Solar system

Solar activity

Solar activity

The solar activity It manifests and can be observed in various ways: spots, bumps or flares and solar wind.

The sun is an active star. Like all stars, it consumes matter and produces energy. But this energy explosion varies according to the areas and also over time. How and why does it happen?


Sunspots have a dark central part known as umbra, surrounded by a clearer region called gloom. Sunspots are dark since they are colder than the surrounding photosphere.

The spots are the place where strong magnetic fields are concentrated. The reason why sunspots are cold is not yet understood, but one possibility is that the magnetic field in the spots does not allow convection under them.

The Sunspots They usually grow and last from several days to several months. Observations of sunspots first revealed that the Sun rotates over a period of 27 days (seen from Earth).

The number of sunspots on the Sun is not constant, and changes over a period of 11 years known as the solar cycle. Solar activity is directly related to this cycle.

Solar bumps

Solar protuberances are huge jets of hot gas ejected from the surface of the Sun, which extend many thousands of kilometers. The biggest flares can last several months.

The magnetic field of the Sun deflects some bumps that form a gigantic arch. They are produced in the chromosphere that is about 100,000 degrees in temperature.

The protuberances of the Sun are spectacular phenomena. They appear in the limbo of the Sun as flaming clouds in the upper atmosphere and lower crown and are formed by clouds of matter at a lower temperature and greater density than their surroundings.

The temperatures in its central part are approximately one hundredth of the temperature of the crown, while its density is about 100 times that of the ambient crown. Therefore, the pressure of the gas inside a protuberance is approximately equal to that of its surroundings.

Solar wind

Solar wind is a flow of charged particles, mainly protons and electrons, that escape from the sun's external atmosphere at high speeds and penetrate the Solar System.

Some of these charged particles are trapped in the Earth's magnetic field by spiraling along the lines of force from one to the other magnetic pole. The northern and southern auroras are the result of the interactions of these particles with the air molecules.

The solar wind speed is about 400 kilometers per second near the Earth's orbit. The point where the solar wind is found that comes from other stars is called heliopause, and is the theoretical limit of the Solar System. It is located about 110 AU from the Sun. The space within the limit of the heliopause, containing the Sun and the solar system, is called the heliosphere.

◄ PreviousNext ►
Structure and composition of the SunThe planets