Lethal combinations of factors for the future of the Earth are named

Extreme solar flares and weak magnetic fields are dangerous for our planet

The aurora in early May 2024 demonstrated the power that solar storms can emit as radiation, but sometimes the Sun does something much more destructive. Scientists have now indicated that solar flares and the weakening magnetic field of our planet may become a decisive factor in the danger for the future of the Earth.

Photo: pixabay.com

Known as «solar particle events,» ejections of protons directly from the surface of the Sun can be beamed into space like a spotlight.

Data shows that about once every thousand years, the Earth is exposed to extreme solar particles that can cause severe damage to the ozone layer and increase levels of ultraviolet radiation on the planet's surface.

Astronomers have analyzed what happens during such extreme events and what happens during periods when the Earth's magnetic field is weak. According to experts, these events could have a significant impact on life on the entire planet.

Under normal conditions, the Earth's magnetic field functions as a giant bar magnet, with lines of force rising from one pole, wrapping around it, and descending again to the other pole, forming a pattern sometimes called an «inverted grapefruit.»

Vertical Orientation at the poles allows some ionizing cosmic radiation to penetrate into the upper atmosphere, where it interacts with gas molecules, creating a glow known as the aurora.

However, over time, the magnetic field changes greatly. Over the past century, the magnetic North Pole has moved across northern Canada at a rate of about 40 kilometers per year, and the magnetic field has weakened by more than 6 percent.

Geological evidence shows that there were periods of centuries or millennia when geomagnetic the field was very weak or even completely absent.

Scientists can see what would have happened without Earth's magnetic field by looking at Mars, which in the past lost its global magnetic field and, as a result, much of its atmosphere.

In May, shortly after the aurora, Mars was hit by a powerful eruption of solar particles. This disrupted the Mars Odyssey spacecraft and caused radiation levels on the planet's surface to increase.

The Sun's outer atmosphere emits a constant, oscillating stream of electrons and protons known as the «solar wind.» However, the star's surface also occasionally emits bursts of energy, mostly protons, as a result of the interactions of solar particles, which are often associated with solar flares.

During each solar cycle (about 11 years), there are hundreds of weak bursts of solar particles, but scientists have found traces of much stronger ones throughout Earth's history. Some of the most extreme were thousands of times stronger than anything recorded by modern instruments. Phenomena of this magnitude occur approximately every few millennia. The last of these occurred around 993 AD and was used to prove that Viking buildings in Canada used wood cut down in 1021 AD.

In addition to its direct effects, solar wind can also set off a chain of chemical reactions in the upper atmosphere that can lead to the destruction of the ozone layer, which absorbs harmful ultraviolet radiation from the sun, which can damage human vision and DNA, increase the risk of skin cancer, and also affect the climate.

Scientists have found that if solar proton radiation had occurred during a period when the Earth's magnetic field was very weak, ozone depletion would have continued for six years, increasing ultraviolet radiation levels by 25 percent and increasing the rate of DNA damage it causes by up to 50 percent. .

The most recent period of weak magnetic field, including a temporary shift of the North and South Poles, began 42 thousand years ago and lasted about a thousand years. Several major evolutionary events occurred around this time, such as the disappearance of the last Neanderthals in Europe and the extinction of marsupial megafauna, including giant wombats and kangaroos, in Australia.

An even larger evolutionary event was also associated with the Earth's geomagnetic field . The origin of metazoans at the end of the Ediacaran period 565 million years ago, recorded in fossils in the Flinders Mountains in South Australia, occurred after a 26-million-year period of weak or no magnetic field.