MISSIONS to scan the skies for habitable planets have come a step closer, after a technique called 鈥渘ulling interferometry鈥� discovered its first planet.
Most planets known so far were found by detecting the gravitational influence on their home star, but nulling interferometry should allow astronomers to see planets directly. It works by combining the light from a star in such a way that it is cancelled out, making fainter details around it more visible.
Philip Hinz of the University of Arizona and his team used the Magellan telescope in Chile to study a 10-million-year-old star called HD 100546. Their nulling interferometer cut out 95 per cent of its light, revealing a gap in the dusty disc surrounding the star. The gap means that a planet is in the process of forming from the dust, Hinz says. He calculates that the planet is a gas giant, several times the mass of Jupiter and about as far from its star as Saturn is from the sun.
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The find is good news for the European Space Agency鈥檚 Darwin mission and NASA鈥檚 Terrestrial Planet Finder, which both hope to use nulling interferometry to find and analyse Earth-sized worlds when they launch in around 15 years鈥� time. In space they will be able to stop all but a millionth of a star鈥檚 light. 鈥淚 see this as a first, preliminary step towards those missions,鈥� Hinz says.