Ask Science
Ask a science question, get a science answer.
Community Rules
Rule 1: Be respectful and inclusive.
Treat others with respect, and maintain a positive atmosphere.
Rule 2: No harassment, hate speech, bigotry, or trolling.
Avoid any form of harassment, hate speech, bigotry, or offensive behavior.
Rule 3: Engage in constructive discussions.
Contribute to meaningful and constructive discussions that enhance scientific understanding.
Rule 4: No AI-generated answers.
Strictly prohibit the use of AI-generated answers. Providing answers generated by AI systems is not allowed and may result in a ban.
Rule 5: Follow guidelines and moderators' instructions.
Adhere to community guidelines and comply with instructions given by moderators.
Rule 6: Use appropriate language and tone.
Communicate using suitable language and maintain a professional and respectful tone.
Rule 7: Report violations.
Report any violations of the community rules to the moderators for appropriate action.
Rule 8: Foster a continuous learning environment.
Encourage a continuous learning environment where members can share knowledge and engage in scientific discussions.
Rule 9: Source required for answers.
Provide credible sources for answers. Failure to include a source may result in the removal of the answer to ensure information reliability.
By adhering to these rules, we create a welcoming and informative environment where science-related questions receive accurate and credible answers. Thank you for your cooperation in making the Ask Science community a valuable resource for scientific knowledge.
We retain the discretion to modify the rules as we deem necessary.
view the rest of the comments
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?
Ooh, interesting point.
I suspect all EM would be shifted according to the angle relative to the target - so at exactly 90° It would be "half shifted" - or zero. (Assumption based on blue/red shift of light).
I'm assuming the traveler is at a percentage of C, not at C (I think being at C is a completely different scenario, like would any EM escape the traveler?).
But I'm only an armchair quantum physicist (I've read a few books over the years). Look forward to what someone who understands Quantum Weirdness has to say.
One would have to be orbiting the other. I don't think you'd get any doppler shift in that signal, because the distance between transmitter and receiver remain constant.
The fun part of that scenario is that emitted photons carry momentum from your motion. If you're moving at a significant fraction of the speed of light, hopefully you're using an omnidirectional transmitter.
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.
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.
To cancel the effect of someone moving away from you, the equipment would simply hold the transmission until you received the whole thing.
Like waiting for someone to finish leaving a message on an amswerimg machine before hitting play.
I see