Philip Morrison was a professor of physics at the Massachusetts Institute of Technology (MIT). He is known for his work on the Manhattan Project during World War II, and for his later work in quantum physics, nuclear physics, high energy astrophysics, and SETI.
Morrison in 1976
Search for extraterrestrial intelligence
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets.
The Wow! Signal
Sensitivity vs range for SETI radio searches. The diagonal lines show transmitters of different effective powers. The x-axis is the sensitivity of the search. The y-axis on the right is the range in light-years, and on the left is the number of Sun-like stars within this range. The vertical line labeled SS is the typical sensitivity achieved by a full sky search, such as BETA above. The vertical line labeled TS is the typical sensitivity achieved by a targeted search such as Phoenix.
Arecibo Telescope in Puerto Rico with its 300 m (980 ft) dish was one of the world's largest filled-aperture (i.e. full dish) radio telescope and conducted some SETI searches.
Microwave window as seen by a ground based system. From NASA report SP-419: SETI – the Search for Extraterrestrial Intelligence