Asteroids, sometimes known as minor planets, are stony relics of our solar system’s early development about 4.6 billion years ago. Most asteroids are unevenly shaped, with the exception of a few that are almost spherical and frequently pitted or cratered. The asteroids rotate in elliptical orbits around the Sun, often fairly wildly, tumbling as they travel.
Although most asteroids are quite small, they do have gravity and can impact the things that come too close. The larger an asteroid’s mass, the more iron (Fe) and nickel (Ni) it contains and the more gravitational force it would possess. The amount of metal is also used by scientists in asteroid classification.
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Structure Of Asteroids
Asteroid bodies are composed of rocks and metals. Some astronomers classify them as minor planets (like the moons of Mars and Saturn). Although most asteroids are quite small, they have gravity and can impact things that come too close.
The larger an asteroid’s mass, the more iron (Fe) and nickel (Ni) it contains as well as gravity. The amount of metal is also used by scientists in asteroid classification. Asteroids are characterized as light or dark using an infrared sensor. The lighter colors contain more metal than the darker colours.
How Are Asteroids Formed?
Asteroids are leftover remnants from the early formation of our solar system about 4.6 billion years ago! The formation of Jupiter prevented any planetary bodies from forming between Mars and Jupiter, creating a gap between the two planets (now known as the asteroid belt) where small objects would collide with each other and fragment into what we call asteroids.
Our solar system contains millions of asteroids, the most of which reside in the main asteroid belt, a region between the orbits of Mars and Jupiter. Trojans are asteroids that pass in front of and behind Jupiter. Near-Earth Objects, or NEOs for short, are asteroids that come dangerously close to Earth. The latter are the asteroids that NASA is keeping an eye on.
There is also an Asteroid Belt between the orbits of Mars and Jupiter. The belt holds small pieces of rock that spin around the Sun in a specific orbit. It is almost like a planet that never formed.
How Fast Do Asteroids Move?
Asteroids travel through space at incredible speeds. The speed at which asteroids move is determined by their distance from the Sun. The faster they are, the closer they are. Even Earth-crossing asteroids, or NEOs, travel at a speed of about 25 kilometres per second.
To put this insane pace into perspective, Apollo astronauts fly from Earth to the Moon in around three days. An asteroid takes around 4 hours to travel the same distance.
Do Asteroids Have The Same Gravity As Earth?
Asteroids are too small to produce significant gravity, thus landing a spacecraft on one would be extremely difficult. Because the radius of the Earth is 6378 km, the surface gravity on an asteroid is 1/6378 of the value on Earth.
If you weigh 150 pounds on Earth, you would weigh 150 pounds/6378 pounds, or approximately a third of an ounce. That is roughly the weight of three pennies on Earth.
Classifications Of Asteroids
Asteroids are classified into three major composition classes: C-, S-, and M-types.
- The most common asteroids are C-type (chondrite). They are black in appearance and are most likely made of clay and silicate rocks. They are among the solar system’s oldest things.
- The S-types (“stony”) are composed of silicates and nickel-iron.
- M-types are metallic (nickel-iron).
The composition of asteroids varies according to their distance from the Sun. After they are formed and partially melted, some endured tremendous temperatures, with iron sinking to the center and forcing basaltic (volcanic) lava to the surface.
Can An Asteroid Hit The Earth?
The Earth may not have to worry about colliding with a comet. Asteroids are a different story. Scientists already believe that a big asteroid struck Earth when dinosaurs were living. That collision could have altered our atmosphere and caused the dinosaurs to become extinct.
If it is small enough, it will burn up in the atmosphere. Larger ones will collide with the planet’s surface. Asteroid collisions were more common hundreds of millions of years ago. The number of asteroids in the Earth’s path reduced through time, and collisions became less common.
Types Of Asteroids
Here are three types of asteroids.
Main Asteroid Belt
The majority of known asteroids orbit within the asteroid belt between Mars and Jupiter, generally with not very elongated orbits. The belt is estimated to contain between 1.1 and 1.9 million asteroids larger than 1 kilometer (0.6 miles) in diameter, and millions of smaller ones.
Early in the history of the solar system, the gravity of newly formed Jupiter brought an end to the formation of planetary bodies in this region and caused the small bodies to collide with one another, fragmenting them into the asteroids we observe today.
These asteroids share an orbit with a larger planet, but do not collide with it because they gather around two special places in the orbit (called the L4 and L5 Lagrangian points). There, the gravitational pull from the Sun and the planet are balanced by a trojan’s tendency to otherwise fly out of orbit.
The Jupiter trojans form the most significant population of trojan asteroids. It is thought that they are as numerous as the asteroids in the asteroid belt. There are Mars and Neptune trojans, and NASA announced the discovery of an Earth trojan in 2011.
These objects have orbits that pass close by that of Earth. Asteroids that actually cross Earth’s orbital path are known as Earth-crossers.
Asteroids are celestial bodies made up of rocks and metals. They do have gravity, though compared to Earth it is much less as they are much smaller.