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Show HN: What if the speed of light was 5 km/h?

rivendell.dmitrybrant.com

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Re: Show HN: What if the speed of light was 5 km/h?

#271

Post by numpad0 »

MathMonkeyMan wrote: post #262
rrr_oh_man wrote: post #233

Earlier quoted context omitted.

So basically "go fuck yourself" if your ISP does not yet support IPv6? I'm not saying that I couldn't fire up Cloudflare Warp, but I think it's a legit issue for average users [0]? [0] https://xkcd.com/2501/

Funnily enough, I use Cloudflare Warp at work, and it breaks my site for what I think are DNS related reasons. Maybe there are some more exotic DNS keys that I need to add. Or I could go back to IPv4 with dynamic DNS, but that would mean changing domain registrars.

NS record for domains usually can be pointed at someone else than the registrar it's on, just fine(unless DNS infra of either one or both goes down). That's entirely separate to registrar transfer.

Re: Show HN: What if the speed of light was 5 km/h?

#273

Post by andsoitis »

atlimar wrote: post #99
santiagobasulto wrote: post #90

Some time ago I had the following shower thought: "the Speed of Light is pretty slow" How i got there: The closest major galaxy to the Milky Way is Andromeda, and is 2.5 million! light-years away. And this is the CLOSEST galaxy, the universe is extremely big. Of course that as you get closer to C, the traveling object will experience time dilation (relative to observer), so the time passed will be less. At 99.999% C,…

> At 99.999% C, the traveler would take ~11,000 years if we add more 9s, is it possible to reduce that number to within a human lifespan?

> if we add more 9s, is it possible to reduce that number to within a human lifespan?

Yes. At 99.99999999% of c it would take 35 years from the perspective of the traveler. However, an observer on earth will still see it taking 2.5m years.

Re: Show HN: What if the speed of light was 5 km/h?

#274

Post by [deleted] »

davidoduk wrote: post #228
santiagobasulto wrote: post #90

Some time ago I had the following shower thought: "the Speed of Light is pretty slow" How i got there: The closest major galaxy to the Milky Way is Andromeda, and is 2.5 million! light-years away. And this is the CLOSEST galaxy, the universe is extremely big. Of course that as you get closer to C, the traveling object will experience time dilation (relative to observer), so the time passed will be less. At 99.999% C,…

So when we think we're looking at Andromeda today, we're actually seeing Andromeda as it happened 2.5 million years ago. That means someone/something? in Andromeda today, with the ability to see Earth clearly, would see some of our ancestors, like Homo habilis. I've always wondered, if we end up being able to travel faster than light, we'd technically be able to look into the past depending on how far we go. 1000 lig…

[deleted]

Re: Show HN: What if the speed of light was 5 km/h?

#275

Post by dotancohen »

dmitrybrant wrote: post #242
adamkurkiewicz wrote: post #79

At first sight, this is remarkably more accurate that the "slower speed of light" game from MIT that was made available all those years ago (~2012). Many issues with the MIT game were discussed here: https://physics.stackexchange.com/questions/43695/how-realis... While the thread lists multiple issues, the issue that I found was with modeling temporal aspects of relativistic doppler (I also reported it on the github…

Thanks! Yes, I'm trying to pay extra close attention to modelling every perceivable effect as closely as possible. The remarkable thing is that none of the mathematics is particularly complicated, so if you get the math right, then all of the predicted effects emerge automatically.

This is probably one of the most important comments on HN, seriously. A concise summary that once we get the model right, the emergent behaviour matches observations.

Very reminiscent of the Casimir effect experiments.

Re: Show HN: What if the speed of light was 5 km/h?

#276

Post by dotancohen »

no_multitudes wrote: post #226
Terr_ wrote: post #140

Earlier quoted context omitted.

In terms of comparisons to human lifespan, I think this one is interesting: If you can somehow accelerate/decelerate at a constant human-acceptable 1G, time dilation means almost anywhere is reachable in a human-lifetime. That coincidence(?) could easily become false if we are accustomed to lower accelerations or lesser lifespans.

> If you can somehow accelerate/decelerate at a constant human-acceptable 1G Well, you also need clarketech heat dissipation and collision deflection technology, if you want to get there without vaporizing.

Details, details. That's mearly an implementation issue.

Re: Show HN: What if the speed of light was 5 km/h?

#277

Post by dotancohen »

Terr_ wrote: post #255
hebelehubele wrote: post #254

Earlier quoted context omitted.

There was a bit in the series "The Expanse" about a what's called "Epstein Drive" where some guy invents a propulsion tech based on fusion and he losts control of his aircraft under an ever-increasing acceleration. After some minutes, his body gets crushed under its own weight before he could reach the controls and slow the spaceship down. https://www.youtube.com/watch?v=1lS_WxQ3zeU

Yeah, certainly a reason to have failsafe timers and dead-man switches when testing new things. While I did read The Expanse , when I think of that class of dangers, what pops to my mind is an old short story Neutron Star (1966) [0]. A financially desperate pilot is hired to discover what killed some researchers while leaving the indestructible starship hull intact... and the thrusters off. [0] https://en.wikipedia.o…

  > failsafe timers and dead-man switches when testing new things.
Aircraft and spacecraft are more than anything, mass constrained. Such failsafes are welcome in software, but neither the bleeding-edge engineers not even the test pilots would support adding failsafe mass if it would affect the tests.

Re: Show HN: What if the speed of light was 5 km/h?

#278

Post by xelxebar »

Terr_ wrote: post #255
hebelehubele wrote: post #254

Earlier quoted context omitted.

There was a bit in the series "The Expanse" about a what's called "Epstein Drive" where some guy invents a propulsion tech based on fusion and he losts control of his aircraft under an ever-increasing acceleration. After some minutes, his body gets crushed under its own weight before he could reach the controls and slow the spaceship down. https://www.youtube.com/watch?v=1lS_WxQ3zeU

Yeah, certainly a reason to have failsafe timers and dead-man switches when testing new things. While I did read The Expanse , when I think of that class of dangers, what pops to my mind is an old short story Neutron Star (1966) [0]. A financially desperate pilot is hired to discover what killed some researchers while leaving the indestructible starship hull intact... and the thrusters off. [0] https://en.wikipedia.o…

Thanks for the Niven reference. Neutron Star was a fun read. I'm currently working through a collection of 80s SF shorts[0]. It's an entertaining lens into the narratives mores of the time, and or own in contrast.

[0]:https://ci.nii.ac.jp/ncid/BB07948947

Re: Show HN: What if the speed of light was 5 km/h?

#279

Post by tcfhgj »

rrr_oh_man wrote: post #233
chungy wrote: post #213

Earlier quoted context omitted.

Have an IPv6 connection.

So basically "go fuck yourself" if your ISP does not yet support IPv6? I'm not saying that I couldn't fire up Cloudflare Warp, but I think it's a legit issue for average users [0]? [0] https://xkcd.com/2501/

Still can switch isp usually

Re: Show HN: What if the speed of light was 5 km/h?

#280

Post by somenameforme »

IAmBroom wrote: post #239
somenameforme wrote: post #190

Earlier quoted context omitted.

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 fu…

> 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 di…

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.

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