MorningSong
16th August 2010, 16:33
Cool! Wonder what's following Earth?:ohwell:
Rachel Kaufman
for National Geographic News
Published August 12, 2010
Neptune's got company—a so-called Trojan asteroid caught in a gravitational "dead zone" caused by a cosmic tug-of-war between the gravitational fields of the gas giant planet and the sun.
In this dead zone the sun and Neptune's gravitational pulls are roughly equal. As a result, the asteroid is held at a fixed distance behind the planet, following—but not orbiting—Neptune as it circles the sun.
These regions where the gravity of the sun and a planet balance out are called Lagrangian points. Lagrangian points L4 and L5—where the new Neptune asteroid was found—are the most stable. The small, rocky bodies caught in these zones share their host planet's orbits.
Trojans have been found at the L4 and L5 points of Jupiter, Mars, and even of two of Saturn's moons.
And where there's one Trojan, there are bound to be more, said astronomer Scott Sheppard of the Carnegie Institution for Science in Washington, D.C., who led the research.
Neptune probably has hundreds of asteroids trailing it, he said—outnumbering even those in the asteroid belt, which circles the sun between the orbits of Mars and Jupiter.
http://news.nationalgeographic.com/news/2010/08/100812-neptune-asteroid-trojan-dead-zone-space-science
Rachel Kaufman
for National Geographic News
Published August 12, 2010
Neptune's got company—a so-called Trojan asteroid caught in a gravitational "dead zone" caused by a cosmic tug-of-war between the gravitational fields of the gas giant planet and the sun.
In this dead zone the sun and Neptune's gravitational pulls are roughly equal. As a result, the asteroid is held at a fixed distance behind the planet, following—but not orbiting—Neptune as it circles the sun.
These regions where the gravity of the sun and a planet balance out are called Lagrangian points. Lagrangian points L4 and L5—where the new Neptune asteroid was found—are the most stable. The small, rocky bodies caught in these zones share their host planet's orbits.
Trojans have been found at the L4 and L5 points of Jupiter, Mars, and even of two of Saturn's moons.
And where there's one Trojan, there are bound to be more, said astronomer Scott Sheppard of the Carnegie Institution for Science in Washington, D.C., who led the research.
Neptune probably has hundreds of asteroids trailing it, he said—outnumbering even those in the asteroid belt, which circles the sun between the orbits of Mars and Jupiter.
http://news.nationalgeographic.com/news/2010/08/100812-neptune-asteroid-trojan-dead-zone-space-science