How many suns are there in the universe?

There is only one sun, and there are many stars that resemble the sun.

There is only one sun, and the sun is just a very ordinary star in the universe, but it is the central object of the solar system.

There is only one sun, and countless other stars.

It should be one, no more.

It can only be said that there is only one at the moment.

If we define the earth as a world, there is only one sun, and if we define the universe as a world, then there are countless suns.

The Sun or Sun is a star located at the center of the Sun[3] system, which is almost an ideal sphere intertwined with a hot plasma and a magnetic field.

Its diameter is approximately 1,392,000 (km, equivalent to 109 times the diameter of the Earth; The mass is about 2,10,30 kilograms (330,000 times that of the Earth), which is about the total mass of the solar system. In terms of chemical composition, about three-quarters of the mass of the Sun is hydrogen, and the rest is almost all helium, including less than 2% of oxygen, carbon, neon, iron, and other heavy elements.

The angle of the Sun's circle in the sky is 32 arc minutes, which is very close to the angular diameter of the Moon as seen from the Earth, and is a wonderful coincidence (the Sun is about 400 times the diameter of the Moon and exactly 400 times the distance from us), making the eclipse look particularly spectacular.

Since the Sun is much closer to us than other stars, its apparent magnitude is reached, making it the brightest object seen on Earth. The Sun rotates once a day (depending on latitude, the equator is faster, the pole is slower, about days), and it orbits the center of the Milky Way once every 100 million years.

The Sun is slightly flattened by its rotation, which is a perfect spherical shape, equivalent to a difference of 6 km between the radius of the equator and the polar radius (21 km for the Earth, 9 km for the Moon, 9,000 km for Jupiter, and 5,500 km for Saturn).

The universe has an infinite number of sun-like stars.

The universe is physically defined as all space and time (collectively referred to as space-time) and their connotations, including all forms of energy, such as electromagnetic radiation, ordinary matter, dark matter, dark energy, etc., of which ordinary matter includes planets, satellites, stars, galaxies, galaxy clusters, and intergalactic matter. The universe also includes physical laws that affect matter and energy, such as conservation laws, classical mechanics, relativity, etc.

While the size of the entire universe is unknown, the size of the observable universe can be measured, with an estimated diameter of 93 billion light-years. In various multiverse theories, a universe is one of the components of a multiverse on a larger scale, and each universe itself includes all of its space and time and its matter.

Introduction to the Solar System

The solar system is a system of celestial bodies centered on the Sun and bound together by the Sun's gravitational pull, including the Sun, planets and their moons, dwarf planets, asteroids, comets, and interplanetary matter. The Solar System is located about 10,000 light-years from the center of the Milky Way (the number of stars in the Milky Way is about 100 billion to 400 billion), and the Sun orbits the galactic center at a speed of 220 kilometers and seconds, about 100 million years. The direction of the Sun's movement is basically towards Vega, near the constellation Hercules.

As of October 2019, the solar system includes the Sun, 8 planets, nearly 500 moons, and at least 1.2 million asteroids, as well as a number of dwarf planets and comets. If Neptune's orbit were used as the boundary of the solar system, the diameter of the solar system would be 60 astronomical units, or about 9 billion kilometers. If bounded by the heliosphere, the Sun can be up to 100 astronomical units (at its thinnest) from the boundary of the solar system.

If the Oort cloud is used as the boundary, the diameter of the solar system may be 200,000 astronomical units.

The above content reference: Encyclopedia - Universe.