On Earth’s Cracks and Crevasses

Earth Day is a wonderful time for reflecting on our planet. In today’s post I wanted to avoid the temptation to simply post a picture of Earthrise, a momentous vista which showed us our fragile planet for the very first time from lunar orbit. Instead, I’ve taken a look at some of the Earth’s cracks and crevasses as seen by NASA’s Terra satellite.

From the Awesome Grand Canyon  …

An image from the NASA Terra spacecraft ASTER radiometer of the Grand Canyon.

(Courtesy NASA/GSFC/METI/ERSDAC/JAROS and U.S./Japan ASTER Science Team)

Over millions of years the Colorado River and its tributaries have carved the Grand Canyon through countless layers of the Earth’s crust. It’s a monumental feat of engineering and earth movement that few people could imagine was possible. The Grand Canyon is an impressive sight from the surface, and its immense size makes it visible from space. This photo taken by Terra’s Advanced Spaceborne Thermal Emission and Reflection (ASTER) radiometer shows an area 25 miles across, and has had a digital elevation map applied to show greater perspective.

This last detail makes me leary of comparing it on an apples-to-apples basis with this next photo, but the spatial resolution is almost the same and these two images come from the same instrument.

… To The Fearsome West Antarctic Ice Shelf

(Courtesy NASA/GSFC/METI/ERSDAC/JAROS and U.S./Japan ASTER Science Team)

Surprisingly perhaps, our Earth can be reshaped over short timescales just as significantly as geologic timescales.  Over the past few decades, the effect of seeping melt water has created this long crevasse. Observed just this past November, it has already almost completely calved a large sheet of ice off of the Pine Island Glacier. Within the next few years, we could see the ice separating here. As it shreds into broken slivers of ice, it will melt more rapidly. This image from Terra’s ASTER radiometer shows an area that is 27 miles across, and 32 miles in length.

You can click on either of these pictures to download high-resolution images from the Jet Propulsion Laboratory Photojournal for closer examination.

The Power of Water

Whether it’s over millions of years, or our lifetime, liquid water has the power to reshape the face of our fragile planet. On Earth Day we can remind ourselves of the inherent vulnerability of the only inhabitable world we have.

For more pictures of our changing planet like these taken from outer space, please see the Jet Propulsion Laboratory’s Photojournal website.

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