Why can television satellites, which broadcast information as electromagnetic radiation, send signals from the vacuum of space? a because electromagnetic radiation increases as the distance increases b because electromagnetic radiation does not need a medium to travel through c because space does not provide a medium that will block the satellite signals eliminate d because space is so vast that light waves can spread out to their full size and strength?

Long ago, we (humans) used to think that every wave needed a medium to travel trough. The hypothetical electromagnetic medium was called Aether, but this brought some predictions of the wave behavior that couldn't be measured. One famous experiment made trying to measure one of this predictions was the Michelson Morley experiment, that tried to measure the Aether drag, the drag of the medium made by the Earth as it travels trough it, kinda like a ship making waves as passed by a canal. So, all this experiments didn't give any results, and no one knew why. Then it came Albert Einstein. In 1905 he published a revolutionary work, that we today call the Special Relativity Theory, that does not needs an aether to explain how the light travels trough space, and its a theory accepted by all scientist (or almost all) today.