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Comment by rootusrootus | Hacker News Reader

Whenever I think about light speed being fast, I imagine myself standing at the edge of the solar system and watching a hypothetical photon travel from the Sun to the Earth and taking 8 minutes. Suddenly it doesn't feel like light is really all that fast except at human scales. 5 km/h would be fascinating though.

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The globe here is, in my opinion, the best such visualization because I've personally travelled the distances depicted.

https://www.reddit.com/r/educationalgifs/comments/qq5cw7/coo...

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.

On the other hand think of the wavelength of light and how absurdly fast the oscillation frequency is to provide a wavelength of a few hundred nm at the speed of light. 8 minutes is a lot of cycles, and 150M km is a lot of wavelengths!

But light is not really even light except at human inference level. Like yes if you were a god like being looking at this and understanding light in a proton level way, it wouldn't be very impressive but I would say that is not the right way to think about physcial phenomena. How can you even be sure time has any definite meaning outside human's concept of it? In that sense what do words faster or slower or minutes even mean

The speed of light is unbelievably slow, not even as a cosmic scale, but on earth.

We cannot play competitive multiplayer games globally, without 300ms ping. I dream of a world playing Black Ops 2 on a original PS3 in 2026 getting into a lobby because latency is low.

How do you arrive at 300ms?

light is 186k miles per second, the other side of the globe is 12.5k miles away - so 67 ms / 130ms+ round trip in optimum conditions. Add more for network hops and consider that fiber is not quite as fast as vacuum.

300ms feels extremely optimistic coming from my perspective of someone living on an island in SE Asia

Simply send your cable through the center of the earth and boom, latency reduced by ~1/2. Remember me when you make billions of $ from my idea.

It'd actually be about 36% shorter :)

Can't wait for the neutrino-internet to launch once they fix the packet loss issue :)

For a city that is far away from anywhere:

https://wondernetwork.com/pings/Auckland

Your real world latency is going to be worse.

This is a great example of information taking time:

https://www.ibiblio.org/harris/500milemail.html

Ultimate counterevidence of an benevolent "intelligent designer"

Still not as unbelievably slow as signals in our body. If you hook up a fiber connection from a button to an LED, then stub your toe on the button, the fiber can be thousands of kilometers long and you'll still (via the LED) see that you've stubbed your toe before you feel it.

This is of course assuming instant activation, a direct connection and no additional latency from network hardware.

The LED will display it first, but will the signal reach your visual centers first? And how about the time for your brain to process that signal and make you consciously aware of the visual vs. the way the pain signal is forwarded to conscious processes?

Fair issues, but none of them impact the fundamental point. I'm not trying to make a point on touch vs. visual sensing or with regard to consciousness (time shifting of visual input is a thing, which could be impactful here, see "chronostasis").

The point is to quickly and accessibly convey an intuitive understanding of the propagation speed of information in biological circuits vs. the max speed of information in our universe (to our current knowledge at least) and in our technology.

For the photon the time passed is 0 right?

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