Cosmic life

The existence and detection of extraterrestrial life are discussed. The evolution of life on earth is not considered possible if earth were 5% closer (runaway greenhouse effect) or 1% farther (runaway glaciation) from the sun, or if the sun were slightly more or less massive or hot. The Space Telescope and a possible interferometer search at infrared wavelengths, which offers a 100,000 times advantage over the visible in the ratio of planetary to stellar power, are proposed to help detect planetary systems about stars such as Barnard's star. The proposed NASA-Ames Project Cyclops, consisting of a 10 km phased array of 1026 dishes (perhaps on the back side of the moon), as well as a Soviet proposal to assemble 2 similar telescopes at the orbit of Saturn, would search in the radio frequency range for planets 100 light years or more distant.