Science


Alchemical symbol for arsenic

Image via Wikipedia

After a 24-hour-long media hype, the official anonuncement came at NASA press conference. No, it’s not about “alien life” evidences recently found. At least, *not yet*. But the results of a recent research are really stunning: Life may exist elsewhere in the universe, under the circumstances we couldn’t even dream of. “Arsenic, in place of phosporus” ? Ground-breaking for sure.

Amplify’d from www.nytimes.com

Scientists said Thursday that they had trained a bacterium to eat and grow on a diet of arsenic, in place of phosphorus — one of six elements considered essential for life — opening up the possibility that organisms could exist elsewhere in the universe or even here on Earth using biochemical powers we have not yet dared to dream about.

The bacterium, scraped from the bottom of Mono Lake in California and grown for months in a lab mixture containing arsenic, gradually swapped out atoms of phosphorus in its little body for atoms of arsenic.

Scientists said the results, if confirmed, would expand the notion of what life could be and where it could be. “There is basic mystery, when you look at life,” said Dimitar Sasselov, an astronomer at the Harvard-Smithsonian Center for Astrophysics and director of an institute on the origins of life there, who was not involved in the work. “Nature only uses a restrictive set of molecules and chemical reactions out of many thousands available. This is our first glimmer that maybe there are other options.”

Felisa Wolfe-Simon, a NASA astrobiology fellow at the United States Geological Survey in Menlo Park, Calif., who led the experiment, said, “This is a microbe that has solved the problem of how to live in a different way.”

Read more at www.nytimes.com

Maxwell_Neanderthal

Image by hairymuseummatt via Flickr

This appears to be a very interesting new theory that comes with a bold (and controversial) study: 40,000 years ago the volcanoes in Europe blew the final whistle for our close relatives, the Neanderthals. The picture provided by the researchers seem consistent with the chronology, though some scholars remain unconvinced. Other theories suggest that modern humans played an important role in the demise of the Neanderthals in a variety of ways including warfare. This is, as far as I know, the first plausible theory on a “catastrophic explanation”. The study is published in the October issue of the journal “Current Anthropology”. Probably a wave of controversy will follow soon by the “orthodox academicians”.

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Illustration of Mitochondrial Eve

Image via Wikipedia

Mitochondria, the fundamental part of a cell which supplies the most of the chemical energy by generating ATP, also gives extremely valuable clues about the human genome. Since it is inherited maternally, all human beings on the earth could be traced back to an individual female lived in Africa who is called “Mitochondrial Eve” and  by the scientists. A recent study of scientists from Rice University suggests that our common “grandma” lived 200,000 years ago. Fascinating story.

Amplify’d from www.archaeologydaily.com

The most robust statistical examination to date of our species’ genetic links to “mitochondrial Eve” the maternal ancestor of all living humans confirms that she lived about 200,000 years ago.

Artist's cross section of a mitochondrion
The Rice University study was based on a side by side comparison of 10 human genetic models that each aim to determine when Eve lived using a very different set of assumptions about the way humans migrated, expanded and spread across Earth. (more…)

A brilliant archaeologist from Tel Aviv University, Prof. Yuval Goren, has developed a new tool which let archaeologists examine the millenia old clay tablets with cuneiform inscriptions and find out amazing details like “who wrote it”. Goren’s device uses X-ray to reveal hidden information about a tablet’s composition without damaging the precious ancient find itself.

Amplify’d from heritage-key.com
Unfortunately, when the Mesopotamian kings exchanged letters, written in cuneiform on small tablets made out of clay, their post offices didn’t record the sender’s return address. Yet, a more thorough look at the composition of the clay tablets can help today’s archaeologists to determine the origins of this correspondence — which can reveal a great deal about ancient rulers and civilizations.  It can offer information about the ancient trade networks, warfare, literature and political ties in the region.
Professor Yuval goren
Luckily, the medium the ancient rulers chose to correspond in, clay tablets, is composed of fine-grained materials, often less than two micrometres in size, and the exact composition differs depending on the clay’s geographical origin.  Examining chemical composition of the artefacts, rather than the texts, can tell archaeologists more about where the writings were created (or at least, where the clay was sourced) and which other tablets with similar composition they relate to.

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Since 1998, our view on Mars have been changing very fast: from a “dead planet” with “nothing interesting at all” to an exciting world that hides the mysteries of life in it.This sounds intriguing to me:

If microbes survive deep below Mars, they could be transported to the surface by water gushing up from deep underground.

Keep an eye on Mars; it seems we’ll get a series of “shocking news” very soon.

clipped from news.bbc.co.uk

White tips may be areas of freshly exposed ice

A probable active glacier has been identified for the first time on Mars.

The icy feature has been spotted in images from the European Space Agency’s (Esa) Mars Express spacecraft.
Ancient glaciers, many millions of years old, have been seen before on the Red Planet, but these ones may only be several thousand years old.
The young glacier appears in the Deuteronilus Mensae region between Mars’ rugged southern highlands and the flat northern lowlands.
“If it was an image of Earth, I would say ‘glacier’ right away,” Dr Gerhard Neukum, chief scientist on the spacecraft’s High Resolution Stereo Camera (HRSC) told BBC News.
“We have not yet been able to see the spectral signature of water. But we will fly over it in the coming months and take measurements. On the glacial ridges we can see white tips, which can only be freshly exposed ice.
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dna.jpg

Two interesting news stories on genetics: One, about creating artificial life and the other is a Nobel awarded, groundbreaking work, titled gene targeting. It’s almost certain that genetics will be the most important scientific discipline in upcoming decades, with the new possibilities and exciting new horizons appear for the humanity. Of course, bringing new “problems” and hot debates too.

Craig Venter, a U.S. scientist and researcher, claims he created an artificial chromosome in his laboratory and injected this to a living bacterial cell. The Guardian reports:

Controversial celebrity US scientist Craig Venter has announced he is on the verge of creating the first ever artificial life form which he hails as a potential remedy to illness and global warming.

Venter told Britain’s The Guardian newspaper Saturday that he has built a synthetic chromosome using chemicals made in a laboratory, and is set to announce the discovery within weeks, possibly as early as Monday.

Despite Venter’s sensational “media show”, the prospect of engineering artificial life forms is highly controversial and likely to trigger a heated debate over the ethics and potential ramifications of such an advance, think some. We’ll see what new discussions will begin in upcoming weeks. You know, scientists have an instinctive reflex to reject all the new and groundbreaking theories that come from their colleagues.

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The mystery surrounding Neanderthals continues. According to the latest studies, our relatives had reached as far as China in Asia, before being wiped off the earth. There is still controversy on how the Neanderthals disappeared. One opinion points at a sudden climate change, while another one claims (more confidently) that our ancestors destroyed them. Weather it was a “holocaust” or an “extinction” caused by climate change, one thing is becoming more and more certain with the latest studies and researches: Neanderthal race was far more wide-spread on our planet than we previously thought. The feature below was clipped from Discovery News:

clipped from dsc.discovery.com

Go East, Old Man

Oct. 1, 2007 — European Neanderthals, modern man’s ill-fated cousins who died out mysteriously some 28,000 years ago, migrated much further east than previously thought, according to a study released Sunday.
Remains from the slope-browed hominid have previously been found over an area stretching from Spain to Uzbekistan, but the new study extends the eastern boundary of their wanderings another 1,250 miles deep into southern Siberia, just above the western tip of what is today China.
The fossils underpinning the study are not new, but the techniques used to analyze them are.
Geneticist Svante Paabo of the Max Planck Institute for Evolutionary Anthropology and colleagues compared mitochondrial DNA (mtDNA) sequences from bones found from two sites — one in Teshik Tash, Uzbekistan and the other from the Altai Mountains in Siberia — with those of specimens from different European sites.

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