Very unusual solar eruption: Extremely strong CME ejected from the far side of the sun

On March 13th, the SOHO coronagraph, a solar telescope, registered an extreme coronal mass ejection or CME in English. The plasma cloud was ejected from the sun at a speed of over 10 million kilometers per hour, which is an unusually high speed – an extreme CME that occurs maybe once or twice over a few decades. The normal speed for an ejected plasma cloud/CME is otherwise around 2 million kilometers per hour.

AURORA from the weak CME that was shot towards Earth on February 11th would never have created a geomagnetic storm rated G2 or even seen as spectacular and far from the poles as it did now, if not for the Earth’s magnetic field being severely weakened. Here, the northern lights are visible on March 15th in Bydgoszcz, Poland. Photo: Roman Banas

The American space agency NASA’s simulations show that the CME was so strong that it created a shockwave in all directions. As Earth was in the exact opposite direction this time, the impact was weak but sufficient to knock out radio traffic on and around both the North and South poles. Although the plasma cloud was ejected from the far side of the sun, away from Earth, the GOES-16 satellite from the U.S. government’s scientific organization, the National Oceanic and Atmospheric Administration (NOAA) found that some of the particles still reached Earth. This further demonstrates how extreme the CME was, and we can conclude that it would have led to catastrophic consequences if it had been directed towards Earth.

Southern lights were seen over Lake Ellesmere in New Zealand on March 15th. Photo: Mike White

Several days after the solar eruption on March 13th, radio traffic on and around the poles continued to be affected. This is because our planet’s magnetic field consists of power lines that run from the magnetic North Pole to the magnetic South Pole. The magnetic field extends tens of thousands of kilometers into space and forms the magnetosphere there. As a result, particles are “diverted” towards the poles, which are more weakly protected, which is why we see auroras in these areas. Warnings were issued, and for three days, shortwave radio in the area was mostly completely knocked out, severely affecting air traffic in the area.

The LASCO CORONAGRAPH is a solar telescope designed to block light coming from the sun to see the, in relation to the sun, extremely weak light emission from the region closest to the sun. It is called the corona and is the sun’s outer atmosphere, which extends far beyond the luminous surface. The corona is very sparse and thin but several million degrees hot. LASCO is one of several instruments onboard the Solar and Heliospheric Observatory (SOHO), an international collaboration between ESA and NASA. Here, the CME is visible shortly after the solar eruption (left) and how the solar halo has spread 144 minutes later (right). Still images: Large Angle and Spectrometric Coronagraph, LASCO

Once again, an unexpected geomagnetic storm

On March 11th, a very weak CME occurred on the sun, which this time was directed towards us. It was so weak that it normally should not have affected Earth at all, but to many people’s surprise, it still caused a geomagnetic storm when it hit Earth on March 15th. Initially classified as a minor G1, it was later upgraded to a moderate G2. This is considerably more alarming than the extreme CME on the sun’s far side two days earlier, as it reminds us of Earth’s increasingly weakened magnetic field… a weakening that researchers in 2010 realized had accelerated at least tenfold in recent decades.

RADIO TRAFFIC DISRUPTED FOR THREE DAYS. The map shows how much radio waves between 3 and 35 MHz were disturbed on March 14th from the extreme CME on the sun’s far side the day before. Shortwave radio (3-30MHz) will not work within the red area due to the ionizing effect of incoming protons. The ionosphere is electrically conductive and therefore reflects radio waves by refraction (refraction) in the ionosphere’s different layers. This normally enables radio communication in these frequency bands, especially shortwave, over long distances. Map: NOAA/SWPC

As a consequence, New Zealand once again experienced celestial displays in the form of southern lights, and in Europe and North America, as far south as the USA, people experienced northern lights. That they could be seen simultaneously on March 15th in both hemispheres is due to the time of year. It was just six days before the March equinox, known as the vernal equinox in the Northern Hemisphere and the autumnal equinox in the Southern Hemisphere, which this year falls on March 20th. Almost equal darkness allows sky watchers in both hemispheres equal opportunities to witness auroras, which are caused by particles from the sun hitting Earth’s upper atmosphere, causing oxygen to glow red and green, and nitrogen to shine purple. A beautiful spectacle at the same time as it is an extremely ominous omen for those who understand that auroras for the second time in such a short period would not have been so spectacular and visible so far from the poles if it were not for Earth’s weakened magnetic field – a disaster-inviting process that is also accelerating.