# Science

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

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1. distance=veloctiy *time
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.

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👨‍🏫
bobpursley

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