The Sun

The Sun, characteristics, dimensions and curiosities

The Sun, characteristics, dimensions and curiosities

The Sun is a star around which the Earth revolves and is the source of energy for planet Earth and all other planets in the Solar System. The star is made up of a hot gas made up mainly of millions of tons of hydrogen and helium.

Our star revolves around itself. However, since it is made up of a large mass of gases, the different regions do not rotate in solidarity, but rather at different speeds, which depend on latitude.

The structure of the Sun is made up of six layers composed of 6 layers: the solar core, the radioactive zone, the radiant zone, the convective zone, the photosphere, the chromosphere and the solar corona.

Nuclear fusion reactions are generated in the nucleus, which are the origin of energy. The photosphere, one of the outer layers, generates the visible light that we see from Earth.

Dimensions of the Sun and physical properties.

As we have already mentioned, it is a star of enormous dimensions compared to the planets of the Solar System, but reduced in reference to the various types of stars present in the universe. From a physical point of view, it is almost spherical in shape and is made up of matter in the plasma state (ionized gas), in particular hydrogen and helium.

Average distance from Earth

149.597.870.700 m


1.391.016 km


6,0877 × 10^12 km²


1,4123 × 10^18 km³


1,9891 × 10^30 kg


1411 kg/m³

What are sun spots?

Sunspots are relatively dark spots on the solar surface. They are associated with relatively colder spots in the photosphere. This relative cooling caused by strong magnetic fields hinders the convection of the plasma.

The heat supply from the core is temporarily reduced. Sunspots disappear over time.

The number of sunspots is a measure of solar activity. If the star is active, it produces short bursts of energy that release charged particles.

What are solar flares?

A solar flare is basically a giant explosion on the solar surface. It occurs when the magnetic field lines of sunspots entangle and erupt.

The material heats up to many millions of degrees Celsius in just minutes. Radiation is emitted across virtually the entire electromagnetic spectrum.

Solar flares are frequent when the Sun is active in the years around solar maximum. Some solar flares can launch huge clouds of solar plasma into space. These eruptions are called coronal mass ejections.

What kind of star is the sun?

The sun is a yellow dwarf, a medium-sized star. This type of star has an average surface temperature of about 6,000 degrees Celsius and its brightness is light yellow, almost white.

Scientists believe that our star is in the middle of its life. When it ages it will turn into a red giant and then it will turn into a white dwarf.

Our star is estimated to be brighter than 85% of the billions of stars in the Milky Way. Most are red dwarfs.

How does the Sun move?

Our star, like all other celestial bodies, is subject to different movements. The main movements consist of:

  1. a movement of revolution around the center of the galaxy along an elliptical path, which occurs at an average speed of 217 km / s and takes approximately 225 million years;
  2. a rotational movement around its own axis. Since it is not a solid body, it is subjected to a differential rotational motion in which the rotational speed varies as the latitude varies. This speed is maximum at the equator (1,993 km / s) and decreases as it approaches the poles.
Publication Date: November 9, 2016
Last Revision: August 8, 2021