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Comment by mulmen | Hacker News Reader

How would FTL communication work? Let’s assume we can literally communicate over any distance instantly. Do we come across as a bit slow to anyone orbiting star S62? “Wow, these earthlings sure are hard to work with. They just can’t seem to keep up!”

Do we have to remember that the people we communicate with have different experiences of time?

Gender identity, sexual orientation, native language. Temporal perception?

Honestly it doesn’t seem hard to overcome. But I do love the idea of shipping off a problem and having it done 20% faster.

But wait, aren’t they 20% farther along in evolutionary terms too? So isn’t that like a multimillion year advantage?

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As others have commented, you can’t send information faster than light. This is because time itself doesn’t run off any kind of central clock. The relationship between two events in time changes depending on where the observer is. There is no way to perfectly synchronise two events which are separated in space. This is called the relativity of simultaneity. FTL communication results in paradoxes because of this.

There is an awesome article on wikipedia that describes it more. Totally blew my mind.

https://en.wikipedia.org/wiki/Relativity_of_simultaneity

As an aside, I’ve found this to be a helpful way to visualise data flowing through distributed systems...

Right but the purpose of the thought experiment is to consider the speed of thought processing, not information delay.

> Do we have to remember that the people we communicate with have different experiences of time?

This is already true on Earth. Different people process information at different speeds. Think about when you're talking to someone who is elderly. Do you slow down a bit so they have a chance to keep up?

Yep, exactly. I was just chatting with someone in the park today who was much slower to process and respond than I am accustomed to. I was able to adapt to that and we had a nice conversation. It’s definitely a thing. Communication is messy.

I do think this thought experiment is a bit different though. In the sense that everyone orbiting S62 is faster than us, by a considerable margin. There will still be individual variances of course but the baseline moves. It’s not just a way you adapt to an individual but to an entire group of people, based on properties of their location.

From reading the comments here, the margin isn't that much, and from their perspective we're the faster ones. Relativity is weird.

Reminds me of that star trek voyager episode with the fast moving planet “Blink of an eye” Hours in our universe, is centuries on this planet that orbits at an incredible velocity.

That episode was a (poor) adaptation of Robert L. Forward's first contact novel "Dargon's Egg". Humanity discovers life on a neutron star, where the intense gravity (billions of gs) enables degenerate matter chemistry where interactions are orders of magnitude faster than in conventional matter.

I highly recommend it.

On my read list, thank you!

>Let’s assume we can literally communicate over any distance instantly.

We can't, that's the whole point of relativity.

Nothing travels faster than light, not even information in any form.

Nothing travels faster than c but light sometimes travels slower than that.

Always, unless you happen to have a way of making perfect vacuums ;)

That too, but I meant actual cases when it is possible to make things go faster than light in a given medium, see also Cherenkov radiation.

If the cow is a sphere...

But the particular simplifying assumption you made invalidates the whole thought experiment. Who is moving faster actually depends on where you're looking from. This turns into complete nonsense if you assume instantaneous communication - who needs to slow down for whom?

> Let’s assume we can literally communicate over any distance instantly. Do we come across as a bit slow to anyone orbiting star S62?

Communicating "instantly" would be a paradox.

Remember there is no absolute reference to which speeds are measured, aka. a "luminiferous aether". Its existence was disproved in the 19th century.

So Earthers are slow for observers on that star, but inhabitants of that star are also slow for Earthers; because speed is relative. Hence the name relativity.

And the reason it doesn't result in a paradox with light-speed communication is that the increasing (resp. decreasing) latency between the two account for the increasing (resp. decreasing) difference of time caused by this discrepancy of an object speeding up away from (resp. toward) the other.

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