On Wednesday we were treated to an enthralling lecture by returning speaker, Will Gater.
Will, an Astrophysics graduate of UCL, is a freelance journalist of astronomy, author of several books and a regular presenter on TV and radio.
Entitled "Alien Worlds: the extraordinary inhabitants of the Milky Way" Will took us on a spectacular tour of the burgeoning field of Exoplanets. Setting the scene with Ancient Greek and Middle Ages philosophical reflections on the Plurality of Worlds, he took us through the groundbreaking discoveries of exoplanets, namely those around Pulsar PSR B1257+12 in 1992, detected by investigating radio pulse anomalies, and then those orbiting a main sequence star, 51 Pegasi, identified in 1995 by the radial velocity method.
Will continued to explain in detail the various methods of detection employed, including the transit method, gravitational micro-lensing and the aforementioned radial velocity "Doppler shift" technique. The Kepler mission, of course, featured largely and how its astonishing catalogue of discoveries continues despite its severely curtailed capabilities owing to mechanical problems.
Will related the initial shock and still not fully understood nature of exoplanetary systems and their dissimilarity to our own. The plethora of close orbiting "hot Jupiters" and "super Earths" and corresponding paucity of systems structured like our Solar System is a distinct puzzle for near-future projects such as the EELT, JWT, TESS and others to try and solve.
Having outlined the caveats in getting too excited about Earth-sized worlds in "Goldilocks Zones" around other stars, Will finished his brilliant (and non-stop!) talk on a fine up-note by presenting the staggering extrapolated statistics of Earth-sized, temperate worlds in the Milky Way. There are probably billions out there, he concluded, as we applauded another truly excellent evening and speaker at WAS lecture-night.