Speaker: Dr Leigh Fletcher (University of Oxford)
The number of giant planets discovered around stars throughout our galaxy has exploded over the last decade, and we now know them to be common features of planetary systems. Given that we'll never be able to observe the physical and chemical conditions on these giant exo-worlds directly, we must now consider the gas and ice giants in our solar system as the four closest examples of a whole class of astrophysical objects. Yet despite decades of exploration and telescopic observation, some of our most basic questions about the origins and physical phenomena at work on these planets remain unanswered. What tropospheric processes cause Jupiter's stripes to change their appearance, such as the 2009-10 fade of the South Equatorial Belt? What powers the incredible planet-encircling storm systems, hexagonal waves and polar vortices observed by the Cassini spacecraft at Saturn? And why do the ice giants appear so different, with sluggish Uranus contrasted with the dynamic cloud variability on distant Neptune? By investigating each of these seemingly isolated phenomena, we are coming closer to explaining how planetary atmospheres vary as a function of distance from the parent star, and how our planetary system formed and evolved over the past 4.5 billion years. We'll discuss the latest Cassini discoveries at Saturn and plans for its end-of-mission in 2017; the challenges of building long-lived robotic spacecraft for the frigid outer reaches of our solar system; and ESA's ambitious new mission to Jupiter and it's collection of potentially-habitable icy satellites (JUICE). Refreshments available from 7pm.