Alien life in our Solar System? Study hints at Saturn’s moon

Enceladus, one of Saturn's many moons. (NASA/AFP)
Updated 27 February 2018
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Alien life in our Solar System? Study hints at Saturn’s moon

PARIS: Humanity may need look no further than our own Solar System in the search for alien life, researchers probing one of Saturn’s moons said Tuesday.
The icy orb known as Enceladus may boast ideal living conditions for single-celled microorganisms known as archaeans found in some of the most extreme environments on Earth, they reported in the science journal Nature Communications.
A methanogenic (methane-producing) archaean called Methanothermococcus okinawensis thrived in laboratory conditions mimicking those thought to exist on Saturn’s satellite, the team said.
On Earth, this type of archaean is found at very hot temperatures near deep-sea hydrothermal vents, and converts carbon dioxide and hydrogen gas into methane.
Traces of methane were previously detected in vapor emanating from cracks in Enceladus’ surface.
“We conclude that some of the CH4 (methane) detected in the plume of Enceladus might, in principle, be produced by methanogens,” the researchers in Germany and Austria wrote.
They also calculated that sufficient hydrogen to support such microbes could be produced by geochemical processes in Enceladus’ rocky core.
The authors had set out to test the hypothesis that conditions on the satellite may be good for hosting methanogenic archaea.
The data, based purely on laboratory study, showed this “could be” so, said Simon Rittmann of the University of Vienna who co-authored the scientific paper.
But the results provide “no evidence for possible extraterrestrial life,” he underlined to AFP.
“Our study only concerns microorganisms. I would like to avoid any speculation about intelligent life,” he said.
Saturn is the sixth planet from the Sun, separated from Earth only by Mars and Jupiter.
It has dozens of moons.
Previous research suggested that Enceladus sports an ocean of liquid water — a key ingredient for life — beneath its icy surface.
The moon is also thought to contain compounds such as methane, carbon dioxide, and ammonia, and its south pole sports hydrothermal activity — a combination of traits that makes it a key target in the search for extra-terrestrial life.
Further research is needed to exclude the possibility that Enceladus’ methane may come from non-biological, geochemical processes, the authors said.


Thaw of Antarctic ice lifts up land, might slow sea level rise

Updated 22 June 2018
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Thaw of Antarctic ice lifts up land, might slow sea level rise

  • The fast rise of the bedrock beneath will lift ever more of the ice onto land, reducing the risks of a breakup of the sheet caused by warming ocean water seeping beneath the ice
  • The process was too slow to save the ice sheet from a possible collapse triggered by global warming

OSLO: Antarctica’s bedrock is rising surprisingly fast as a vast mass of ice melts into the oceans, a trend that might slow an ascent in sea levels caused by global warming, scientists said on Thursday.
The Earth’s crust in West Antarctica is rising by up to 4.1 centimeters (1.61 inches) a year, an international team wrote in the journal Science, in a continental-scale version of a foam mattress reforming after someone sitting on it gets up.
The rate, among the fastest ever recorded, is likely to accelerate and could total 8 meters (26.25 feet) this century, they said, helping to stabilize the ice and brake a rise in sea levels that threatens coasts from Bangladesh to Florida.
“It’s good news for Antarctica,” lead author Valentina Barletta of the Technical University of Denmark and Ohio State University told Reuters of the findings, based on GPS sensors placed on bedrock around the Amundsen Sea in West Antarctica.
Much of the West Antarctic ice sheet, which has enough ice to raise world sea levels by more than three meters (10 feet) if it ever all melted, rests on the seabed, pinned down by the weight of ice above.
The fast rise of the bedrock beneath will lift ever more of the ice onto land, reducing the risks of a breakup of the sheet caused by warming ocean water seeping beneath the ice.
The uplift “increases the potential stability of the West Antarctic Ice Sheet against catastrophic collapse,” the scientists wrote.
Last week, another study said that three trillion tons of ice had thawed off from Antarctica since 1992, raising sea levels by almost a centimeter — a worsening trend.
It often takes thousands of years for the Earth’s crust to reshape after a loss of ice. Parts of Scandinavia or Alaska, for instance, are still rising since the end of the last Ice Age removed a blanket of ice more than a kilometer thick.
A further report this month found that the West Antarctic ice sheet expanded about 10,000 years ago, interrupting a long-term retreat after the last Ice Age, because of a rise of the land beneath.
But it said the process was too slow to save the ice sheet from a possible collapse triggered by global warming.
One of the lead authors of that study, Torsten Albrecht at the Potsdam Institute for Climate Impact Research, told Reuters on Thursday: “The expected eight-meter (26.4-foot) uplift in 100 years in the Amundsen Sea region ... seems rather small in order to prohibit future collapse.”