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الاثنين، 3 سبتمبر 2012

New 1st-Time Discovery of Key Building Block for Life in the Universe

New 1st-Time Discovery of Key Building Block for Life in the Universe
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August 29, 2012 New 1st-Time Discovery of Key Building Block for Life in the Universe

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A team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has spotted sugar molecules in the gas surrounding a young Sun-like star. This is the first time sugar been found in space around such a star, and the discovery shows that the building blocks of life are in the right place, at the right time, to be included in planets forming around the star. Sugar is the common name for a range of small carbohydrates (molecules containing carbon, hydrogen and oxygen, typically with a hydrogen:oxygen atomic ratio of 2:1, as in water).

The astronomers found molecules of glycolaldehyde — a simple form of sugar [1] — in the gas surrounding a young binary star, with similar mass to the Sun, called IRAS 16293-2422. Glycolaldehyde has been seen in interstellar space before [2], but this is the first time it has been found so near to a Sun-like star, at distances comparable to the distance of Uranus from the Sun in the Solar System. This discovery shows that some of the chemical compounds needed for life existed in this system at the time of planet formation.

“In the disc of gas and dust surrounding this newly formed star, we found glycolaldehyde, which is a simple form of sugar, not much different to the sugar we put in coffee,” explains Jes Jørgensen (Niels Bohr Institute, Denmark), the lead author of the paper. “This molecule is one of the ingredients in the formation of RNA, which — like DNA, to which it is related — is one of the building blocks of life.”

Glycolaldehyde has been detected in two places in space so far — first towards the Galactic Center cloud Sgr B2, using the National Science Foundation's (NSF) 12 Meter Telescope at Kitt Peak (USA) in 2000, and with the NSF's Robert C. Byrd Green Bank Telescope (also USA) in 2004, and in the high-mass hot molecular core G31.41+0.31 using the IRAM Plateau de Bure Interferometer (France) in 2008.

“What it is really exciting about our findings is that the ALMA observations reveal that the sugar molecules are falling in towards one of the stars of the system,” says team member Cécile Favre (Aarhus University, Denmark). “The sugar molecules are not only in the right place to find their way onto a planet, but they are also going in the right direction.”

The gas and dust clouds that collapse to form new stars are extremely cold and many gases solidify as ice on the particles of dust where they then bond together and form more complex molecules. But once a star has been formed in the middle of a rotating cloud of gas and dust, it heats the inner parts of the cloud to around room temperature, evaporating the chemically complex molecules, and forming gases that emit their characteristic radiation as radio waves that can be mapped using powerful radio telescopes such as ALMA.

IRAS 16293-2422 is located around 400 light-years away, comparatively close to Earth, which makes it an excellent target for astronomers studying the molecules and chemistry around young stars. By harnessing the power of a new generation of telescopes such as ALMA, astronomers now have the opportunity to study fine details within the gas and dust clouds that are forming planetary systems.

"A big question is: how complex can these molecules become before they are incorporated into new planets? This could tell us something about how life might arise elsewhere, and ALMA observations are going to be vital to unravel this mystery,” concludes Jes Jørgensen.

The many spectacular image of the Rho Ophiuchi (oh'-fee-yu-kee) clouds at top of page highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the star Rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light. The red and yellow regions shine primarily because of emission from the nebula's atomic and molecular gas. Light from nearby blue stars knocks electrons away from the gas, which then shines when the electrons recombine with the gas.

The dark regions are caused by dust grains - born in young stellar atmospheres - which effectively block light emitted behind them. *The Rho Ophiuchi star clouds, well in front of the globular cluster M4 visible above on far lower left, are even more colorful than humans can see - the clouds emits light in every wavelength band from the radio to the gamma-ray.

The image below shows the Rho Ophiuchi star-forming region in infrared light, as seen by NASA’s Wide-field Infrared Explorer (WISE). IRAS 16293-2422 is the red object in the centre of the small square. The inset image is an artist’s impression of glycolaldehyde molecules, showing glycolaldehyde’s molecular structure (C2H4O2). Carbon atoms are shown as grey, oxygen atoms as red, and hydrogen atoms as white.

In the WISE infrared image of Rho Ophiuchi, blue and cyan represent light emitted at wavelengths of 3.4 and 4.6 micrometres, which is predominantly from stars. Green and red represent light from 12 and 22 micrometres, respectively, which is mostly emitted by dust.

This research was presented in a paper “Detection of the simplest sugar, glycolaldehyde, in a solar-type protostar with ALMA”, by Jørgensen et al., to appear in Astrophysical Journal Letters.

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The Daily Galaxy via ESO

Image Credit:ALMA (ESO/NAOJ/NRAO)/L. Calçada (ESO) & NASA/JPL-Caltech/WISE Team and top of page: Adam Block, KPNO Visitor Program, NOAO, AURA, NSF

Posted at 08:45 AM | Permalink

Comments

The idea that the building blocks of life are just a normal function of newborn stars and star systems is an amazing one. It really does make the mind run wild with the possibilities out there in a universe so vast. Simply amazing.

Posted by:Matthew |August 29, 2012 at 09:24 AM

Indeed, within the heavens and earth are signs for the believers.(Quran Surat Al Jathiya (45:3))

Have those who disbelieved not considered that the heavens and the earth were a joined entity, and We separated them and MADE FROM WATER EVERY LIVING THING?Then will they not believe? (21:30)
Mentioned 1433 years ago in the Quran the book that Jesus (peace be upon him), the prophet of Allah was taking about. Gospel of John chapter 16 verse 14-16)

Posted by:Abid Ahmad |August 30, 2012 at 03:05 PM

Indeed.

Posted by:Ruth Mc |September 01, 2012 at 08:38 AM

الثلاثاء، 28 أغسطس 2012

NASA Asks "How Did Phosphorus Become a Key Building Block of Life on Earth?"

NASA Asks "How Did Phosphorus Become a Key Building Block of Life on Earth?"
NASA Asks "How Did Phosphorus Become a Key Building Block of Life on Earth?" The Daily Galaxy --Great Discoveries Channel: Sci, Space, TechFollow the Daily Galaxy Add Daily Galaxy to igoogle page

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August 24, 2012 NASA Asks "How Did Phosphorus Become a Key Building Block of Life on Earth?"

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Phosphorus is not abundant in the universe or in molecular clouds as seen above the Lagoon nebular that create the building blocks of life, yet it is vital to life on Earth, even though our planet doesn’t provide us with very much of the element to work with. A team of astrobiologists, led by Matthew Pasek of the University of South Florida, is now studying how phosphorus biochemistry may have originated at the dawn of life. Their work is being supported by NASA’s Exobiology and Evolutionary Biology program.

Through their work, Pasek's team hopes to provide the phosphorus chemical landscape through the first two billion years of Earth's geologic history. This could help uncover when and how life came to depend so strongly on this element. "The time and mode of phosphorus entry into life is a really intriguing puzzle," says Nicholas Hud from Georgia Tech. Hud believes phosphorus may not have been one of the ingredients in the life's first recipe. "Nucleic acids, proteins and lipids all use phosphorus, but we can imagine that it was a later substitution of simpler molecules," Hud argues.

In nucleic acids, for instance, the "glue" role of phosphate could have been filled by glyoxylate, a molecule still used in life today. Hud thinks phosphorus might have started out as a trace element in a few biological processes, and only later did life realize all the potential that phosphorus has for life. "Once life developed the molecular machinery that allowed incorporation of phosphorus, and even the 'harvesting' of phosphorus, life would have moved to a higher level," Hud says. "The inclusion of phosphate likely represented a major evolutionary advance in life (if it was not there at the very beginning) and therefore is extremely important for understanding the origin and early evolution of life."

Phosphorous is scarce on the Earth, particularly at the surface, and is primarily found in some type of phosphate. Pasek’s team hopes to provide the phosphorus chemical landscape through the first two billion years of Earth’s geologic history. This could help uncover when and how life came to depend so strongly on this element.

“Once life developed the molecular machinery that allowed incorporation of phosphorus, and even the ‘harvesting’ of phosphorus, life would have moved to a higher level,” says team member Nicholas Hud of Georgia Tech. “The inclusion of phosphate likely represented a major evolutionary advance in life (if it was not there at the very beginning) and therefore is extremely important for understanding the origin and early evolution of life.”

To understand how phosphorus obtained its prominent role, scientists are modeling the early geochemical environment on Earth and in space. The most common elements in a typical cell are hydrogen, oxygen, carbon, nitrogen, phosphorus and sulfur. All of these, except phosphorus, are in the top ten of most abundant elements in the solar system. Phosphorus comes in at number 17.

"Phosphorus is the least abundant element cosmically relative to its presence in biology," says Matthew Pasek of the University of South Florida. This scarcity of phosphorus is even more acute on the Earth's surface, where much of the phosphorus is locked up in certain minerals that life has difficulty making use of. So how did life come to depend on this relatively rare element? Pasek is heading an effort to account for the possible chemical pathways that phosphorus could have taken to become available for life on the early Earth.

Can't get enough Phosphorus doesn't usually get as much attention as other essential nutrients like calcium and iron, but the element P shows up in a surprisingly wide range of biological molecules. For starters, phosphorus is an important structural element in DNA and RNA. Both of these genetic molecules have a sugar-phosphate backbone.

The phosphate (PO4) works as a kind of "super glue," since it has three oxygen atoms that will carry charges in solution. Two of these oxygen atoms form ionic bonds with two neighboring sugars, while the third oxygen is left "dangling" with a negative charge that makes the whole DNA or RNA molecule negatively charged. This overall charge helps to keep the molecule from drifting out of its proscribed location.

The backbone of standard DNA (the blue spiral ribbon-like structure in the image below) contains an alternating chain of linked phosphate and sugar molecules. Not many molecules could perform this three-charge juggling act. Arsenate is one possibility. Recently, a group of researchers claimed to have found a microbe that could use arsenate in place of phosphate, but controversy remains over this presumed discovery.

"The jury is still out over arsenate, but it's clear that phosphate is the best option when given a choice," Pasek says. Phosphate plays other roles in the cell besides that in DNA. It shows up three times in adenosine triphosphate, or ATP, which is a vital form of energy storage in cells. Many biological functions require the energy from the breakdown (or burning) of ATP, which is often called the "molecular unit of currency" in energy transfer. "The human body makes its weight in ATP each day and burns it," Pasek explains.

Phosphorus also has an important role in vertebrates, whose bones and teeth contain apatite, a highly stable phosphate mineral. Getting your vitamin P Because of its vital role, all organisms on Earth must find a source of phosphorus. Humans and other animals get their phosphorus from eating plants (or by eating animals that eat plants). Plants pull out phosphorus compounds from the soil, but a lot of this is recycled material from decaying organic matter. One of the best known molecules for carrying energy around our bodies is adenosine triphosphate (ATP).

Plants aren't able to recycle all of the available phosphorus in the soil, so some of it ends up going into the ocean through runoff. There, it can be used by marine organisms, but eventually the phosphate settles on the seafloor where it becomes incorporated into rock sediments. Once the phosphorus is locked up in insoluble minerals, it takes a very long time for it to return to a form that plants and other organisms can use. Indeed, the phosphorus cycle is one of the slowest element cycles of biological importance. Not satisfied with waiting for geological processes to free up phosphorus, humans currently spend a lot of effort mining "rock phosphate" and chemically modifying it to make fertilizer. And there's the rub for astrobiologists.

The first life forms wouldn't have had anyone to sprinkle P-rich fertilizer on them, so where did they get their phosphorus from? A different path Most of the phosphorus on the Earth's surface is found in some type of phosphate. The reason, Pasek explains, is that phosphate is the lowest energy state for P in our planet's oxygen-rich environment. But other—more reduced—phosphorus compounds exist as well. Enlarge The Phosphorus cycle.

"Reduced phosphorus is more chemically reactive than phosphate," Pasek says. This extra reactivity could have helped phosphorus sneak its way into the game of life billions of years ago. Examples of reduced phosphorus compounds include phosphides. These molecules are typically combinations of phosphorus and metals, like the zinc phosphide found in rat poison or the iron-nickel phosphide called schreibersite.

The Earth contains a lot of phosphide, but most of it is in the core, buried beneath 2,000 miles of rock. On the surface, one of the most common, naturally-occurring phosphides is schreibersite, which doesn't come from below but from above in the form of meteorites. *"We can't get out core material from Earth, but we do have access to the core material of asteroids that have broken apart to create meteorites," Pasek says.

Phosphides tend to form wherever oxygen is scarce and metals are abundant. Hence, the cores of most astronomical bodies have phosphides. Phosphides can also form when a phosphate mineral is struck by lightning or a high-energy impact. Pasek and his colleagues have studied geologic samples of phosphides, and they have found that most of the phosphides on the Earth's surface came from meteorites. Over time, much of this material has evolved to phosphates. The team estimates that 1 to 10 percent of the phosphates currently found on Earth came from meteorites.

Although phosphides and other reduced phosphorus compounds play no major part in current biology, they may have been more prominent as life struggled to make a foothold on this planet. With computer simulations, Pasek and his colleagues are modeling P-related chemistry at different time periods from the beginning of the solar system up to the early stages of life. They focus on the Earth, but they are also looking at other places besides where P chemistry may have been important, like comets and the moon Titan. They have augmented their simulations with experiments, in which schreibersite and other meteoric minerals are added to a "primordial soup" of water and organic molecules. The mixtures have produced some organo-phosphorus compounds that are similar to those found in biology.

"We have had good luck with our experiments so far," Pasek says.

The Daily Galaxy via Astrobio.net and http://astrobiology.nasa.gov/articles/life-s-first-taste-of-phosphorus/

Image credit Credit: U.S. National Library of Medicine

Posted at 06:00 AM | Permalink

Comments

Is it because of the simple role of gravity on earth? That complex chains are able to be created. Maybe I don't know what i'm talking about.

Posted by:Justin |August 24, 2012 at 06:43 AM