Leaky Earth?
We’ve been shouting out into the cosmos for quite some time now. Electromagnetic waves of various intensities and frequencies have been streaming away from Earth for well over a century, the remnants of TV broadcasts, mobile phone conversations, satellite transmissions, and military, civil and astronomical radars.
We’ve even deliberately tried to get ET’s attention — a controversial practice known as METI (Messaging to Extraterrestrial Intelligences). There have been many such attempts, including the 2001 Teen-Age Message to the Stars organized by the Russian cosmologist Alexander Zaitsev. His work, and those of others, have been criticized as being insanely risky given the dearth of information we have about the nature of ETIs. Two years ago, John Billingham and James Benford called for a global moratorium on METI, an initiative similar to the one David Brin and myself worked on last decade.
But now, owing to all this human activity, the Earth has a radiosphere that’s inexorably billowing outwards at the speed of light — a clear signal that’s just waiting to be picked up.