PLANETS rarely play peekaboo. But if you are quick, you can spot them before they hide away again.
One of the most promising techniques used to detect alien worlds is 鈥渕icrolensing鈥�, which can spot smaller-sized planets than rival techniques. It involves watching how a planet鈥檚 gravity bends the light of a distant background star. So far, only four planets have been discovered this way, because such events are temporary, random and do not recur.
Last week, however, astronomers added a feather to microlensing鈥檚 cap. A team led by Scott Gaudi of Ohio State University in Columbus announced it had used the technique to find a multi-planetary system ().
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The planets鈥� size ratio and orbits resemble a scaled-down version of Jupiter and Saturn, the researchers say, but the system is colder than our own because its star is relatively dim.
鈥淚t鈥檚 a big breakthrough,鈥� says Sara Seager of Massachusetts Institute of Technology. 鈥淲e鈥檙e seeing a triumph of the new technique.鈥�
