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astronomy, solar physics, solar studies, STEREO, stereo spacecraft, sun, sunspots

The Sun in Stereo

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Two Perspectives

The is the Sun from my place on February 6, 2011.

Okay, everybody and his or her cat is jumping on this story about the Sun today — and for several good reasons:  1)  it’s great science about our nearest star and 2) it’s freaking cold out throughout much of the U.S. (and probably the rest of the Northern Hemisphere, and some of us will take any Sun we can get.

We get irrationally attached to that bright thing in the sky during the cold winter months — it’s our lifeline, the source of our warmth, and the hottest thing in the solar system. Small wonder we look for it after a few days of snow and when it shows up, some of us go outside and marvel at it (and the snowplows, who come, tank-like, to liberate us) after the storms.

But, there’s another perspective we can take on the Sun — and that’s our study of it as a star.  Sure, we all know it’s a giant sphere of superheated gases, plasmas if you will. And that heat is what powers the solar system, warms our planet, and bathes us in light.

That scientific perspective is what fuels today’s release of the STEREO mission’s first (darned-near-180-degree) view of the Sun. It shows us our nearest star in virtual stereo quality, as seen by two spacecraft that are studying it from opposite sites of Earth’s  orbit.

Latest image of the far side of the Sun based on high resolution STEREO data, taken on February 2, 2011 at 23:56 UT when there was still a small gap between the STEREO Ahead and Behind data. This gap will start to close on February 6, 2011, when the spacecraft achieve 180 degree separation, and will completely close over the next several days. Credit: NASA (Click to luxuriate.)

In the next few days, the STEREO spacecraft will be at a true 180 degrees apart (the images shown here were taken when the spacecraft were 179.7 degrees apart, and closing in on their final positions fast).

The image we see here is how STEREO sees the far side of the Sun. The first thing you notice is that line of black — that’s a data gap that will be closed when the two spacecraft are in their final positions. The true beauty of STEREO’s work is that it will allow scientists to study the Sun in true 3D.  It’s a big step forward for solar physics because 3D shows us that the Sun truly is a sphere of hot plasma, and that plasma gets woven and threaded through some incredibly intricate and ever-changing magnetic fields.

The action of those magnetic fields powers the incredible activity we see on the “surface” of the Sun and in it s superheated atmosphere. STEREO’s images and data are finally giving solar physicists the ability to fly around the Sun and study it year-round.

The STEREO spacecraft configuration. Courtesy NASA.

This is because the two spacecraft are at two separate points along Earth’s orbit and they virtually DO fly around the Sun over the course of a year, giving us a long-term view of our star and its activity.

Using STEREO, it is now possible to follow the evolution of an active sunspot or flare region on the opposite side of the Sun from Earth, all by using the twin spacecrafts’ abilities to see the Sun in both hemispheres. Scientists will be able to track that active region before it rotates around to face us — giving us plenty of time to take action if the activity is going to mess with our satellites, the ISS,  and power grids and telecommunications systems.

In fact, the National Oceanic and Atmospheric Administration’s Space Environment Laboratory is using data from the STEREO spacecraft to make ever-more-accurate models of outbursts from the Sun called “coronal mass ejections”. These explosions belch out huge masses of charged particles out from the Sun. They create what’s known as “space weather” — changes in the geomagnetic environment in near-Earth space. When those clouds of charged particles hit our planet’s magnetic field, the result can be as benign as a gorgeous display of northern or southern lights, or as disastrous as a power grid failure or fried satellite electronics. So, STEREO will be a huge help in predicting solar storms and helping us avoid the worst consequences of them.

Check out the STEREO web page for more images and cool videos.  And, keep following this story — there’s a LOT more we’re going to learn about the Sun from the STEREO perspective!

Finally, here’s a big shout-out to my old friend and grad school office “roomie”, Dr. Lika Guhathakurta. She’s the STEREO program scientist at NASA and I imagine she’s just thrilled with the data she and her team are seeing.  Hey Lika!  This one’s for you!

solar studies, sun, sunspots

Sinuous Solar Ropes

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An Active Solar Region

Sunspot 1087 as imaged by Britta Suhre, a Germany amateur observer who took this image from her backyard in Germany. Credit: Britta Suhre, via Spaceweather.com

No, this isn’t a picture of an animal fur up close and personal — it’s a fantastically detailed image of an active area on the Sun’s surface.  The image is a highly magnified view of sunspot 1087. You can see a filament winding across the surface of the sunspot region, which is many times wider than our own planet.  Observers are monitoring the solar flares emanating from this area.  Click on the image to enlarge it and you’ll be amazed at the detail.  And, this is just one tiny region of the Sun!

You might wonder how people can get such wonderful images of the sun’s active regions. Of course, they don’t do it by looking directly at the Sun — that’s a recipe for disaster if you plan on using your eyes for anything else during your lifetime.  Of course, there are those folks who think it’s okay to look at the Sun for a few seconds — but even a short glance can do damage to your retina. And, forget about looking through a telescope or binoculars — that’s an even bigger risk to your eyesight. But, if you have a special filter for your telescope, or you have eclipse viewer glasses (which allow you to look safely at the Sun), you can do some solar observations.  People like Britta Suhre use specialized filters and cameras attached to telescopes to capture these views — and really, looking at those images is the very safest way you can enjoy the gorgeousity (technical term) of the active solar regions that the Sun is presenting to us as it ramps up to its maximum active state.  Want to see more solar images, there are plenty of places to do it:

Spaceweather.com frequently posts images of the Sun. Also check out the National Solar Observatory, the STEREO Mission site, the Solar and Heliospheric Observatory Homepage, the Wilcox Solar Observatory, the Institute for Solar Physics in Sweden , the Solar Dynamics Observatory and many others that you can find by simply Googling the term “solar observatory”.  Happy hunting!

P.S.  By the way, there’s a chance for people living at high latitudes to see possible aurorae action from solar activity. Check Spaceweather.com for more details.