Question

The film interstellar used several outcomes of Einstein’s general theory of relativity to raise questions about bonds within family members and the long-term survival of the human race. Assuming that space travel, as depicted interstellar is possible (this is a stretch), what communication problems had to be solved for Cooper to communicate with Murph and his family back on earth? Communications were done by transmitting and receiving electromagnetic radiation. Describe the effects Gargantua would have electromagnetic signals sent from inside the wormhole to earth.

Answer 1

for communication to happen, a transmitter and a receiver are required

the EM waves emitted from the transmitter need to travel along the general direction of the receiver

when a massive blackhole is present, it bends everything in its presence

as shown in the movie, light is bent a significant amount when passing beside the black hole

so if EM waves get bent and does not travel in the intended direction of the receiver, communication can not take place

so in order for communication to happen, there has to be some kind of repeater or an array of receivers near the black hole which can continue to receive the communication and re-transmit the same

so that the intended path can be maintained.