the story of Asteroids

Asteroids, sometimes called minor planets, are rocky remnants left over from the first formation of our system about 4.6 billion years ago.

The currently known asteroid count is 958,660.

Most of this ancient space rubble are often found orbiting the sun between Mars and Jupiter within the most belt . Asteroids home in size from Vesta—the largest at about 329 miles (530 kilometers) in diameter - to bodies that are but 33 feet (10 meters) across. the entire mass of all the asteroids combined is a smaller amount than that of Earth's Moon.

Most asteroids are irregularly shaped, though a couple of are nearly spherical, and that they are often pitted or cratered. As they revolve round the sun in elliptical orbits, the asteroids also rotate, sometimes quite erratically, tumbling as they are going . quite 150 asteroids are known to possess alittle companion moon (some have two moons). There also are binary (double) asteroids, during which two rocky bodies of roughly equal size orbit one another , also as triple asteroid systems.

---

Asteroid Classifications

Main Asteroid Belt: the majority of known asteroids orbit within the belt between Mars and Jupiter, generally with not very elongated orbits. The belt is estimated to contain between 1.1 and 1.9 million asteroids larger than 1 kilometer (0.6 mile) in diameter, and many smaller ones. Early within the history of the system , the gravity of newly formed Jupiter brought an end to the formation of planetary bodies during this region and caused the tiny bodies to hit each other , fragmenting them into the asteroids we observe today.

Trojans: These asteroids share an orbit with a bigger planet, but don't hit it because they gather around two special places within the orbit (called the L4 and L5 Lagrangian points). There, the gravitational pull from the sun and therefore the planet are balanced by a trojan's tendency to otherwise fly out of the orbit. The Jupiter trojans form the foremost significant population of trojan asteroids. it's thought that they're as numerous because the asteroids within the belt . There are Mars and Neptune trojans, and NASA announced the invention of an Earth trojan in 2011.

Near-Earth Asteroids: These objects have orbits that pass accessible that of Earth. Asteroids that really cross Earth's orbital path are referred to as Earth-crossers. As of June 19, 2013, 10,003 near-Earth asteroids are known and therefore the number over 1 kilometer in diameter is assumed to be 861, with 1,409 classified as potentially hazardous asteroids - people who could pose a threat to Earth.

---

How Asteroids Get Their Names

The International Astronomical Union's Committee on Small Body Nomenclature.is a little less strict when it involves naming asteroids than other IAU naming committees. So out there orbiting the sun we've giant space rocks named for Mr. Spock (a cat named for the character of "Star Trek" fame), rock musician Frank Zappa, beloved teachers like Florida’s Cynthia L. Reyes, and more somber tributes like the seven asteroids named for the crew of the spacecraft Columbia killed in 2003. Asteroids also are named for places and a spread of other things. (The IAU discourages naming asteroids for pets, so Mr. Spock stands alone).

Asteroids also are given variety , for instance (99942) Apophis.