Astronomers of the University of Colorado at Boulder in the United States concluded that the sun could generate a burst of energy thousands of times more powerful than ordinary flares, which would cause great damage to technological civilization. Such events, called super flashes, were usually recorded in young and active stars, and at first, they were thought to be impossible in the solar system.
Outbreaks are a release of significant amounts of energy in a stellar atmosphere. They generate magnetic fields near the spots – the cold parts of the photosphere. Young stars, fast-rotating stars, binary stars (their companions should be close to each other) and red dwarfs have high magnetic activity. Their fields with a force of several thousand Gauss (0.1-0.4 Tesla) affect vast areas of the surface, which contributes to the occurrence of super flashes with a luminosity of ten or a million times higher than that of the largest solar flares (with an energy of 10 in the 32nd degrees erg). It would seem that humanity was lucky: the Sun rotates slowly, its magnetic fields are weak – nothing indicates that it has enough forces for a super flash.
However, thanks to the data obtained using the Kepler space telescope, scientists began to find evidence of the occurrence of super flashes in stars of spectral class G (this includes the modern sun). Stars that produce extreme flashes have such a large number of spots that, as they rotate, periodic changes in brightness occur, which can be seen with astronomical instruments. Generally speaking, the appearance of a huge number of spots is a clear sign of increased magnetic activity. A large number of similar events were discovered, which made it possible for researchers to estimate the probability of a super flash in the Sun.
Scientists have found that super-flares with energies up to 10 in the 35th-degree erg can occur once every several thousand years for stars that rotate just as slowly as the sun. The frequency of flashes with an increase in its strength decreases according to a power law, that is, the stronger the flash, the less often it occurs. Therefore, astronomers have come to the conclusion that the Sun occasionally, once every several thousand years, is capable of generating sufficiently powerful magnetic fields to create a catastrophic event.
In one of the past scientific works, researchers conducted observations of 50 solar-type stars producing super flashes. More than half (34) of them were single, and all the parameters of the stellar atmosphere (temperature, surface gravity, metallicity) were typical of G-class stars. They demonstrated the very periodicity in the change in brightness that occurs during rotation and the presence of a large number of spots. Also, scientists have measured the content of lithium, whose large number is characteristic of active and young stars.
With age, the lithium content in the stars decreases as the luminaries become colder, the metal sinks into the hot subsoil, where it is destroyed in nuclear reactions. Some stars have little lithium, rotate slowly, but still, produce fairly powerful flares. However, to confirm that the Sun could be dangerous, astronomers did not have enough spectroscopic data about single stars, because many of the systems studied were binary.
In a new study, experts studied 23 more Sun-like stars that had super-flashes. These stars were originally discovered now by the “late” Kepler telescope. It is worth noting that all of them rotate a little faster than the Sun, whose rotation period around its axis is about 25 days. Of the 23 stars, 18 of the brightest were selected (to eliminate the influence of noise), and of them, in turn, identified five binary systems. In addition, astronomers also looked at another 28 solar-type stars for which no super-flashes were recorded.
Given the combined data on 43 stars, astronomers confirmed a direct correlation between the number of sunspots and the magnetic activity of stars, as well as the fact that old stars like the Sun can actually produce super flash. In addition, the maximum flare energy is not strictly dependent on the speed of rotation of stars, and powerful energy emissions up to 10 in the 35th-degree erg can occur on slowly rotating stars. Super flashes with energy up to 5 * 10 to the 34th degree. Erg occurs on old solar-type stars about once every 2-3 thousand years.
However, according to researchers, current statistics are not enough to confidently answer the question of whether the Sun can produce a catastrophically powerful flash. Scientists are not quite sure that the stars studied do not have any unaccounted properties that are absent from the Sun. But, based on the available data, the likelihood that a super-flash could occur in the next hundred years is rather high. Astronomers plan to study the mechanism of outbreaks and the effect they can have on nearby planets.
Superflash will not lead to mass extinction and environmental disaster, despite the fact that it will be thousands of times stronger than a conventional solar flare. It does not burn forests and does not overwhelm all people and animals on Earth with harmful ultraviolet radiation. However, its consequences will be difficult for human civilization, whose existence is closely connected with satellite and other technologies. A burst of high-energy radiation would be fatal to electronics and telecommunications systems and could be deadly for astronauts in orbit.
An outburst on the Sun creates large plasma emissions from the solar photosphere, which rush into space and collide with the Earth’s magnetic field, creating a geomagnetic storm. Another damaging factor is ionizing radiation, which is responsible for the formation of the ionosphere around the Earth. Charged particles can penetrate higher layers of the atmosphere, causing auroras and disruptions in radio communications.
Superflash can literally lose all artificial satellites, and passengers on planes making flights through the polar regions will receive high doses of radiation. Serious damage to the power system will lead to a massive outage. Most likely, there will be a depletion of the ozone layer with an increase in the damaging effects of ultraviolet radiation on human skin. The incidence of cancer, cataracts will increase, as well as the risk of sunburn will increase. Restoring the atmosphere will take months or years.