Today, August 21, 2017, the Moon briefly slid in front of the Sun, casting its shadow onto the Earth–the deepest part of which (called the umbra) passing across the United States from Salem, Oregon to Charleston, South Carolina. I arranged to be positioned at the latter location, and thus experienced for the first time solar eclipse totality from 2:46 to 2:47 and a half p.m. this afternoon. It was, as they say, a mind-blowing experience…if just in the sheer sense of seeing something entirely different happening to the usually very typical Sun in the middle of what would otherwise be a very typical day. (Except that it was neither of those.)
Below are some of my photos from the event.
Many of the features seen on the Sun might look like tongues of flame or fiery eruptions, but there’s no fire or lava on the Sun – its energetic outbursts are driven by powerful magnetic fields that rise up from its internal regions and twist, loop, and coil far out into space.
In addition to these far-reaching lines there is a network of magnetic fields that cover the Sun’s “surface” (that is, its photosphere) like a web – a web outlined by the edges of large-scale features called supergranules. Created by rising zones of hot solar material, these 35,000km-wide “bubbles” on the photosphere carry bundles of magnetic regions to their edges, fueling the network.
What one team of researchers has now found , through long-term observations with the Hinode satellite, is that the supergranules are able to replenish the entire magnetic surface web in a surprisingly short time – only 24 hours.
Active region 1163-1164 kept the show going this morning, February 27 2011, with a large coronal mass ejection (CME) that erupted at around 4:30am EST from the Sun’s western limb. The animation above was made from ten high-resolution images taken by the Solar Dynamics Observatory, and shows this particular flare in action. (Click the image for a larger version of the animation.)
The small circle at upper left is the proportional size of Earth.
Coronal mass ejections are huge bubbles of gas bounded by magnetic field lines that are ejected from the Sun over the course of several minutes or even hours. If they are directed toward Earth, the cloud of charged solar particles can interact with our magnetosphere and cause anything from increased auroral activity to radio interference to failure of sensitive electromagnetic equipment.
As this active region rotates towards Earth over the next few days we may come under fire from solar flares aimed our way…or not. Really no way to predict such things until we see them happen, in which case we have a day or so before the ejected particle cloud crosses the 93 million miles between the Sun and Earth.
This same region produced a large flare just a couple of days ago…view an animation of that here.
Image: Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. Animation by J. Major.
Today at 7:35 UT, hours before the final Discovery shuttle launch, the Sun had a launch of its own: an M3-class solar flare spewed a giant plume of material hundreds of thousands of miles into space. Luckily this ejection was not facing Earth at the time, but the active region responsible is gradually rotating into view from the Sun’s western limb.
The animation above shows the coronal mass ejection associated with the flare, made from eight images taken by NASA’s Solar Dynamics Observatory using its AIA 304 imaging camera.
It can’t be said for sure whether or not this active region will produce more Earth-directed flares once it rotates our way, but we sill find out for sure within the next week!
Credit: Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. Animation by J. Major.
‘Tis the season…the season for solar activity, that is! Last week was just the beginning, even though it saw some of the most powerful solar flares of the past four years send charged solar particles streaming toward Earth. Luckily our magnetosphere was in such a position to absorb much of it, creating some beautiful aurora for those stationed at points north. Some electromagnetic problems occurred around the globe but, for the most part, it wasn’t too disruptive considering the level of activity the Sun was exhibiting.
Once that particular sunspot region rotated away from direct line-of-sight with Earth we got a look at the next active regions, numbered 1161 and 1162, which sent out their own flares on the 18th and 19th. The animation above was made from SDO images taken with its AIA 131 camera, showing a flash of magnetic energy spreading out between the sunspots in the area. This spans about 40 minutes of actual time with the energy expanding a distance equal to about 20 Earths! Incredible.
These regions on the northern hemisphere of the Sun have since rotated past the direct line of sight with Earth as well, although since solar flares can send out particle clouds that curve and arc through space there is still a danger from M-class outbursts. And there’s another active region currently on the opposite side of the Sun, seen by NASA’s STEREO spacecraft, which is steadily moving into position…it will be facing Earth in about a week. Will that fizzle out or send more flares our way? No way to tell, but with all these eyes on our star we at least have some fair warning!
“We cannot tell if there is going to be a big storm six months from now, but we can tell when conditions are ripe for a storm to take place.”
– Juha-Pekka Luntama, European Space Agency
This is shaping up to be an interesting solar maximum, that’s for sure. Even if we’re lucky enough to avoid any real problems from flares we’ll certainly be getting some amazing views!
Image: NASA/SDO and the AIA, EVE and HMI science teams. Edited by J. Major.