Lecture by Alan Rubin

Researcher at the Earth, Planetary, and Space Sciences Department, UCLA

Icy planetesimals that formed in the outer reaches of the solar system are occasionally perturbed closer to the Sun. In these warmer environs they emit gas and dust and form extensive tails. Comets have bewitched, bothered and bewildered observers since ancient times. One appeared in the sky after Caesar was assassinated in 44 BCE (interpreted as his soul ascending into Heaven); and one heralded Harold's demise and William the Conqueror’s success at the Battle of Hastings in 1066 CE. Comets may also have been responsible for delivering water, organics and other volatiles to Earth early in the history of our planet, setting the stage for the origin of life.