Archive for the ‘ice’ Category

n pole

Instead of snow and ice whirling on the wind, a foot-deep aquamarine lake now sloshes around a webcam stationed at the North Pole. The meltwater lake started forming July 13, following two weeks of warm weather in the high Arctic. In early July, temperatures were 2 to 5 degrees Fahrenheit (1 to 3 degrees Celsius) higher than average over much of the Arctic Ocean, according to the National Snow & Ice Data Center.

Meltwater ponds sprout more easily on young, thin ice, which now accounts for more than half of the Arctic’s sea ice. The ponds link up across the smooth surface of the ice, creating a network that traps heat from the sun. Thick and wrinkly multi-year ice, which has survived more than one freeze-thaw season, is less likely sport a polka-dot network of ponds because of its rough, uneven surface.

July is the melting month in the Arctic, when sea ice shrinks fastest. An Arctic cyclone, which can rival a hurricane in strength, is forecast for this week, which will further fracture the ice and churn up warm ocean water, hastening the summer melt. The Arctic hit a record low summer ice melt last year on Sept. 16, 2012, the smallest recorded since satellites began tracking the Arctic ice in the 1970s.

http://www.livescience.com/38347-north-pole-ice-melt-lake.html

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It’s time to add Mercury to the list of worlds where you can go ice-skating. Confirming decades of suspicion, a NASA spacecraft has spotted vast deposits of water ice on the planet closest to the sun.

Temperatures on Mercury can reach 800 degrees Fahrenheit (427 degrees Celsius), but around the north pole, in areas permanently shielded from the sun’s heat, NASA’s Messenger spacecraft found a mix of frozen water and possible organic materials.

Evidence of big pockets of ice is visible from a latitude of 85 degrees north up to the pole, with smaller deposits scattered as far away as 65 degrees north.

The find is so enticing that NASA will direct Messenger’s observation toward that area in the coming months — when the angle of the sun allows — to get a better look, said Gregory Neumann, a Messenger instrument scientist at NASA’s Goddard Space Flight Center in Maryland. [Latest Mercury Photos from Messenger]

“There is an ongoing campaign, when the spacecraft permits, to look further northward,” said Neumann, the lead author of one of three Mercury studies published online in the Nov. 29 edition of the journal Science.

Researchers also believe the south pole has ice, but Messenger’s orbit has not allowed them to obtain extensive measurements of that region yet.

Messenger will spiral closer to the planet in 2014 and 2015 as it runs out of fuel and is perturbed by the sun’s and Mercury’s gravity. This will let researchers peer closer at the water ice as they figure out how much is there.

Speculation about water ice on Mercury dates back more than 20 years.

In 1991, Earth-bound astronomers fired radar signals to Mercury and received results showing there could be ice at both poles. This was reinforced by 1999 measurements using the more powerful Arecibo Observatory microwave beam in Puerto Rico. Radar pictures beamed back to New Mexico’s Very Large Array showed white areas that researchers suspected was water ice.

A closer view, however, required a spacecraft. Messenger settled into Mercury’s orbit in March 2011, after a few flybys.  Almost immediately, NASA used a laser altimeter to probe the poles. The laser is weak — about the strength of a flashlight — but just powerful enough to distinguish bright icy areas from the darker, surrounding Mercury regolith.

Neumann said the result was “curious”: There were few bright spots inside craters.

Team member John Cavanaugh was pretty sure of what they were finding, Neumann recalled. Cavanaugh had been a part of NASA’s Lunar Reconnaissance Orbiter team, and he had seen a similar strange pattern on Earth’s moon when LRO found ice at the lunar poles in 2009.

Flash heating on Mercury would mix nearly all of its ice with the surrounding regolith – as well as with possible organic material borne to the planet by comets and ice-rich asteroids.

“So what you’re seeing is the fact that water ice can’t survive indefinitely in these locations because the temperatures apparently spike up,” Neumann said.

The team expected to find water ice on Mercury. Indeed, Messenger already drew a link this year between permanently shadowed areas on the planet and the “radar bright” spots seen from Earth.

All researchers needed to do was point their instruments in the right spot, seek out bright areas and then measure the temperature and composition.

Messenger’s neutron spectrometer spotted hydrogen, which is a large component of water ice. But the temperature profile unexpectedly showed that dark, volatile materials – consistent with climes in which organics survive – are mixing in with the ice.

“This was very exciting. You are looking for bright stuff, and you see dark stuff – gee, it’s something new,” Neumann said.

Organic materials are life’s ingredients, though they do not necessarily lead to life itself. While some scientists think organics-bearing comets sparkedlife on Earth, the presence of organics is also suspected on airless, distant worlds such as Pluto. Scientists say comets carrying organic bits smashed into other planets frequently during the solar system’s history.

Researchers are now working to determine if they indeed saw organics on Mercury. So far, they suspect Mercury’s water ice is coated with a 4-inch (10 centimeters) blanket of “thermally insulating material,” according to Neumann’s paper.

It will take further study to figure out exactly what this material is, but Neumann said the early temperature curves could show organic materials such as amino acids.

http://www.livescience.com/25132-water-ice-mercury-messager-discovery.html

 

Ancient microbes have been discovered in bitter-cold brine beneath 60 feet of Antarctic ice, in permanent darkness and subzero temperatures of Antarctica’s Lake Vida, located in the northernmost of the McMurdo Dry Valleys of East Antarctica.

In the current issue of the Proceedings of the National Academy of Sciences, Nathaniel Ostrom, Michigan State University zoologist, has co-authored “Microbial Life at -13ºC in the Brine of an Ice-Sealed Antarctic Lake.” Ostrom was part of a team that discovered an ancient thriving colony, which is estimated to have been isolated for more than 2,800 years living in a brine of more than 20 percent salinity that has high concentrations of ammonia, nitrogen, sulfur and supersaturated nitrous oxide—the highest ever measured in a natural aquatic environment.”It’s an extreme environment – the thickest lake ice on the planet, and the coldest, most stable cryo-environment on Earth,” Ostrom said. “The discovery of this ecosystem gives us insight into other isolated, frozen environments on Earth, but it also gives us a potential model for life on other icy planets that harbor saline deposits and subsurface oceans, such as Jupiter’s moon Europa.”Members of the 2010 Lake Vida expedition team, Dr. Peter Doran (professor, University of Illinois, Chicago), Dr. Chris Fritsen (research professor, Desert Research Institute, Reno, Nev.) and Jay Kyne (an ice driller) use a sidewinder drill inside a secure, sterile tent on the lake’s surface to collect an ice core and brine existing in a voluminous network of channels 16 meters and more below the lake surface. 

On the Earth’s surface, water fuels life. Plants use photosynthesis to derive energy. In contrast, at thermal vents at the ocean bottom, out of reach of the sun’s rays, chemical energy released by hydrothermal processes supports life. Life in Lake Vida lacks sunlight and oxygen. Its high concentrations of hydrogen gas, nitrate, nitrite and nitrous oxide likely provide the chemical energy used to support this novel and isolated microbial ecosystem. The high concentrations of hydrogen and nitrous oxide gases are likely derived from chemical reactions with the surrounding iron-rich rocks.

Consequently, it is likely that the chemical reactions between the anoxic brine and rock provide a source of energy to fuel microbial metabolism. These processes provide new insights into how life may have developed on Earth and function on other planetary bodies, Ostrom said. The research team comprised scientists from the Desert Research Institute (Reno, Nev.), the University of Illinois-Chicago, NASA, the University of Colorado, the Jet Propulsion Laboratory, Montana State University, the University of Georgia, the University of Tasmania and Indiana University.

For more information: “Microbial life at −13 °C in the brine of an ice-sealed Antarctic lake,” by Alison E. Murray et al. PNAS, 2012. http://www.pnas.org/content/early/2012/11/21/1208607109.abstract Journal reference: Proceedings of the National Academy of Sciences.

http://www.dailygalaxy.com/my_weblog/2012/11/ancient-microbial-life-found-thriving-in-permanent-darkness-60-feet-beneath-antarctica-ice.html