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.

This is pretty nifty: a new elevation map of the Earth has just been released by NASA and Japan. It’s a "significantly improved" version of one that came out in 2009.

It uses Japan’s ASTER, the Advanced Spaceborne Thermal Emission and Reflection Radiometer, an instrument on board NASA’s Terra satellite. Terra is an Earth-observer, with detectors on board used to study various properties of our planet. ASTER looks both straight down and slightly behind the satellite’s track on the Earth is it passes. Over time stereo image pairs are created, and these can be used to create very high-resolution elevation maps (called topographic maps) of the surface of the Earth.

The new images are higher-res than before, and cover the Earth better to the tune of 260,000 more images. As an example of what can be done, they used it to make this map of the Grand Canyon:

[Click to enmesanate.]

One thing that struck me as funny when I read it: the coverage of ASTER’s observations goes from the Equator to as far north and south as 83° latitude… and they say that this is 99% of the Earth! That sounds odd, doesn’t it? You’d think the north and south poles of the Earth from 90° to 83° would be more than that, but in fact it’s true.

The portion of a sphere above a certain latitude line is called a cap, and the area of that cap depends on the latitude in question, and the radius of the sphere. I drew myself a diagram, fiddled with the numbers a bit, and found that the area of the Earth north of 83° compared to the surface area of the northern hemisphere is about 0.75%! So in fact, ASTER covered a bit more than 99% of the Earth’s surface, even if it never got past that 83°latitude.

Math! Surprising people since the time of Pythagoras.

Anyway, if you want to download the ASTER data yourself, you can: it’s public. Japan has a copy, and so does the USGS. I imagine it won’t be long before it’s integrated into Google Earth and all that too. Living in the future is pretty cool.

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

About a year ago, an enormous iceberg split off the Petermann glacier in Greenland. Taken by the current, it headed south, and just last month was off the coast of Labrador. The iceberg was over 20 km (12 miles) long.

On August 22, NASA’s Terra satellite took a look at it and saw this:

I have nothing much to add here, except to make sure you understand that a chunk of ice significantly bigger than Manhattan Island broke in half.

Ships aren’t alive, and even if they were the existence of their souls would be in doubt. But still, the idea appeals to me that somewhere, somehow, the Titanic is laughing.

Image credit: Jeff Schmaltz, MODIS Rapid Response, NASA Goddard Space Flight Center.

In Chile, the volcano Puyehue-Cordón explosively erupted in June, sending thick layers of ash to the east over the country and into Argentina. While the activity has died down, an ash plume still flows from the stratovolcano, and was spotted by NASA’s Terra satellite on July 8:

Chile is on the left, Argentina on the right. The image shows a region over 400 km (240 miles) across, giving you an idea of just how long that plume is… and see all that beige covering Argentina? That’s ash. As the wind has shifted the plume has changed direction, covering vast swaths of land with volcanic ash.

NASA’s Earth Observatory has several spectacular images of the eruption seen from space, and The Big Picture has them from the ground.

Credit: NASA images courtesy Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center

I’ve collected quite a few images of volcanoes from space 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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I have seen some amazing volcano pictures in my time, but this one just released by NASA is way, way up on the list of pure, freaking, awesome:

[Click to hephaestenate.]

That spectacular image is from the Earth Observing-1 satellite, and shows the Nabro volcano in Eritrea, a country bordering the Red Sea on the horn of Africa. The volcano has been erupting for a couple of weeks, but its isolated location has made it difficult to get observations from the ground. The best views have been from satellites like EO-1.

This picture, taken on June 24, is false color; red is actually near-infrared, showing the intense heat generated by the lava in the caldera and flowing off to the northwest (upper left). The blue cloud is likely water vapor, and additional clouds are from gases escaping from the cooling lava. The caldera crater is obvious, and to give you a sense of the scale of this beast is about 6 km (3.6 miles) across.

(more…)

Within hours of posting about the eruption of the Icelandic volcano Grimsvötn, I found out that helicopter footage of the plume (with tons of lightning) has been posted on Vimeo by Jon Gustafsson:

Lightning is common in volcanic plumes, but this one produced quite a bit more than usual. The footage is striking. Ha ha.

Also, NASA released a beautiful image of the plume as seen by the Earth-observing Terra satellite:

[Click to hephaestenate.]

Note the scale; the ash column is over 20 km (12 miles) across. I said in the post earlier it reached 11 km in height; however the NASA news release states that it reached over 20 km high!

There is some indication the ash may be a threat to air travel in the UK, too. That’s a bummer; Eyjafjalajökull disrupted air travel for weeks. Let’s hope this one subsides sooner.

Video from Jon Gustafsson on Vimeo; Terra image from Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC

Home.

Image credit: NASA