Short History of Jansky – January 1932

Modified Bruce Array: Harald Friis design December 1932 Jansky’s 1932 Data - 1937

9.5 m Parabolic Reflector! Strip Chart output From Strip Chart to Contour Plot… 1940 Ap. J. paper…barely Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The Reber’s 160 MHz contour map published in the ApJ in 1944. This shows the northern sky in equatorial coordinates. The & Hendrik van de Hulst Lieden Observatory 1944 Predicted HI Line Detection of …… Ewen & Purcell

21 cm HI Line (1420 MHz)

Purcell HI Receiver: Doc Ewen (1951) in Optical

Origin of SETI Nature, 1959

Philip Morrison 1959 Project Ozma: April 6, 1960

Tau Ceti & Epsilon Eridani Cosmic Background: Penzias & Wilson 1965

• 20 ft Echo Horn (Sugar Scoop): • Harald Friis design Pulsars: Bell and Hewish 1967 Detection of Pulsars: ~100ft of chart/day

Chart recording of the pulsar Examples of scintillating detection and an interference signal somewhat later in time. Fast chart recording of pulsar emission (LGM nomenclature is “Little Green

Arecibo Message: 1974 Big Ear OSU Wow! Signal, Aug. 15, 1977

Sagitarius, Chi Sagittari star group NRAO 36ft Kitt Peak Telescope

The Drake Equation

The Drake equation states that: where: N = the number of civilizations in our galaxy with which communication might be possible; and R* = the average rate of star formation per year in our galaxy fp = the fraction of those stars that have planets ne = the average number of planets that can potentially support life per star that has planets fℓ = the fraction of the above that actually go on to develop life at some point fi = the fraction of the above that actually go on to develop intelligent life fc = the fraction of civilizations that develop a technology and desire to communicate. L = the length of time for which such civilizations release detectable signals into space