Making an active sun visible
Posted November 21, 2011
We often think of the sun as a kind of smooth yellow disc, maybe with an odd sunspot or prominence, and an otherwise smooth, stable producer of the energy that we take for granted every day. In some respects, it really is. However, when viewed in great detail with the appropriate instruments and using a a variety of wavelengths within the electromagnetic spectrum, it becomes more obvious how much is really going on there.
One of the instruments that really gives us a fascinating look at what's happening with the sun is an orbiter called the Solar Dynamics Observatory, launched back in February of 2010 and providing some amazing imagery ever since (earning the nickname "Hubble for the sun"). A week or so ago, the SDO was sending imagery that showed an unusual filament of magnetism (the dark streak in the two images that stretches from above the upper left limb of the sun down to near the center, a distance of more than three times that from the earth to the moon. Since then, that feature has rotated to the right and eventually snapped and become less organized, but it made for a neat set of images first.
The SDO is also great for visualizing just how "dynamic" the sun really is. For a better sense of that, video really helps, and you might enjoy perusing some 48 hour lapses of solar activity available at the first of the video links I included. On that page, you can select different filtered views to the right of the movie window, and just above those selections, you can change which part of the sun is in zoomed in on. There's also plenty more to peruse on the site, using the "Data" and "Gallery" menus. The second link is to a YouTube video showing a massive eruption of material from the sun that occurred on June 7 of this year, shown in several wavelengths. It really highlights the difference in what can be seen visually and what shows up when filtered for wavelengths that our eyes can't process. Enjoy the view!