Pieces of rocky matter called asteroids revolve among the planets in our solar system. Too small to be considered planets, asteroids are a “hangover” from the early formation of the solar system, making them about 4.6 billion years old. There are three types of asteroids – the materials that make up their composition determine them.
C-type or those that contain large amounts of carbon are the most common – accounting for about 75 percent of asteroids. These gray asteroids are usually made of clay, minerals and silicate rocks. M-types contain large amounts of metals such as iron and nickel, which most likely contributes to their red color. S-types can vary from red to green in color and are composed mainly of silicate materials, as well as iron and nickel.
As these rocks move around the sun, they can collide with planets, create shooting stars and form large belts. Here are four amazing facts about asteroids that you may not have known.
1. They can have a big impact
Asteroids collide with planets. Not all are extinction events, but some asteroids have affected Earth in a massive way. About 66 million years ago, a mountain-sized asteroid hit the shores of Mexico’s Yucatan Peninsula, creating the Chixulub Crater. Its impact and damage have changed life on Earth and are thought to have contributed to the extinction of the dinosaurs.
The collision caused a tsunami and fires, along with huge amounts of dust and soot. The sulfur from the evaporated rock acidifies the oceans and blocks some of the sun, reducing the amount of light that reaches the Earth. This inhibits plant growth, leading to a bigger problem in the food chain. There have been other collisions with asteroids, the largest being between 35 million and more than two billion years ago.
2. They form the asteroid belt
Most known asteroids are located in the asteroid belt located between the orbits of Mars and Jupiter. According to NASA, the currently known number of asteroids exceeds 1.1 million. They vary in size, ranging from small as dust particles to stones up to thousands of feet in diameter. Yet the total collective mass of all asteroids is still less than the mass of the Earth’s moon.
Despite the fact that there are millions (if not more) of asteroids in the belt, they are located far apart – approximately 600,000 miles. Therefore, spacecraft can fly through the belt without colliding with any asteroids. In 1973, a space probe called Pioneer 10 was the first to pass through the asteroid belt.
3. They can become planets
Ceres is the largest object in the asteroid belt and is responsible for a third of the total mass of the belt. Italian priest and astronomer Giuseppe Piazzi discovered Ceres in 1801, and experts reclassified it from an asteroid to a dwarf planet in 2006.
The dwarf planet is a celestial body that has enough mass to approach a round shape and orbit the sun. However, they are smaller than actual planets and do not have enough gravitational force to accumulate material in their orbits. Ceres is an icy dwarf planet with daily temperatures around minus 100 degrees Fahrenheit. The night is even colder, at an amazing minus 225 degrees. There is no atmosphere and one day is nine hours long. Scientists believe that Ceres may have sustained life at some point.
4. They can have moons
Some asteroids are large enough to have moons. In 1993, the Galileo spacecraft discovered the first asteroid satellite. Ida, an S-type asteroid, has a moon named Dactyl. Several other moons orbiting asteroids have since been discovered.
These include one named Petit-Prince, which is eight miles wide and orbits the asteroid, Eugenia. The asteroid Pulkova also has a moon of similar size. Scientists believe that asteroid moons were created by the collision of two asteroids. If the conditions are right, a piece can be cut and sent into orbit. According to NASA, more than 150 asteroids have moons, and some even have two.
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