This video compresses about an hour of solar activity around a sunspot to a little over ten seconds.
Via APOD:
The Sun’s surface keeps changing. The above movie shows how the Sun’s surface oozes during a single hour. The Sun’s photosphere has thousands of bumps called granules and usually a few dark depressions called sunspots.
Today’s Astronomy Picture of the Day is a spectacular view of four of the moons of Saturn and a partial view of the rings. Image and the explanation below courtesy of APOD and NASA. You may need to click on the image to enlarge it to original size to see the fourth moon “Pan.”
Explanation: A fourth moon is visible on the above image if you look hard enough. First — and farthest in the background — is Titan, the largest moon of Saturn and one of the larger moons in the Solar System. The dark feature across the top of this perpetually cloudy world is the north polar hood. The next most obvious moon is bright Dione, visible in the foreground, complete with craters and long ice cliffs. Jutting in from the left are several of Saturn’s expansive rings, including Saturn’s A ring featuring the dark Encke Gap. On the far right, just outside the rings, is Pandora, a moon only 80-kilometers across that helps shepherd Saturn’s F ring. The fourth moon? If you look closely in the Encke Gap you’ll find a speck that is actually Pan. Although one of Saturn’s smallest moons at 35-kilometers across, Pan is massive enough to help keep the Encke gap relatively free of ring particles.
APOD has a spectacular video of a comet impacting the Sun followed by a coronal mass ejection.
I browsed through my copy of QST magazine yesterday. QST is the publication of the American Radio Relay League, an amateur radio (ham radio) organization. In it, I read an interesting scientific hypothesis explaining the dearth of sunspots we have seen over the past several years. The theory holds that plasma currents deep inside the sun may have interfered with the formation of sunspots and prolonged the solar minimum.
Later in the article, there is mention of a secondary consequence of the minimum in that “space junk” can remain in low Earth orbit due to the upper atmosphere collapsing. You can read this very interesting article at this link.
NASA-sponsored research has resulted in the first computer model that explains the recent period of decreased solar activity during the sun’s 11-year cycle.
This recent solar minimum, a period characterized by a lower frequency of sunspots and solar storms, was the deepest observed in almost 100 years. The solar minimum has repercussions on the safety of space travel and the amount of orbital debris our planet accumulates.
. . .
During this deep solar minimum, the sun’s magnetic field weakened, allowing cosmic rays to penetrate the solar system in record numbers, making space a more dangerous place to travel. At the same time, the decrease in ultraviolet radiation caused Earth’s upper atmosphere to cool and collapse.
As a consequence space debris stopped decaying and started accumulating in Earth orbit due to decreased atmospheric drag. These effects demonstrate the importance of understanding the entire solar cycle, during both minimum and maximum.
Emphasis added.
Old Sol continues to increase in activity, moving toward the eleven-year peak. Solar activity affects climate, auroras, (possibly) the electric power grid and radio propagation. For an impressive animation of this comparison, play the video below. To view the full-sized video, click here.
From SOHO Pick of the Week:
A side-by-side comparison of the Sun from precisely two years ago (left, from SOHO) to the present (right, from Solar Dynamics Observatory) dramatically illustrates just how active the Sun has become (Mar. 27-28, 2011). Viewed in two similar wavelengths of extreme ultraviolet light, the Sun now sports numerous active regions that appear as lighter areas that are capable of producing solar storms. Two years ago the Sun was in a very quiet period (solar minimum). The Sun?s maximum period of activity is predicted to be around 2013, so we still have quite a ways to go.
Maybe if the cloud cover burns off here this evening, we will be able to see the perigee full moon. I looked at the weather maps for here and the old house in California and it appears that we may not get to see much of it, if any. We did see it big and bright last night when it was at 92% of full, though. It sure was pretty.
We are planning to depart tomorrow morning for the old house. We have some business there this coming week. The weather report says that we’re going to encounter rain, perhaps along the entire route. We’re not looking forward to driving in the rain, but c’est la vie.
Moon widget lifted from moonconnection.com
Consider, if you will, the minute capability of humans to change their environment as compared to the awesome and spectacular events occurring daily on our Sun. Global warming, my @$$.