by The sun has been spewing out some pretty powerful outbursts in recent weeks, but one that happened a few days ago is a real doozy.
On March 12, a spacecraft monitoring the Sun recorded a massive amount of material blown off the far side of the Sun by a coronal mass ejection. Detected as an expanding cloud, or halo, of solar debris, it sped away from the sun at exceptionally fast speeds of 2,127 kilometers (1,321 miles) per second.
The sun spitting out flares and coronal mass ejections is nothing new, but this one was something special.
Usually, eruptions on the other side tend not to hit Earth, because they face the opposite direction; but it was so intense that satellites orbiting our planet picked up the signal from particles of the outburst accelerated by the outburst shock wave right in our corner of space.
It may seem like the sun has been playing some pranks lately, and it has. It is approaching the peak of its cycle — a roughly 11-year loop in which the sun’s activity peaks and wanes. We’re heading for solar maximum, probably in the next two years, when the sun is most active, teeming with sunspots and erupting with powerful flares.
These cycles are linked to the sun’s magnetic field, which reverses polarity every 11 years, though scientists are still trying to figure out why. This polar reversal occurs at solar maximum; the magnetic field at the poles weakens to zero and then re-emerges with the opposite polarity. North becomes south, south becomes north.
During this time, sunspots appear in large numbers. These are temporary spots on the sun with stronger magnetic fields, whose lines often get confused, snap, and reconnect. When this happens, a huge amount of energy is released in the form of a solar flare. These can sometimes cause coronal mass ejections, ejecting tons of material and magnetic fields from the sun into space.
At the time of writing, there are currently about 100 sunspots on the sun, some of which are clustered into sunspot regions. Some sunspot areas may persist for a long time, lighting up repeatedly, before disappearing from view as the sun rotates.
A few days prior to the recent CME — given its unusual designation of R-type, for rare — a particularly active sunspot region rotated to the far side of the sun. Before it dissipated on March 4, the region dubbed AR3234 (in ascending order of strength) emitted 49 C-class flares, 12 M-class flares, and 1 X-class flare — the most powerful kind of flare our Sun is capable of. .
Whether AR3234 was responsible for the R-type flare is not known; it is certainly plausible. But solar scientists certainly want to know more about it.
Fortunately, the Parker Solar Probe was right in the line of fire for the CME. It sent signals back to Earth telling Parker’s engineers that its systems are nominal; now we just have to wait for the next download of Parker’s data to read the flare’s readings. That will take place after March 17, when the probe must make a close solar flight.
In the meantime, we can only hope that other solar observatories, such as NASA’s Solar and Heliospheric Observatory (SOHO) and Solar Dynamics Observatory (SDO), and the European Southern Observatory’s Solar Orbiter (which produced a powerful coronal mass ejection last year) on the other hand) ), also collected a significant amount of data about the event.
It’ll be fun to learn more about what our sun does when it thinks we can’t see it.
