I’m asking this because there is a scifi book I’m reading, and in the book there’s a scene where someone is communicating with a person in a spacecraft moving at lightspeed. I know their ability to communicate would probably not be possible, but let’s just put that aside for a second. Hypothetically, if you could communicate with someone moving lightspeed, would the time dilation make it so that they would appear to be moving and speaking very slowly relative to you?
So, I would assume that you would be communicating through radio waves. If an object broadcasting a signal moving at the speed light away from you, I would further assume you experience a severe Doppler effect. To the point that I don’t think you would experience anything coherent. You would receive small packets of information at a time, scattered across several million years.
This is just my initial impression on the fly, do not take this as any sort of gospel. I also did some communcations work for a time. So, this is tickling my brain and I might spend the rest of my evening in my books.
If we assume that the person moving at light speed is going in circles about the stationary person instead of linearly away. Would the radio waves be doppler shifted if transmitted orthogonally?
In principle you could have equipment that cancels out any doppler effect, no?
That’s awesome, let me know if you find anything interesting
Oh boy, I went down a rabbit hole. This has been bothering me to the point where I called in some favors and found some public info for what the current hypothesis on “near” light speed communications is. Because light speed is impossible…for now haha. But let’s use some assumptions.
First, light speed travel is possible. Second, that we have superior tracking technology. To the point where we can find the exact location of a traveling at light speed object in space.
The best option we have now is using photonics for communications. This bypasses using radio waves by using an array of lasers that are pointed toward a receiver, which is in turn pointed to the transmitter. We can see why space and light speed travel makes this difficult. It’s hard to track objects in space at very high speeds with the precision needed for this level of communication.
The reason photonics is the best option is, it opens up significantly more frequencies to work with. And some frequencies travel farther and faster than others. If we ever master light speed and light speed communications, I would bet money now it’s photonics. Because what’s faster than light?
Let me know if you have any questions, I’d be happy to answer. Please do not ask about FTL, crazy things start happening then. <- in jest, if you wanna ask you can. Engineers I know argue about it to the point of almost fighting. But that’s engineers for you.
I appreciate the dedication!
The lasers idea is interesting.
Don’t all frequencies of light travel at the same speed?
You are correct, my sincerest apologies. Light at different frequencies can carry more/less data. I will leave my mistake, as failures are the price of progress. I will not make that mistake again and be more careful. Thank you for your kindness.
Edit: Clarification; different frequencies affect data transfer rate
Ah that makes sense
No problem mate. Thanks for all your info and the detailed responses
The last thing I’ll say is, you still need to over come the Doppler effect. But if you can send large enough packets quick enough, you can mitigate some of the issues. The biggest thing is sending something across long distances quickly. That’s the biggest issue. For that, unfortunately, you need faster than light. I hope the information provides a more exciting journey through your story.
In my opinion, the only way to have faster than light communications is a massive breakthrough on the quantum scale. Entanglement is so new and unknown, that I have no idea if that’ll be the answer. It doesn’t seem so to me, though. But quantum mechanics breaks so many laws of classical mechanics, it’s crazy. You’d almost need some wormhole to communicate using classical techniques. I.e radio, photonics, etc. Which I think is where I rest. Photonics for high data transfer pointed at a wormhole. Then someone receives it in the other side. You still have Doppler effect, but much more mitigated. Hope you enjoyed my diatribe. Much love and peace to you, friend.
A wormhole is a cool idea.
Much love and peace to you as well
I remember in the game series Mass Effect they spoke of being able to break the EM communication barrier problems. They used a quantum entangled pair. Wiggle one, and the other instantaneously adopts the same position anywhere in the universe.
FTL travel needs FTL coms and radio ain’t that. Star Trek handwavium called it subspace. Both of science fiction, but hey, isn’t that what all this is about.