What is the difference between an asteroid and a large planet

According to the new rules in 2006, let's start with the big planet standard. There are 3 in total:

1。A celestial body that orbits the Sun.

2。There is enough mass to overcome the stress of the solid with its own gravity to bring it to the shape of hydrostatic equilibrium (colloquially speaking, close to spherical).

3。It can clear other small objects in approximate orbits.

There are a total of 8 celestial bodies in the solar system that meet this criterion. It's the eight planets.

The next ones that meet criteria 1 and 2, but not 3 are called "dwarf planets". A total of 4 are known: Pluto, Charon, Ceres, and China.

Only 1 is met. Those that do not match 2 and 3 are asteroids. That's in the thousands. From this, it can be deduced that the asteroid criteria are: 1, orbiting the sun; 2, not round; 3. Other celestial bodies in the vicinity of the orbit cannot be cleared.

The main difference is in mass and volume. The mass and volume of asteroids are significantly smaller than that of large planets. In addition, in terms of appearance, asteroids are all strangely shaped because of their small mass. The big planets, on the other hand, are all nearly spherical.

To put it simply, asteroids are small and irregularly shaped; Large planets are larger and generally spherical or ellipsoidal.

Asteroids are a class of members of the solar system family that are much smaller than the moons of large planets and are generally located between the orbits of Mars and Jupiter – the asteroid belt. They are characterized by their small size and low mass, and the largest asteroids have a diameter of less than 800 kilometers.

Like the big planets, they orbit the Sun in an elliptical orbit. Since the Italian astronomer Piazzi accidentally discovered the first asteroid Ceres in 1801, tens of thousands of asteroids have been discovered, and the number of officially registered asteroids that have obtained the "citizenship" of the solar family has reached more than 5,300 by the end of 1994.

Asteroids may be small, but they have played an important role in the study of astronomy in the past. Asteroids can also be used to determine the mass of planets. When an asteroid approaches a large planet, the perturbation of the large planet will inevitably affect its orbit, and the actual mass of the planet can be calculated from the small changes in its orbit.

1. The quality is different.

Planets: The masses must be large enough to overcome the gravitational pull of a solid to achieve a hydrostatic equilibrium shape (nearly sphere-like).

Asteroid: A celestial body that is much smaller in size and mass than a planet.

2. The causes are different.

Planets: On the edge of a star, it may absorb a lot of cosmic dust, take the sun as an example: the sun absorbed a lot of dust about 4 billion years ago, and the dust collided with each other and stuck together.

For a long time, a large number of planetary embryos called stars appeared, and at that time there were at least billions of stars moving around the sun. The law of action between stars is that if there is a huge difference in the size of two stars, and the speed of each other is not large, after colliding, the small star will be attracted by the big star and eaten.

Asteroids: Asteroids are remnants of matter after the formation of the solar system. There is a speculation that they may be the remains of a mysterious planet that was destroyed by a massive cosmic collision in ancient times.

3. The history is different.

Planets: Five classic planets that have been visible to the naked eye since time immemorial, and they have had important influences on theology, religious cosmology, and ancient astronomy. In ancient times, astronomers recorded how some specific points of light were moving across the sky relative to other stars.

The ancient Greeks called these points of light "planetes asteres" or simply "planētoi" (wanderers), from which the name planet is derived.

Asteroids: The discovery of asteroids is closely linked to the Titius-Bode rule, according to which there should be a planet at an astronomical distance from the Sun, where Piacci, the first asteroid, Ceres, was discovered.

A planet usually refers to a celestial body that does not emit light on its own and orbits a star. Its rotation is often in the same direction as the rotation of the star it orbits. Generally speaking, planets need to have a certain mass, and the mass of the planet must be large enough to be nearly spherical, and it cannot undergo nuclear fusion reactions like stars.

Asteroids are celestial bodies in the solar system that are similar to planets orbiting the sun, but much smaller in size and mass than planets, and the vast majority of asteroids are concentrated in the asteroid belt between the orbits of Mars and Jupiter.

The largest asteroid discovered by 1990 was Ceres, but after 2000, some asteroids discovered in the Kuiper Belt were larger in diameter than Ceres. The quaoar has a diameter of 1280 km. The largest asteroids began to be reclassified and were defined as dwarf planets.

The eight planets of the solar system are Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, and Mercury.

The eight planets are the eight large planets of the solar system, according to the distance from the sun from near to far, they are in order, they are the source of the water ( ) Venus ( ) Earth ( ) Mars ( ) Jupiter ( ) Saturn ( ) Uranus ( ) Neptune ( ) Most of the eight planets have the same rotation direction as the orbital direction. There are only two exceptions: Venus and Uranus. Venus rotates in the opposite direction to its revolution.

Definition of planets: first, celestial bodies that must orbit stars; Second, the mass is large enough to rely on its own gravity to make the celestial body spherical; The third is that there should be no other objects near this orbit.

According to this division, there are only eight planets in the solar system: water, metal, earth, fire, wood, and earth, plus the eight planets of Split Faith and Neptune. In contrast to the concept of nine planets mentioned before 2006, Pluto was classified as a dwarf planet and removed from the list of nine planets in the solar system in Resolution 5 adopted at the 26th session of the International Astronomical Union, held in Prague on 24 August 2006.

It must be a celestial body orbiting the star - Pluto coincides. The mass is large enough to rely on its gravitational pull to make the celestial body appear spherical, but Pluto has not been able to clear other objects in its orbit and is therefore downgraded to a dwarf planet.

The smallest planet is Mercury.

Mercury, 4,879 kilometers wide and weighing kilograms, is a small world that is nearly 20 times lighter than Earth's mass and about twice as small in diameter.

Mercury (English: Mercury; Latin: Mercurius), because of its rapid movement, it was called Mercury in ancient Europe, which means the messenger god of ancient Roman mythology.

In ancient China, the name of Chenxing was accompanied by Xian, and Sima Qian, the author of the Western Han Dynasty's "Historical Records of Tianguanshu", found that Chenxing was gray from actual observation, which was associated with the Five Elements Doctrine, and named it Mercury with black water.

Mercury's trajectory: Mercury has no seasons, its surface is full of craters, similar to the Moon and other moons, and its geology has been inactive for billions of years. It is the only planet that resonates with the Sun's orbit.

The time for each three revolutions is almost the same as the time for two revolutions around the nucleus. Looking at Mercury from the Sun, with reference to its rotation and revolution, there is only one solar day every two Mercury years.

The orbit is located on the inner side of the Earth (the same as Venus), so it can only appear in the sky at dawn and dusk and during the day, not around midnight. The brightness of Mercury varies greatly from Earth to solstance, but its maximum elongation from the Sun is only.

In the Northern Hemisphere, Mercury can only be seen in the early hours of the morning or twilight at dusk. While the great elongation occurs at latitudes south of the equator, Mercury can be seen in the middle latitudes of the Southern Hemisphere in completely dark skies. <>