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Are we Alone? - The Search for Life beyond the Earth. Ian Morison Emeritus Professor of Astronomy Gresham College. Star-stuff. Ring Nebula. M1 The Crab Nebula. Elsewhere in our own Solar System. We could find other simple life-forms here. Canals on Mars?. The Face on Mars!.
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Are we Alone? - The Search for Life beyond the Earth. Ian Morison Emeritus Professor of Astronomy Gresham College
Elsewhere in our own Solar System We could find other simple life-forms here.
Viking on Mars • Two Viking Spacecraft landed on Mars in 1976 to search for evidence of life.
Jupiter 4 major moons – discovered by Galileo Io Europa Ganymede Callisto
Breaking up of the surface • Icebergs!
Can we see any exo-planets? A real problem due to the overwhelming brightness of the star orbited by the planet.
HST using a coronograph • The Hubble Space Telescope has observed a planet in orbit around the star Formalhaut.
Indirect Detection Methods The RADIAL VELOCITY or DOPPLER WOBBLE method
51 Pegasi b • The first planet detected around a normal star. • Period just 4 days! • A gas giant very close to its star.
Planetary Transits Detect the transit of a planet as it crosses the face of the star. This results in a slight drop in luminosity. This can only work if the orbital plane of the planet includes the Earth.
HD 209458 b • 150 light years from Earth. • Planet orbits every 3.5 days. • 4 million miles from its star. • Atmospheric temperature ~2000K.
We could detect evidence of life by observing the spectra of the planet’s atmosphere.
SETI The Search for Extraterrestrial Intelligence
The Seminal Paper • In 1959 Giuseppe Cocconi and Phillip Morrison published a paper in Nature in which they pointed out that given two telescopes of the size of the newly built 250ft Mk1 Radio Telescope at Jodrell Bank it would, in principle, be possible to communicate across inter-stellar distances.
They suggested that any search should target the nearest Sun-like stars as these live long enough and are hot enough to allow life a chance to evolve on a planet at a suitable distance from them. A target list was provided including TauCeti and Epsilon Eridani. Where to look? Locations
Where to look? Frequency • They pointed out that the background noise (atmosphere, Galaxy, CMB etc.) was a minimum between ~1 to 10 GHz. • This band included the (radio) Hydrogen Line at 1.4 GHz and the OH Lines at ~ 1.6 GHz. • The band from 1.4 to 1.6 GHz is called the Water Hole
Project Ozma • In 1960 Frank Drake and his colleagues at Green Bank, West Virginia, used the Tatel 85ft telescope to make the very first SETI observations in what was called Project Ozma.
Project Ozma • They were given use of a new, state of art, low noise parametric amplifier and made observations over a 400 KHz band around the Hydrogen Line at 1420 MHz. • They observed Tau Ceti and Epsilon Eridani for a total of two months, but only detected the, then top secret, U2 Spy plane!