Ever since the radio was invented, humanity has inadvertently beamed signals into the outer reaches of space. Every broadcast radio and television show ever aired is currently venturing across the universe, carrying our cultural signal to potential alien life that may or may not have the ability to decipher our strange entertainment.
However, with the dawn of satellite technology, Earth is broadcasting considerably fewer signals and as such, our planet has become nearly silent.
While old-style TV transmitters might generate one million watts, the power of a satellite signal was around 20 watts. Satellites also aimed their transmissions at the Earth, with almost none being allowed to escape into space.
Use of cable prevented the leakage of signals even more effectively.
”Now the actual amount of radiation escaping into space is about two watts, not much more than you get from a cell phone,” said Dr Drake.
”If this continues into the future very soon our world will become undetectable. Using ourselves as an example, it means the difficulty of finding other civilisations will be much greater.
”We’re going to have to search many more stars and many more frequencies.”
Any alien civilisations that existed were likely to be far more advanced than ours, he said. Their analogue TV age probably came and went long ago, before humans even thought about searching the sky for signs of intelligent life.
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