Three amazing views of our Sun to start off your week

Monday, December 15, 2014, 1:16 PM - As the NASA video above shows, solar flares and coronal mass ejections (CMEs) are spectacular events, but that's not all that's going on in the Sun's atmosphere. Check out the videos below to see some of the more spectacular other types of 'solar weather' that occur.

The Sun may appear as a constant in our daytime skies - uniform and unchanging in its brightness, with only the weather between us and space affecting how we see it. However, view the Sun from above all that weather, using the right set of filters on your optics to pick out the details, and you can see that the Sun has a set of weather all its own. This is not weather based on water and wind, as it is here on Earth, but instead on blazing hot plasma and magnetism.

The Sun is made from intensely hot plasma - hydrogen and helium gases with their electrons stripped away - and the movement of all this electrically-charged plasma gas generates some equally intense magnetic fields. When these fields get concentrated in places near the Sun's surface, they make it much more difficult for the plasma to flow, causing it to cool and form sunspots. This concentration also causes the magnetic fields to extend beyond the surface, forming loops that reconnect with the surface somewhere else. This chaotic activity can produce some very interesting forms of 'weather' on the Sun that we can see using satellites like NASA's Solar Dynamics Observatory (SDO).

Persistent Coronal Hole

The video above presents three different views of the Sun from SDO, with the transition between colours taking us upward through the layers of the Sun's atmosphere. The final view is a combination of red, green and blue filtered images, which shows off the Sun's corona - its upper atmosphere, where the solar wind originates. Stretching across the south pole is a dark region known as a coronal hole.

Normally, the corona looks like the upper three-quarters of the view, with SDO picking up the filaments and streamers of solar plasma being heated up as they are trapped in this portion of the atmosphere by the magnetic loops. These regions produce a slow stream of solar wind that blows away from the Sun, out into the solar system. However, once in awhile, the magnetic fields end up extending much further out into space and they do not reconnect with the surface. The plasma in these regions simply flows directly from the Sun's surface out into the solar system, leaving a wide region where there's little to no material in the Sun's atmosphere to be heated up. Since this gives a nearly unobstructed view of the Sun's surface, which has a temperature of roughly 6,000 degrees C, it shows up very dark in the three-filter combination from SDO, since that is extremely 'chilly' compared to the 1-2 million degree temperatures C that the rest of the view is picking up.

Drooping Loops

The magnetic loops mentioned above are generated by the motion of the plasma, but the plasma is controlled by the shape of the magnetic loops. So, when the loops extend beyond the surface, they drag this plasma along with them, which show up as bright arcs above the surface to SDO. The above view, filtering for material that's around 1 million degrees C, shows off these loops extremely well. From December 7-9, a collection of what NASA called 'drooping loops' were seen along the eastern limb of the Sun, extending far out from where they originated from, but almost hugging the surface, so that they appeared to 'droop' down as if they were threads hanging off a ball of yarn.

Filament 'Liftoff' and 'Ribbon Flare'

Although there's a significant amount of attention paid to sunspots and the solar flares and coronal mass ejections they can generate, solar filaments can cause flares too. These dark streams of cooler solar plasma, which can stretch across fast distances through the Sun's atmosphere, are 'locked' in place by magnetic fields. If one of these filaments suddenly lifts off from the Sun and disappears, it sets off a chain-reaction in the material around it, producing what are known as Hyder, or 'ribbon' flares. Rather than a confined explosion of X-rays from a sunspot, the flares spread out from the region where the filament vanished. With the filament liftoff and flare above, which occurred on December 12, it looks like the surface of the Sun is being ripped apart into a canyon of fire, which is then quickly bridged by numerous glowing loops of plasma that stream out to link up with the region on the other side of the small coronal hole that was next to the filament.

Do any of these effect us here on Earth?

Solar flares and CMEs get most of the attention because, overall, they represent the most significant threat. This isn't to us here on the ground, mind you, since the Earth's atmosphere generally protects us from any harmful effects. However, x-rays blasted out by flares can and do cause radio blackouts on the side of the Earth facing the Sun at the time they go off. Also, geomagnetic storms that result from CME's impacting on Earth's magnetic field have the potential to damage the electronics on satellites, and some have even caused blackouts here on the ground (this happened in Quebec in 1989).

For the three types of 'solar weather' above, coronal holes allow solar matter to stream away from the Sun much faster than normal, which increases the speed and strength of the solar wind. This can cause geomagnetic storms here on Earth, when this more intense solar wind washes over the planet's magnetic field. Generally, it takes a very powerful CME (or powerful combination of CMEs, as we saw in 2012) to generate geomagnetic storms strong enough to affect our technology, though. Coronal loops, as seen in the 'drooping loops' video, are harmless, though, as the plasma caught up in them isn't going anywhere except straight back to the surface of the Sun. However, if the magnetic field 'snaps', that's what causes a CME. Finally, Hyder flares are capable of having an effect here, but that's fairly rare. Typically, they aren't as powerful as your 'standard' solar flares, so they don't generate the same blast of high-energy particles at us, and they're not often associated with CMEs either. So they don't pose much of a risk, overall.

For the most part, these examples of 'solar weather' are just here for our enjoyment, and to fuel our fascination with the Sun.

CLICK BELOW TO WATCH: NASA spies a fiery 'dragon' lifting off from the surface of the Sun.