Hi brainboxes out there. A tv or radio signal is transmitted and this is picked up within seconds by the reciever ( tv or radio). What happens to the signal? Where does it go? And why can't that signal be picked up at a later time? Thanks for any info.
Radio waves travel in a straight line mostly. Although certain wavelengths are partially reflected back to Earth by the ionosphere by the time they circle the Earth the energy has usually been absorbed or has dispersed too much to be recovered.
I takes about 2.5 seconds to bounce a signal off the Moon but most broadcasters do not rely on a moving target which is only available a various times of the day or night.
Imagine switching on and off a powerful light bulb on top of a hill. Where does the light go? Why can't the light be picked up at a later time? The answers to these questions are much the same as for your radio or tv signal.