THE PAST two decades have seen astronomers’ catalogue of planets expand over two-hundredfold, as new techniques and better telescopes have found more than 2,000 of them orbiting stars other than the sun. But in the solar system itself, the list of planets has actually shrunk—Pluto having been downgraded from that status in 2006. The number of the sun’s planetary companions has thus fallen from nine to eight.
Now, a pair of astronomers from the California Institute of Technology think they have evidence that will restore the sun’s tally to its previous value. Their analysis of objects orbiting in the Kuiper Belt, a ring of frozen asteroids that circle beyond the orbit of Neptune (and of which Pluto is now regarded as the largest member), suggests to them that something about ten times as massive as Earth has distorted those orbits. If you knew where to look, this planet-sized object would be visible through a suitable telescope. And Konstanin Batygin and Michael Brown believe they do know.
As they write in the Astronomical Journal, they have analysed the orbits of Kuiper-Belt objects and found six that behave...Continue reading
Source: Science and technology http://ift.tt/1RTszfw
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