Hard Rocks And Heavy Metals




Asteroids are small, rocky worlds, with no atmosphere, that revolve around the sun. Too small to be classified as planets, they are categorized as planetoids, or even dwarf planets. In fact, if you were to add up the mass of each asteroid, the total mass would still be smaller than that of Earth’s Moon. But, despite their small size, they are still very dangerous, as many of them have collided with Earth in the past, and many are expected to collide with Earth in the future. Therefore, if there’s an asteroid coming our way, it would be wise to be prepared, which is why scientists are eager to learn as much as they can about asteroids, their orbital characteristics, their numbers and what they are made of. The more we know, the greater the chances of us avoiding a potential disaster in the future.

Source: ESO (

Planets and asteroids are formed in a similar way. The process that helped create planets is called accretion. When the universe was in its formative stage, two objects would usually collide and remain stuck together, thus forming one larger object. Some of those objects acquired enough mass to become planets, while the others became asteroids. An example which best illustrates that is Ceres, which was once thought of as an asteroid, but is now a dwarf planet, and it goes to show that asteroids might accumulate enough mass to start generating gravity in the future and become planets in their own right. Most asteroid are located between Mars and Jupiter, in area called the Asteroid belt, which holds more than 200 asteroids with a diameter over 100 kilometers. According to research, the belt also contains more than 750,000 asteroids larger than 1 km in diameter, and millions of other smaller ones. Almost all asteroids are irregularly shaped, although there are a few exceptions, like Ceres. Even though they revolve around the Sun, their orbit can be quite erratic, as they appear to randomly tumble through space. Binary asteroids also exist, which occurs when two asteroids orbit around each other. Some of them have been captured by gravity of the neighboring planets and they become moons, such Mars’ moons Deimos and Phobos, as well as outer moons of Jupiter, Saturn, Uranus and Neptune. Seeing as they’ve remained unchanged for 4.6 billions of years, they could prove an interesting subject for research into the properties of the early Solar System.

Source: NASA/JPL (

  Asteroids can be comprised of various substances, depending on what planet they broke away from in a collision, as well as the chemical reactions that might have occurred while orbiting the Solar System. Those that are the closest to the Sun consist of carbon for the most part, while the ones that are further away are made of silicate rock. Asteroid can be composed out of various metals too, the most common one being iron, with about 80%, and the rest being nickel, iridium, platinum, gold and many others. According to astronomers, one metal-rich asteroid contains more metal than has ever been used by the entire human race.

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