What of these best describes an asteroid?

Answer 1

Asteroids, sometimes called minor planets or planetoids, are small rocky bodies in orbit around the Sun, especially in the inner Solar System; they are smaller than planets but larger than meteoroids. The term "asteroid" has historically been applied primarily to minor planets of the inner Solar System, as the outer Solar System was poorly known when it came into common usage.

Most known asteroids are found in the Main Belt between Mars and Jupiter, or in the Kuiper Belt past the orbit of Neptune. But there are thousands that orbit at least as close to the Sun as Earth. The vast majority of asteroids are smaller than 1 kilometer in diameter. The largest asteroid in the Main Belt is Ceres, which has been designated a dwarf planet.

The distinction between asteroids and comets is made on visual appearance: comets show a perceptible lighted envelope or aura while asteroids do not. This is caused by the release of volatile substances, mostly frozen gases, from the comets' interiors.

Asteroids are rocky fragments left over from the formation of the solar system (about 4.6 billion years ago!). They can be found orbiting the sun in an area between Mars and Jupiter called the "Asteroid Belt". This asteroid belt, or "main belt" contains probably millions of asteroids.

Asteroids get their name from the Greek word that means "star-like", a misnomer now considering today's scientific classifications made from our new space data. Asteroids are actually more appropriately referred to by astronomers and other scientists as "minor planets" or "planetoids" (which means "planet-like").

Some facts about asteroids:

• Asteroids are celestial bodies/objects that are in the solar system.
• An asteroid orbits the planets and sun and moon as a "mid-sized celestial object" - from 10 meters to 1000 km in diameter.
• They are a mixture of stone, heavy and light elements, and possibly gasses (in solid, liquid, frozen, or plasma states/organic/inorganic).
• One will often have meteoroid clouds nearby or trailing them (may be considered as comets).
• It may be moving either in orbit around another celestial object or floating or traveling on its own accord.
• They are also called minor planets, planetoids, centaurs
• Classifications of smaller asteroids are:

C-type, carbonaceous

S-type, siliceous

M-type, metallic

There are many good reference sources on the Internet about asteroids. Try some of the web sites listed in the related links section for this question below.

Answer 2

The Apollo asteroids are a group of near Earth asteroids named after "1862 Apollo", the first asteroid of this group to be discovered. Some can get very close to the Earth, making them a potential threat to our planet. One of the smaller asteroids named 2008 TC3 was a meteoroid 2 to 5 meters (7 to 16 ft) in diameter that entered Earth's atmosphere on October 7, 2008, It exploded an estimated 37 kilometers (23 mi) above the Nubian Desert in Sudan. The largest known is 1866 Sisyphus, with a diameter of about 10 km. It is comparable in size to the Chicxulub object whose impact might of caused the extinction of the dinosaurs.

Answer 3

Asteroids are essentially debris left over from the formation of the solar system, Most orbit in the asteroid belt between the orbits of Mars and Jupiter.

Answer 4

Small, rocky and cold.