Live data from Hacker News

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

rivendell.dmitrybrant.com

221–230 of 259 posts

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

#221

Earlier quoted context omitted.

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

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

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

#222

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,…

> "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.

The speed of light is high. It's just that the universe has expanded into an unimaginably large area by now.

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

#223

I don't understand movement: "W" makes me appear to move backwards, "S" makes me appear to move forwards. When I use space to stop, I move back to where I started. Is this a bug or am I just really confused?

Look closely at the floor. You're not moving backwards.

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

#224

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,…

Yeah, space exploration/colonization can be only made by species that live a million years, or can pass the same goal across many generations forward.

Maybe it's the answer to Fermi paradox: aliens are all around, we're just too fast for them to communicate.

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

#225

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,…

Yeah, space exploration/colonization can be only made by species that live a million years, or can pass the same goal across many generations forward. Maybe it's the answer to Fermi paradox: aliens are all around, we're just too fast for them to communicate.

Relativity fixes that a little, you don't need to go light speed to make it all over the place within your lifetime, it's the observers who sent you off that will never reap the fruits of their effort.

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

#226
post #140

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,…

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.

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

#227
post #163

Earlier quoted context omitted.

> If you accelerate at 1g constantly for 1y you travel 0.5 light years Can't we accelerate past 1G constantly? Or do we expend so much energy doing it that we can't realistically do it with today's technology?

Not with current technology. That was kind of the physics “trick” in the book ‘Project Hail Mary’, where the astrophage provided enough energy and propulsion to be able to sustain 1G of acceleration.

The astrophage was pumped around the ship to act as shielding for cosmic rays too.

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

#228

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 light years away and you can see your ancestors on earth.

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

#230
post #91

Fun fact: given that the meter is defined in terms of speed of light (and cesium frequency), "changing the speed of light" is a counterfactual impossibility, what is actually changing are some other fundamental constants.

If we realized tomorrow we had the speed of light slightly wrong, we wouldn't change the length of a meter, we would change the definition of the meter. We've redefined the meter thrice already.

We wouldn't "release" that because there is simply no way to tell if it is wrong. The past redefinitions happened because previous definitions were too ambiguous rather than "wrong".
Post reply on HN