Scouting for Not-So-Distant Worlds

After it blasted off into space in 2009, NASA’s Kepler Space Telescope sniffed out thousands of potential planets around other stars, simply by watching for the dips in starlight as planets pass over – transit – the disc of their stars. Among its portfolio of planets are gas giants like Jupiter, but many of these are so close to their stars that their atmospheres sizzle at over a thousand degrees. Others are Neptune-sized, or smaller ‘super-Earths’ lurking in their stars’ habitable zones.

Yet the great strengths that led to Kepler’s success were also its weakness; it stared at one patch of sky in the Milky Way constantly, amongst the patterns of the constellations Lyra and Cygnus where the density of stars is highest. While the mission may have seen more stars in this area of sky, some of the stars and their transits that Kepler observed are so faint that ground-based telescopes can’t conduct follow-up observations. What’s needed is a telescope, or a set of telescopes, that can look for planetary transits of the closest and brightest stars across a much wider area of sky.