What are the constituent units of the universe from the highest to the bottom?

First of all, we are in the universe, which is composed of hundreds of billions of galaxies and some other dark matter, intergalactic dust and other matter. The part of the universe that is currently observable to humans is called the total galaxy. We humans are in the Milky Way, one of these hundreds of billions of galaxies, with nebulae, star systems (such as our solar system), interstellar matter, and so on.

Nebulae are the cradle of the birth of stars, such as the Orion Nebula (on the spiral arm of the constellation Orion in the Milky Way) is constantly giving birth to new stars, but not all nebulae are in the Milky Way, other galaxies have nebulae like the Milky Way, such as the Large Magellanic Cloud, which is not in the Milky Way. The solar system is located on the spiral arm of the Milky Way constellation Orion, and there are eight planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Pluto has now been expelled from the planet and reduced to a dwarf planet). In addition to Mercury and Venus, all other planets have moons orbiting it, the Earth has one moon on the Moon, and Saturn has the most moons, with 26 confirmed. Planets, asteroids, comets, and meteoroids all orbit around the central celestial body, the Sun, which makes up the solar system.

The Sun accounts for the total mass of the solar system, with a diameter of about 1.4 million kilometers, and the largest planet, Jupiter, has a diameter of about 140,000 kilometers. The size of the solar system is about 12 billion kilometers (bounded by Pluto). There is evidence that there are other planetary systems outside the solar system as well.

And then it is said that from large to small: the universe - galaxies (such as the Milky Way, the Andromeda Galaxy. Star systems (e.g., the solar system), nebulae, black holes (some black holes move between galaxies) – planetary systems (e.g., the Earth-Moon system).

Nebula contains almost all malleable objects except planets and comets. Their main component is hydrogen, followed by nitrogen, and also contains a certain proportion of metallic and non-metallic elements. Studies in recent years have also found that they contain substances such as organic molecules.

Universe (total galaxy) Supercluster (local supercluster) Group of galaxies (cluster of galaxies) Galaxy.

A celestial body that looks like a mist. All non-stellar clouds of gas and dust outside the Milky Way. Sun Li, "Xiulu Collection, Confucianism of All Nations, Joyful Parting, Small Introduction":

Life is like a nebula in space, it is integrated, ever-changing, interrelated, and mutually causal. He Jingzhi's "Songbook: East Wind Thousands of Miles": "The nebulae of the infinite universe are echoing to us.

Ai Qing "Hymn to Light": "Every human being is a life, and human beings are a speck of dust in the Milky Way Nebula. ”

"When is the bright moon, ask the wine to ...... the sky"For thousands of years, human beings have looked at the starry sky and painstakingly pursued the laws of change in the universe. The advent of telescopes has greatly broadened the horizons of human beings, allowing us to observe the universe through them. However, due to the obstruction of the atmosphere and the limitations of dark clouds, fog, rain and snow, day and night, the telescope is very difficult to observe from the ground that the nebula is like "seeing the birds from the bottom of the lake".

With the development of space technology, scientists decided to move the telescope into the sky, beyond the atmosphere, so that it could observe the universe without obstruction. On April 24, 1990, with the launch of the space shuttle Discovery, this great idea finally came to fruition. Since then, the earth has a proud "space giant eye".

Systematically: Universe - Total Galaxy - Local Group of Galactics - Milky Way.

Solar system - Earth.

In terms of size: Universe - galaxies - celestial bodies (large black holes, stars, etc.) - planets - chemicals - molecules - atoms - elementary particles.

A more microscopic spatiotemporal structure of energy.

There are two kinds of units, one is light years, and the other is the parsec, which can be prefixed respectively, such as "100,000" and "million", and the parsec generally does not use "100 million" as a prefix. Please refer to the second gap information.

Hope it helps! ^_

Mastering the two commonly used ones is enough to bluff the blind.

One is a light year, which is the distance that light travels in a year. Light is 300,000 kilometers per second, you can calculate how far it can go in a year, this is the distance of one light year.

The other is an astronomical unit, which is the average distance from the earth to the sun, which is called an astronomical unit. This distance takes 8 minutes to walk.

The "standard astronomical unit" in terms of Earth-to-Sun distance is abbreviated as au

The distance traveled at the speed of light for a year's time - "light years" (there are also other units of length produced by other travel times, such as: "light seconds" and "light minutes".)

Used to describe the "parsec" of distances between stars

1. The distance in the solar system is usually measured in the Earth-Sun distance as an astronomical unit, denoted as AU, for example, the average distance between Venus and the Sun is 000 000 km from Mars to the Sun = 100 million km.

2. Distances at larger scales in the universe are usually measured in light-years. One light-year is equal to the distance that light travels in a year.

One light year = 9,460,730,472, kilometers = hundreds of millions of kilometers.

Light-year?? Said I don't know if it's more professional.

The units used in astronomy to measure the scale of the universe are mainly as follows:

Astronomical unit (AU)", e68a8462616964757a686964616f31333262383037 "light year (ly)", parsec gap (pc).

Their specific meanings are:

Astronomical unit: The average distance between the Sun and the Earth (i.e., the half-long diameter of the Earth's orbit) is 1 au, i.e., 100 million kilometers.

Light-years: The distance traveled by light in a year in a vacuum is 1ly, or 63,271 AU, or trillion kilometers.

Seconds: If the opening angle of the radius of the orbit of a certain point in space to the earth is 1 arc second, then the distance from this place to the earth is defined as 1pc, that is, light years, that is, 206256au, which is equal to trillions of kilometers.

Astronomical units are mainly used for celestial bodies in the solar system, such as Mars to the Sun at an average distance of about 40 AU from Pluto to the Sun.

However, expressing the distance between stars in astronomical units is difficult. For example, even Proxima Centauri, the closest star to us, is 267,000 AU away, and the farthest galaxy that can be observed so far is nearly 900 trillion AU, which is another large "astronomical number".

Proxima Centauri is light-years away, i.e., the farthest galaxy is 13.7 billion light-years, or 4.2 billion parsecs. Although this number is still very large, it feels like nature is much more comfortable than 1300 trillion kilometres or 900 trillion astronomical units.

The units of length larger than the parsec are "kiloparsec (kpc)" and "megaparsec (mpc)" with 1kpc being 1000pc and 1mpc being 1,000,000pc. Therefore, the distance of the farthest galaxy is about 4250 MPc, which is not too big.

A light-year is the length of a year that light travels.

The second gap is that if you look at the line between the sun and the earth from a star in the universe, the line between the star and the sun, as well as the line with the earth, will form an angle, when the angle is 1 arc second, the average distance between the star and the sun and the earth is 1 second difference.

1 astronomical unit = 100 million kilometers;

1 light year = 9,460,500,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,

1 parsec = light year = 206265 astronomical unit = 30.8 trillion kilometers.

I don't understand what kind of unit of measurement you have in this metaphysics.

Modern science mostly uses how many light years, how many astronomical units (AU) and how many seconds of difference (PC), the largest unit is the second difference, one second difference = 206265 astronomical units = light years = 308568 billion kilometers.

According to your statement, the biggest thing is the universe: the universe is up and down in all directions, and the universe is said to be in the past and present, what are you a mystery?

Light-years, measured by the distance traveled by light in a year, are now the largest units in the universe

Astronomers measure the distance of the universe in light years marked as or or , which is mainly used to measure the distance of objects outside the solar system. 1 light-year is defined as the distance traveled by light in a year in a vacuum. The speed of light in a vacuum is c kilometers and seconds, so 1 light-year is equal to a trillion kilometers, or 10,000 astronomical units, or parsecs.

The closest star to the Sun (Proxima Centauri) is light-years away from the Sun. The Milky Way is about 100,000 light-years in diameter. The depth of the universe observed by humans has reached 15 billion light-years.

The astronomical unit is also a unit of distance used in astronomy and is denoted A. One of the astronomical constants. It is mainly used to measure the distance between celestial bodies in the solar system, and is also used to indicate the diameter or distribution range of diffuse nebulae, globular clusters, etc.

It was once defined as the average distance from the center of mass of the Earth-Moon system to the Sun without perturbation. In the 1976 astronomical constant system, it is defined as the distance at which light travels in a vacuum in seconds. Its value is kilometers.

One astronomical unit is equal to a light-year, or parsec.

The parsec is also a unit of distance used in astronomy. It is mainly used to measure the distance of extrasolar objects. A 1 parsec is defined as the distance at which the celestial body has an annual parallax of 1.

The parsec is the reciprocal of the annual parallax, which is 0 for celestial bodies1 , its distance is 10 parsecs, and the annual parallax of the celestial body is 0At 01, the distance is 100 parsecs, and so on.

1 parsec is equal to a light-year, or 206265 astronomical unit, or a trillion kilometers . When measuring distant galaxies, parsecs are too small, and are often measured in kiloparsecs (kpc) and millions.

An astronomical unit is the distance from the Earth to the Sun.