A river runs through it — on Titan

The Cassini probe, in orbit around Saturn, has captured a new radar image showing a long river on Titan, Saturn’s largest moon.

From the European Space Agency:

“The international Cassini mission has spotted what appears to be a miniature extraterrestrial version of the Nile River: a river valley on Saturn’s moon Titan that stretches more than 400 km from its ‘headwaters’ to a large sea.

It is the first time images have revealed a river system this vast and in such high resolution anywhere beyond Earth.

Scientists deduce that the river is filled with liquid because it appears dark along its entire extent in the high-resolution radar image, indicating a smooth surface.

[…]

Titan is the only other world we know of that has stable liquid on its surface. While Earth’s hydrologic cycle relies on water, Titan’s equivalent cycle involves hydrocarbons such as ethane and methane.

Images from Cassini’s visible-light cameras in late 2010 revealed regions that darkened after recent rainfall.”

Credit: d
Credit: NASA/JPL/ESA/ASI — http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageID=4700

HT: Clastic Detritus

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Earth at Night

NASA recently released Earth at Night, a global view of the planet at night, with city lights, oilfield flares, night time fishing fleets, and auroras.

Google has created a wonderful viewer for this data, which can be found at its Earth at Night 2012 site.

Earth at Night zoomed out to show the entire planet
Earth at Night zoomed out to show the entire planet
Northeast United States
Northeast United States
Montana, where night skies are always black
Montana, where night skies are always black
Netherlands, Belgium, and northern France, where you would be lucky to see Jupiter on a cloudless night
Netherlands, Belgium, and northern France, where you would be lucky to see Jupiter on a cloudless night
Korean Peninsula. Note the lights from fishing fleets off the coast of South Korea. Note also how dark North Korea is.
Korean Peninsula. Note the lights from fishing fleets off the coast of South Korea. Note also how dark North Korea is.

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NASA Earth Observatory — Images from November 2012

From NASA Earth Observatory’s Image of the Day — my favorites for November 2012:

A Changed Coastline in New Jersey — These images show why building (or rebuilding) on a barrier island is not a really good idea. These two aerial photos show a view of Mantoloking, New Jersey before and after “Superstorm” Sandy in October, 2012.

date
March 18, 2007
eo_sandy1
October 31, 2012

 

Kilomanjaro’s Shrinking Ice Fields — For whatever reason, the Snows of Kilomanjaro are shrinking.

The EO site explains:

Despite Mount Kilimanjaro’s location in the tropics, the dry and cold air at the top of the mountain has sustained large quantities of ice for more than 10,000 years. At points, ice has completely surrounded the crater. Studies of ice core samples show that Kilimanjaro’s ice has persisted through multiple warm spells, droughts, and periods of abrupt climate change.

But trends beginning more than a century ago suggest Kilimanjaro’s peaks may soon be ice-free. Between 1912 and 2011, the mass of ice on the summit decreased by more than 85 percent. Researchers say it’s no longer a question of whether the ice will disappear but when. Estimates vary, but several scientists predict it will be gone by 2060.

Rising air temperatures due to global warming could be contributing to the ice loss, but a number of other factors are just as important, if not more so. An increasingly dry regional atmosphere, for example, is starving the mountain of the fresh snow needed to sustain the ice fields. Drier air is also reducing cloud cover and allowing more solar energy to warm the ice surfaces.

eo_kilomanjaro1

Northern Ice Field — Credit: Kimberly Casey, NASA

 

Ashfall from the Karymsky Volcano — It seems that there is always a volcano erupting somewhere in Kamchatka.

eo_karymsky

 

Bylot Island in Winter and Summer — Bylot Island is in the Canadian Arctic. The winter shot, with the sun very low in the sky, has elongated shadows which accent the topography.

eo_bylot_winter

eo_bylot_summer

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Thin ice and the importance of Quaternary geology

From NASA Earth Observatory:

2011 Sea Ice Minimum

From the description (emphasis added):

In September 2011, sea ice covering the Arctic Ocean declined to the second-lowest extent on record. Satellite data from NASA and the National Snow and Ice Data Center (NSIDC) showed that the summertime ice cover narrowly avoided a new record low.

[…]

Melt season in 2011 brought higher-than-average summer temperatures, but not the unusual weather conditions that contributed to the extreme melt of 2007, the record low. “Atmospheric and oceanic conditions were not as conducive to ice loss this year, but the melt still neared 2007 levels,” said Walt Meier of NSIDC. “This probably reflects loss of multi-year ice in the Beaufort and Chukchi seas, as well as other factors that are making the ice more vulnerable.”

The low sea ice level in 2011 fits the pattern of decline over the past three decades, said Joey Comiso of NASA’s Goddard Space Flight Center. Since 1979, September Arctic sea ice extent has declined by 12 percent per decade.

“The sea ice is not only declining; the pace of the decline is becoming more drastic,” he noted. “The older, thicker ice is declining faster than the rest, making for a more vulnerable perennial ice cover.”

While the sea ice extent did not dip below the record, the area did drop slightly lower than 2007 levels for about ten days in early September 2011. Sea ice “area” differs from “extent” in that it equals the actual surface area covered by ice, while extent includes any area where ice covers at least 15 percent of the ocean.

Arctic sea ice extent on September 9, 2011, was 4.33 million square kilometers (1.67 million square miles). Averaged over the month of September, ice extent was 4.61 million square kilometers (1.78 million square miles). This places 2011 as the second lowest ice extent for both the daily minimum and the monthly average. Ice extent was 2.43 million square kilometers (938,000 square miles) below the 1979 to 2000 average.

Climate models have suggested that the Arctic could lose almost all of its summer ice cover by 2100, but in recent years, ice extent has declined faster than the models predicted.

A few years back, I blogged about a report that the Arctic Ocean may have been ice-free around 6000-7000 years ago, so this may be a natural cycle. Or it may be caused by human-induced global warming. I don’t know. I ended that post with the following:

I’m not a global warming denier, which bothers some of my friends. I do believe that human activities are affecting Earth’s climate. This does point out, however, the importance of geological studies of Quaternary (ice age to present) climate systems. Whatever is happening today, even if caused by humans, can only be fully understood in its geological context.

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Earth Observatory images

A few NASA Earth Observatory images from the past few months:

Mataiva Atoll, Tuamotu Archipelago, South Pacific Ocean, August 30, 2010

Credit: ISS Expedition 24 Crew

This image makes a great desktop background. The full-resolution image doesn’t have labels.


The Water Planet, October 2, 2010

Credit: NASA MODIS

Arthur C. Clarke once remarked, “How inappropriate to call this planet Earth when it is quite clearly Ocean.”


Susitna Glacier, Alaska, October 20, 2010

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

Note the complex ice deformation along much of the length of glacier. Most of the lower portion of the glacier is completely covered by debris.


Strong Extratropical Cyclone Over the US Midwest, October 29, 2010

Credit: NASA GOES Project Science Office

This low pressure system brought severe weather to much of the central U.S., and set a record low atmospheric pressure for a non-hurricane storm in the U.S.


Matusevich Glacier, Antarctica, November 7, 2010

Credit: NASA EO-1 team

Nile River Delta at Night, November 8, 2010

Credit: ISS Expedition 25 Crew

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Earth Observatory goodies

Here are some more great images from NASA’s Earth Observatory:

Glacial Dust off Alaska --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40973
Upsala Glacier, Argentina --- http://earthobservatory.nasa.gov/IOTD/view.php?id=41251
Sediment in the Gulf of Mexico --- http://earthobservatory.nasa.gov/IOTD/view.php?id=41237
Sediment in the Gulf of Mexico --- http://earthobservatory.nasa.gov/IOTD/view.php?id=41237
Athabasca Oil Sands --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40997
Mid-November Colorado Snowstorm --- http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=41305&src=nha (Yippee! We got about 8 inches here in Lakewood; our fourth snowfall of the season already!)

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Earth Observatory — recent images

Some recent images from NASA’s Earth Observatory Image of the Day:

Ash and Steam Plume, Soufriere Hills Volcano, Montserrat
Ash and Steam Plume, Soufriere Hills Volcano, Montserrat --- 10/19/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40803
Marion Island, South Africa --- 10/18/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40806 --- Note the smaller cones on the flanks of this volcanic island
Marion Island, South Africa --- 10/18/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40806 --- Note the smaller cones on the flanks of this volcanic island in the Indian Ocean southeast of South Africa.
Oblique View of the Arnica Fire, Yellowstone National Park, Wyoming --- 10/12/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40681
Oblique View of the Arnica Fire, Yellowstone National Park, Wyoming --- 10/12/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40681
Rainfall from Typhoon Parma --- 10/10/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40687 --- The Philippines got hit three times by this one typhoon.
Rainfall from Typhoon Parma --- 10/10/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40687 --- The Philippines got hit three times by this one typhoon.
Glaciers Flow into a Greenland Valley --- 9/13/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40169
Glaciers Flow into a Greenland Valley --- 9/13/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40169
Black Point Lava Flow, Arizona --- 9/7/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40076
Black Point Lava Flow, Arizona --- 9/7/2009 --- http://earthobservatory.nasa.gov/IOTD/view.php?id=40076

Grace and Peace