India, Oct. 10 -- What does it look like, our history of trying to find alien life? How far back does it go?

* 1899: Strange, repeating beeps

Nikola Tesla, the Serbian-American innovator who helped advance radio communication and the adoption of electricity, was tinkering with a radio-wave receptor in his lab when he picked up strange repeating beeps. He thought they came from aliens attempting to reach us. It turned out they were just cosmic noise; chirps from the magnetic fields disturbed by large planets in our solar system. Already, though, the idea that we might someday "meet the neighbours" was generating excitement.

* 1924: America's "Big Listen" for Mars

The eccentric astronomer David Todd somehow convinces the US Navy to help...