Plenty of habitable planets – somewhere

Earthlings could be one step closer to finding another planet to inhabit after researchers at the University of Auckland revealed a new method for finding Earth-like planets in the Milky Way.

They think there could be up to 100 billion planets that humans could live on – not too hot and not too cold – but still have to find them.

Dr Phil Yock, of the university’s physics department, said the group would use data from gravitational microlensing, already used at the Mt John Observatory at Tekapo, and the National Aeronautics and Space Administration’s Kepler space telescope, as well as several new telescopes around the world.

He said Kepler measured the loss of light from a star when a planet orbited between Earth and the star, and microlensing measured the deflection of light from a distant star that passed through a planetary system en route to Earth – an effect predicted by Albert Einstein in 1936.

Yock said planets could be detected easier if a worldwide network of moderate-sized, robotic telescopes was available to monitor them.

Coincidentally, a network of one and two-metre telescopes is being deployed – three in Chile, three in South Africa, three in Australia and one each in Hawaii and Texas.

Yock said it was estimated there would be 100 billion Earth-like planets in the galaxy.

‘‘Kepler finds Earth-sized planets that are quite close to parent stars, and it estimates there are 17 billion such planets in the Milky Way,’’ he said.

‘‘These planets are generally hotter than Earth, although some could be of a similar temperature [and therefore habitable] if they’re orbiting a cool star called a red dwarf.

‘‘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 Earth.

‘‘Of course, it will be a long way from measuring this number to actually finding inhabited planets, but it will be a step along the way.’’

It is expected the data from the telescopes will be supplemented by measurements using the telescope at Mt John, a telescope in Chile known as OGLE, and the recently opened Harlingten telescope in Tasmania.