What makes up the belt between the orbits of mars and Jupiter? Asteroids. What are sometimes called planetiods (or small planets)? Asteroids. What has a surface that is about 100º F. Asteroids. Read my report to find out more about asteroids.

Asteroids are planetary bodies that revolve around the Sun. Most of them are located in the asteroid belt between Mars and Jupiter. Astronomers think over 30,000 asteroids are out there and that over 1,150 in the belt have diameters larger than 18 miles (30 km).

Scientists have two predictions on how the asteroids in the belt were formed. The first is that a long time ago another planet lay where the asteroid belt is now. The planet broke apart and formed all the asteroids. The other is that, a 10th planet was trying to form with the debris that was leftover from the Big Bang. But what happened was the planet instead formed into the asteroid belt.

What types of asteroids are there?

Asteroids are divided into three major types depending on their chemical composition and their reflective power. Their chemical compositions are how much of each chemical they have and their combinations. Their reflective power is how much light they reflect. Let’s look at these types.

C-type: More than 75% of the known asteroids are C-type. They’re very dark. They have the same chemical composition as the Sun without hydrogen, helium and other volatiles that cause the Sun to burn hot.

S-type: 17% of the known asteroids are S-type. They’re relatively bright. These types are made of metallic nickel-iron, combined with iron and magnesium-silicates a composition that makes them more reflective.

M-type: about 7% of the known asteroids are M-type. These asteroids are extremely bright. They’re 100% nickel-iron and this composition gives them a lot of reflective power.

The biggest asteroid known is 1 Ceres. It has a diameter of about 600 miles, which is almost 1/3 the size of the moon. 1 Ceres was discovered by Giuseppe Piazzi on, January 1, 1801. 2 Pallas, the 2nd largest, 3 Juno, the 3rd discovered, and 4 Vesta, the 3rd largest, were discovered in the next few years. The top 4 asteroids sizewise would be, Ceres, Pallas, Vesta and 10 Hygiea.

Asteroids vary greatly when it comes to size. One of the smallest known asteroids, named 1991 BA, is only 20 feet in diameter. They are not visible with the naked eye. However many asteroids can be seen with binoculars or small telescopes.

Scientist have ways to determine the size of an asteroid. They can compare its distance from the Sun and the wavelength of light it reflects. They also use the amount of heat the asteroid gives off to determine its size.

In 1991, Galileo, the NASA space probe, took the first detailed photographs of an asteroid named Gaspra. It was irregular in shape and it’s size was about 12 miles x 7 1/2 miles x 7 miles.

Scientist believe that an asteroid, six miles in diameter, hit the earth the earth sixty five million years ago. The dinosaurs and other exotics species all became extinct. When the asteroid hit the earth at a high speed it kicked up millions of tons of dust and dirt into the air. It blocked out the sun for months and changed the climate. The plant eating dinosaurs’ food source died out and they starved to death.

Many scientist predict that on average a large asteroid could hit earth every 500,000 to 1,000,000 years. Most asteroids exist in belt between Mars and Jupiter’s orbit. Yet some asteroids move into a collision path with the earth.

These asteroids can range in size from tiny pebbles to more than 40 miles in diameter.

An international group of scientists have tracked the locations of as many as 900 large asteroids. The odds of one of them hitting us soon is small, but scientists are preparing if one comes into close range of the earth.