Life in the Universe

Searching For Intelligent Life

What is challenging about listening for alien radio signals?

The success of this kind of search depends not only on the existence of intelligent extraterrestrial life, but also on life intelligent enough to figure out how to send such signals. Furthermore, radio signals weaken fairly quickly. After traveling even a few dozen light-years, the interstellar medium can scatter and muffle such signals significantly, so much so that even Earth’s largest radio telescopes would not be able to detect them.


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