Interesting Facts About Asteroids

by Jerry Coffey on June 24, 2009

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An artists impression of an asteroid belt(credit: NASA)

An artists impression of an asteroid belt(credit: NASA)

Do your friends think that you know a lot about asteroids? Do you really know all that much? Well, here are several interesting facts about asteroids. Some you may already know, others, hopefully, will be new to you. Asteroids are an interesting aspect of space that need to be studied more.

1.Asteroids and planets share a common birth. The process that helped form the planets is called accretion. During the beginning of the universe when two bodies would collide they would stick together forming a larger body. The planets and asteroids were formed in this manner. Obviously the planets accrued more mass than most of the asteroids. But, as seen by the asteroid Ceres being a dwarf planet, some asteroids came very close to garnering enough mass and generate gravity just enough to possible become planets in their own right.

2.Asteroids are made of different things. Asteroids are made of different minerals and substances. Their composition depends on the planet they broke away from in a collision, as well as the chemical reactions they might have experienced while orbiting in the solar system. The asteroids nearest to the Sun are mostly carbonaceous while the ones further away are composed of silicate rock. The metallic asteroids are made of up to 80% iron with the rest being nickel with many other metals such as iridium, palladium, platinum, and gold mixed in. Some are also made of half silicate and half metallic.

Asteroid composition has been classified in the following way:

C class asteroids: They are found in the Earth’s outer belt and are darker and more carbonaceous than the ones found in the S class.
D class asteroids: They are also known as Trojan asteroids of Jupiter and are dark and carbonaceous in composition.
S class asteroids: They are found in the Earth’s inner belt, closer to Mars and are composed of mostly stone and iron.
V class asteroids: They are a far-out group of asteroids that follow a path between the orbits of Jupiter and Uranus, and are made of igneous, eruptive materials.

3.Most asteroids are covered in dust. This dust is called regolith. It is a rocky rubble more that dust and is the result of constant collisions in space. These collision are between asteroids and any other body that crosses their path. The larger object wins and ends up covered in the rubble from the losing object. Sometimes space weathering has shown that some asteroids are OC meteorites that are covered in regolith.

4.Impact events shaped the asteroids. Nearly every object in space, including Earth, has been shaped in some way or another by impact events. Every heavenly body has at least two impact craters on its surface. These impact events can destroy an asteroid or cause tow asteroids to join together. The impact can cause changes in orbit, rotation, or axial tilt. There is no way to tell haw many asteroid there were 100 million years ago or how many there will be in a million years from now.

5.An asteroid may have killed the dinosaurs. The Chicxulub impact crater is thought to be 65 million years old. It is also thought to be the source of the climate changes that led to the extinction of all of the dinosaurs. The debris that must have been thrown in the air after an asteroid large enough to create a crater that is over 180 km in diameter is hard to imagine. Those dinosaurs that didn’t die right away probably suffered from starvation before their deaths. What a horrible way to go.

6.Planets are not the only ones with moons. The spacecraft Galileo proved that point in 1993 when it did a flyby of the asteroid 243 Ida and discovered its moon dactyl. That was the first object to be found to have a moon of its own that was not a planet. Several others have been discovered since, but the first was the most exciting for astronomy.

7.Asteroids like to group together. There are four main groups that the asteroids are grouped in: the main belt, the Kuiper belt, Trojans, and the scattered disc. The Oort cloud is another group of asteroids that is too far out in space to really study so all that is known about it is in theory. The main belt orbits between Jupiter and Mars. It has been theorized that the gravitational anomalies of Jupiter have prevented the main belt from becoming a planet of its own. The scattered disc is a subset of the Kuiper belt. Because their orbits take them well beyond 100AU from the Sun they as the coldest objects in the Solar System. Due to its unstable nature, astronomers now consider the scattered disc to be the place of origin for most periodic comets. Many of the objects in the Oort cloud are thought to have originated in the scattered disc.

8.Near Earth Asteroids. NEAs are monitored by NASA’s SENTRY and NEAT programs. An NEA caused quite a stir in the last few years because of how close it came to the Earth. It was close enough that the government started taking precautions for an impact. There will be another close call in 20 years and one following that 8 years later. Neither should get close to the Earth unless some odd gravitational keyhole grabs them off orbit. Astronomers hope to have a spacecraft ready to intercept and study these NEAs as the pass the Earth.

These are just a few of the interesting facts about asteroids that you can find. Some of the impact craters on the Earth have been mined and had many useful minerals taken from them. Sudbury is now one of the largest mining communities in the world. The incident near the Tunguska River in Siberia is thought to be the newest asteroid impact on the Earth. There are almost too many interesting facts about asteroids to put them all in one article.

Hopefully, you have found some new stuff to surprise your friends with!

References:
NASA: Asteroids
NASA: Asteroid Litograph
NASA: What are Asteroids?

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