Early this morning, the Sun erupted with an explosion I can only describe as ginormous. We're in no danger from it, but the size and scope of this thing are simply spectacular. Here's a video I put together of the event using Helioviewer, a public-domain solar viewer:
Yowza! [Make sure to set the resolution to at least 720p, and make it full screen to get the full effect.]
What you're seeing here is a solar flare (an enormous explosion of pent-up magnetic energy) coupled with a prominence (a physical eruption of gas from the surface). This event blasted something like a billion tons of material away from the Sun. Note the size of it, too: while it started from a small region on the Sun's surface, it quickly expanded into a plume easily as big as the Sun itself! I'd estimate its size at well over a million kilometers across. It looks like most of the material fell back down to the Sun's surface; that's common, though sometimes such an event manages to blast the material completely away into space.
The above video shows the Sun in the ultraviolet (304 Angstroms for those playing at home, quite a bit bluer than what the eye can naturally see) and is colored orange to make it easy to see.The folks at Helioviewer put together a close-up looking at even higher energy; it's still UV but at 171 Angstroms: [UPDATE: Drat. That video has been taken down. Sorry about that, folks.]
Again, may I say, yowza! The material is silhouetted against the Sun's brighter surface, making it appear dark. I think the expanding circle you can see is a shock wave pummeling the Sun's surface, but it might be a line-of-sight effect of the edge of the explosion, like seeing a soap bubble's bright edge.
You can read more about this event at the very cool Geeked on Goddard blog. The energy of the event was colossal. A good flare can release up to 10% of the Sun's total energy, the equivalent of billions of nuclear bombs exploding. What's funny to me is that this wasn't all that big a flare; it was rated as a class M2.5, far lower in energy than the vast explosions from the Sun back in February.
Again, the good news is that we're not in any danger from this; it wasn't aimed our way (most of these types of events miss us). But as I've said before, the solar cycle is heating up and we can expect to see more incredible events from our friendly neighborhood star in the coming years.
Credit: NASA/SDO, animation made using Helioviewer. [Note: I had originally used the wrong units when indicating the wavelength of light seen in the videos -- nanometers instead of Angstroms -- so I've corrected that and changed the text a bit to make it clearer.]
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