How do radio waves transmissions work in space? How long does it take to send/receive signals ?
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Radio is basically the same thing as light.
You know how on a rainbow you can go from blue to green to yellow and red. Our eyes can’t see beyond that, but the spectrum goes much father in both directions. Beyond red we have infra-red and then microwaves and then radio waves. In the other direction you get ultra-violet and x-ray and gamma rays.
The difference between the light you can see with your eyes and radio waves is the same sort of difference as the one between blue and red only much more so.
Light/Radio/microwaves etc work in space the same way they work on earth. In fact they work a bit better, because in space there is nothing that gets in the way.
In ages past people mistakenly thought that light would need a medium like sound waves travel through air. They thought there would be some sort of “ether” out there for radio waves to travel through. That was wrong. Light/radio does not need a medium. It can travel through nothingness.
Radio travels at the speed of light, just like light does, since it really is a sort of light.
On earth we can usually treat the speed of light as instanteous it is received when it gets sent.
If you try to sent radio waves to the moon and back, the time it takes is long enough that even humans notice the delay. Other planets like Mars are so far away that it will take minutes or hours for radionsignals to travel there and be sent back.
Other stars are light years away and radionwaves that reach us from distant natural radio sources are ancient by human standards.
Right now we only really have radio communications with a small number of robots and probes that are far away enough for the light speed delay to matter. All humans in space since the end of the Apollo program have staid close by earth.
Another 8ssue with radio communications in spaces is that things in orbitbtend to move really fast compared to the ground and that space stations and space ships tend to spend half their time in places where the earth is between you and them and radio signals don’t travel through rock all that well. Relays are necessary to radio with humans in space for more than a very short while.
Fun fact:
When Ham Radio was still a big thing, people who used it as a hobby tried to compete to reach other operators as far away as they could and send postcards to each other to confirm long distance contacts.
Some manged to reach the ISS or other manned NASA vehicles via Ham Radio and got postcards from NASA to prove that they 5alke with someone in space via Radio.
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