Nov 4, 2013
Since 2011, and again in october 2013, new discoveries have rendered inescapable the fact that precursors of life (DNA) were existing at immense distances—such as that of a gas cloud neighboring out galactic center, that is,
Building Blocks of Life Found in Galactic Cloud
Discovery News March7-2013-- Building Blocks of Life Found in Galactic Cloud
Mar 7, 2013 01:29 PM ET // by Markus Hammonds
http://news.discovery.com/space/astronomy/icy-clues-for-lifes-origins-130307.htm
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You and I are both made up of an eclectic collection of organic molecules. A lot of interesting molecules go into making up all life on Earth, from the amino acids which make up proteins to the nucleobases that encode our very DNA, but where they exactly come from (on a cosmic scale) is still one of science’s great mysteries. And as with any good mystery, the only solution will be to solve each of the separate pieces of the puzzle — and the latest piece of this puzzle has just been spotted in a huge gas cloud in the center of our galaxy.
Top 10 Places To Find Alien Life
Finding things like amino acids in space directly is a difficult business. So, instead of finding them directly, a team using West Virginia’s Green Bank Telescope, led by Anthony Remijan, discovered two other molecules –
cyanomethanimine and
ethanamine — both of which are precursor molecules. In other words, these molecules are the early steps in the chain of chemical reactions that go on to make the stuff of life.
Astrochemists are steadily discovering larger and more complex molecules in interstellar space. Recent years have seen the discoveries of glycolaldehyde, which is arguably the simplest type of sugar, and ethyl formate, one of the molecules responsible for the flavor and aroma of rum and raspberries. This latest discovery might not sound quite as appetizing, but it’s no less important.
When hunting for new molecules, astrochemists frequently turn their telescopes towards the galactic center. Drifting in the Milky Way’s core, is a hulking interstellar cloud known as Sagittarius B2 (or Sgr B2 for short). Spanning 150 light-years in size, Sgr B2 is one of the galaxy’s largest clouds, up to 40 times as dense as any other the Milky Way has to offer.
Sgr B2 is also something of a benchmark for molecule hunters. Roughly 25,000 light-years from Earth, and only about 390 light years from the supermassive black hole lurking in the galactic center, if any molecule can be found in the interstellar medium, it can be found here.
The two molecules that Remijan and his team found, cyanomethanimine and ethanamine, are expected to be precursors to the nucleobase adenine and the amino acid alanine, respectively. This makes them potentially very important discoveries. It’s expected that molecules like this form, and continue to react, on the surfaces of interstellar ice grains. These ice grains condense like hailstones in the freezing conditions of interstellar clouds. Once formed, some molecules escape into the vacuum of space, while others react further — forming increasingly complex molecules.
Remijan noted that, ”Finding these molecules in an interstellar gas cloud means that important building blocks for DNA and amino acids can ‘seed’ newly-formed planets with the chemical precursors for life.” Logical, because the vast interstellar clouds where these molecules are formed are the very same clouds that go on to collapse into stars and planets.
Extraterrestrial
amino acids and DNA nucleobases like adenine have been found in meteorites, suggesting that there must be mechanisms occurring in space that create them. If they can be created in space, it’s likely that they can also been seen using telescopes. All we need to do is make sure our telescopes are sensitive enough, look in the right places, and make sure we know what it is we’re looking for.
Hopefully, if astrochemists keep looking for complex molecules like these, we’ll eventually be able to answer some of the biggest questions out there — such as the question of how life first started on our planet, how it might happen on other planets, and whether or not we’re alone in the galaxy.
Image: The reflection nebula IRAS 10082-5647, illuminated by a young star. Places like this could be where complex molecules are formed and incorporated into newly forming star systems. Credit: ESA/Hubble & NASA
Life Elements Came from Space
Discovery News March1-2011—
Mar 1, 2011 03:00 AM ET
http://news.discovery.com/space/life-elements-space-110301.htm
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The team from the University of Arizona say they have discovered a "carbonaceous chondrite" meteorite -- found in 1995 and called "CR2 Grave Nunataks 59229" -- contains relatively high amounts of ammonia and amino acids.
A meteorite offers new clues into how essential biomolecules laid the foundation for life on Earth.
THE GIST
Researchers have long been trying to explain the origin of the ammonia that triggered the formation of the first biomolecules on Earth. Meteorites may have released compounds including hydrocarbon chains and a large amount of ammonia, which is rich in nitrogen.
A meteorite found in Antarctica adds extra impact to the theory that the essential building blocks of life on Earth came from outer space, say scientists.
The team from the University of Arizona say they have discovered a "carbonaceous chondrite" meteorite -- found in 1995 and called "CR2 Grave Nunataks 59229" – that contains relatively high amounts of ammonia and amino acids.
Carbonaceous chondrites meteorites contain abundant organic materials as they have not been melted, and much of their original chemical composition remains intact.
The research, led by Professor Sandra Pizzarello, is published in Proceedings of the National Academy of Sciences.
Researchers have been trying to explain the origin of the ammonia that triggered the formation of the first biomolecules on Earth.
It was initially thought that the early Earth's atmosphere would have freed up nitrogen to bond with other elements. But more recently, scientists have theorized that nitrogen atoms in the primordial atmosphere had a natural tendency to bond with each other, forming inert nitrogen gas N2. The bonds between the atoms in this gas are stable and strong, which makes it difficult to break the molecules down or to combine with other elements, such as hydrogen or carbon.
Under these conditions the nitrogen would not be available to bond with other elements in order to form the compounds and chains that form the building blocks of life.
"The current geochemical evidence of early Earth's atmosphere, combined with known photochemical destruction of ammonia, has left prebiotic scenarios struggling to account for a constant provision of ammonia," write Pizzarello and her co-authors.
That means scientists had to look for an alternative source.
Pizzarello and colleagues wanted to know if meteorites like "CR2 Grave Nunataks 59229" could provide an answer.
They collected powder from the meteorite, treated it with water at high temperature and pressure, and analyzed the resulting compounds.
They found the rock released compounds including hydrocarbon chains and a large amount of ammonia, which is rich in nitrogen.
This abundant release of ammonia from a carbonaceous chondrite meteorite is unprecedented, Pizzarello and colleagues write.
Chemical analysis of the nitrogen from the meteorite shows that the atomic isotope is not the same as those currently found on Earth. The researchers say that knocks out the possibility that the ammonia resulted from contamination during the experiment.
"The findings appear to trace CR2 meteorites' origin to to cosmochemical regimes where ammonia was pervasive," the authors write. That, they speculate, was the first step on the pathway to life on Earth.
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