There are eight planets in the Milky Way, which one of the original galaxies disappeared?

I didn't find any information about it, but I can provide some information about the planets in the solar system.

In Resolution 5 adopted at the 26th International Astronomical Union (IAU) held in Prague on 24 August 2006, Pluto was classified as a dwarf planet and removed from its original planetary sequence, which is now the Eight Planets Theory.

The eight planets in the solar system are Mercury, Venus, Earth, Mars, Jupiter, and Tianzheng: I didn't find any relevant information, but I can provide some answers about the planets in the solar system: There are eight large planets in the solar system, and they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune in descending order from the sun.

There are eight planets in the solar system, as well as the dwarf planet Pluto, which was removed from the nine planets of the solar system in Resolution No. 5 adopted at the 26th International Astronomical Union in Prague on 24 August 2006.

The International Astronomical Union Assembly voted to partially adopt a new definition of planets and downgrade Pluto from a planet to a "dwarf planet."

Pluto was canceled because the definition of planets needed to be revised. As for the reason, it is because people have discovered a large number of celestial objects that are very similar to Pluto, so in order not to include those celestial bodies in the list of planets, Pluto has to be kicked out of the planetary family.

The eight planets in the Milky Way are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

There are many planets in the vast galaxy, among which there are eight planets that are familiar to mankind. Let's find out.

01 Mercury (Latin: Mercurius, symbol:

Of the eight planets in the solar system, Mercury is the closest planet to the Sun. China calls it Chenxing. It orbits the Sun once every Earth day, and it also rotates three times per revolution.

Mercury has the largest orbital inclination of any planet in the solar system.

02 Venus (English venus, pinyin jīnxīng), one of the eight planets of the solar system, is also known as Taibai Star, Qixing Star or Chang Gung Star.

03 Earth is one of the eight planets in the solar system, the third planet in order of near and far from the sun, and it is also the terrestrial planet with the largest diameter, mass and density in the solar system, 100 million kilometers away from the sun. The Earth rotates from west to east while revolving around the Sun.

04 Mars (Latin: martis, symbol:

It is one of the eight planets in the solar system, the fourth planet in the solar system from the inside to the outside, and belongs to terrestrial planets, with a diameter of about 53% of the earth and a mass of 11% of the earth. The inclination angle of the axis of rotation and the rotation period are similar to those of the earth, and one revolution is about twice the time of the earth's revolution.

05 Jupiter (English: Jupiter, Latin: iovi, symbol:

It is the largest and fastest rotating planet among the eight planets in the solar system, and the fifth farthest planet from the sun. It has a mass of one-thousandth the mass of the Sun and a mass of the other seven planets in the Solar System combined. Since Jupiter, Saturn, Uranus, and Neptune are all gas planets, they are also called Jupiter-like planets (Jupiter and Saturn are collectively called gas giants).

06 Saturn (English: saturn, Latin: saturnus, symbol:

It is one of the eight planets in the solar system, and its distance from the sun ranks sixth in the solar system. Saturn is a gas giant, known as the star in ancient Greece (Ancient Greek: English:

chronos), ancient Chinese people called Saturn Rising.

07 Uranus (Latin: uranum, symbol:

Or ), one of the eight planets in the solar system, is the seventh planet (astronomical unit) in the solar system from the inside out, its third largest planet in the solar system (larger than Neptune) and fourth in mass (smaller than Neptune), almost lying sideways around the sun.

08 Neptune (Latin: neptunium, symbol:

It is one of the eight planets in the solar system. Neptune's orbital semi-major axis is the astronomical unit (8th among the planets in the solar system), the mass is the mass of the Earth (3rd), and the radius is the radius of the Earth (4th).

The Milky Way has unexpectedly many galaxies, called extragalactic galaxies. In the 17th century, some hazy celestial objects were discovered one after another, so they were called "nebulae". Some nebulae are gaseous, while others are thought to be cosmic islands of stars like the Milky Way, and they are so far away from Earth that they cannot be distinguished from those hazy objects made of a large number of stars.

In the 20s of the 20th century, the American astronomer Hubble discovered a celestial body called "Cepheid variables" in the Andromeda Nebula, thus calculating the distance of the nebula, and finally affirmed that it was a celestial system outside the Milky Way, calling them "extragalactic galaxies". Extragalactic galaxies, or galaxies for short, are celestial systems located outside the Milky Way and consisting of billions to hundreds of billions of stars, nebulae, and interstellar matter. About 1 billion extragalactic galaxies have been discovered.

The Milky Way is also just an ordinary galaxy. It is estimated that there are more than 100 billion extragalactic galaxies, and they are like islands scattered in the vast ocean, so they are also called"Cosmic Island"。

From the discovery of extragalactic galaxies, we can look back at our Milky Way. It is just an ordinary galaxy, a member of a family of hundreds of billions of galaxies, an island in the ocean of the universe, a tiny, tiny part of the infinite universe.

There are 1000 400 billion galaxies in the Milky Way. Among them, the main ones include stars, star clusters, nebulae, and various types of interstellar gas and interstellar dust. In addition, there are more than a dozen satellite galaxies scattered around the Milky Way in an area of hundreds of thousands of light-years, which are growing by slowly devouring the surrounding dwarf galaxies.

How many galaxies are there in the Milky Way The Milky Way is a giant barred spiral galaxy (a type of spiral galaxy) that is elliptical in shape and has a huge disk structure, and the Milky Way has a total of 4 spiral arms, two main spiral arms and two unformed spiral arms, which are 4500 light-years apart. The Sun is located on the Orion Arm, a branch of the Milky Way, at a distance of about 10,000 light-years from the galactic center, containing 120 billion stars. The Milky Way consists of 100 billion 400 billion stars and a large number of star clusters, nebulae, and various types of interstellar gas and interstellar dust.

90% of the Milky Way is made up of stars. The Milky Way, with a total mass of about a trillion times that of the Sun, belongs to the local group of galaxies, and the nearest extragalactic galaxy is the Dwarf Canis Major galaxy 10,000 light-years away. The Milky Way has two companion galaxies (satellite galaxies):

Large Magellanic clouds and Small Magellanic clouds, galaxies opposite the Milky Way are called extragalactic galaxies. The Milky Way, the Andromeda Galaxy and the Triangular Galaxy are the three main galaxies in the Local Group of Galaxies, which in total has about 50 galaxies, and the Local Group is part of the Local Supercluster. Other Milky Way systems orbit the Milky Herculid, with the closest being the Dwarf Canis Major, followed by the Sagittarius Dwarf Elliptical Galaxy, the Ursa Minor Dwarf Galaxy, the Auriga Dwarf Galaxy, the Sextant Dwarf Galaxy, the Celestial Furnace Dwarf Galaxy, and the Leo Dwarf Galaxy.

The number of planets in the Milky Way is smaller than that of stars, while the number of stars in the Milky Way is between 100 billion and 400 billion. Analysis: Because most scientists believe that the number of planets in the Milky Way is not so large, so far, there are no more than 2,000 exoplanets observed by humans, because the planets do not emit light, so it is difficult to observe, so it is also difficult to ** how many planets are in the Milky Way.

But it is impossible for all stars to have eight planets like our solar system, and there are many dwarf planets and asteroids, and in some of the star systems that have been observed, many of them are even non-planetary. Companion galaxies of the Milky Way: The Milky Way has two companion galaxies (satellite galaxies):

Large Magellanic clouds and wheat ellanic clouds. The galaxies opposite the Milky Way are called extragalactic galaxies. The Milky Way, the Andromeda Galaxy, and the Triangulum Galaxy are the three main galaxies in the Local Group of Galaxies, which in total has about 50 galaxies, and the Local Group is part of the Local Supercluster.

The Milky Way is surrounded by a number of dwarf galaxies in the local group of galaxies, the largest of which is the Large Magellanic Galaxy with a diameter of 10,000 light-years, and the smallest is the Carina dwarf galaxy. Other Milky Way systems orbit the Milky Herculid, with the closest being the Canis Major dwarf galaxy, followed by the Sagittarius dwarf galaxy, the Ursa Minor dwarf galaxy, the Euffle dwarf galaxy, the Sextant dwarf galaxy, the Celestial Furnace dwarf galaxy, and the Leo i dwarf galaxy. See entry:

Companion galaxies, extragalactic galaxies, galaxy clusters, superclusters.

Scientists conducted the first planetary census of our galaxy and found that there are at least 50 billion planets in the galaxy. The figures are extrapolated from earlier results from NASA's Kepler telescope, which took two years to collect through a three-and-a-half-year, roughly $600 million mission. William Poluck, science director of the Kepler telescope project, said scientists estimate that there could be several planets around the star based on the total number of planets found in the first year of observation of a small piece of the night sky.

Planets can be spotted by Kepler telescopes as they pass between the Earth and their parent stars. According to **, about some of the stars in the sample have planets the size of Earth (50% to 125% of the diameter of Earth). Should have a super-Earth (125% to 200% of the diameter of the Earth).

Planets the size of Neptune (2 to 6 times the diameter of Earth). A planet the size of Jupiter (6 times larger in diameter than Earth). Astronomers say that when the Kepler telescope is 1,000 light-years away from Earth, it will notice a passing Venus when it looks at our Sun, and the probability of seeing Earth is only one in eight.

To estimate the total number of planets in the Milky Way, scientists first used observations to determine the number of stars in the Milky Way. For years, scientists thought there were 100 billion stars in the Milky Way, but last year a Yale scientist thought that number could be closer to 300 billion.