400
Can astronauts talk in space? IF so how?
There is no air therefore no sound in space.
Sound is carried by vibrations of molecules. When you talk here on Earth, air molecules transmit the vibrations and allow others to hear you. In open space there are very few molecules at all so there is nothing to carry the vibrations.
Radios use radio waves to transmit information from one to another. These waves move through space by themselves so they can be transmitted from one astronaut to another.