Searching for Extraterrestrial Intelligence: From Project Ozma to Breakthrough Listen and the Debate on Contact

To the point

Life beyond Earth is plausible, but interstellar contact is more likely through signals than ships because Bernard Oliver showed the enormous energy cost of near-light travel, so humans sent Pioneer plaques and Voyager records and now search with radio, optical, and infrared methods led by Frank Drake’s Project Ozma, Yuri Milner’s Breakthrough Listen, and Jill Tarter at the Allen Telescope Array, using the Drake equation to estimate how many civilizations might exist based on their lifetimes L, while ethics and governance questions about actively transmitting remain debated.