Five questions about solar storms, which are expected to grow during the year, and their possible consequences on Earth

Residents of polar zones (and even less extreme latitudes) will see all colors. The number of northern and southern lights will increase in the coming months, as solar flares, which cause these nocturnal spectacles, will be especially numerous. Solar storms are linked to the activity of the Sun, which experiences an eleven year cycle and currently A phase of high activity. The European Space Agency (ESA) reported the most powerful solar flare event of the current cycle on February 23.

The Frederic Pitout, assistant astronomer at the Institute for Research in Astrophysics and Planetology (ERAP), says the peak is expected at the end of the year or early next. Till then the activity will increase. It can also have concrete consequences on our daily lives. An event that raises questions that Franceinfo answers.

1 What is the origin of solar flares?

A manifestation of solar flares “Variable Magnetism” of the sun The latter, summarized by Frederick Pitout, behaves like a giant magnet that changes direction during each cycle. This significant change is accompanied by an increase in its activity, which is visible in the spots that appear on its surface.

On February 13, the European Space Agency released two images of the Sun taken by its Solar Orbiter probe. The first was taken in February 2021, while the most recent minimum activity is from December 2019. The surface of our star appears relatively uniform.

The second was taken in October 2023. At this time, the Sun was not yet as active as February 2024. However, the panorama is distinctly different from the previous image. Here, large and numerous spots can be clearly identified.

These spots, witnesses of our sun’s activity, are the center of solar flares – scientists use the term “coronal mass ejection” (CME). During these events, the Sun ejects plasma, “Very hot electrically charged gas”, summarizes Frederick Pitout. When the power of this phenomenon is high, we talk about solar storm.

2 How big is a solar flare?

The scale of the solar flare is astronomical. Sunspots can be several times the diameter of the Earth (which is about 12,750 km). According to scientist Pierre Henriquet, the powerful explosion that took place on February 22 (called AR3590) was about 16 times the diameter of our planet. It was a Class X explosion, the most powerful category of five degrees: A, B, C, M and

Filaments that emerge from spots during solar flares extend for thousands of kilometers. American space agency NASA has shared an image comparing the size of Earth and the X-class flare on February 21.

3 What happens when a solar storm hits Earth?

The Sun constantly emits elements, very slow, low-energy particles. This is what partly makes up the solar wind, in which our star’s atmosphere is bathed. This bubble, called the heliosphere, is very broad, as this NASA image shows.

Particles of There are solar flares “very fast, sometimes up to a fraction of the speed of light” (about 300,000 km per second), notes expert Frederic Pitout. Some may take several days to reach us while the fastest can reach within fifteen hours, While the Sun is on average about 150 million kilometers away.

Highly energetic, these particles collide with Earth’s magnetic barrier, called the magnetosphere. They pass through it and come into contact with the Earth’s atmosphere. This is where they give rise to the famous Northern Lights (in the Northern Hemisphere) or Southern Lights (in the Southern Hemisphere).

4 What damage can solar flares do to Earth?

Behind the magical lights of the Northern and Southern Lights lie potential problems for our electrical infrastructure and our satellites, especially in the event of a violent solar flare, warns franceinfo Olivier Katz, forecaster at the Alpes Operational Space Meteorology Center.

“In the event of a strong solar flare, anything that is ferrous, that can conduct electricity and that is very long on Earth, such as pipelines or electrical cables, can be affected by surges. We can imagine blackouts.”

Olivier Katz, space weather forecaster

at franceinfo

Extreme solar storm “Could affect critical infrastructure and halt certain economic sectors”Quentin Verspiren, coordinator of the Protect project within ESA, agrees.

The last documented violent episode dates back to 1859. It is nicknamed the Carrington phenomenon after the British astronomer who studied it. During this explosion, so much electricity was generated Olivier Katz notes that telegraphs were damaged and people were able to communicate through these message transmission systems, when they were disconnected. He points out that in the Caribbean, the Northern Lights were also seen far from the poles.

A phenomenon as powerful as Carrington in the 21st century “could put almost all satellites in orbit out of service and severely impact the power grid”, writes La Cité de l’espace, reporting the conclusions of a 2013 study for the insurance company Lloyds. For North America alone, the damage bill could be as high as $2.6 trillion.

A solar storm of unimaginable violence passed close to Earth in 2012. It could be “Returning Contemporary Culture to the 18th Century” If it had reached our planet, according to NASA. An unusually powerful event could damage critical facilities on Earth that would take a generation or two to repair or replace, warns Oliver Katz.

The proliferation of electronic devices and the ever-increasing use of devices that rely on satellite data make us more vulnerable than ever to solar storms. “When you use Google Maps to find your route and get to a restaurant, the map was created with Earth observation satellites. For the little blue dot that locates you and calculates the best route, you use navigation satellites.Underlines expert Quentin Verspieren.

This type of research can be done all over the world thanks to telecommunications satellites, continues the coordinator of the ESA Protect project, noting that we also know whether to take our umbrella thanks to weather reporting satellites. “Finally, this seemingly trivial gesture uses satellite data that comes from an infrastructure that has a total cost of hundreds of billions of euros”It emphasizes.

A mere disruption to the satellite navigation and timing services, which work together, will have cascading consequences. He emphasizes that electricity networks, transport networks or even telecommunications on a country or continent scale are integrated with these satellites and will be affected.

“The international financial system and the banking system in general is controlled by this. Stock exchanges will be blocked and we will not be able to withdraw money from ATMs or pay by card.”

Quentin Verspiren, from the European Space Agency

at franceinfo

If our dependence is great and the possible effects are significant, experts contacted by franceinfo ask us not to fall into catastrophism, emphasizing the rarity of events that could be extremely problematic.

5 Can we expect solar storms?

Our knowledge of the Sun’s magnetism is still incomplete. For example, its peak activity was expected to be in 2025, but it may end up being a little earlier, which shows our shortcomings. The process by which sunspots appear, as well as their exact behavior, still remains a mystery. It is still difficult for us to estimate the travel time of the particles ejected during the explosion. “We still have a lot of uncertainty”Quentin Verspiren admits.

However, knowledge is advancing, thanks to ongoing missions such as the Solar Orbiter, and will be further expanded with ESA’s Vigil mission in the 2030s. The aim is to refine our space weather forecasts specifically for authorities to issue warnings. Take precautionary measures in case of severe solar storm. This could, for example, include grounding the plane for as long as necessary (several hours or several days) to avoid problems if the satellite navigation system were to be disturbed or interrupted.

Quentin Verspiren adds that discussions have started across the European continent, so that an entity with the right skills could be operational for the next cycle in eleven years. Before that, vigilance is required until the next peak of activity.