Communicating at Near-Light Speed - Time Dilation

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• SF Alba
In summary, when a person moves around a circle at high speed, they experience time dilation. This affects the rate at which they can communicate with people in a stationary position. If the person is talking to someone at the center of the circle, they can communicate without any issues. However, if they are talking to someone who is moving around the circle, the person at the center of the circle will experience time dilation more than the person talking to them, causing the person talking to experience the conversation as appearing to be slower than normal.
SF Alba
So, I've been wondering: how would time dilation affect communications?
For the sake of visualisation, imagine the Flash is running at 99% the speed of light in a circle around a fixed position. There's a building in this position, and inside this building are his friends. Due to time dilation, they should be experiencing time at different rates. Assuming the usual problems(wind muffling comms, drag etc.), are a non-issue, and that he is talking to his friends through conventional radio communications, would others perceive him to be talking much slower than normal, if, from his perspective, he was talking at a normal rate? If so, at what rate would he have to talk to be able to communicate with them?

If you'd prefer, you can swap the Flash for a spaceship and the building for an asteroid; like I said, it's just to help with visualisation.

Well, to start off, his friends would have to tune their receiver differently as the radio signal would be affected by relativistic Doppler shift. Exactly what would be observed depends on the direction the Flash is running in.

SF Alba said:
So, I've been wondering: how would time dilation affect communications?
For the sake of visualisation, imagine the Flash is running at 99% the speed of light in a circle around a fixed position. There's a building in this position, and inside this building are his friends. Due to time dilation, they should be experiencing time at different rates. Assuming the usual problems(wind muffling comms, drag etc.), are a non-issue, and that he is talking to his friends through conventional radio communications, would others perceive him to be talking much slower than normal, if, from his perspective, he was talking at a normal rate? If so, at what rate would he have to talk to be able to communicate with them?

If you'd prefer, you can swap the Flash for a spaceship and the building for an asteroid; like I said, it's just to help with visualisation.
Taking the spaceship case, the Lorentz factor for 99% of c is about 7. You take it from there.

Draw a spacetime diagram with a sequence of periodic transmissions.
Note the receptions.
As mentioned by @Orodruin , this involves the Doppler Effect.

m4r35n357
robphy said:
Draw a spacetime diagram with a sequence of periodic transmissions.
Note the receptions.
Seriously, do this.

Signalling between circular moving observer and observer at the center of the circle (presumed inertial) is a special case . The situation is stationary with a lot of symmetry (rotation, time translation). Using this, the exact answer can be written down with virtually no computation or diagramming. Nor do you need to worry about Doppler.

After the fact, it is interesting to explain both observers' point of view with proper application of Doppler, helping understand the nuances of transverse Doppler.

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1. What is time dilation and how does it relate to communicating at near-light speed?

Time dilation is a phenomenon in which time appears to pass slower for objects moving at high speeds. It is a consequence of Einstein's theory of relativity and is directly related to communicating at near-light speed because the closer an object gets to the speed of light, the more pronounced the effects of time dilation become.

2. How does time dilation affect communication at near-light speed?

Time dilation can cause delays in communication when objects are moving at near-light speed. This is because time appears to pass slower for the object in motion, making it seem like the communication is taking longer to reach its destination. The closer the object gets to the speed of light, the longer the delay will be.

3. Is it possible to communicate at exactly the speed of light?

No, it is not possible to communicate at the speed of light. According to the theory of relativity, as an object approaches the speed of light, its mass increases infinitely and it would require an infinite amount of energy to accelerate it to the speed of light. Therefore, an object can never reach the speed of light and communication at exactly this speed is not possible.

4. How do scientists account for time dilation in their communications at near-light speed?

Scientists account for time dilation by using precise calculations and adjustments in their communication systems. They also take into consideration the effects of time dilation when planning for missions that involve communication at near-light speed. Advanced technologies and mathematical models are used to accurately predict and account for the effects of time dilation.

5. Are there any practical applications for communicating at near-light speed?

Yes, there are practical applications for communicating at near-light speed. For example, it is essential for space exploration and communication with astronauts on long space missions. It also has applications in satellite communication and in high-speed data transmission on Earth. However, the technology and infrastructure required for communicating at near-light speed are still in development and not yet widely available.

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