U.S.A, Jan 30, 2017: NASA scientists have developed a new chemical assay that could aid the search for life on exoplanets by identifying the presence of amino acids, the compounds that make up proteins and are the building blocks of life.
The test uses a liquid-based technique known as capillary electrophoresis to separate a mixture of organic molecules into its components.
It was designed by researchers from NASA’s Jet Propulsion Laboratory (JPL) in the US specifically to analyse for amino acids, the structural building blocks of all life on Earth.
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The method is 10,000 times more sensitive than current methods employed by spacecraft like NASA’s Mars Curiosity rover, according to researchers.
One of the key advantages of the new way of using capillary electrophoresis is that the process is relatively simple and easy to automate for liquid samples expected on ocean world missions.
It involves combining a liquid sample with a liquid reagent, followed by chemical analysis under conditions determined by the team.
By shining a laser across the mixture – a process known as laser-induced fluorescence detection – specific molecules can be observed moving at different speeds. They get separated based on how quickly they respond to electric fields.
While capillary electrophoresis has been around since the early 1980s, this is the first time it has been tailored specifically to detect extraterrestrial life on an ocean world, said Jessica Creamer, a postdoctoral scholar at JPL.
“Our method improves on previous attempts by increasing the number of amino acids that can be detected in a single run,” Creamer said.
“Additionally, it allows us to detect these amino acids at very low concentrations, even in highly salty samples, with a very simple ‘mix and analyse’ process,” she said.
The researchers used the technique to analyse amino acids present in the salt-rich waters of Mono Lake in California.
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The lake’s exceptionally high alkaline content makes it a challenging habitat for life, and an excellent stand-in for salty waters believed to be on Mars, or the ocean worlds of Saturn’s moon Enceladus and Jupiter’s moon Europa.
The researchers were able to simultaneously analyse 17 different amino acids, which they are calling “the Signature 17 standard.” These amino acids were chosen for study because they are the most commonly found on Earth or elsewhere.
“Using our method, we are able to tell the difference between amino acids that come from non-living sources like meteorites versus amino acids that come from living organisms,” said the project’s principal investigator, Peter Willis of JPL.
The study was published in the journal Analytical Chemistry. (IANS)
While sea ice in the Arctic continues to be on the decline, a new research from the US Space agency NASA suggests that it is regrowing at faster rates during the winter than it was a few decades ago.
The findings showed that since 1958, the Arctic sea ice cover has lost on average around two-thirds of its thickness and now 70 per cent of the sea ice cap is made of seasonal ice, or ice that forms and melts within a single year.
But at the same time, that sea ice is vanishing quicker than it has ever been observed in the satellite record, it is also thickening at a faster rate during winter.
This increase in growth rate might last for decades, explained the researchers, in the paper to be published in the journal Geophysical Research Letters.
However, this does not mean that the ice cover is recovering, though. Just delaying its demise.
“This increase in the amount of sea ice growing in winter doesn’t overcome the large increase in melting we’ve observed in recent decades,” said lead author Alek Petty, a sea ice scientist at NASA’s Goddard Space Flight Center in Maryland.
“Overall, thickness is decreasing. Arctic sea ice is still very much in decline across all seasons and is projected to continue its decline over the coming decades,” she added.
To explore sea ice growth variability across the Arctic, the team used climate models and observations of sea ice thickness from the European Space Agency’s CryoSat-2 satellite.
They found that in the 1980s, when Arctic sea ice was on average 6.6 feet thick in October, about 3.3 extra feet of ice would form over the winter.
This rate of growth may continue to increase, and in the coming decades, we could also have an ice pack that would on average be only around 3.3 feet thick in October, but could experience up to five feet of ice growth over the winter.
However, by the middle of the century, the strong increases in atmospheric and oceanic temperatures will outweigh the mechanism that allows ice to regrow faster, and the Arctic sea ice cover will decline further, Petty said.
The switch will happen once the sea ice is less than 1.6 feet thick at the beginning of winter, or its concentration — the percentage of an area that is covered in sea ice — is less than 50 per cent, she noted. (IANS)