posted by Timothy .
ive got 2 questions:
the star Vega is 25 lightyears away from us. if we sent a radio message to Vega, and another civilization on a planet circling that star answered us, in what year could we expect to hear a reply?
why was it necessary to make radio telescopes so much bigger than optical telescopes?
i looked in my textbook but i couldn't find the answer
50lightyears= 1lightyear/year * time
time= 50 years. Duh.
radio telescopes have to collect enough energy to overcome the energy in background radiation, so radio telescopes are big.