About once every thousand years, Earth experiences an extreme solar event that can cause severe damage to the ozone layer and increase ultraviolet (UV) radiation levels at the surface. Over the past century, the north magnetic pole has moved across northern Canada at about 40 kilometers per year, and the field has weakened by more than 6%. Geological records show that there have been periods of centuries or millennia when the geomagnetic field was very weak or even absent.
The Earth’s magnetic field provides a vital protective cocoon by deflecting electrically charged radiation from the sun. In its normal state, it functions like a giant bar magnet, with field lines rising from one pole, looping around it, and plunging back down at the other pole, in a pattern sometimes called an “inverted grapefruit.” The vertical orientation at the poles allows some ionizing cosmic radiation to penetrate all the way down to the upper atmosphere, where it interacts with gas molecules to create the glow we call the aurora borealis.
We can see what would happen without Earth’s magnetic field by looking at Mars, which lost its global magnetic field and, as a result, much of its atmosphere in the distant past. In May, shortly after the aurora borealis, Mars was hit by a strong solar particle event. It disrupted the Mars Odyssey spacecraft and produced radiation levels on the Martian surface that were about 30 times higher than what you’d get from a chest X-ray.
The Sun’s outer atmosphere emits a constant fluctuating stream of electrons and protons known as the “solar wind.” However, the Sun’s surface also occasionally emits bursts of energy, mostly protons, in solar particle events that are often associated with solar flares.
Protons are much heavier than electrons and carry more energy, so they reach lower altitudes in the Earth’s atmosphere, exciting gas molecules in the air. However, these excited molecules only emit X-rays, which are invisible to the naked eye.
Hundreds of solar-weak particle events occur in each solar cycle (roughly 11 years), but scientists have found traces of much more powerful events throughout Earth’s history. Some of the most extreme were thousands of times stronger than anything recorded by modern instruments.
Extreme solar particle events occur roughly every few millennia. The most recent one occurred around 993 CE and was used to show that Viking buildings in Canada used timber cut in 1021 CE.
In addition to the immediate effect, solar particle events can also trigger a chain of chemical reactions in the upper atmosphere that can deplete the ozone layer. Ozone absorbs harmful ultraviolet radiation from the sun, which can damage vision and DNA (increasing the risk of skin cancer) and affect the climate.
Such an event could deplete ozone for about a year, increasing UV levels at the surface and increasing DNA damage. But if the solar proton event occurred during a period when the Earth’s magnetic field was very weak, the ozone damage would last for six years, increasing UV levels by 25% and increasing the rate of solar-induced DNA damage by up to 50%.
The most recent period of weak magnetic field, including a temporary switch between the north and south poles, began 42,000 years ago and lasted for about 1,000 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 linked to the Earth’s geomagnetic field. The origin of multicellular animals at the end of the Ediacaran period (565 million years ago), recorded in fossils in the Flinders Ranges of South Australia, occurred after a 26-million-year period of weak or absent magnetic field.
Similarly, the rapid evolution of different animal groups in the Cambrian explosion (around 539 million years ago) has also been linked to geomagnetism and high levels of UV light. The simultaneous evolution of eyes and hard body shells in several unrelated groups has been described as the best way to both detect and avoid harmful incoming UV rays, in “light flight.”
Astronomers from the United States have found that shock waves present in the structure of the solar wind can collide with the Earth’s magnetosphere and in some cases generate not only bright auroras, but also powerful electric currents on the Earth’s surface that can damage electrical networks, according to the journal Frontiers in Astronomy and Space Sciences.
Typically, such power grid failures usually occur during powerful geomagnetic storms, as happened, for example, in Canada in March 1989. However, weaker but frequently occurring shock waves can also pose a serious threat to ground-based transmission networks.
The researchers came to this conclusion while studying how various space weather events affected a gas pipeline in southern Finland, located near the community of Mantyasälä. A large part of the pipeline is located inside the zone where the northern lights occur. This allows it to be used as a scientific tool to track electrical currents generated on the Earth’s surface by “space weather”.
Experts studied how the electrical characteristics of this gas pipeline changed from 1995 to 2023. The researchers compared these measurements with various manifestations of “space weather” that were recorded by the Wind and ACE probes in the immediate vicinity of the Earth’s North Pole during particularly bright flashes of the northern lights.
In total, the researchers studied three hundred such incidents, the analysis of the properties of which indicated that in some cases unusually strong electric currents arose in the gas pipeline, which were caused by the collision of shock waves from the solar wind with the Earth’s magnetosphere. The strength of this current was determined by the angle at which the shock wave collided with the planet’s magnetic shell, as well as the position of the north magnetic pole relative to the Sun and Mantyasyal.
As astronomers note, with a certain combination of the collision angle and the position of the north magnetic pole, the strength of such induced electric currents can exceed 20 amperes, which can pose a significant threat to power grids and sensitive equipment. This must be taken into account when building infrastructure both in the Arctic and in neighboring regions of the Earth, the researchers concluded.
A powerful magnetic storm that hit Earth in May 2024 caused northern lights even in places where they are rarely observed, for example, in northern Mexico, and in Russia – in Crimea. It also disrupted the work of GPS satellites, which made it difficult for farmers in the United States; many were forced to interrupt sowing campaigns. But what can already be attributed to more alarming “bells and whistles” is the formation of a series of hurricanes.
Scientists from Florida State University reconstructed data on storms in the northeastern Gulf of Mexico. They then compared this data with fluctuations in total solar radiation. Solar activity was tracked by tree rings – its peaks and troughs are known to be indicated by the carbon-14 content of wood. The results showed that over the past 5,500 years, in certain periods (11 cases), the frequency of tropical cyclones has increased sharply by 40%. These periods had one thing in common – the Sun was aggressive.
According to scientists’ theory, a more active Sun sends more energy to Earth, which heats the oceans and provides “fuel” for tropical storms. Today, the star is on its way to its maximum. In May, the planet registered a magnetic storm with a G4 intensity on a 5-point scale. Experts rated it as “strong.”
These findings appeared in print at a time when the hurricane season had already started in America. It promises to be a record-breaking one – meteorologists expect at least 20 storms. Scientists noted that, in addition to solar radiation, their intensification is also facilitated by high temperatures in the Atlantic Ocean (close to record-breaking), the development of La Niña weather conditions in the Pacific Ocean, weakening trade winds in the Atlantic and less wind shear, the MIR24 Internet portal reports with reference to Science Direct.
Eruptions of dark plasma, also called “cold” solar flares, have a 60 percent chance of causing radio blackouts on Earth, the Daily Mail reported, citing data from the US National Oceanic and Atmospheric Administration (NOAA). “The flare could disrupt radio, aviation and satellite communications if it occurs by Friday at the earliest,” the publication writes.
According to NOAA data cited in the publication, the probability of radio blackouts on Earth due to flares is 60 percent.
So-called “cold” solar flares, which have lower temperatures than “warm” ones, have only become the subject of serious study by astrophysicists in the last decade. They have been found to emit microwave radiation at least as much as “warm” solar flares, and also produce higher peak frequencies of gyrosynchrotron radiation, the exact form of radiation responsible for the flare’s intense and destructive radio emission.
For example, a solar flare from sunspot AR3738 occurred late Saturday (July 13) at 10:34 p.m. ET (02:34 UTC July 14), and NASA’s Solar Dynamics Observatory captured the dynamic scene from space. The flare caused shortwave radio losses in Australia, Southeast Asia, and Japan shortly after the eruption. These losses often occur after powerful solar flares due to the intense bursts of X-rays and extreme ultraviolet radiation emitted during these events.
Radiation from solar flares travels toward Earth at the speed of light and ionizes (electrically charges) the upper atmosphere upon arrival. This ionization creates a denser environment for high-frequency, short-wave radio signals to pass through, facilitating long-distance communication. As the radio waves interact with electrons in the ionized layers, they lose energy through increased collisions, which can degrade or completely absorb the radio signals.