The sun has just exploded to life, blasting a huge coronal mass ejection (CME) into space. This is the largest such event for several years.
In case you haven’t noticed, our nearest star has been a little subdued of late, and trying to find even the smallest of sunspots (an indicator of solar activity) was becoming a lost cause. But not anymore! It would appear the sun is getting its act together, exhibiting an uptick in sunspot numbers, increased magnetic activity and more explosive events (flares and CMEs) as solar activity increases toward “solar maximum,” predicted to reach its peak in 2013.
As noted in Nicole Gugliucci’s article yesterday, we are slowly beginning to understand the root cause behind these magnetic explosions and how solar phenomena such as CMEs impact our planet. For an idea about the fireworks that are sparked when solar wind particles slam into our atmosphere, have a read of Irene Klotz’s article “Earth Gets Geomagnetic Wallop.”
Fortunately, we have the Solar and Heliospheric Observatory (SOHO) continuously keeping an the sun, and the groundbreaking solar observatory watched the eruption in all its glory.
In the SOHO images at the top of this post, the fine detail of million degree plasma wrapped inside the expanding magnetic “bubble” of the CME is detailed. Both images were taken with SOHO’s Large Angle and Spectrometric Coronagraph (LASCO), an instrument that gives us a wide-angle view of the environment surrounding the sun (a.k.a. the corona).
“C2″ is one of LASCO’s coronagraphs looking up to 6 solar radii from the sun’s surface (top image, left) and “C3″ is a wider angle coronagraph looking out to 32 solar radii (right). The C3 image was taken nearly an hour after the C2 image, showing how much the CME had expanded in that short time.
But the fun isn’t over yet. As the CME erupted, a cooler, structured cloud of solar plasma called a “prominence” grew above above the solar surface:
This image wasn’t captured by the LASCO instrument, it was imaged by SOHO’s Extreme ultraviolet Imaging Telescope (EIT). EIT is sensitive to solar plasma emitting extreme ultraviolet light (from plasma with temperatures between 20,000 and 2 million Kelvin), and in this case, the EIT 304A filter is showing us the structure of plasma at temperatures around 20,000 Kelvin.
As the current solar cycle continues, we can expect more CMEs like this one, and it’s likely a few may be directed at Earth. This emphasizes the importance of SOHO and the recently launched NASA Solar Dynamics Observatory (SDO) so we can better understand the nature of CMEs and better predict when they might threaten our planet.
Image credit: NASA/ESA/SOHO