The Globe & Mail reports that a small asteroid called 2002 AA29 is in a circular orbit following the same general path around the sun as the Earth. Sometimes it speeds up and gets ahead of us and sometimes it slows down and drops behind. On Wednesday, the asteroid will be within 6 million kilometres of Earth–closer than it has been in almost a century. During this close approach, the Earth’s gravity will cause the asteroid to swing into a slightly lower, faster orbit. In 95 years, it will lap us and approach Earth again from behind. Earth’s gravity then will force the asteroid into a higher, slower orbit and Earth will move ahead. In another 95 years, the Earth will approach from behind and the cycle will be repeated. It is this cycle of Earth’s gravity interacting with it during its periodic approaches that will keep it at bay forever. In 600 years it will somewhat orbit the Earth for 40 years before continuing back on its previous orbit. Even if the 60 metre-wide asteroid did strike the Earth, it would not cause planetwide destruction as did the 10-kilometre-wide asteroid that created the Chicxulub crater in Mexico’s Yucatan Peninsula and is theorized to have killed the dinosaurs 65 million years ago. Instead, the impact would create a crater about a kilometre across, similar to the Barringer meteor crater in Arizona.