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Loki
02-22-2010, 06:26 PM
Space rock contains organic molecular feast (http://news.bbc.co.uk/1/hi/sci/tech/8516319.stm)

Scientists say that a meteorite that crashed into Earth 40 years ago contains millions of different carbon-containing, or organic, molecules.

http://newsimg.bbc.co.uk/media/images/47305000/jpg/_47305154_r350418-analyzing_stardust-spl.jpg

Although they are not a sign of life, such organic compounds are life's building blocks, and are a sign of conditions in the early Solar System.

It is thought the Murchison meteorite could even be older than the Sun.

The results of the meteorite study are published in the Proceedings of the National Academy of Sciences.

"We are really excited. When I first studied it and saw the complexity I was so amazed," said Philippe Schmitt-Kopplin, lead researcher on the study from the Institute for Ecological Chemistry in Neuherberg, Germany.

"Having this information means you can tell what was happening during the birth of the Solar System," Dr Schmitt-Kopplin told BBC News.

"Meteorites are like some kind of fossil. When you try to understand them you are looking back in time," he explained.

The researchers says the identification of many different chemicals shows the primordial Solar System probably had a higher molecular diversity than Earth.

The Murchison meteorite landed in a town of that name in Australia in 1969. It has been examined before by scientists looking for specific compounds but this is the first non-targeted analysis and has confirmed a huge variety of carbon-based chemicals.

A study using high resolution analytical tools including spectroscopy allowed the team to identify 14,000 different compounds.

The scientists extrapolated the number on the basis of previous analyses done on natural organic matter.

The ultra-high-resolution mass spectrometry used shows only a fraction of the compounds that exist in the material being analysed, in this case the meteorite.

However the scientists say the prior studies allow them to make a good estimate of the total number of compounds. "We were very conservative in our calculations and interpolation," said Dr Schmitt-Kopplin.

"We have to crush a few milligrams from the core of the meteorite to enable the extractions with solvents and thus we only see the extractable fraction."

Burning question

Scientists believe the Murchison meteorite could have originated before the Sun was formed, 4.65 billion years ago. The researchers say it probably passed through primordial clouds in the early Solar System, picking up organic chemicals.

Dr Schmitt-Kopplin hopes the findings might contribute to the debate over how life on Earth originated.

"I guess many people working in these fields with access to this knowledge will have some further hypothesis and will possibly be having some of their hypotheses confirmed."

"Where did we come from and what happened before? We all have that question inside us."

The team is also analysing other meteorites but say Murchison is probably the most complex they have studied.

Grey
02-22-2010, 06:33 PM
Totally thought this was going to be a thread about the genre of music. :(

Interesting nonetheless.

Lenny
03-01-2010, 09:35 AM
contains millions of different carbon-containing, or organic, molecules.
Why do we assume that life must be carbon-based? The article writer defines "organic"(life) as 'carbon-containing'.

Lenny
03-02-2010, 04:00 PM
Why do we assume that life must be carbon-based? The article writer defines "organic"(life) as 'carbon-containing'.
I was curious and came up with this:


Non-Carbon Based Life Forms
Carbon is great molecular glue—there’s not doubt about it. Just add water and you’ve got life. Well, maybe it’s not quite that simple, but carbon and water do seem to be a winning combo, at least on planet Earth. That may be why we’ve been limiting ourselves in our search for extraterrestrial life. The carbon/water combo has worked so well for our own conditions, that we simply can’t imagine anything else supporting life.

Currently, our search for extra-terrestrial life forms has been focused on planets similar to ours. The perplexing idea exists, however, that what would be death to us on Earth, may be life to other beings. What we’re looking for may not lie in our version of the “sweet spot”.

It is definitely worth considering that other options do exist besides water and carbon. Alternative biochemists speculate that there are several atoms and solvents that could potentially spawn life. It is also worth considering that because humans are carbon-based beings, who do their lab work under conditions on planet Earth, we may be a bit biased towards carbon thinking.

Not everyone is a “carbon chauvinist”, however. So far, scientists have already hypothesized several interesting alternatives to carbon. Various elements become more stable and capable of forming complex molecules when under strange (from a human perspective) thermal and atmospheric conditions. For example, silicone-based chemicals would be more stable than equivalent hydrocarbons in a sulphuric-acid-rich setting, which has been noted in some extraterrestrial environments.

Even counter-intuitive elements such as arsenic may be capable of supporting life under the right conditions. Even on Earth some marine algae incorporate arsenic into complex organic molecules such as arsenosugars and arsenobetaines. Several other small life forms use arsenic to generate energy and facilitate growth. Chlorine and sulfur are also possible elemental replacements for carbon. Sulfur is capably of forming long-chain molecules like carbon. Some terrestrial bacteria have already been discovered to survive on sulfur rather than oxygen, by reducing sulfur to hydrogen sulfide.

Nitrogen and phosphorus could also potentially form biochemical molecules. Phosphorus is similar to carbon in that it can form long chain molecules on its own, which would conceivably allow for formation of complex macromolecules. When combined with nitrogen, it can create quite a wide range of molecules, including rings.

So what about water? Isn’t at least water essential to life? Not necessarily. Ammonia, for example, has many of the same properties as water. An ammonia or ammonia-water mixture stays liquid at much colder temperatures than plain water. Such biochemistries may exist outside the conventional water-based "habitability zone". One exciting example of such a location would be Saturn's largest moon Titan.

Hydrogen fluoride methanol, hydrogen sulfide, hydrogen chloride, and formamide have all been suggested as suitable solvents that could theoretically support alternative biochemistry. All of these “water replacements” have pros and cons when considered in our terrestrial environment. What needs to be considered is that with a radically different environment, comes radically different reactions. Water and carbon might be the very last things capable of supporting life in some extreme planetary conditions. In any case, it is not beyond the realm of feasibility that our first encounter with extraterrestrial life will not be a solely carbon-based occasion. http://ufo.whipnet.org/alien.races/non-carbon.life/index.html

Birka
03-02-2010, 05:55 PM
I saw a show on the Discovery channel about this. Some scientists are now theorizing that all of the carbon on the earth came this way over billions of years, from meteorites. This had to happen before the formation of the atmosphere, so they would not have been burned up. They found some that had almost all of the amino acids needed for life as we have here on this planet.

They also theorize that huge gold deposits were formed the same way from meteorites.

Tabiti
03-03-2010, 06:30 AM
Watched on NG how amino acids actually survive even in critical conditions - heat, huge explosions.

Why do we assume that life must be carbon-based? The article writer defines "organic"(life) as 'carbon-containing'.
It's not necessary, however the life we know today is only carbon-based.