The influence of the gravity of the other planets has the potential to dramatically change its orbit, however, making it a potential threat to Earth in the year 4479.
Such a strategy would involve the use of a nonexplosive projectile sent to strike the object in a particular location at high speed to change its orbit and possibly to fragment it.
This is a much smaller distance than that between the Earth and the Sun, for instance, and it means that if the Sun were a black hole, the Earth would not change its orbit.
The flight of Endeavour, which took off from Cape Canaveral, Fla., last Friday, had gone according to plan until early today, when mission control ordered the shuttle to change its orbit slightly to avoid a piece of space debris.
NASA and others aim to test this strategy in 2022 with the Double Asteroid Redirection Test, in which a spacecraft will deliberately crash into the smaller member of a binary asteroid system in an attempt to change its orbit around the larger body.
Professor Alan Fitzsimmons, an astronomer at Queen's University Belfast, UK, said: "In 2029, it will pass so close to us that Earth's gravity will change its orbit.
After a few more weeks of low-altitude crossings across the day side of the comet, Rosetta will change its orbit and take the final plunge on the comet's surface at the end of September.
In his book Star Trails, David Levy (of Shoemaker-Levy 9 fame) mentions how a Deep Impact mission scientist described that collision-- It's [the] revenge of the dinosaurs!"--Earth-life reacollision-- Ittrike bacollision-- Itand slightly change its orbit.
In space, there are small perturbing forces that can slow a satellite down or change its position within its orbit.
As the Earth orbits the Sun, it changes its position relative to the other stars in the sky.
