![]() ![]() It's that tight orbit around the sun which, when averaging out all the distances between the planets, keep Mercury from ever getting too far away from any given planet. The team built an animation showing how even though Earth and Venus briefly pass each other, Mercury's close proximity to the sun meant that its nearest and farthest distances from Earth weren't that different. Army put together a new model published Tuesday in Physics Today that breaks down the average distance among planets - and it turns out that they're all, on average, closest to Mercury. Scientists from NASA, Los Alamos National Lab, and the U.S. Sure, Venus comes closer to Earth than Mercury, but it also spends a lot of time on the opposite side of the sun. In fact, it says that every other planet in the solar system's nearest neighbor is Mercury as well. Ready to get your mind blown? A new model of the planets' orbit shuffles things around, calculating that Earth's closest neighbor, on average, is actually Mercury. "If we could observe it from Earth, it would be quite a spectacle," Zeebe says.You probably learned in school - or space camp - that Venus is Earth's closest planetary neighbor. And in seven other cases, it hit Venus, with no ill effects for our world. Like Laskar, Zeebe found that in roughly 1% of his simulations, the planet eventually acquired a highly elliptical orbit. "It's like if someone was in a lake, he fished for 2 hours, he says, 'I don't find any fish, so there are no fish in this lake.'" Zeebe counters that his simulations, though fewer, better track Mercury when it moves fast, as it does when it's on an elongated orbit that carries it close to the sun.īoth scientists agree on one point: Mercury faces possible trouble. Laskar says Zeebe didn't run enough simulations to discover such a rare event. In 2009, Laskar and a colleague performed a larger number of computer simulations-2501-and found one case in which a planet hit Earth, demonstrating that our world is vulnerable to colossal collisions. In the 20 September issue of The Astrophysical Journal, Zeebe states that our planet's orbit is highly stable for at least the next 5 billion years and that the odds of another world smashing into us are extremely slim.īut Jacques Laskar, an astronomer at the Paris Observatory, blasts the new work. The chemical element 'Mercury' also bore the name of the messenger god. Mercury also lent his name to NASA’s first manned space program the object of this program was to put a man into orbit around the planet. Zeebe reports good news for modern man: In no simulation did any planet hit Earth. Mercury is the closest planet to the sun, and also the one with the quickest orbit around the sun. Each simulation differed from the rest because Mercury started from a slightly different position. That's how much computer time he used to run 1600 simulations of the solar system's future. "No one will ever get six uninterrupted weeks on this machine ever again," Zeebe says. But physicist Richard Zeebe had a rare opportunity: The University of Hawaii, Manoa, where he works, was testing a Cray supercomputer it had just bought. Then Mercury can hit Earth-or, through its gravity, jostle the orbits of the other inner planets so that Venus or Mars crashes into us instead.Ĭomputing the positions of the planets over a period of 5 billion years as they gravitationally interact is a daunting task. Its only a little more than five percent as. For example, simulations show that in some cases Mercury, which already has a fairly elliptical orbit, can get yanked by Jupiter's gravity so that the little planet crosses Venus's orbit. Its surface area only occupies about 15 percent of the Earths surface area. Over millions of years, even a 1-centimeter difference in a planet's position can alter its future position, and the positions of other planets its gravity tugs on, by millions of kilometers. It's hard to predict the fate of our solar system, because no one knows the exact positions of the planets today. Still, not everyone agrees that we're safe. Now, new simulations of our solar system's future suggest such a catastrophe is less likely than previously thought. That's a doomsday scenario scientists have said is a small but real possibility. One day, Mercury could slam into Earth, obliterating all life on our planet.
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