Tag: Terra satellite

A big dust storm… in Alaska?

By Phil Plait | November 20, 2010 7:18 am

[Note: At the bottom of this post is a gallery of amazing NASA satellite images of the Earth!]

I need to make a list of the stuff I love about science, because I keep coming up with more. This time, it’s how surprising the Earth can be, even though we live on the dang thing.

For example, when I think of dust storms, I think of China and the Sahara or maybe the Dust Bowl in the U.S. I certainly don’t think of Alaska! But then, NASA’s Terra satellite set me straight:


[Click to 49thstatenate.]

Check that out! An actual series of dust storms blowing off the coats of Alaska! The cause was obvious in retrospect: as billions of tons of glacier flow languidly across the landscape, they crush the rocks underneath into powder called — get this — glacial flour. This gets deposited as mud underneath the glacier. When the glacier recedes a bit, the mud dries, and the wind can blow it away.

Tadaa! Dust storms off the coast of Alaska. Maybe Marian knows all about these, but for me, that’s a first.

The stuff I learn from NASA. Man.

Here are some other amazing images of the Earth from space! Use the thumbnails and arrows to browse, and click on the images to go through to blog posts with more details and descriptions.




By Phil Plait | June 22, 2010 3:05 pm


Image credit: NASA and the MODIS Rapid Response Team

CATEGORIZED UNDER: NASA, Piece of mind, Pretty pictures

Volcano on volcano action

By Phil Plait | February 19, 2010 11:00 am

I know I just posted a volcano image from the Terra Earth-observing satellite, but another just came in and it’s so beautiful I can’t help myself. So here’s a little bit of awesome for your Friday afternoon. Behold!

See? Told you.

What we have here are two volcanoes on February 13 erupting simultaneously in Kamchatka. The northern one, Klyuchevskaya, is the tallest and most active in the region. The other one, Bezymianny, is 10 km (6 miles) to the south, and is much smaller (2900 meters/9500 feet vs. 4800 m/15,900 feet) for Klyuchevskaya). Both are spewing a plume high into the air; from the whitish color it appears to be more steam than ash, though the northern, larger volcano is reported to be sending out lava and rock fountains as well. Between the two you can see some clouds, too.

I don’t suppose too many folks live near these two monsters, which is a good thing. I can’t imagine what it must look like to be, say, 10 kilometers east of the two and see them both blasting out plumes reaching up 6 kilometers (3.5 miles) high. But one day I’d love to witness something like that! Maybe from farther away, though. Wow.

Image credit: by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team


Terra spots an impact on, um, Terra

By Phil Plait | February 1, 2010 7:00 am

While high over the grasslands of Kazakhstan, the Terra Earth-observing satellite saw something interesting… can you spot it in this image?


Not so easy, is it? But if you look just left of center you’ll see this:


See it there, right in the center? It’s the Chiyli impact crater, an ancient scar from a cosmic collision. The crater is roughly 1.5 km across (about a mile) — about the same size as Meteor Crater in Arizona — meaning the object that created it was something smaller than a football field, moving at perhaps 30 km/sec (20 miles/sec). It hit about 46 million years ago, give or take. Long after the dinosaurs, but long before us, too. Note that it’s a double-rimmed crater too, which sometimes form in large impacts depending on the conditions of the impactor and the ground.

This is a false-color image, at least part of which is in the infrared; vegetation appears red, water blue, and bare land is "earth tones" (browns and tans). This sort of imagery allows scientists to investigate how vegetation, land, and water change over time.

terra_chiyli_flippedWhen I first saw this image, I didn’t see it as a crater, but more as a raised annulus, a ring in the ground. I knew immediately that this meant that in the picture, the sunlight was coming up from the bottom, and it turns out that’s correct. It’s a cool and optical illusion; when we see craters illuminated from below, they look like domes, and vice-versa. In the picture here, I flipped the image and now, to me at least, it looks more like the depression that it really is. The wide inner rim is more obvious, too.

Here’s an even better example:

Is it a dome… … or a crater?

It just goes to show you that finding evidence of extra-terrestrial events on Earth can be tough, and even when you find them you can’t rest easy. They’re apt to fool you one way or another.

CATEGORIZED UNDER: Astronomy, DeathfromtheSkies!

'tis a bit nippy, guvnah!

By Phil Plait | January 7, 2010 12:00 pm

As I write this, it’s about -15 C outside where I live in Boulder, and even the snow looks like it’s shivering. So I’m not sure if I’m happy to share the grief or feel badly about the weather for folks in the UK, who generally don’t get (metric, I suppose) tons of snow. But then I saw this image from NASA’s Earth observing Terra satellite:

Holy Haleakala, that’s gorgeous! I won’t say I’m exactly glad they got lots of snow, but still, wow. Sorry, my anglic friends, but your suffering has produced this stunning beauty.

The image was taken on January 7, 2010 at around noon local time. The image above has 1 km pixels, but you can also grab the image in higher-res 500 meter and 250 meter versions, too.

CATEGORIZED UNDER: Cool stuff, NASA, Pretty pictures
MORE ABOUT: snow, Terra satellite, UK

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