New method may find 100 billion Earth-like worlds

Researchers in New Zealand are championing a new planet hunting technique


Credit: Thinkstock

New Zealand's Mount John Observatory is on the hunt for exoplanets.

NASA’s Kepler space observatory has been doing a fantastic job finding Earth-like planets by detecting the tiny fluctuations in the light from distant stars caused by orbiting worlds. So far, the observatory has confirmed over 100 planets using this reliable technique called the transit method. But now, researchers at The University of Auckland are using an alternative technique that could see them discover as many as 100 billion.

The team’s new method uses gravitational microlensing, which measures the deflection of light as the gravitational field of planets in its path distorts it.

This method is being used by a collaboration between Japan and New Zealand, Microlensing Observations in Astrophysics (MOA), at New Zealand’s Mount John Observatory.

Despite the excitement surrounding this advanced planet hunting process, Kepler won’t be left redundant. The method proposed by the New Zealand research team will rely on a combination of data from microlensing and the Kepler space observatory to find as many Earth-like planets as possible.

Credit: NASA, ESA, K. Sharon (Tel Aviv University) and E. Ofek (Caltech)

This Hubble image shows gravitational lensing in action as the light from a distant quasar is bent and multiplied by the gravity of a cluster of galaxies in front of it.

Lead researcher Dr Phil Yock from the University of Auckland’s Department of Physics explained how the two planet spotting techniques would be applied together, “Kepler finds Earth-sized planets that are quite close to parent stars, and it estimates that there are 17 billion such planets in the Milky Way,” he said.

“Our proposal is to measure the number of Earth-mass planets orbiting stars at distances typically twice the Sun-Earth distance. Our planets will therefore be cooler than the Earth. By interpolating between the Kepler and MOA results, we should get a good estimate of the number of Earth-like, habitable planets in the Galaxy. We anticipate a number in the order of 100 billion.”

Simulations carried out by Yock and his colleagues showed that the tiny deflections of light caused by Earth-sized planets could be detected more easily if they had a worldwide network of telescopes dedicated to the job.

This proposed network of 1m and 2m telescopes is now being realised by an organisation called Las Cumbres Observatory Global Telescope Network (LCOGT) with three telescopes in Chile, three in South Africa, three in Australia, and one each in Hawaii and Texas.

The Liverpool Telescope in the Canary Islands, the 1.8m MOA telescope at the Mount John Observatory, Poland’s 1.3m OGLE telescope in Chile and the 1.3m Harlingten telescope in Tasmania will support the network.


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