Watching the Sun

After the deepest solar minimum in 100 years, the sun is finally kicking into high gear. According to [Space Weather][1], the sun spent 260 days without any sunspots in 2009; in 2010, so far, that number has plummeted to 45.

[![blog post photo][2]][3] _Image of the 400,000 km filament in extreme UV by NASA’s Solar Dynamics Observatory. _ The past week, especially, has been a fierce one. On Saturday, an [incredible 400,000 km filament ][4]stretched across the sun’s face — it’s grown to 500,000 km since then, as [Space Weather notes][5], spanning a distance greater than the Earth to the moon. Another filament ran perpendicularly, while multiple groups of sunspots mottled the surface and a few prominences blew off the edges. All this magnetic activity doesn’t always come without consequences — on Saturday, a sunspot erupted in a [M1-class flare][4], while on Monday, the huge filament erupted in a [C2-class flare][5], though luckily, not in the direction of Earth.

We’re still learning so much about the sun, despite being so relatively close. Missions like NASA’s [SDO][6], [STEREO][7], [SOHO][8] and others are constantly studying and taking measurements to complete (or completely rewrite) our solar models. We wrote earlier this year about research on the [Great Conveyor Belt][9] showing speeds scientists had not predicted, leading to a possible upheaval in our whole thinking about sunspot activity. And there’s the SDO mission, studying solar storms and their effect on both the solar surface and here on Earth. Its Atmospheric Imaging Assembly can [record flares in eight temperature bands][10], allowing detailed study that may one day help us protect our technological infrastructure.

[![blog post photo][11]][12] _[_Photo by Erin Braswell_][13], courtesy the Smithsonian National Air and Space Museum._

Science aside, there is an awe and sense of perspective gained when viewing the images sent back from these orbiting spacecraft. In a country where barely half the people even know that the sun is a star, the visual aids are especially helpful to give life to the center of our solar system. I’m luckier than most — I get to see this sunspotting, prominence-blowing star with a mere eight minute delay every Saturday at the [National Air and Space Museum][14] in Washington, D.C., where I volunteer at their year-old [Public Observatory][15]. What spurred me to write about it today was the view last weekend, quite possibly the most exciting, active sun I’d ever seen. If you’ve only ever experienced the sun sitting ‘idly’ in the sky each day, perhaps a few colorful sunrises or sunsets, it can be difficult to appreciate the roaring, tumultuous place it can be.

Indeed, many visitors are surprised to see an observatory open during the day, but a safe view of the sun, broiling-over before their very eyes can be a rare treat. It often spurs fascinating discussions in basic heliophysics, leaving visitors with important bits of knowledge to remember whenever they feel warmth on their faces. On Saturday, we discussed the giant filament — which to first-time viewers looked like an amazingly huge ‘crack’ on the surface — the magnetic activity that creates all this chaos and how it differs from Earth’s magnetic activity, the real size of the sun (the most visible sunspot, looking like a speck of dust in the scope, was actually about the size of the Earth, a fact that usually elicits an amazed “Really??”).

So I suppose all of this is a bit of prosthelytizing my belief that, in addition to feeding our interest by keeping up with the news, everyone should take some time out to focus our own eyeballs on the sky every once in awhile. If you’re in the D.C. area, check out the Public Observatory at the Air and Space Museum to view the sun (and the occasional planet up during the day) through our hydrogen-alpha filtered sunscope or the welder’s glass-sporting Dobsonian — handmade (and autographed!) by amateur astronomer-extraordinaire [John Dobson][16] himself. Read the museum’s recent blog post about [imaging the sun][17] at the Observatory (like the one above). You can also visit [Astronomy in DC][18] for other nearby events.

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