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Solar Flare. Credit: NASA

The Sun’s temper led to its most epic eruption, but what triggered it?

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Jun 15, 2021, 11:29 AM EDT

Stars may appear all glowy and mystical, but they can actually have outrageous tempers. The star we orbit is no exception.

From solar flares to full-on coronal mass ejections, the Sun can break out in unpredictable explosions, some of which are so powerful and energetic that they can actually reach Earth and mess with our electronic and radio signals (among other things). Now NASA scientists have observed the most enormous tantrum our star has ever thrown. Because it is a mashup of a coronal mass ejection, a solar jet and a partial eruption, this monstrosity is being appropriately called the Rosetta Stone eruption since it combines all three types of stellar outrage.

This is the first time a phenomenon has combined elements of all three types of events at once. Because scientists see it as a missing link, it is named after the ancient rock which is engraved in Egyptian and Greek in three different scripts. It could be the missing link to what triggers the Sun to have outbursts.

What the team of scientists saw with NASA’s Solar Dynamics Observatory and NASA and ESA’s joint Solar and Heliospheric Observatory was an anomaly. The Sun was belching out material from its corona, or outer atmosphere, that was too much to qualify as a jet, but not enough for a coronal mass ejection. It later started to eject some cooler material that ultimately ended up as a partial eruption after some of it fell back down. It only made sense to the scientists, led by Emily Mason of NASA Goddard, that something with the characteristics of three types of solar eruptions could only mean that the same unknown force was setting them all off.

“The unique mixture of major eruption properties observed during this event places severe constraints on the structure of the filament channel field and, consequently, on the possible eruption mechanism,” Mason said in a study recently published in The Astrophysical Journal.

 

 

Solar filaments are actually monster arcs of plasma in the solar atmosphere that are most likely to be found above sunspots. They are kept in place by magnetic fields, appearing dark because they are somewhat cooler than the surface of the Sun. Their lifespan can be anywhere from days to months. The Rosetta Stone eruption happened around the same filament. Filaments most often form when the Sun’s magnetic field is especially temperamental, around the same time that darker, cooler sunspots form because the magnetic field is interrupted — prime time for coronal mass ejections and other solar tantrums.

Coronal mass ejections, or CMEs, are the most powerful type of solar eruption that can interfere with GPS signals, get in the way of radio communications, bring on power outages, cause our electronic infrastructure to glitch and otherwise affect how we communicate on Earth. They happen when bubbles aggravated by the Sun’s magnetic field spew plasma and magnetic field material from its corona into space. That material can travel up to nearly 1,900 mph and reach our planet in 15 to 18 hours at its fastest. Partial eruptions stars like CMEs, but are unable to make it all the way. Solar jets erupt as much narrower streams of particles.

The Rosetta Stone event had it all. When it first erupted, Mason and her team noticed that there was too much material to call it a jet, but not enough for a coronal mass ejection. Seeing a partial eruption emerge from the same region meant that not only are all three of these phenomena probably set off by the same mechanism, but whatever that mechanism is must have something that can also mitigate explosions in the Sun’s corona, which would explain why what happened next was only a partial eruption. The most intense coronal mass ejections take place where the Sun is most magnetically unstable. That may or may not hint at what is going on here.

Terrifying things can happen when something disrupts the Sun’s magnetic field. Any field lines that are broken and then realign in a process called magnetic reconnection can make our star vomit out unbelievable amounts of energy and possibly make our star angry enough for part of its atmosphere to explode into a coronal mass ejection. Magnetic reconnection also cause strange events like coronal rain.

For now, what exactly caused this hybrid explosion remains a mystery, but revealing the cause might help has figure out how to predict potentially hazardous space weather so we can protect our power grid here on Earth. Just keep wearing SPF.