Comment by somenameforme | Hacker News Reader

Comment by somenameforme | Hacker News Reader

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I wish the guy who created this included a 'your perceived velocity relative to [some fixed point]'. The speedometer shows what an at rest observer would perceive your velocity as, not what you would perceive it is. The 'magic' of relativity is that the speed of light is not really a speed limit. You can travel endlessly far ahead of it. Distance and time then begin to distort, and you effectively travel into the future, but you can go arbitrarily faster than it.

If we ever reach the technology to enable relativistic starships (basically able to accelerate at 1g or so for years at a time), then the universe is going to get seriously weird. Not only for us, but also for people in the distant future who will regularly have ancient relics from the past traveling into their time, when they will likely scarcely resemble us, and going 'Hello fellow... humans?' That'd be some next level archaeology opportunities though.

It'll also be socially odd as the elite and powerful travel off into the future seeking immortality, unable to ever return, at least so far as we currently understand.

> The 'magic' of relativity is that the speed of light is not really a speed limit. You can travel endlessly far ahead of it. Distance and time then begin to distort, and you effectively travel into the future, but you can go arbitrarily faster than it.

You cannot. The speed of light limits you, even as you approach it, by changing distance itself.

There is no absolute distance between two points; all astronomical distances are calculated in a non-relativistic framework. This is perfectly acceptable, since we all live in that framework relative to each other, and even if we were talking to multi-generational "friends" on Alpha Centauri, it would still hold true for both sides (to within an imperceptible error).

This is why it is sometimes suggested that photons don't "travel" at all; because they move at c, every spot they go to is the same spot to them. A divide-by-zero non-error.

You cannot what? Everything I said is completely accurate. As is your conclusion - with the speed of particles being infinite, from their perspective.

This is also why it's 100% possible for a human to travel to Alpha Centauri, or even the edge of the known universe all within a single human lifetime, from his own perspective. Of course for an at rest observer, billions of years would have passed, but for him - mere decades.

Again, relativistic speeds change distance (from what we experience at non-relativistic speeds). At no point do you travel faster than light - the world you are leaving will appear redshifted. If you were going faster than light, the background would simply disappear, as its photons would not reach you (yet).

Ah I see what you're arguing! Yes you're certainly correct, that you will not measurably perceive yourself traveling faster than light as the universe will contort itself endlessly to ensure that doesn't happen. I'm imprecisely speaking of your distance/time relative to a fixed point at rest if you yourself were at rest as well.

Nothing can be observed travelling faster that speed of light in the observer's proper time, but many things can be observed having travelled faster than the speed of light, when considering the traveler's proper time and the traveler's observation of distance before and after the journey.

Yip, I think we're all saying the same thing, but with varying degrees of unspoken assumptions on a topic where we all, generally wisely, think other people have no idea what they're talking about.

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