Massive Solar Storm Slamming Into Earth Sparks Aurora Around the World

Stunning pink and purple colors blanketed the night sky over the U.S. and many other countries on Monday due to a massive G3 geomagnetic storm slamming into our planet.

These beautiful light shows are as a result of solar matter colliding with our atmosphere. The sun released two huge plumes of solar plasma as coronal mass ejections (CMEs) on February 24 and 25, which have soared through space towards the Earth over the last few days.

At around 1:00 a.m. EST on February 27, NOAA's Space Weather Predictions Center (SWPC) officially observed G3 (strong) geomagnetic storms, which remained for much of the day.

G2 (moderate) storms are expected to continue into February 28. These geomagnetic storms are what caused the spectacular aurora, visible as far south as Minnesota and Wisconsin in the U.S., and France in Europe, with the southern lights being seen as far north as Tasmania in Australia. Previous G3 storms have caused auroras to be seen as far as Oregon and Illinois.

"The colors in the aurora are the result of particles in the upper atmosphere becoming excited by collisions with particles coming from within the magnetosphere and some from within the solar wind," Brett Carter, an associate professor in space science at RMIT University in Australia, told Newsweek. "The different colors are the result of electrons relaxing from different energy levels from oxygen (the most common reds and greens) and nitrogen (dark reds/blues)."

The further towards the equator you are, the redder the lights appear, as you tend to only see the top parts of the lights.

"That red color is usually also rather faint since you do not have that many of the oxygen atoms around at such high altitudes," Daniel Brown, an associate professor in astronomy and science communication at Nottingham Trent University in the U.K., told Newsweek. "But, if you have a strong enough activity like we are getting now, there are enough exciting particles in the CME to interact with more oxygen and make the red brighter."

The aurora are caused by solar particles slamming into the Earth and the interactions between the CME's magnetic field and the Earth's magnetic field.

"Almost all magnetic effects at Earth are due to a combination of the solar wind magnetic field and pressure," Martin Connors, a professor of space science and physics at Athabasca University in Canada, told Newsweek. "The solar wind normally flows past at 300 to 700 km/s (that is about a million miles per hour) with up to 10 particles per cubic centimeter (like 10 atoms in the size of a sugar cube: most people call this a 'vacuum'). There is also a very small magnetic field in the solar wind, far smaller than what turns compasses at the surface of Earth."

Earth's own magnetic field adjusts to the solar wind, usually keeping us safe in a magnetic bubble. A CME brings faster and denser solar wind, and a stronger magnetic field, which can impact our magnetic field and disrupt it.

"If the solar wind magnetic field direction changes, it can tear its way into our bubble, and if the speed and density increase, the pressure pushes our bubble back. Depending on how magnetic field, particles, and speed change, we get various effects. If the magnetic field in the solar wind is in the right direction, and also there are lots of particles flowing very fast, we get a bigger storm," Connors said.

It's also not just about how big and how fast the CME is, as the direction its magnetic field is pointing also impacts on the effects it will have, Huw Morgan, head of the Solar Physics group at Aberystwyth University in the U.K., told Newsweek.

"If it points the opposite direction to Earth, the CME can have more of a disruptive effect. But size and speed also matter of course—so a large, fast CME with a southward magnetic field is the perfect storm," Morgan said.

The stronger the geomagnetic storm, the further south the northern lights can be seen. G4 storms can be seen as low as Alabama and northern California, and G5 storms, the strongest on the NOAA space weather scale, can cause auroras to be visible from Florida and southern Texas.

Other than the gorgeous displays seen across the country, G3 storms can also impact infrastructure and other technology both on Earth and in orbit. The NOAA space weather scale states that G3 storms can impact power systems, requiring voltage corrections.

"These storms can influence more than just the power grid infrastructure," Carter said. "The use of GPS can be impacted due to variations in the ionosphere, and the orbits of satellites in low-Earth orbit experience increased atmospheric drag due to the swelling of the upper atmosphere. NOAA's G-scale (and the Australian Bureau of Meteorology's G-scale) give a nice overview of what effects one should expect from a G3 storm, along with their associated frequency (about 200 every 11 years or so)."

G3 storms can also impact spacecraft operations by increasing drag on low-Earth-orbit satellites.

"Noting here the interesting factor of additional satellite drag, which was one thing overlooked for a star link satellite deployment a while back causing many of these to be lost. So such activity will require low orbit satellites to readjust their orbits," Brown said.

The effects of the weakening solar storms are expected to continue over the next day or so.

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