Mercury’s chaotic orbit poses no threat to Earth, says study

Science : Because of the gravitational interactions among the planets in our solar system, the planets’ positions can change over millions of years. Astronomers had predicted that over time Mercury’s already elliptical orbit could become sufficiently perturbed that the planet could crash into Earth. According to a recent study by Richard Zeebe of the University of Hawaii at Manoa, however, that doomsday scenario is unlikely. Over a six-week period, he ran 1600 computer simulations to compute the planets’ positions over the next 5 billion years. He reports that none of the simulations “led to a close encounter involving the Earth or a destabilization of Earth’s orbit.” His findings disagree with a 2009 study by Jacques Laskar of the Paris Observatory, who says that out of the 2501 simulations he ran, Earth was struck by another planet in at least one instance. Both researchers agree, nonetheless, that Mercury is going to have problems: Its orbit is likely to change course over time, and eventually it will collide with either Venus or even the Sun.