The Terra satellite is designed to study our planet from space, examining the environment over large scales and in high resolution. While passing over south Africa it took this seemingly normal — if still very beautiful — image:

I rotated it, so north is to the left. You can see land to the left, the southernmost tip of Africa, called Cape Agulhas. To the top is the Indian ocean, with the Atlantic to the right. A weather system is forming there, and all looks as it should… until your gaze settles all the way to the right (south). Wait… what’s the blue swirly thing?

Holy otology! Is that a giant ear?

Nope. It’s an eddy, a vortex, in the ocean, probably spun off the ocean current that flows around the southern cape of Africa. These eddies can dredge up material from deeper waters, including nutrients. Phytoplankton in the water feeds of those nutrients, and bang! Plankton bloom.

The plankton flows along with the water, coloring it blue, making it stand out eerily against the water. As I pointed out in an earlier post about these blooms, we can learn a lot about the environment from them. Plankton are sensitive to climate change, for example, and can act as indicators of the water’s physical characteristics.

When I see an image like this I think of all the funding cutbacks NASA is facing right now — and yeah, I’ll be writing about that soon. Our planet is on a cusp right now, and I can’t help but fret about the opportunities we might miss if we step back from space. Exploring space, even just being in space, has given us a perspective on our home world we couldn’t possibly have achieved otherwise. Some things, once begun, shouldn’t be stopped. Try as they might, some politicians can’t make us unsee what we’ve seen, and unlearn what we’ve learned.

Unless we let them, of course. I won’t, and I hope you won’t either. Let the picture above serve as a reminder: when it comes to keeping track of the Earth, we have to keep our eyes and ears open.

Sometimes, the images from the Cassini Saturn probe are so cool it’s tempting just to post them and say, "Look at THAT!"

See what I mean? [Click to gigantesenate.]

But of course, I can’t just leave it at that. This image, taken on January 4, 2012, is a bit different than most. Sure, we see Saturn’s magnificent rings, nearly edge on from this perspective. And we’ve seen this icy moon Enceladus many, many times (see Related Posts below for tons more pictures). Look at the bottom of the moon: see those fuzzy streaks? Those are geysers of water spewing from cracks in the moon’s south pole! Cassini has been studying them intently ever since they were discovered; they are proof that liquid water exists under the surface of Enceladus, though it’s still being argued over whether it’s in pockets, like lakes, or the whole moon has an ocean of water under the surface.

Despite all that, I keep getting drawn to the crescent shape itself. We can never see that from Earth. Saturn is much farther out from the Sun than we are, and geometry demands that from home we always see these worlds nearly fully lit by the Sun. The only way to see them like this is to go there.

But also, that giant circular feature is really interesting. It’s big, maybe 200 km (over 100 miles) across, and a bit darker than the surrounding surface. I tried locating it on an atlas of Enceladus, but it wasn’t obvious at all. I thought it might be an impact basin, but a little scrounging online led me to a paper by Cassini imaging team leader Carolyn Porco, which says there are no large impact basins on Enceladus! So what is it?

Well, why not go to Dr. Porco herself? I sent her a note, and she kindly replied. That region is called Diyar Planitia, and it stands out among the surrounding terrain because it’s much smoother. It does have narrow surface features, but they’re too small to be seen at this resolution. At the low angle at which we’re seeing it here, it looks a little bit darker than the rougher terrain around it, so it’s easier to see (which is why on an atlas it’s harder to find). It is roughly circular, but that may simply be coincidence. Enceladus has been massively resurfaced, with some areas much older than others, due to various forces under the surface — looking this all up I learned a new one, called diapirism, where lower density material underneath higher density material can rise up and break through. That’s one process that’s helped change the surface of Enceladus over the eons.

That’s pretty nifty. And think about that! Today I learned of what is to me a new region of the solar system, one that has an interesting and complicated history, molded by vast forces over long-stretched times, one of which was also new to me. How wonderful to get all that from what’s otherwise just a pretty picture!

But of course, in science, there’s no such thing as just a pretty picture. Science is a tapestry, a vast complex fabric interwoven with countless threads. Each of those threads is amazing, each important, and each leads to another. And that’s where the true beauty of science lies.

It’s been a while since I posted a cool image of a volcano from space! So here’s one that’s simply lovely: Puyehue Cordón Caulle in Chile, which has been continuously erupting for several months now:

This was taken by NASA Earth Observing-1 satellite on January 26, 2012. The ash has been falling for so long it’s covered the entire complex in a finely ground layer, coloring this area taupe (or ecru, or, as I like to call it, tan). You really should click to haphaestenate that picture; the full-sized shot is amazing. There’s so much to see, like the ash cloud streaming away from that vent, the detail in the big caldera… but my favorite part I think are the sharply-colored lakes in the region, which are such a contrast to the dull brown everywhere else (you can see one of those lakes in the bottom left corner of the picture above — look for the blue spot). For scale, the caldera’s bowl is about 2 km (1.2 miles) across.

Unfortunately, as pretty as this is, the implications are not so good: the forest in that area is suffering due to all that ash. Volcanic ash is not like some small-grained powder: under a microscope you can see it looks far more like ground glass, each grain festooned with dozens of sharp corners and edges. Breathing that stuff in is not good for your lungs. And, of course, it’s heavy — it’s rock, after all — so when it falls in large amounts it can do a lot of damage, especially if it rains.

Satellite imagery of active volcanoes is critically important: some small-minded politicians might mock it, but monitoring them saves lives. And, of course, there’s all the amazing science we learn as well.

Credit: NASA/EO-1

I love these satellite views of volcanoes from space, and I’ve collected quite a few into a gallery slideshow. Click the thumbnail picture to get a bigger picture and more information, and scroll through the gallery using the left and right arrows.]

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Hey, guess where I’ll be?

Yeah, there. Well, a little to the left of that big blob. Ypsilanti, Michigan, to be exact. On February 15th I’m giving my "Death from the Skies!" talk at Eastern Michigan University at 7:00 p.m. It’s free, so if you’re in the area drop on by! I lived in Ann Arbor for three years, so it’ll be cool to head back there.

And if you live in the Bethlehem PA area, I’ll be at Geroge Hrab’s concert a few days later! And then the live Nerdist podcast in Boulder March 2, and then SXSW on March 12th, and more stuff coming too.

Geez, I need to post a calendar. OK, I’ll put that on my list. If only I had a calendar to remind me…

Tip o’ the spacesuit visor to Fragile Oasis for the picture, which was taken on the ISS on January 30, 2012, because I assume the astronauts were excited that I’d be there. Credit: Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth."

Sometimes, I like to think of a photon of light as a car on a road. As the road dips and curves, a car has to follow that path, dipping and curving as well. It might be weird to think of space as curving, but it does. Gravity from massive objects warps space, and a beam of light moving through that curved space curves along with it.

This is the principle behind what’s called gravitational lensing. A beam of light passing by an object — a big galaxy, say, or a cluster of galaxies — bends one way. A beam headed in a slightly different direction bends a slightly different way. This can really mess with what we see… which I can prove! Check this out: a Hubble image of the galaxy RCSGA 032727-13260.

What a mess! All those arcs and blue smudges are images of that one galaxy. The light from that galaxy traveled nearly 10 billion light years to get here! But when it was halfway here, that light passed by the big cluster of galaxies — the red fuzzballs — in the middle of the image. As it did, the curvature of space distorted and warped the light from the galaxy, and by the time it reached us here at Earth the image looks like this. The outstretched, smeared-out arc is amazing; I’ve never seen one that long and well-defined before.

Not only that, but the image gets broken up into several separate images. There are no fewer than four different repetitions of the background galaxy in the big image. To show that, I put three of them together here. It’s goofed up, to be sure, but you can kinda sorta see they are the same galaxy, flipped over and/or smudged out.

The cool thing about this is we can learn about the more distant galaxy by examining these images. (more…)

I really don’t think I need to add anything to this. Set it to HD, make it full screen, and turn the sound up.

Tip o’ the magnetometer to Tom Lowe, aka Timescapes.

In case you were wondering what the snow was like here in Colorado the other day…

[Click to ensnowflakenate.]

That’s an image taken by NASA’s Aqua satellite on February 5, 2012. I live in Boulder, to the northwest of Denver (which is labeled), right on the edge of the Rockies. We got well over 30 cm here locally, and it was deeper in other places. Typical of the area, though, the Sun was out the next day, and now our yard looks like a fairyland of sparkles.

It’s unusual to get a heavy snowfall like this in February (we do get big ones, but later in the year) and from what I’ve heard this was a record for a February. And not to overextend the post to climate change, but a) weather is not climate… unless you add time, and 2) contrary to any soundbite you might hear, snowstorms will actually become more common as the Earth warms. Warmer weather means more evaporation, so more moisture in the air. It’s still cold higher up in the atmosphere, and it’s still cold in the winter over land, so a warmer planet overall means more snow in some places. I’m not attributing this event to global warming, to be clear. But it’s the kind of thing we can expect in the coming years.

NASA image courtesy Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC

- Snowpocalypse 2011 from space!
- Lovely, frigid ripples
- Icy swirls around a patient volcano