Some scientific adventures are as fascinating for the casual observer as they are for an engaged specialist. One such is the Search for Extraterrestrial Intelligence (SETI), driven by the premise that if there is life on another planet (especially in the form of intelligent beings), then it could have reached a level of technological advancement equal to ours or perhaps greater. And just as we have tried to find such life out there, these alien beings may be looking for us as well.
Across the vast distances of the cosmos, electromagnetic-wave signals are our best bet to identify ourselves and others. They range from radio signals concentrated in a narrow frequency range to pulsating wideband signals.
Researchers also need to have the proper means and techniques to differentiate naturally occurring waves, like radio noise from the magnetosphere of Jupiter or the environs of stars, from those transmitted from more interesting sources. Waves from space are also distorted en route to the earth and whatever information they carry may not survive the journey intact.
