The sun is an ordinary star, and it has spent about half of its main sequence career on the Herro diagram.

It is a hot gas (strictly speaking, plasma) ball with a mass of 1989 100 billion tons (about 330,000 times the mass of the earth) and a diameter of1392,000 kilometers (about 109 times the diameter of the earth). Its average density is 1.4 times that of water, but this average density implies a wide density range, from the ultra-high density core to the thin outer layer.

As a star sun, its overall appearance attributes are: apparent magnitude is -26.3, luminosity is 38.3 billion watts, absolute apparent magnitude (Mv) is +4.83, and absolute thermal magnitude (Mb) is 4.8. It is a yellow G2 dwarf with an effective temperature equal to 5770℃ Kelvin. The average distance between the sun and the earth around it is 149597870km(499.005 light seconds or 1 astronomical unit).

By mass, its material composition is 7 1% hydrogen, 26% helium and a small amount of heavy elements. The angular diameter of the circular surface of the sun in the sky is 32 minutes, which is very close to the angular diameter of the moon as seen from the earth. This is a wonderful coincidence (the diameter of the sun is about 400 times that of the moon, and the distance from us is just 400 times that of the earth and the moon), which makes the eclipse look particularly spectacular.

Because the sun is much closer to us than other stars, its apparent magnitude reaches -26.8, making it the brightest celestial body on earth. The sun rotates once every 25.4 days (average period; The equator rotates faster than high latitudes) and revolves around the center of the Milky Way every 200 million years.

The sun is slightly flattened due to its rotation, which is 0.00 1% different from the perfect sphere, which is equivalent to a difference of 6km between the equatorial radius and the polar radius (the earth is 2 1km, the moon is 9km, Jupiter is 9000km, and Saturn is 5500km). Although the difference is small, it is important to measure this flatness, because any slightly larger flatness (even 0.005%) will change the influence of solar gravity on Mercury's orbit, making the test of general relativity based on Mercury's perihelion precession unreliable.

2. Knowledge about the sun, the earth and the moon

Its volume is 6.5438+0.3025 million times that of the earth, and it is the central celestial body in the solar system.

An ordinary star in the milky way galaxy. It is about10.50 million kilometers away from the earth and has a diameter of about10.392 million kilometers. It takes more than 3500 years to walk from the earth to the sun, and more than 20 years to fly.

Average density 1.409g/cm3, mass 1.989 * 10 33g, surface temperature 5770℃, center temperature 15008400℃. From inside to outside, there are the nuclear reaction area of the sun, the troposphere of the sun and the atmosphere of the sun.

Thermonuclear reactions continue in its central region, and the energy generated is emitted into space by radiation. One of the 2.2 billion energies radiates to the earth and becomes the main source of light and heat on the earth.

Stars also have their own life history, from birth, growth to aging and finally to death. They are different in size, color and evolution.

The connection between a star and life is not only that it provides light and heat. In fact, the heavy atoms that make up planets and living matter are produced in the process of explosions at the end of some stars' lives.

The sun is an ordinary star. The moon is also called "the moon".

Its day is equivalent to 29 days of the earth. Before the invention of the telescope, ancient people could only look up at the bright moon with their eyes on clear nights.

Seeing the moon's surface flickering and strange in shape, people made up beautiful myths such as the Goddess Chang'e flying to the moon, Wu Gang's felling of Guangxi, Yu Mian's tinkering with medicine and so on. The ancient Greeks regarded the moon as the beautiful hunting goddess themis, and regarded the silver bow that the goddess never left when hunting as the astronomical symbol of the moon.

Age: 4.6 billion years old period of revolution: 365.25 days rotation period: 23.56 hours volume: 10832 billion cubic kilometers mass: 600 billion tons average density: 550g/cm3 equatorial radius: 6378. 140km polar radius: 6356.755km surface area: 5/kloc-.

Of course, there are many other languages. In Roman mythology, the goddess of the earth is called Tellus-fertile land (Greek: Gaia, mother of the earth). The earth is the third closest planet to the sun and the fifth largest of the eight planets.

3. Knowledge about the sun, the moon and the earth

The earth is one of the eight planets in the solar system, ranking third in the order from near to far from the sun. It is also the earth-like planet with the largest diameter, mass and density in the solar system, with a distance of1.500 million kilometers from the sun.

The earth rotates from west to east and revolves around the sun at the same time. [1] It has a natural satellite-the moon, forming a celestial system-the earth-moon system.

It originated from the primitive solar nebula 4.6 billion years ago. The equatorial radius of the earth is 6378. 137km, the polar radius is 6356.752km, the average radius is about 637 1km, and the equatorial circumference is about 40076km. It is an irregular elliptical sphere with slightly flat equator and slightly protruding poles.

The surface area of the earth is 5 1 100 million square kilometers, of which 7 1% is ocean and 29% is land. Seen from space, the earth looks blue. There are core, mantle and shell structures inside the earth, and hydrosphere, atmosphere and magnetic field outside the earth.

The earth is the only known celestial body with life in the universe at present, and it is the home of millions of creatures, including human beings.

What else do you know about the sun, the earth and the moon?

Tropic year: Seen from the earth, the time for the sun to circle the ecliptic of the celestial sphere, that is, the time from the vernal equinox to the vernal equinox, is also called the solar year. 1 tropical year = 365.24220 days = 365 days, 5 hours, 48 minutes and 45.5 seconds. Sidereal year: refers to the time required for the earth to make a 360-degree revolution, 1 sidereal year = 365.2564 days = 365 days, 6 hours and 9 minutes 10 second. It applies to astronomy, not to calendars. As for why the annual meeting of stars is slightly longer than the tropical year, it is due to the gravitational influence of the moon, the sun and the planets, which makes the rotation axis of the elliptical earth protruding from the equator move slowly around the Yellow River (corresponding to the spring equinox, the Yellow River retreats westward at the rate of 50.24 minutes per year, moves westward at 65,438+0 degrees in 765,438+0 years, and moves once in 25,800 years), that is, the precession phenomenon. When we say a year, we mean the year of the tropic of cancer.

29 days of the first lunar month 12 hours, 44 minutes and 22.8 seconds; The sidereal month is 27 days, 7 hours and 43 minutes, 1 1.559 seconds. When we say a month in the lunar calendar, we mean the "new moon".

Ask God for knowledge about the sun, the earth and the moon.

The solar system and the celestial system that orbits the sun and is dominated by its gravity are called the solar system.

The members of the solar system include the sun and planets around the sun (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune), more than 2,000 asteroids with confirmed orbits, 66 satellites and many comets and meteoroids. Its volume is1.41.200 million cubic kilometers, which is 1.3025 times that of the earth. A medium-sized star in the Milky Way.

It is about10.50 million kilometers away from the earth and has a diameter of about10.392 million kilometers. It takes more than 3500 years to walk from the earth to the sun, and more than 20 years to fly. Average density 1.409g/cm3, mass 1.989 * 10 33g, surface temperature about 6000℃, center temperature 15008400℃.

From inside to outside, there are the nuclear reaction area of the sun, the troposphere of the sun and the atmosphere of the sun. Thermonuclear reactions continue in its central region, and the energy generated is emitted into space by radiation.

One fifth of the energy radiates to the earth, becoming the main source of light and heat on the earth. Stars also have their own life history, from birth, growth to aging and finally to death.

They are different in size, color and evolution. The connection between a star and life is not only that it provides light and heat.

In fact, the heavy atoms that make up planets and living matter are produced in the process of explosions at the end of some stars' lives. The sun is an ordinary astronomical symbol of a star: volume: 1 302 500 times the volume of the earth; Rotation period: 25-30 days; Distance from the nearest star: 4.3 light years; Cosmic year: 225 million years; Diameter: 1 392 000 km (109 times the diameter of the earth); Radius: 699. Mass of rice: 1.989 * 10 30 kg (332 946 times that of the earth) Temperature: about 5770℃ (surface) 15.6 million℃ (core) 5 million℃ (corona) Volume:1. 1 0.27 cubic meters (10.3 million times the earth), total radiation power: 3.83 *10.26 joules/second, average density:10.409 g/cm3, and average distance between the sun and the earth:10.5.

Age: about 5 billion years old.

6. Astronomical knowledge of the sun, the moon and the earth

In fact, this is just a reference question, not an astronomical knowledge.

You can explain to your daughter that she and her mother are in the same car. If the car runs smoothly and all the windows are hung with curtains, we can only see the people inside the car and not feel the car moving. When the curtains are opened, we can see the scenery outside and know that the car is moving. In fact, the phenomenon you mentioned is the same.

When we are inside the earth, we can't feel the earth turning. The earth turns smoothly, but when we look up and see the sun and the moon, just like the curtains of a car are pulled open, we don't know that the earth is turning until we have a reference. Regarding the operation of the sun, the earth and the moon, first of all, the sun is a star (as the center of the solar system, it can be said that it is constant, and of course the sun also rotates around its own axis). The earth is a planet (revolving around the sun and the moon is a satellite (protecting the earth from rotating and revolving around it like a guardian). One revolution of the earth is called a day or a month, and one revolution of the earth around the sun is called a year. Of course, what I said above can only be aimed at primary school students. I hope it helps you. 65438+ 10 month 1 1. If it does, we can explain the day we usually talk about. Actually, it's not sidereal day, nor is it Sun Day. Sidereal day is the rotation period calculated by the earth with reference to a distant star. This data is 23 hours, 56 minutes and 4 seconds, and the solar day we refer to in our daily life is an integer based on sidereal day, which is 24 hours. There are actually two concepts about the revolution of the earth, which is what we call the year. One is 365, 6: 09, 10 second, which is the real period of the earth's revolution. The other is the tropic year, which means that the direct point of the sun moves back and forth in a sinusoidal curve between the north and south of the earth's return to the present. The time of a cycle is 5: 48: 46 on 365. Because there are some specific time points (vernal equinox, summer solstice, autumn solstice, winter solstice) and they are closely related to people's production and life, this is what we call the last year, that is, the knowledge of geography in senior one. Then there is the saying that the moon rotates and revolves. It is true that when facing the earth, people will never see the opposite side of the moon, but many people think that this is the reason why the moon does not rotate. In fact, the moon is spinning, just because the rotation time and revolution time of the moon are the same. I don't know if I can understand it, that is to say, a year of the moon (because the moon is a satellite, in fact, its revolution can't be called a year) is exactly the same as a day on the moon, because this synchronization of rotation and revolution makes the moon always face the earth. Let me add that there is no necessary connection between the year and Japan. Planets orbit the stars once a year and satellites orbit the planets once a month. The planet revolves around itself once a day, which is not what we usually say. A year is 12 months and 365 days. This ratio only exists at the end of the earth, which provides a little common sense about Polaris, which is actually rotating (usually we say that Polaris is forbidden to move). Actually, it's because Polaris itself is very slow. Then it must be pointed out that Polaris is not the name of a star, but the name of a class of stars. Now Polaris is a star in Ursa minor. In a few years, the star in Draco will take its place in the north celestial pole and become the new Polaris. In addition, there is no invivo, just because there is no such bright star in the south celestial pole.

7. Knowledge about the Earth, the Moon and the Sun

The sun is the central celestial body in the solar system and the source of light and heat for planets.

It is an ordinary star in the Milky Way, located about 65,438+00 thousand parsec from the center of the Milky Way and about 8 parsec from galactic plane, and rotates around the center of the Milky Way with other stars. The sun is a gas ball with a diameter of about 1.4* 106 km. Due to gravity, the density and temperature of the sun increase inward.

The surface temperature is about 6000K, and the density is extremely thin. There can be no solid or liquid at such a high temperature. There are a few molecules in the area with the lowest temperature on the surface of the sun, but most substances exist in the form of atoms.

The central temperature of the sun is over 1.5* 107K, the pressure is about 3.4 *1kloc-0/2 Newton/cm ~ 2, and the density reaches160g/cm ~ 3. In this high temperature, high pressure and high density environment, the thermonuclear reaction of hydrogen to helium occurred. The sun is the celestial body that has the closest relationship with human beings except the earth, and it is also the only star that can examine its surface structure in detail, so people have always attached great importance to the study of the sun.

The following table lists some basic data about the sun.