be kinda sweet though, if it didn't blind you immediately.

Re:Caution: Chinese Weaponization of Space

[AKAImBatman]

We must proceed with caution by ceasing these speed-of-light simulations. The Chinese would surely use them to advance their space-weaponization program.

Why does this troll keep showing up? The Chinese don't have the resources to compete with the US. They've attempted manned space travel several times (even outright copying the Dynasoar design) and every time have had to cut it because of the cost. For now, I wouldn't worry too much about the Chinese one-upping the US on their own technology. Start worrying when they launch an Orion (not bloody likely).

Note that the Chinese space program is completely under the auspices of the Chinese department of war. By contrast, in the USA, NASA is an entirely civilian effort.

This is a GOOD thing. Remember what happened when the space program was under the United States department of war? (Specifically the Air Force?) That's right, some good engineering was done, but we didn't GET anywhere. It wasn't until NASA was formed that the US actually got into the race.

Re:How long?

[mnmn]

Blind you? The photons rate entering your eyes looking backward would be much less, so it'll be pretty dark. You wouldnt feel a thing if the velocity is constant.

Looking forward.. now thats a different story.

Uh, what about the Dopler effect?

[CrowScape]

Wouldn't the blueshift when traveling at such speeds push everything out the visible spectrum? So you wouldn't actually see anything, you'd just get a nasty dose of Gamma waves... or worse?

Traffic Lights..

[medgooroo]

if, ignoring science and all that hoohah stuff, you could ride a bike at the speed of light around the place, would there be any need for traffic regulation or do collisions just become so hideously unlikely that it doesnt matter? /ot

Re:Sounds like a wonderful experience...

[Jerf]

Well, at the speed of light... yes, things going at the speed of light experience nothing that can be called the progression of time.

But matter can't travel that fast, only things without mass. So, there is the interesting question of what you have that you would call a "bike" or "you".

Physics does not break at the speed of light, but intuitive physics is dead. Relativity is a strain on it at any high speed but just forget lightspeed.

(As I always do when this topic comes up, if you want a crack at understanding this stuff for real, try Reflections on Relativity [mathpages.com], free online.)

Re:How long?

[Phleg]

Actually, light travels towards and away from you at light speed, no matter your speed. So the number of photons entering your pupils would be exactly the same.

Re:Tübingen project got the colors wrong

[sixpaw]

I doubt it was a matter of forgetting; it's much more likely that they decided including the frequency shift would detract from the simulation. Visible light covers a comparatively narrow spectrum, from 700 to 400nm, and at the velocities they're covering any visible-light emissions would have shifted completely out of that band; at a fairly modest velocity like v=.8c, the doppler effect already produces a frequency shift of 3x, carrying a 400nm wavelength all the way up to 1200nm. I put together a good chunk of the doppler-shift portion of Dr. Ping-Kang Hsiung's simulation of these visual effects back in the early 90s [acm.org] (though I'm not among that paper's authors), and getting it to look interesting was far and away the most difficult part of the simulation.

Re:Tübingen project got the colors wrong

[Bios_Hakr]

But the shift would occour across the entire spectrum. Assuming there is something in the >400nm range, it'd shifted into visible, no?

Of course, far blue carries less information than far red.

Still, it'd be cool to see the effect of ultraviolet being shifted through the visible spectrum.

Cherenkov (sp?) light...

[Anonymous Coward]

Cherenkov light is sort of an example of that. It is caused by particles travelling faster than the speed of light in water. That's not faster than C, since C is just the speed of light in a vacuum.

Close, but not quite

[Anonymous Coward]

There isn't any law of relativity that says "an object in acceleration always has a slower clock than an object in an inertial state".

That being said: there is a competition between a clock in orbit running slower than a ground clock due to its speed, and running faster due to it being in weaker gravity (gravitational time dilation). For the GPS clocks, those shifts are 7,200 ns/day and 45,900 n/s day, respectively, so the latter wins out, and the clocks run faster. See this page [wits.ac.za].

Re:Cosmos

[d474]

Carl Sagan always had a way blending the cold of science with the warmth of humanity. It's always easier to "get it" with science if you allow the implications sink into your emotions. That's where the meaning comes from.