Public Lecture Report

The Future of Planet Hunting

By Professor Don Pollacco, Queen's University Belfast

Monday 8 August

Trinity College, Dublin

"There are infinite worlds both like and unlike this world of ours." – Epicurus, circa 300BC

The search for exoplanets is one of the most exciting fields in astronomy and will perhaps one day answer the question of whether we are alone in the universe. Although searching for alien worlds dates back to ancient times the techniques needed to detect them have only recently been developed with the first exoplanet being discovered in 1992. The possibility of finding life on another planet is a thrilling one not only for astronomers but also for a huge proportion of the general public, and this was clearly evident at Astronomy Ireland’s August lecture in Trinity College on Monday night. The Schroedinger theatre was packed full of people eager to hear Professor Don Pollacco from Queen's University, Belfast, speak about the next generation of exoplanet surveys and get a clue as to where in our galaxy we may find our alien neighbours.

Prof Pollacco is a research astronomer in the Astrophysics Research Centre at QUB, and he is part of a team who uses and operates SuperWASP instruments. SuperWASP is a leading extra-solar planet detection programme. It consists of two robotic observatories that operate all year round allowing astronomers to cover both hemispheres of the sky. The observatories each consist of eight wide-angle cameras that simultaneously monitor the sky for planetary transit events. Prof Pollacco explained that a transit occurs when a planet passes in front of its parent star temporarily blocking some of the light from it. The SuperWASP instruments look for these tiny dips in the brightness of the parent star. The eight wide-angle cameras allow them to monitor millions of stars simultaneously enabling the detection of rare transit events.

A large percentage of the exo-planets discovered are those known as ‘hot jupiters’, large gaseous plants, some of them with only a 4 day orbit period like 51 Pegasus b discovered in 1995. This planet is approximately 150 times the size of Earth, yet is closer to its parent star than Mercury is to the Sun.

The search for exo-planets has prompted many questions both scientific and philosophical. It has forced us to examine and question what our definition of life is, and what alien life might look like if and when we do find evidence of it. Is it arrogant to believe that life only exists on our planet, that out of the 200 billion stars in our galaxy, life has only evolved around one? And if we surmise that this is the case then we are left with the bottomless question - why? So perhaps better to assume we are not alone and take comfort from the Drake Equation, explored at our lecture, which estimates that there are around 20,000 extraterrestrial civilizations in the Milky Way galaxy at present!

Since Antiquity many have held the belief that we are not alone, that life must exist elsewhere. “There are infinite worlds both like and unlike this world of ours” said the Ancient Greek philosopher Epicurus (c300BC) – and he was an Aquarian, so he should know!

If you could not attend the lecture, order a copy of the DVD HERE.