Lecture 34 - Exoplanets
The area of research that has attracted great attention in recent years is that of planet formation, recognised by the awarding of (2/3rd of) the 2019 Nobel prize to Michel Mayor and Didier Queloz ``for the discovery of an exoplanet orbiting a solar-type star''.
In the past decade, NASA's Kepler Space Telescope has detected more than 3000 exoplanets ranging from sub-Earth-sized planets to huge gas giants that dwarf even our Jupiter, with densities ranging from that of styrofoam to iron. Astronomers find them close to their parent or host stars with scorching temperatures, to a great number in the so-called 'habitable zone' in which life (as we know it) can flourish.
Even before Newton’s time, there were assertions that the stars were just like the sun, but far away. Some even went on to conjecture that there must be planets orbiting many of the stars. The first extrasolar planet was found in 1995. Today, nearly 6,000 exoplanets have been discovered. In this lecture, I discuss some of the current ideas on how planets form from gas and dust, left over from the formation of the host star.