Astronomers find solar-powered asteroid
For the first time, an international team of astronomers has been able to show that the acceleration of an asteroid's rotation is powered by solar energy. Astronomers had for some time predicted that the Sun was involved in the speed of an asteroid's spinning, but it took a fleet of telescopes to prove that the time it takes to rotate decreases by 1 millisecond each year as a consequence of the heating of the asteroid's surface by the Sun. Scientists believe that the asteroid 2000 PH5 may eventually spin faster than any other known asteroid in the solar system and perhaps even break apart. 'The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect is believed to alter the way small bodies in the solar system rotate,' said Stephen Lowry of Queens University Belfast in the UK. He is the lead author of one of the two papers in which this work is reported. 'The warming caused by sunlight hitting the surfaces of asteroids and meteoroids leads to a gentle recoil effect as the heat is released,' he added. 'By analogy, if one were to shine light on a propeller over a long enough period, it would start spinning.' Although the YORP effect is an almost immeasurably weak force, it builds up over millions of years. Scientists believe that the YORP effect may be responsible for spinning some asteroids so fast that they break apart and form double asteroids. The YORP effect also plays a role in changing the orbits of asteroids between Mars and Jupiter. Despite its importance, the effect has never been seen acting on a solar system body, until now. The effect was witnessed using the European Southern Observatory's Very Large Telescope, along with the New Technology Telescope in Chile and telescopes from the Czech Republic, the Canary Islands, Hawaii and Spain.