• Wednesday May 27,2020


We explain everything about the Sun, its component parts, its temperature and other characteristics. In addition, the Solar System.

The Sun is the closest star to Earth.
  1. What is the sun?

The Sun is the closest star to the planet Earth, located 149.6 million kilometers away. All the planets of the Solar System orbit around them at different distances, attracted by their gigantic gravity, as well as the comets and asteroids we know. The Sun is commonly known as Astro Rey .

It is a fairly common star of our galaxy, the Milky Way: it is neither too big nor too small compared to its millions of sisters. Scientifically, the Sun is classified as a yellow dwarf star, of type G2 .

It is currently in its main sequence of life. It is located in an outer region of the galaxy, in one of its spiral arms, 26, 000 light years from the galactic center.

However, the size of the Sun is such that it represents 99% of the entire mass of the Solar System, equivalent to about 743 times the total mass of each and every planet combined, and about 330, 000 times the mass of our planet.

Its diameter is 1.4 million kilometers, so it is the largest and brightest object in the earth's sky. That is why their presence makes the difference between day and night.

Moreover, the Sun is a huge plasma ball, almost round. It consists mostly of hydrogen (74.9%) and helium (23.8%), as well as a small portion (2%) of heavier elements such as oxygen, carbon, neon and iron.

Hydrogen is the main fuel of the Sun. However, due to combustion it becomes helium, leaving behind a layer of "ashes" of helium as the star progresses in its main life cycle.

  1. Structure and parts of the Sun

Each layer of the Sun has its own temperature and characteristics.

The Sun is a spherical star, with a slight flattening at its poles, the result of its rotation movement. In spite of being a gigantic and continuous atomic bomb of fusion of atoms of hydrogen, the enormous force of gravity that its mass grants compensates the thrust of the internal explosion, reaching thus a balance that allows the continuity of its existence.

The Sun is structured in layers, more like an onion. These layers are:

  • The core The innermost region of the Sun, which occupies a fifth of the star's total: about 139, 000 kilometers of its total radius. It is there where the gigantic atomic explosion of hydrogen merging takes place; but the gravity in the solar nucleus is such that it takes about a million years for the energy produced in this way to surface.
  • The radiant zone It is composed of plasma, that is, of gases such as helium and / or ionized hydrogen, and is the region that allows the easiest radiation of energy towards the outer layers, which considerably decreases the temperature recorded in this place.
  • The convective zone It is a region where gases cease to be ionized, making it more difficult for energy (in the form of photons) to escape out of the Sun. This causes energy to A can escape only by caloric convection, much more slowly. Thus, the solar fluid heats unevenly, causing dilation, loss of density and ascending or descending currents, such as an interior tide.
  • The photosphere The region of the Sun where visible light is emitted, which is perceived as bright granules on a darker surface, although it is a transparent layer about 100 to 200 km deep. The surface of the star is considered, and it is where the sunspots appear.
  • The chromosphere The outer layer of the photosphere itself is so called, much more translucent and still difficult to appreciate, since it is opaque due to the brightness of the previous layer. It has a size of around 10, 000 km and seen during an eclipse, it has an exterior reddish hue.
  • The solar corona The weakest layers of the outer atmosphere of the Sun are thus known, in which the temperature rises considerably with respect to the inner layers. This is a mystery of solar nature. However, there are low densities of matter along with intense magnetic fields, crossed by energy and matter at very high speeds, as well as by numerous X-rays.
  1. Sun Temperature

As we have seen, the temperature of the Sun varies according to the region of the star, although for our standards it is, in all, incredibly high.

Temperatures close to 1.36 x 10 6 degrees Kelvin (i.e. about 15 million degrees Celsius) can be recorded in the solar core, while on the surface the temperature drops to just barely 5, 777 K (around 5, 505 C), and rise again in the solar corona to 2 x 10 5 degrees Kelvin.

  1. Importance of the Sun for life

The Sun is indispensable for photosynthesis, and therefore for life on our planet.

Due to its continuous emission of electromagnetic radiation, including the light perceptible by our eyes, the Sun provides heat and illumination to our planet, making life possible as we know it. For this reason, the Sun is irreplaceable.

Its light allows photosynthesis, without which the atmosphere would not contain the oxygen levels we need, nor the plant life to sustain the different trophic chains. On the other hand, its heat keeps the climate stable, allows the existence of liquid water and energizes the different climatic cycles.

Finally, solar gravity keeps the planets orbiting around them, including Earth. Without him there would be no day and night, there would be no seasons, and the Earth would surely be a cold and dead planet, as are many of the outer planets.

This is reflected in human culture: the Sun usually occupies a central place in the religious imaginary, as a fertile father god, throughout almost all known mythologies. All the great gods, kings or messiahs have been in one way or another associated with their brightness, while death, nothingness and the evil or secret arts are associated with night and night.

  1. Solar system

The planets and other objects of the Solar System orbit around the Sun.

We call the planetary neighborhood where the Earth is located, that is, the circuit of eight planets that constantly orbit the Sun. This neighborhood is part of the Local Interstellar Cloud, part of the Local Bubble of the Ori n arm. It is estimated that it emerged 4, 568 million years ago, as a result of the collapse of a molecular cloud.

It consists of the following objects:

  • The Sun, the only star located in its center.
  • The inner planets, smaller in size and solid: Mercury, Venus, Earth and Mars. Next to them, their respective moons or satellites.
  • The outer planets, gigantic balls of icy gas: Saturn, J piter, Neptune and Uranus. Next to them, their respective moons or satellites.
  • Dwarf planets, such as Pluto, Ceres or Shovels.
  • The asteroid belt that separates the inner planets from the outer ones.
  • The belt of Kuiper and the Oort cloud, two sets of trans- Neptunian objects from which comets come.

More in: Solar System

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