Question 1: Why are comets not planets? According to the new definition adopted by the General Assembly of the International Astronomical Union, a planet refers to a celestial body that rotates around the sun, and its own gravity is enough to overcome its rigid physical force to make the celestial body spherical and clear other objects near its orbit. Definition of dwarf planet: A celestial body with enough mass to be spherical like a planet, but unable to clear other celestial bodies near its orbit. Pluto and some similar stars have been reclassified as "dwarf planets", similar to the previous title "Asteroids". The International Astronomical Union has also defined a third kind of small star orbiting the sun, named "all-solar celestial body", which mainly includes many asteroids, comets and other naturally formed satellites.

Question 2: What is the difference between a star, a comet and a planet? Distinguish stars from spherical or quasi-spherical celestial bodies that are composed of hot gas and can glow by themselves in nature. Definition of planet: 1, which must be a celestial body orbiting a star; 2. The mass must be large enough, and its own gravity must be balanced with the rotational speed to make it spherical; There can't be a celestial body bigger than it in the orbit of revolution. Generally speaking, a planet must be more than 800 kilometers in diameter and more than 5 billion tons in mass. Comets are generally ellipses with small mass and high orbital eccentricity, and comets have tails when approaching constancy.

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Question 3: What are the main differences between planets and comets? There seems to be some questions in the answer upstairs, right?

Planets are in orbit, but so should comets. Otherwise, how could Comet Halley return after 76 years?

The first difference between a planet and a comet is that they look different. On the earth, a planet is a point with the naked eye. If the brighter one can walk, it looks like a fog (the comet visible to the naked eye must have entered the solar system). If you look through a telescope, the planet can see a round surface, but the comet looks like a fog.

Second, the mass of planets is much greater than that of comets, and the mass of the earth is 6.02 * 10 24 kg, which is equivalent to1000 billion medium-mass comets compared with comets.

The third is the material composition of both. For terrestrial planets, it is mainly made of silicate, but comets are made of volatile dry ice, ammonia and other substances, so when they are close to the sun, these substances will volatilize in large quantities, in addition to the nucleus far away from the sun, there will be coma and tail.

Question 4: Are comets stars? Not a star (it seems really stupid to me, hehe), but a comet is a member of the solar system, which consists of three parts: a nucleus, a coma and a tail. Nucleus and coma are collectively called "coma heads", which are mainly composed of frozen gas, ice, gravel and stones in the universe.

I am a sword, the factory is a spark, I would like to live like lightning, I would like to die like a comet-Gao.

At the age of 24, Gauss gave up the study of pure mathematics and studied astronomy for several years.

At that time, the astronomical community was worried about the huge gap between Mars and Jupiter, and thought that there should be planets between Mars and Jupiter that had not been discovered. 180 1 year, Italian astronomer Piazi discovered a new star between Mars and Jupiter. It was named Cere. Now we know that it is one of the asteroid belts of Mars and Jupiter, but at that time, there was endless debate in the astronomical circles. Some people say it's a planet, others say it's a comet. We must continue to observe to judge, but Piazi can only observe its 9-degree orbit, and then it will disappear behind the sun. So it is impossible to know its orbit, and it is impossible to determine whether it is a planet or a comet.

Gauss became interested in this problem at this moment, and he decided to solve this elusive star trajectory problem. Gauss himself created a method to calculate the orbits of planets with only three observations. He can predict the position of the planets very accurately. Sure enough, Ceres appeared in the place predicted by Gauss. This method-although it was not announced at that time-was the "least square method".

Question 5: How to distinguish planets, stars, satellites and comets? What you need is the simplest answer!

Star: It reacts violently, gives off light and gives off heat, such as the sun.

Planet: It rotates periodically around a star, such as the Earth, under the gravitational force of the star. See senior high school physics for details.

Satellite: Under the gravity of stars and planets, the planets are larger and rotate periodically around them. Like the moon.

Comet: It is composed of cosmic dust, broken ice particles and other substances. It is influenced by many forces, but more by stars, such as the famous Halley's Comet and comet hale-bopp.

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