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Extreme space weather: predicting and designing our way around solar storms

Space weather is not something most of us think about on a daily basis. But the charged particles and the Sun’s magnetic field are constantly sweeping through space and colliding with the Earth’s magnetic field. Every now and then the aurorae fill the sky with light dancing along these field lines. The most extreme space weather, however, occurs when the Sun hurls billions of tons of energized particles directly toward Earth at speeds of up to 3,000 kilometers per second.

These explosions, known as coronal mass ejections (CMEs), lift off from the Sun’s outer atmosphere – the corona, and can cause intense geomagnetic storms and negatively affect astronauts, satellites and spacecraft.

CME and geomagnetic storms

Geomagnetic storms occur when the earth’s magnetic field is disturbed. The most extreme geomagnetic storms are caused by CMEs.

CMEs really energize the Earth’s magnetic field, says James Spann, head of space weather at NASA. “The impact of a CME on a magnetized body like Earth can be very catastrophic depending on its size and speed.”

One of the most intense CMEs is believed to have occurred on September 1, 1859 (the Carrington Event), reaching Earth 17.5 hours later and triggering a large geomagnetic storm. Auroras were seen as far south as the Caribbean, and telegraph lines caught fire as communications were cut to various locations around the world.

For nearly a hundred years, scientists have known that small to moderate CMEs are more likely to occur when the Sun is more active and produces more sunspots, about every 11 years. But there have been doubts as to whether more extreme events, like the Carrington event, also follow the solar cycle.

In a new study, a team of researchers led by Mathew Owens, professor of space physics at the University of Reading in the UK, found that more extreme CMEs are also more likely to occur during peak solar activity.

“These are the ones that concern us the most, but they seem to be more predictable than previously thought,” says Owens.

The researchers looked at 150 years of disturbances in the Earth’s magnetic field and selected the most extreme CMEs that had occurred and compared them to solar cycles. Dating back to 1749, we have experienced 24 complete solar cycles, with the current solar cycle expected to be in the active phase between 2024 and 2026.

The Carrington event occurred about six months before the peak of solar activity in Cycle 10, which is consistent with what we have found, and since then there have been around six geomagnetic storms that would be considered like the most extreme, explains Owens.

Effects on Earth Technology

During a geomagnetic storm, changes in magnetic fields induce currents along power lines that can damage transformers and cause power outages. The most serious event occurred on March 13, 1989 and left six million people without electricity in Quebec, Canada, for nine hours.

The potential impact on society is much greater today because of the great degree to which we depend on technology, says Howard Singer, chief scientist at NOAA’s Space Weather Prediction Center. “The number of technological systems that can be affected by space weather continues to grow. “

Singer refers to the 60,000 subscriptions to space weather products, some of which rely on space weather forecasts and alerts to make informed decisions; for example, deciding when not to schedule power grid maintenance or when flights over polar regions need to be redirected. Space weather can even affect farmers who use technologies like GPS to help make decisions about how best to manage crops.

The interconnection of technological systems makes society particularly vulnerable to large geomagnetic storms, as power outages can disrupt the delivery of essential goods and services. “Extreme events are rare, but when they do, we better be prepared,” Singer says.

One of the main tools for predicting whether a CME is heading towards Earth is the coronograph, an instrument that blocks light from the Sun’s photosphere so that the corona and CME can be observed. The fastest CMEs arrive within a day of liftoff from the Sun and can take up to four days to reach Earth.

On August 31, 2012, a long filament of solar matter that hovered in the sun’s atmosphere, the corona, erupted in space at 4:36 p.m. EDT. Coronal Mass Ejection, or CME, traveled at over 900 miles per second. The CME did not travel directly to Earth, but connected to the Earth’s magnetic environment, or magnetosphere, causing auroras to appear on the night of Monday, September 3. (Credit: NASA Goddard Space Flight Center / Public Domain via Wikimedia Commons)

Risks to satellites, spacecraft and astronauts

CMEs can also pose a risk to satellites and spacecraft in space, as charges can build up on the surface and inside electronic components.

However, efforts to monitor the Sun for CMEs and technical safeguards against the potential effects of space weather are not without payoff.

Earlier this year, NASA observed a CME take off from the Sun on April 17 that was due to strike Mars when the Ingenuity Mars helicopter would make its second flight.

“We were happy to be able to warn that something was going to happen. We’ve done a lot to protect our satellites and spacecraft, but it was a new kind of technology, so you never really know it’s going to be perfect until it’s tested in the field ”, explains Alexa Halford, researcher in space physics at Nasa.

Technical safeguards as well as space weather forecasts can also help reduce the exposure of astronauts to radiation that can be caused by CMEs. When we think of human space exploration, we want to know what we’re getting into, like you’re packing for a vacation somewhere else, ”says Halford.

When it comes to space weather, CMEs can produce some of the most extreme events on and above the Earth’s surface. Since the Carrington event, scientists have come a long way in predicting when extreme events could impact Earth and understanding how to protect astronauts and instruments.

“We all live in the Sun’s extended atmosphere, so studying how solar activity varies and the response to that variability is really the focus of research in heliophysics and space weather,” says Spann.


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Cory E. Barnes

The author Cory E. Barnes

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