A Major X Class Solar Flare Just Slammed Into Earth

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A Major X Class Solar Flare Just Slammed Into Earth

NASA’s Solar Dynamics Observatory captured the flare on July 3. NASA/SDO

The strongest solar flare seen in four years erupted from the surface of the sun early Saturday and smacked into our planet’s atmosphere eight minutes later.

An explosion from a new and unnamed sunspot produced the X-class flare, the first of solar cycle 25.

The blast of x-rays traveled toward earth at the speed of light, colliding with the top of our atmosphere and causing a shortwave radio blackout over the Atlantic ocean and coastal regions. The below blackout map shows where radio operators may have noticed the weirdness around 10:30 a.m. ET

The map shows where the blast of x-rays from the solar flare impacted the atmosphere the strongest. NOAA/SWPC

Astronomer and space weather watcher Dr. Tony Phillips says the sunspot that produced the X1.59 flare appeared suddenly, like a cloudless day that quickly turns stormy.

“Yesterday it did not even exist, highlighting the unpredictability of solar activity,” Phillips writes at Spaceweather.com. “More flares may be in the offing, so stay tuned.”

There appears to be little risk of an accompanying coronal mass ejection (CME) with this flare. A CME is a burst of hot, charged plasma that often occurs alongside a flare. The particles from a CME can take a few days to reach earth and cause additional interference with radio and electrical systems when they arrive.

Fortunately, the sunspot that produced this flare was on the edge of the sun’s face, making it unlikely that a CME would be directed towards Earth.

Solar flares are classified by their X-ray brightness as A, B, C, M or X with A being the smallest and X being the brightest and largest. This was the first X flare tossed off by the sun since a new solar cycle began in December 2019.

The sun undergoes an approximately 11-year-long activity cycle in which it swells to a peak at the middle of the cycle and then begins to quiet down until the end of the cycle when it all repeats.

While this is the first major flare of the young solar cycle, it measured just a X1.59, when the last solar cycle gave us a far more powerful X9 flare in 2017. All this means it’s worth heeding Phillips’ warning that stronger flares are likely on the way in the coming months.

In the past strong flares and CMEs have produced widespread power outages and communications blackouts. There is some concern that we are overdue for a catastrophic solar storm which could do unprecedented damage to power grids on the ground and the record number of satellites now in orbit, potentially crippling systems on the ground that rely on satellite communications.

Solar Flares: What Does It Take to Be X-Class?

Solar flares are giant explosions on the sun that send energy, light and high speed particles into space. These flares are often associated with solar magnetic storms known as coronal mass ejections (CMEs). The number of solar flares increases approximately every 11 years, and the sun is currently moving towards another solar maximum, likely in 2013. That means more flares will be coming, some small and some big enough to send their radiation all the way to Earth.

The biggest flares are known as “X-class flares” based on a classification system that divides solar flares according to their strength. The smallest ones are A-class (near background levels), followed by B, C, M and X. Similar to the Richter scale for earthquakes, each letter represents a 10-fold increase in energy output. So an X is ten times an M and 100 times a C. Within each letter class there is a finer scale from 1 to 9.

SOHO captured this image of an X28 class solar flare erupting on Tuesday, October 28, 2003.

The Solar and Heliospheric Observatory (SOHO) spacecraft captured this image of a solar flare as it erupted from the sun early on Tuesday, October 28, 2003.Image Credit: ESA & NASA/SOHO› View larger

The Halloween solar storms of 2003 resulted in this red aurora visible in Mt. Airy, Maryland.

The Halloween solar storms of 2003 resulted in this aurora visible in Mt. Airy, Maryland.Image Credit: NASA/George Varros› View larger

C-class and smaller flares are too weak to noticeably affect Earth. M-class flares can cause brief radio blackouts at the poles and minor radiation storms that might endanger astronauts.

And then come the X-class flares. Although X is the last letter, there are flares more than 10 times the power of an X1, so X-class flares can go higher than 9. The most powerful flare measured with modern methods was in 2003, during the last solar maximum, and it was so powerful that it overloaded the sensors measuring it. The sensors cut out at X28.

The biggest X-class flares are by far the largest explosions in the solar system and are awesome to watch. Loops tens of times the size of Earth leap up off the sun’s surface when the sun’s magnetic fields cross over each other and reconnect. In the biggest events, this reconnection process can produce as much energy as a billion hydrogen bombs.

If they’re directed at Earth, such flares and associated CMEs can create long lasting radiation storms that can harm satellites, communications systems, and even ground-based technologies and power grids. X-class flares on December 5 and December 6, 2006, for example, triggered a CME that interfered with GPS signals being sent to ground-based receivers.

NASA and NOAA – as well as the US Air Force Weather Agency (AFWA) and others — keep a constant watch on the sun to monitor for X-class flares and their associated magnetic storms. With advance warning many satellites and spacecraft can be protected from the worst effects.