New study shows mysterious solar particle explosions could destroy the ozone layer, bathing Earth in radiation for years

The stunning aurora borealis in early May this year showed just how powerful solar storms can be in the form of radiation, but sometimes the Sun does something even more destructive. These bursts of protons ejected directly from the Sun’s surface are known as “solar particle events,” and they can shoot out into space like a searchlight.

Records show that Earth experiences an extreme solar particle event about every thousand years, which can cause severe damage to the ozone layer and increase levels of ultraviolet radiation at the surface.

We have analyzed what happens during such an extreme event in paper Posted on July 1st in Proceedings of the National Academy of SciencesWe also show that at times when Earth’s magnetic field is weak, these events can have a significant impact on life across the planet.

Earth’s Critical Magnetic Shield

The Earth’s magnetic field provides a vital protective cocoon for life, deflecting electrically charged radiation from the Sun. In its normal state, the magnetic field acts like a giant bar magnet, with field lines rising from one pole, wrapping around it, and then descending down at the other, in a pattern sometimes described as an “upside-down grapefruit.” The vertical orientation at the poles allows some ionizing cosmic radiation to penetrate down into the upper atmosphere, where it interacts with gas molecules to create the glow we know as the aurora.

However, the magnetic field changes dramatically over time. Over the past century, the North Magnetic Pole has moved across northern Canada at a speed of about 40 kilometers per year, and the magnetic field has weakened due to changes in the atmosphere. More than 6%Geological records indicate that there were periods lasting centuries or millennia when the Earth’s magnetic field was very weak or even completely absent.

We can see what might happen without Earth’s magnetic field by looking at Mars, which lost its global magnetic field in the ancient past, and most of its atmosphere as a result. In May, shortly after the aurora borealis, Powerful solar particle hits Mars. The operation has been disabled. Mars Odyssey The spacecraft caused radiation levels on the surface of Mars to be about 30 times higher than what you would receive during a chest X-ray.

Proton force

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 sporadically emits bursts of energy, mostly protons, in solar particle events—often associated with solar flares.

Protons are much heavier than electrons and carry more energy, so they reach low altitudes in the Earth’s atmosphere, exciting gas molecules in the air. However, these excited molecules only emit X-rays, which cannot be seen with the naked eye.

Hundreds of weak solar particle events occur every solar cycle (roughly 11 years), but scientists have found traces of much stronger events throughout Earth’s history. Some of the most extreme events were thousands of times more powerful than anything recorded with modern instruments.

Extreme Solar Particle Events

These extreme solar particle events occur roughly every few thousand years. The most recent one occurred around AD 993 and has been used to show that Viking buildings in Canada were used Wood cut in 1021 AD.

Less ozone, more radiation.

In addition to their immediate impact, solar flares can also trigger a series of chemical reactions in the upper atmosphere that can lead to ozone depletion. Ozone absorbs harmful ultraviolet radiation from the sun, which can damage eyesight and DNA (increasing the risk of skin cancer), as well as impacting the climate.

in our country New studyWe used large computer models of global atmospheric chemistry to examine the effects of an extreme solar particle event.

We found that such an event could deplete ozone levels for a year or so, raising UV levels at the surface and increasing DNA damage. But if a solar proton event occurred during a period when Earth’s magnetic field was very weak, the ozone damage would persist for six years, increasing UV levels by 25% and boosting the rate of sun-induced DNA damage by up to 50%.

Particle explosions from the past

But how likely is this deadly combination of weak magnetic field and intense solar proton events? Given how frequently they occur, they are likely to occur together relatively frequently.

In fact, this combination of events may explain many mysterious events that have occurred in Earth’s past.

The most recent period of weak magnetic field—including a temporary shift in the north and south poles—began 42,000 years ago and lasted about 1,000 years. Several major evolutionary events occurred in the intervening period. It happened around this time.Such as the disappearance of the last Neanderthals in Europe and the extinction of large marsupials including Giant wombats and kangaroos in Australia.

A larger evolutionary event has also been linked to the Earth’s magnetic field. The origin of multicellular animals occurred at the end of the Ediacaran period (565 million years ago), recorded in fossils found in the Flinders Ranges of South Australia, after a period of 26 million years of evolution. weak or absent magnetic field.

Similarly, the rapid evolution of diverse groups of animals in the Cambrian explosion (about 539 million years ago) has also been linked to geomagnetism and high levels of ultraviolet radiation. The simultaneous evolution of eyes and hard body shells has also been linked in multiple unrelated groups. described As the best way to detect and avoid incoming harmful UV rays, “Escape the Light”.

We are still at the beginning of exploring the role of solar activity and Earth’s magnetic field in the history of life.

This article was republished from Conversation Under a Creative Commons license. Read Original Article.