Stories of Astronomy 2012

Bringing undiscovered Earths into focus

USING A NEW OBSERVATORY BEING BUILT NORTH OF HOBART, RESEARCHERS AT THE UNIVERSITY OF TASMANIA ARE GEARING UP TO FIND WHETHER THE UNIVERSE HARBOURS MORE PLANETS LIKE EARTH. CREDIT: JOHN GREENHILL, UNIVERSITY OF TASMANIA.
USING A NEW OBSERVATORY BEING BUILT NORTH OF HOBART, RESEARCHERS AT THE UNIVERSITY OF TASMANIA ARE GEARING UP TO FIND WHETHER THE UNIVERSE HARBOURS MORE PLANETS LIKE EARTH. CREDIT: JOHN GREENHILL, UNIVERSITY OF TASMANIA.

How many of the planets scattered across the Universe have the potential to harbour life? An observatory being built in Tasmania is poised to help answer just that question.

Astronomers at the University of Tasmania (UTas) currently use the Mount Canopus Observatory in Hobart to search for Earth-like planets orbiting distant suns—but the growing city is compromising the observatory’s view of space. “Light is driving us away,” says John Greenhill, the Observatory’s director.

Thanks to a $2 million donation, UTas is receiving a new 1.3-metre optical telescope, and it has also been given a new wide-field imaging camera. The University will house the telescope in an observatory, being built about 70 kilometres north of Hobart at Bisdee Tier, which will have no such light pollution problems. “The new observatory will have a camera with a much bigger field of view, so we can measure many more planetary candidates at the same time,” says John.

The UTas team is part of a global network of astronomers who spot exoplanets—planets outside our Solar System—using a technique called ‘gravitational microlensing’. Whenever one star passes in front of another, the gravity of the nearer star acts like a lens, focusing the light of the more distant star. Within that brightening light, planets orbiting the nearer star can be detected, including details about their size and distance from their host-star.

Most of the exoplanets discovered so far are much larger and hotter than Earth, but the gravitational microlensing technique is particularly sensitive to revealing planets more like those in the Solar System, says John. “We already have evidence that planetary systems like our own, and cool rocky planets similar to Earth-mass, may be very common,” he says.

The team is currently waiting for their new telescope to arrive from Canada, where it was built. “We’re optimistic that we will be able to start observations before the end of the year,” John says.

PHOTO: USING A NEW OBSERVATORY BEING BUILT NORTH OF HOBART, RESEARCHERS AT THE UNIVERSITY OF TASMANIA ARE GEARING UP TO FIND WHETHER THE UNIVERSE HARBOURS MORE PLANETS LIKE EARTH. CREDIT: JOHN GREENHILL, UNIVERSITY OF TASMANIA.

School of Mathematics and Physics, University of Tasmania, Hobart
Dr John Greenhill, Tel: +61 (3) 6226 2429, John.Greenhill@utas.edu.au, fcms.its.utas.edu.au/scieng/physics/