(ORDO NEWS) — We all know perfectly well that the planets are round – this is already something taken for granted. But have you ever noticed that asteroids, comets and other small space bodies have very unusual shapes?
For example, comet Churyumov-Gerasimenko has a shape that is often compared to a duck. Or look at the photo of the asteroid Arrokoth (Ultima Thule), which was discovered by the Hubble telescope in 2014, vaguely resembles a dumbbell. In addition to them, there are many other space objects with unusual structural features.
For many people, realizing the difference in the shapes of asteroids and planets can be a big discovery. But scientists have long noticed this phenomenon and today they can give an exhaustive explanation of this pattern.
How does gravity affect asteroids?
According to Alessondra Springmann, an employee of the Lunar and Planetary Laboratory at the University of Arizona, the unusual shape of most celestial bodies can be explained by the absence of gravitational forces acting on them.
The planets and their satellites are large, which is why gravity can evenly affect the entire surface of cosmic bodies and help them take the shape of a ball. But asteroids and comets are very small relative to the planets, so gravity cannot even out their shape.
However, it is important to note that the absence of gravitational influence alone is not capable of “blinding” bizarre shapes from space stones. For this, additional forces must act on objects flying in space.
The planets are regular, but the asteroids are not, and there is an explanation for this
The result of an asteroid collision
Some asteroids have an unusual shape because, throughout their history, they have collided with other space objects and even connected with them. A good example of this set of circumstances is the asteroid Arrokoth, which is located at a distance of 6.5 million kilometers from Earth.
This celestial body has the shape of a dumbbell, and in some sources it is compared with sticky pancakes. Astronomers believe that Arrokoth acquired its bizarre shape because it was formed from two small space objects that revolved around each other for a long time and, eventually, collided and merged together.
Asteroid Arrokoth is also known as Ultima Thule
The structure of asteroids affects their shape
Other unusual asteroids are Bennu and Ryugu – they have the shape of a rhombus. Researcher Alessondra Springmann believes that the reason for the bizarre shape is the geological structure of objects.
In general terms, the asteroids Bennu and Ryugu are just “gravel piles”. Their structure is very porous, so even the speed of rotation can affect their shape. And this indicator, according to researchers, directly depends on the degree of absorption and return of solar energy.
Asteroid Bennu is shaped like a diamond
Why is the Churyumov-Gerasimenko comet shaped like a duck?
At the beginning of the article, I mentioned the Churyumov-Gerasimenko comet, which has the shape of a duck. Astronomers believe that the unusual shape of this space object is also associated with its composition and structure.
It is believed that the comet is predominantly made of ice, and not only water. As the comet approaches the Sun, this ice undergoes a process of sublimation, that is, it becomes a gas, skipping the liquid phase. The resulting gas is ejected into space, forming a temporary atmosphere around the comet.
According to Alessondra Springmann, jets of gas can give objects the most unusual shapes. In addition, the shape of the Churyumov-Gerasimenko comet may be related to its origin. There is reason to believe that, like the asteroid Arrokoth, it was formed as a result of the merger of two space objects.
Asteroid Churyumov – Gerasimenko
The universe is full of bizarre space objects. In the solar system alone, scientists have counted about a hundred thousand asteroids – according to data for 2017, astronomers know about the existence of 729,626 minor planets, and today their number is even greater.
After the discovery of each asteroid, scientists evaluate its danger to the Earth, because there is always a risk that the trajectory of its flight crosses our planet. This means that the probability of a collision can be very high. At the moment, the asteroid mentioned above is the most dangerous asteroid for humanity.
According to preliminary calculations, the space object will reach us in about 2182. Fortunately, scientists are already developing systems to protect against space objects.
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