In our Solar system there are many things that revolve around the Sun — that is, are in his orbit. The earth goes around the Sun for 365 days. Seven other planets also go around the Sun together with its satellites, and together with them and other things, including asteroids and comets. But what is actually asteroids and comets? Why do people confuse them? Fell — star, an asteroid or a comet? How to explain to a child what is a comet and an asteroid, how do they differ? Let’s face it.
An asteroid is just a rock orbiting the Sun. Asteroids are smaller planets, but some of them can be very large. The biggest, according to scientists, this is Vesta — more than 550 kilometers in diameter. The smallest ever studied were in two-meter.
How many in the Solar system asteroids?
In our system 780 290 asteroids, but not all of them are made from the same material. Scientists have divided them into three different groups depending on the composition they may be metallic, rocky or consist of species that are more similar to clay or contain silicon.
We’re still trying to learn more about asteroids. Japanese probe “Hayabusa-2” arrived at the asteroid Ryugu. The mission of the NASA OSIRIS-REx is on its way to another asteroid — Bennu. Each mission will take a sample from the asteroid’s surface and bring back dust and rocks on the Ground.
“Hayabusa-2” have already done a lot of measurements at Ryugu. The spacecraft is circling around the asteroid had already sent three cars to the surface. One of the cars — lander which is not very moved and explored the surface for 17 hours. Scientists on Earth are already investigating the measurement module, to find out more about how you formed this asteroid. Two other machines are much smaller and designed to move on the surface by jumping. They explore the asteroid on September 21.
Asteroids are cool.
But what is a comet?
In the Solar system known comets are much smaller than asteroids — 3526.
The comet, unlike the asteroid, more like dirty ice than stone. The middle of the comet, called the nucleus, is rather small and remains fixed, passing through the outer limits of the Solar system. The comets usually orbit away from the Sun, where it’s much colder than closer to the Ground. Sometimes comets get near the Sun in orbits.
Approaching the Sun, the comet heats up, heats the ice and begins to flow steam, creating a cloud of gas and dust that follow the comet nucleus. This coma — fluffy tail of a comet. As the movement of the comet dust and gas are behind it, creating a tail that can stretch for hundreds of thousands of kilometers. Closer to the Ground the tail looks bright stripe in the sky. It happens not often, but when happens — it looks amazing. People around the world watched the comet for thousands of years.
Basically, we are anywhere near the comets. The Stardust mission flew through the tail of one comet and brought to Earth samples in 2006. The mission of “Rosetta”, which ended in 2016, shot over 100 000 amazing photographs of the surface of the comet.
Although close to the Ground rushes several comets every year, many of them can only be seen through a telescope. When the comet has a coma is so bright that you can see with your own eyes, it’s a real holiday.
Now, what’s the main difference between comets and asteroids — the asteroid is composed of rock or metals, and the comet from the frozen material that melts when approaching the Sun.
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Ilya Hel