The article tells about what a solar prominence is, how it can be dangerous for people and by what signs it is classified.
The sun
Life on our planet has existed for almost 4 billion years, and there are a lot of reasons why it was born and continues to exist. This is the climate, the gas composition of the atmosphere, the period of revolution of the planet around its axis, the force of its attraction and, of course, the distance from the Sun. The earth is in the so-called habitable zone, that is, at an optimal distance from the star, which ensures the maintenance of a comfortable existence of most species. And what happens to planets located too close to the central star of the system can be seen in the example of Mercury - it is completely scorched and empty.
As we see, all these factors form an extremely complex and ramified system, all the elements of which must maintain their fragile balance so that the history of the development of living organisms on our planet continues.
Prominences
But, of course, there are many obvious and hidden dangers that can deprive this system of the necessary balance. And processes that may be fraught with danger for all living things and not only occur on the Sun. For example, the so-called solar or magnetic storms. Weather-sensitive people and various equipment often suffer from them. During such storms prominences come off from the Sun and rush to the nearest planets. Fortunately, most of them are not so large as to lead to tragic consequences. Why are prominences dangerous, and what is it? We will talk about this in this article.
Definition
Prominences are the dense condensations of colder matter, compared with the rest of the Sun. During periods of activity, they rise above the surface of the star and are held there by its magnetic field. Simply put, prominences are giant fountains of incandescent solar matter that are held in by the attraction of a star. But sometimes, during times of especially strong solar activity, plasma flows fly beyond the limits of the photosphere of the Sun and rush in all directions, including towards our planet. This phenomenon is called magnetic or solar storm.
Description
One of the first scientific references to prominences is associated with a solar eclipse, which occurred in 1185. But due to the imperfection of instruments and the weak development of astrophysics, the scientific study of prominences began in the middle of the 19th century. In 1868, Pierre Jansen, using a new method of observing this phenomenon without a solar eclipse, concluded that they exist in a gaseous state.
By virtue of their nature, prominences are something that they managed to study well only using the achievements of scientific and technological progress: slow motion and artificial near-earth observation satellites.
They are clearly visible during solar eclipses of a full nature. Such phenomena are observed by means of special instruments: prominence-telescopes, filters, coronographs, chromospheric telescopes and others. If we consider the projection of prominences onto the disk of the Sun, then they look like dark elongated fibers of various thicknesses. So prominences are a phenomenon that can only be observed with a conventional telescope during a total solar eclipse.
In fact, we figured out what solar prominences are, now we will consider their types.
Kinds
If we talk about the appearance, then prominences are ragged structures, similar to filaments or clots of plasma of various shapes. They also constantly move and change their shape. Their classification is carried out according to dynamic or morphological characteristics. Consider their classification by appearance, features of the movement of matter and speed:
- Calm . In them, the substance moves most slowly. The shape is also changing very slowly. If we talk about the time of their life, then it ranges from several weeks to several months. Occur in all heliographic latitudes. Most often they can be observed near sunspots of a late stage of development. The temperature is approximately 15,000 degrees Celsius.
- Active . Such a prominence, the photo of which can be seen below, differs in that the plasma flows from the geyser base towards the photosphere, as well as from one prominence to another, move at a very high speed. Their temperature is 25,000 degrees Celsius. And by the way, many active prominences are formed from calm, but in this case their existence time is from several minutes to a day.
- Eruptive . If we talk about the appearance, then most of all such prominences resemble huge fountains with a height of more than one and a half million kilometers above the surface of our luminary. The plasma velocity reaches hundreds of kilometers per hour, and their shape changes very quickly. They do not exist for long, and as they increase in height, they gradually completely dissipate.
- Loop-like prominences appear in the form of small clouds above the chromosphere. Usually over time they merge into one large cloud, which then emits jets of hot gas towards the chromosphere. Such phenomena rarely occur for more than a few hours.
So now we know that the solar corona has prominences, and what species exist.
Theory of occurrence
Despite the fact that solar activity has been studied for a very long time, there is still no single and complete theory that would explain the occurrence of prominences and all other related phenomena. This is partially explained in part by the combined action of electric and magnetic forces with the gravity of the sun.
The chemical composition of the prominence clearly corresponds to the layer from which it was formed. But the physical conditions of the existence of the phenomenon are often associated with the chemical composition. For example, the spectrum of calm prominences is dominated by lines of hydrogen, ionized calcium. And in those associated with sunspots, the lines of various metals are most clearly distinguished.
The fact of the long existence of some of their varieties indicates that the substance is held by the magnetic force of the star. This assumption was confirmed by a number of spectroscopic observations.
Danger
As we have already discussed, a prominence is an element of the activity of the chromosphere of the sun and some of its physical processes. First of all, the danger is represented by those that come off the surface of the star and rush into interstellar space. Depending on the strength, they can disable satellites in Earth orbit and even kill the ISS crew. Entering into a reaction with the magnetosphere of our planet, prominences also form powerful magnetic storms that adversely affect the well-being of weather-sensitive people and interfere with the operation of radio communication systems and various electronic equipment. Fortunately, prominences, which are able to break away from the surface of the Sun and cause such harm, are extremely rare.
But, if we consider the most sad option, when the prominence is large, it can greatly damage the atmosphere of our planet or even destroy all life.