Tag: Hydrogen (page 2 of 4)

Could Saturn’s moon Titan host an alternate type of life?

March 5, 2015 / / 0 Comments


Titan


Excerpt from mashable.com

In a world first, chemical engineers have taken a different look at a question astronomers and biologists have been pondering for decades: Does Saturn moon Titan host life?

Of course, Titan is way too hostile for life as we know it to eke out an existence — it is a frigid world awash with liquid methane and ethane and a noxious atmosphere devoid of any liquid water. But say if there is a different kind of biology, a life as we don't know it, thriving on the organic chemistry that is abundant on Titan's surface?

Normally, astrobiologists combine what we know about Earth's biosphere and astronomers zoom in on other stars containing exoplanets in the hope that some of those alien world have some similarities to Earth. By looking for small rocky exoplanets orbiting inside their star's habitable zones, we are basically looking for a "second Earth" where liquid water is at least possible. Where there's liquid water on Earth, there's inevitably life, so scientists seeking out alien life 'follow the water' in the hope of finding life with a similar terrestrial template on other planets.

Titan, however, does not fall into this category, it is about as un-Earth-like as you can get. So, chemical molecular dynamics expert Paulette Clancy and James Stevenson, a graduate student in chemical engineering, from Cornell University, Ithaca, New York, have looked at Titan in a different light and created a theoretical model of a methane-based, oxygen-free life form that could thrive in that environment.

There is no known template for this kind of life on Earth, but the researchers have studied what chemicals are in abundance on Titan and worked out how a very different kind of life could be sparked.

As a collaborator on the NASA/ESA Cassini-Huygens mission, Lunine, professor in the Physical Sciences in the College of Arts and Sciences’ Department of Astronomy, has been fascinated with the possibility of methane-based life existing on Titan for some time, so he joined forces with Clancy and Stevenson to see what this hypothetical life form might look like.

In their research published in the journal Science Advances on Feb. 27, Clancy and Stevenson focused on building a cell membrane "composed of small organic nitrogen compounds and capable of functioning in liquid methane temperatures of 292 degrees below zero (Fahrenheit; or 94 Kelvin)," writes a Cornell press release. On Earth, water-based molecules form phospholipid bilayer membranes that give cells structure, housing organic materials inside while remaining permeable. On Titan, liquid water isn't available to build these cell membranes.

"We're not biologists, and we're not astronomers, but we had the right tools," said Clancy, lead researcher of the study. "Perhaps it helped, because we didn't come in with any preconceptions about what should be in a membrane and what shouldn't. We just worked with the compounds that we knew were there and asked, 'If this was your palette, what can you make out of that?'"

The researchers were able to model the ideal cell that can do all the things that life can do (i.e. support metabolism and reproduction), but constructed it from nitrogen, carbon and hydrogen-based molecules that are known to exist in Titan's liquid methane seas. This chemical configuration gives this theoretical alien cell stability and flexibility in a similar manner to Earth life cells.
"The engineers named their theorized cell membrane an 'azotosome,' 'azote' being the French word for nitrogen. 'Liposome' comes from the Greek 'lipos' and 'soma' to mean 'lipid body;' by analogy, 'azotosome' means 'nitrogen body.'" — Cornell
"Ours is the first concrete blueprint of life not as we know it," said lead author Stevenson, who also said that he was inspired, in part, by Isaac Asimov, who wrote the 1962 essay "Not as We Know It" about non-water-based life.

Having identified a possible type of cell membrane chemistry that functions in the Titan environment as a cell on Earth might, the next step is to model how such a hypothetical type of biology would function on Titan. In the long run, we might also be able to model what kinds of observable indicators we should look for that might reveal that alien biology's presence.

That way, should a mission be eventually sent to Titan's seas, sampling the chemical compounds in the soup of organics may reveal a biology of a very alien nature.
Scientists have been trying to know if life could exist on Titan, the largest moon of Saturn. According to scientists, there are possibilities that life could survive amidst methane-based lakes of Titan. After conducting many studies, they have found signs of life on Titan, but the scientists also said that life will not be like life on earth.
As per some scientific reports, Titan is the only object other than earth which has clear evidence of stable bodies of surface liquid. Like earth, the moon has mountains, islands, lakes and storms, but it doesn’t have oxygen, which is a major element to support life. It means that only oxygen-free and methane-based can exist on Titan.
According to lead researcher Paulette Clancy, “We didn’t come in with any preconceptions about what should be in a membrane and what shouldn’t. We just worked with the compounds that, we knew were there and asked, ‘If this was your palette, what can you make out of that”.
Clancy said although they are not biologists or astronomers, they had the right tools to find life on Saturn’s largest moon. Adding to that, the researchers didn’t know what should be in a membrane and what should be not. They worked with compounds and found that life can exist on Titan, but would be very different from earth’s life, Clancy added.
According to reports, the researchers had used a molecular dynamics method to know about Titan. They screened for suitable candidate compounds from methane for self-assembly into membrane-like structures. As per the researchers, the most promising compound they discovered was an acrylonitrile azotosome, which is present in the atmosphere of Titan.
As per the researchers, acrylonitrile has shown good stability and flexibility similar to that of phospholipid membranes on Earth. It means that the Saturn largest has atmosphere and conditions to support life in a different way than earth.
- See more at: http://perfscience.com/content/2141391-life-titan-would-be-different-earth#sthash.2Kqc3Ewf.dpuf

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NASA creates ingredients of life in harsh simulated space conditions

March 5, 2015 / / 0 Comments


The machine NASA scientists used to zap out three components of our hereditary material from a chunk of ice.


Excerpt from cnet.com

 We know a whole lot about life on our planet, but one mystery persists: how it got here.

NASA scientists working at the Ames Astrochemistry Laboratory in California and the Goddard Space Flight Center in Maryland may have just found a clue to that mystery. They've determined that some of the chemical components of our DNA can be produced in the harsh crucible of space.


To reach their conclusion, they created a chunk of ice in their lab containing molecules known as pyrimidine. These molecules, which consist of carbon and nitrogen, form the core of three chemicals found in DNA and RNA, the genetic composition of all Earth-based life.

Pyrimidine is also found on meteorites, which prompted the researchers to explore how it reacts when frozen in water in space.
So they put their chunk of ice in a machine that reproduces the vacuum of space, along with temperatures around -430°F and harsh radiation created by high-energy ultraviolet (UV) photons from a hydrogen lamp.

They found that not only could the pyrimidine molecules survive these brutal conditions, but the radiation actually morphed some of them into three chemical components found in DNA and RNA: uracil, cytosine and thymine. 

"We are trying to address the mechanisms in space that are forming these molecules," Christopher Materese, a NASA researcher working on these experiments, said in a statement. "Considering what we produced in the laboratory, the chemistry of ice exposed to ultraviolet radiation may be an important linking step between what goes on in space and what fell to Earth early in its development."
Added Scott Sandford, a space science researcher at Ames, "Our experiments suggest that once the Earth formed, many of the building blocks of life were likely present from the beginning. Since we are simulating universal astrophysical conditions, the same is likely wherever planets are formed."

While this research might help fill in a piece of the puzzle of our cosmic origins, another mystery remains. Scientists don't exactly know where meteoric pyrimidine comes from in the first place, although they theorize that it could arise when giant red stars die. And the search continues...

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Mars Had an Ocean, Scientists Say, Pointing to a Treasure Trove of New Data

March 5, 2015 / / 0 Comments





Excerpt from nytimes.com

After six years of planetary observations, scientists at NASA say they have found convincing new evidence that ancient Mars had an ocean.

It was probably the size of the Arctic Ocean, larger than previously estimated, the researchers reported on Thursday. The body of water spread across the low-lying plain of the planet’s northern hemisphere for millions of years, they said.

If confirmed, the findings would add significantly to scientists’ understanding of the planet’s history and lend new weight to the view that ancient Mars had everything needed for life to emerge.
“The existence of a northern ocean has been debated for decades, but this is the first time we have such a strong collection of data from around the globe,” said Michael Mumma, principal investigator at NASA’s Goddard Center for Astrobiology and an author of the report, published in the journal Science. “Our results tell us there had to be a northern ocean.”
But other experts said the question was hardly resolved. The ocean remains “a hypothesis,” said Ashwin Vasavada, project scientist of the Curiosity rover mission at the Jet Propulsion Laboratory in Pasadena, Calif.

Dr. Mumma and Geronimo Villanueva, a planetary scientist at NASA, measured two slightly different forms of water in Mars’ atmosphere. One is the familiar H2O, which consists of two hydrogen atoms and one oxygen atom.

The other is a slightly “heavier” version of water, HDO, in which the nucleus of one hydrogen atom contains a neutron. The atom is called deuterium.

The two forms exist in predictable ratios on Earth, and both have been found in meteorites from Mars. A high level of heavier water today would indicate that there was once a lot more of the “lighter” water, somehow lost as the planet changed.

The scientists found eight times as much deuterium in the Martian atmosphere than is found in water on Earth. Dr. Villanueva said the findings “provide a solid estimate of how much water Mars once had by determining how much water was lost to space.”

He said the measurements pointed to an ancient Mars that had enough water to cover the planet to a depth of at least 137 meters, or about 450 feet. Except for assessments based on the size of the northern basin, this is the highest estimate of the amount of water on early Mars that scientists have ever made.

The water on Mars mostly would have pooled in the northern hemisphere, which lies one to three kilometers — 0.6 to 1.8 miles — below the bedrock surface of the south, the scientists said.
At one time, the researchers estimated, a northern ocean would have covered about 19 percent of the Martian surface. In comparison, the Atlantic Ocean covers about 17 percent of Earth’s surface.

The new findings come at a time when the possibility of a northern ocean on Mars has gained renewed attention.

The Curiosity rover measured lighter and heavier water molecules in the Gale Crater, and the data also indicated that Mars once had substantial amounts of water, although not as much as Dr. Mumma and Dr. Villanueva suggest.

“The more water was present — and especially if it was a large body of water that lasted for a longer period of time — the better the chances are for life to emerge and to be sustained,” said Paul Mahaffy, chief of the atmospheric experiments laboratory at the Goddard Space Flight Center.

Just last month, the science team running the Curiosity rover held its first formal discussion about the possibility of such an ocean and what it would have meant for the rest of Mars.

Scientists generally agree that lakes must have existed for millions of years in Gale Crater and elsewhere. But it is not clear how they were sustained and replenished.

“For open lakes to remain relatively stable for millions of years — it’s hard to figure how to do that without an ocean,” Dr. Vasavada said. “Unless there was a large body of water supplying humidity to the planet, the water in an open lake would quickly evaporate and be carried to the polar caps or frozen out.”

Yet climate modelers have had difficulty understanding how Mars could have been warm enough in its early days to keep water from freezing. Greenhouse gases could have made the planet much warmer at some point, but byproducts of those gases have yet to be found on the surface.

James Head, a professor of geological sciences at Brown University, said in an email that the new paper had “profound implications for the total volume of water” on ancient Mars.

But, he added, “climate models have great difficulty in reconstructing an early Mars with temperatures high enough to permit surface melting and liquid water.”

Also missing are clear signs of the topographic and geological features associated with large bodies of water on Earth, such as sea cliffs and shorelines.

Based on low-resolution images sent back by the Viking landers, the geologist Timothy Parker and his colleagues at the NASA Jet Propulsion Lab reported in 1989 the discovery of ancient shorelines. But later high-resolution images undermined their conclusions.

Still, Dr. Parker and his colleagues have kept looking for — and finding, they say — some visible signs of a northern ocean. The new data “certainly encourages me to do more,” he said in an interview.

Other researchers have also been looking for signs of an ancient ocean.

In 2013, Roman DiBiase, then a postdoctoral student at the California Institute of Technology, and Michael Lamb, an assistant professor of geology there, identified what might have been a system of channels on Mars that originated in the southern hemisphere and emptied steeply into the northern basin — perhaps, they said, water flowing through a delta to an ocean.

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Astronomers find star speeding out of the galaxy

March 5, 2015 / / 0 Comments





(Reuters) - Astronomers have found a star hurtling through the galaxy faster than any other, the result of being blasted away by the explosion of a massive partner star, researchers said on Thursday.
The star, known as US 708, is traveling at about 746 miles (1,200 km) per second, fast enough to actually leave the Milky Way galaxy in about 25 million years, said astronomer Stephan Geier with Germany-based European Southern Observatory, which operates three telescopes in Chile.

"At that speed you could travel from Earth to the moon in five minutes," noted University of Hawaii astronomer Eugene Magnier.
US 708 is not the first star astronomers have found that is moving fast enough to escape the galaxy, but it is the only one so far that appears to have been slingshot in a supernova explosion.

The 20 other stars discovered so far that are heading out of the galaxy likely got their impetus from coming too close to the supermassive black hole that lives at the center of the Milky Way, scientists report in an article in this week’s edition of the journal Science.

Before it was sent streaming across the galaxy, US 708 was once a cool giant star, but it was stripped of nearly all of its hydrogen by a closely orbiting partner. Scientists suspect it was this feeding that triggered the partner’s detonation.

If confirmed, these types of ejected stars may provide more insight into how supernova explosions occur. Since the explosions give off a fairly standard amount of radiation, scientists can calculate their distances by measuring how bright or dim they appear and determine how fast the universe is expanding.

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Strange find on Titan sparks chatter about life

March 2, 2015 / / 0 Comments


Titan


Excerpt from nbcnews.com

Studies may suggest methane-based organic processes ... but maybe not  
New findings have roused a great deal of hoopla over the possibility of life on Saturn's moon Titan, which some news reports have further hyped up as hints of extraterrestrials.
However, scientists also caution that aliens might have nothing to do with these findings.

All this excitement is rooted in analyses of chemical data returned by NASA's Cassini spacecraft. One study suggested that hydrogen was flowing down through Titan's atmosphere and disappearing at the surface. Astrobiologist Chris McKay at NASA's Ames Research Center speculated that this could be a tantalizing hint that hydrogen is getting consumed by life.

"It's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," McKay said.

Another study investigating hydrocarbons on Titan's surface found a lack of acetylene, a compound that could be consumed as food by life that relies on liquid methane instead of liquid water to live.
"If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth," McKay said.
However, NASA scientists caution that aliens might not be involved at all.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," said Mark Allen, principal investigator with the NASA Astrobiology Institute Titan team. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results."
McKay told Space.com that "both results are still preliminary."

To date, methane-based life forms are only speculative, with McKay proposing a set of conditions necessary for these kinds of organisms on Titan in 2005. Scientists have not yet detected this form of life anywhere, although there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product. 

On Titan, where temperatures are around minus-290 degrees Fahrenheit (-179 degrees Celsius), any organisms would have to use a substance that is liquid as its medium for living processes. Water itself cannot do, because it is frozen solid on Titan's surface. The list of liquid candidates is very short — liquid methane and related molecules such as ethane. Previous studies have found Titan to have lakes of liquid methane.

Missing hydrogen? 

The dearth of hydrogen Cassini detected is consistent with conditions that could produce methane-based life, but do not conclusively prove its existence, cautioned researcher Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore. Strobel wrote the paper on hydrogen appearing online in the journal Icarus.

Strobel looked at densities of hydrogen in different parts of the atmosphere and at the surface. Previous models from scientists had predicted that hydrogen molecules, a byproduct of ultraviolet sunlight breaking apart acetylene and methane molecules in the upper atmosphere, should be distributed fairly evenly throughout the atmospheric layers.

Strobel's computer simulations suggest a hydrogen flow down to the surface at a rate of about 10,000 trillion trillion molecules per second. 

"It's as if you have a hose and you're squirting hydrogen onto the ground, but it's disappearing," Strobel said. "I didn't expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should 'float' to the top of the atmosphere and escape."

Strobel said it is not likely that hydrogen is being stored in a cave or underground space on Titan. An unknown mineral could be acting as a catalyst on Titan's surface to help convert hydrogen molecules and acetylene back to methane.

Although Allen commended Strobel, he noted "a more sophisticated model might be needed to look into what the flow of hydrogen is."

Consumed acetylene? 

Scientists had expected the sun's interactions with chemicals in the atmosphere to produce acetylene that falls down to coat Titan's surface. But when Cassini mapped hydrocarbons on Titan's surface, it detected no acetylene on the surface, according to findings appearing online in the Journal of Geophysical Research.

Instead of alien life on Titan, Allen said one possibility is that sunlight or cosmic rays are transforming the acetylene in icy aerosols in the atmosphere into more complex molecules that would fall to the ground with no acetylene signature.

In addition, Cassini detected an absence of water ice on Titan's surface, but loads of benzene and another as-yet-unidentified material, which appears to be an organic compound. The researchers said that a film of organic compounds is covering the water ice that makes up Titan's bedrock. This layer of hydrocarbons is at least a few millimeters to centimeters thick, but possibly much deeper in some places. 

"Titan's atmospheric chemistry is cranking out organic compounds that rain down on the surface so fast that even as streams of liquid methane and ethane at the surface wash the organics off, the ice gets quickly covered again," said Roger Clark, a Cassini team scientist based at the U.S. Geological Survey in Denver. "All that implies Titan is a dynamic place where organic chemistry is happening now."

All this speculation "is jumping the gun, in my opinion," Allen said.

"Typically in the search for the existence of life, one looks for the presence of evidence -- say, the methane seen in the atmosphere of Mars, which can't be made by normal photochemical processes," Allen added. "Here we're talking about absence of evidence rather than presence of evidence — missing hydrogen and acetylene — and oftentimes there are many non-life processes that can explain why things are missing."

These findings are "still a long way from evidence of life," McKay said. "But it could be interesting."

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Rare doomed planet with extreme seasons discovered

February 25, 2015 / / 0 Comments


Kepler432b.jpg
Illustration provided by the University of Heidelberg of the orbit of Kepler-432b (inner, red) in comparison to the orbit of Mercury around the Sun (outer, orange). The red dot in the middle indicates the position of the star around which the planet is orbiting. The size of the star is shown to scale, while the size of the planet has been magnified ten times for illustration purposes. (Graphic: Dr. Sabine Reffert)


Excerpt from foxnews.com/science


A rare planet has been discovered, and it doesn’t seem like a stop anyone would want to make on an intergalactic cruise. Found by two research teams independently of each other, Kepler-432b is extreme in its mass, density, and weather. Roughly the same size of Jupiter, the planet is also doomed- in 200 million years it will be consumed by its sun. “Kepler-432b is definitively a rarity among exoplanets around giant stars: it is a close-in gas-giant planet orbiting a star whose radius is 'quickly' increasing,” Davide Gandolfi, from the Landessternwarte Koenigstuhl (part of the Centre for Astronomy of the University of Heidelberg), told FoxNews.com. “The orbit of the planet has a radius of about 45 million kilometers [28 million miles] (as a reference point, the Earth-Sun distance is about 150 million kilometers [93.2 Million miles]), while most of the planets known to orbit giant stars have wider orbits. The stellar radius is already 3 million kilometers [almost 2 million miles] (i.e., about 4 times the Sun radius) and in less than 200 million years it will be large enough for the star to swallow up its planet.”

Gandolfi, a member of one of the research groups who discovered the rare planet, explains that much like Jupiter, Kepler-432b is a gas-giant celestial body composed mostly of hydrogen and helium, and is most likely to have a dense core that accounts for 6 percent or less of the planet’s mass. “The planet has a mass six times that of Jupiter, but is about the same size!” he says. “This means that it is not one of the largest planets yet discovered: it is one of the most massive!” The planet’s orbit brings it extremely close to its host star on some occasions, and very far away at others, which creates extreme seasonal changes. In its year - which lasts 52 Earth days - winters can get a little chilly and summers a bit balmy, to say the least. According to Gandolfi, “The highly eccentric orbit brings Kepler-432b at ‘only’ 24 million kilometers [15 million miles] from its host star, before taking it to about three times as far away. This creates large temperature excursions over the course of the planet year, which is of only 52 Earth days. During the winter season, the temperature on Kepler-432b drops down to 500 degrees Celsius [932 degrees Fahrenheit], whereas in summer it can goes up to nearly 1000 degrees Celsius [1832 degrees Fahrenheit].”

Then again, if you are crazy enough to visit Kepler-432b, you’d better do it fast. As stated before, its host star is set to swallow the planet whole in 200 million years, making the celestial body a rare find. “The paucity of close-in planets around giant stars is likely to be due to the fact that these planets have been already swallowed up by their host stars,” Gandolfi says. “Kepler-432b has been discovered ‘just in time before dinner!” The host star, which is red and possesses 1.35 times the mass of our sun, has partly exhausted the nuclear fuel in its core, and is slowly expanding, eventually growing large enough to swallow Kepler-432b. According to Gandolfi, this is a natural progression for all stars. “Stars first generate nuclear energy in their core via the fusion of Hydrogen into Helium,” he explained. “At this stage, their radii basically do not change much. This is because the outward thermal pressure produced by the nuclear fusion in the core is balanced by the inward pressure of gravitational collapse from the overlying layers. In other words, the nuclear power is the star pillar! Our Sun is currently ‘burning’ hydrogen in its core (please note that I used quotes: ‘burning’ does not mean a chemical reaction- we are talking about nuclear fusion reaction). However, this equilibrium between the two pressures does not last forever. Helium is heavier than hydrogen and tends to sink. The stellar core of the Kepler-432b's host star is currently depleted of hydrogen and it is mainly made of inert helium. The star generates thermal energy in a shell around the core through the nuclear fusion of hydrogen into helium. As a result of this, the star expands and cools down. This is why we call it ‘red giant’- the reddish color comes from the fact that the external layers of the atmosphere of the star are cooling down because they expand.”

Both research teams (the other was from the Max Planck Institute for Astronomy in Heidelberg) used Calar Alto Observatory’s 7.2- foot telescope in Andalucia, Spain. The planet was also studied by Landessternwarte Koenigstuhl researchers using the 8.5-foot Nordic Optical Telescope on La Palma, which is located in Spain’s Canary Islands.

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‘Firefly’ Starship to Blaze a Trail to Alpha Centauri?

February 21, 2015 / / 0 Comments

The Icarus Interstellar 'Firefly' starship concept could use novel nuclear fusion techniques to power its way to Alpha Centauri within 100 years.Adrian MannExcerpt from news.discovery.com As part of Icarus Interstellar's continuing series ...

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Was this Star Nibiru? Scientists Discover Star Made Closest Approach to Our Solar System 70,000 Years Ago

February 17, 2015 / / 0 Comments


Astronomers identify the closest known flyby of a star to our solar system Photo Credit: Flickr


Excerpt from americanlivewire.com

A low-mass red dwarf star passed through the outer Oort Cloud 70,000 years back in the closest approach made by any star into our system, discovers a team of researchers from various countries.

Lying in the constellation Monoceros and known as Scholtz’s star, it is a part of a binary system and has 8% the mass of the sun. Its companion, a brown dwarf, is said to have 6%.
The lowest end of the stellar spectrum, brown dwarfs are larger than gas giants but not as much so as to sustain hydrogen fusion for a larger period of time.

Due to its faint appearance, Scholtz’s star was discovered only a year ago by astronomer Ralf Dieter-Scholz in Potsdam, Germany, through the use of NASA’s WISE (Wide Field Infrared Survey Explorer), which mapped the entire sky in infrared during the years 2010 and 2011.

At the same time, the radial velocity of the star depicted that it was moving away from the solar system much faster than expected.
These motions led the researchers to conclude that either the star is headed toward our system, or moving away from it.

After analyzing the data, Mamajek concluded, “…The radial velocity measurements were consistent with it running away from the Sun’s vicinity–and we realized it must have had a close flyby in the past.”

Through the use of computer models, it was seen that the star passed about 5 trillion miles from our solar system around 70,000 years ago.

Mamajek and his team are 98 percent certain Scholtz’s star traveled through the outer Oort Cloud.

Although Scholtz’s star is 10th magnitude, too dim to be seen with the naked eye, it is magnetically active, which can cause it to flare at times and become significantly brighter. If this happened during its close approach to our solar system, prehistoric humans might have actually seen it.

The researchers published their findings in Astrophysical Journal Letters.

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Mysterious Galaxy X Found Finally? Dark Matter Hunters Would Like To Believe So

February 17, 2015 / / 0 Comments

Excerpt from techtimes.comAstronomers have long suspected strange ripples in hydrogen gas in the disk of our Milky Way galaxy are caused by the gravity of an unseen dwarf galaxy dominated by dark matter -- and now they think they've found this "Gal...

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ALMA uncovers stellar nurseries in the Sculptor Galaxy, 11.5 million light years from home

February 17, 2015 / / 0 Comments



ALMA uncovers stellar nurseries in the Sculptor Galaxy, 11.5 million light years from home
The Sculptor Galaxy


Excerpt from sciencerecorder.com

Starburst galaxies are named for their ability to convert gasses rapidly into new stars, at an accelerated speed that can sometimes be 1,000 times more rapid than your average spiral galaxy, such as the Milky Way. Why the disparity? In order to further investigate the reason that some galaxies seem to “burst” into being, whereas others take the better part of a few billion years, an international team of astronomers analyzed a cluster of star-forming gas clouds in the heart of NGC 253 – the Sculptor Galaxy, with the aid of the Atacama Large Millimeter/submillimeter Array (ALMA). The Sculptor Galaxy is among starburst galaxies closest to the Milky Way.

“All stars form in dense clouds of dust and gas,” said Adam Leroy, in an interview with Astronomy magazine. Leroy is an astronomer at Ohio State University in Columbus. “Until now, however, scientists struggled to see exactly what was going on inside starburst galaxies that distinguished them from other star-forming regions.”

Therefore, Leroy and his colleagues turn to the ALMA which is capable of examining star changing structures even in systems as distant as Sculptor. Already, they have successfully charted distribution and movement of various molecules within several clouds located at the Sculptor Galaxy’s core.

Because NGC 253, which is disk-shaped, is in the stages of a very intense starburst and located approximately 11.5 million light-years from home, it is the perfect target for study. ALMA picks it up with remarkable precision and resolution, so much so that the team was able to isolate and identify ten different stellar ‘nurseries,’ in which stars were in the process of forming. To appreciate the magnitude of this feat, it would have been impossible with previous telescopes, which blurred the regions together into one glow. 

“There is a class of galaxies and parts of galaxies, we call them starbursts, where we know that gas is just plain better at forming stars,” said Leroy. “To understand why, we took one of the nearest such regions and pulled it apart — layer by layer — to see what makes the gas in these places so much more efficient at star formation.”

More importantly, they recognized the distribution of several 40 millimeter-wavelength “signatures,” that given off by various molecules at the center of Sculptor Galaxy, signaling that a number of conditions were responsible for the development of these stars. This accounts for the diversity of the states of different stars corresponding to where they are found in star-forming clouds. One important compound, all too familiar and unwelcome on Earth, carbon monoxide (CO), correlates with massive envelopes of gases that are less dense within the stellar nurseries. Others, such as hydrogen cyanide (HCN), were present in the more dense reaches of active star formation. The rarer the molecules, for example, H13CN and H13CO+, suggest regions that are even denser.

Indeed, when the data was compared, researchers found that the gas clouds of the Sculptor Galaxy were ten times denser than those found in spiral galaxies, suggesting that because the clouds are so tightly packed, they can form star clusters much more rapidly than the Milky Way. At the same time, they give us further insight as to how stars are born, showing us the physical changes along the way, allowing astronomers a working model to compare with our own galaxy. 

“These differences have wide-ranging implications for how galaxies grow and evolve,” concluded Leroy. “What we would ultimately like to know is whether a starburst like Sculptor produces not just more stars, but different types of stars than a galaxy like the Milky Way. ALMA is bringing us much closer to that goal.”

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Stephen Hawking warns that attempting to contact aliens could invite disaster

February 13, 2015 / / 0 Comments

Excerpt from cambridge-news.co.ukWhat is known as Active Seti will be under serious discussion this week at the annual meeting of the American Association for the Advancement of Science (AAAS) in San Jose, California. Seti spokesman Dr Seth...

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A ‘bionic leaf’ that turns sunlight into fuel

February 11, 2015 / / 0 Comments


Excerpt from cnbc.com

By Robert Ferris



The invention could pave the way for numerous innovations—by converting solar power into biofuels, it may help solve the vexing difficulty of storing unused solar energy, which is one of the most common criticisms of solar power as a viable energy source.
The process could also help make plastics and other chemicals and substances useful to industry and research.


The current experiment builds on previous research led by Harvard engineer Daniel Nocera, who in 2011 demonstrated an "artificial leaf" device that uses solar power to generate usable energy. 

Nocera's original invention was a wafer-like electrode suspended in water. When a current runs through the electrode from a power source such as a solar panel, for example, it causes the water to break down into its two components: hydrogen and oxygen. 

Nocera's device garnered a lot of attention for opening up the possibility of using sunlight to create hydrogen fuel—once considered a possible alternative to gasoline. 

But hydrogen has not taken off as a fuel source, even as other alternative energy sources survive and grow amid historically low oil prices. Hydrogen is expensive to transport, and the costs of adopting and distributing hydrogen are high. A gas station owner could more easily switch a pump from gasoline to biofuel, for example.


Now, Nocera and a team of Harvard researchers figured out how to use the bionic leaf to make a burnable biofuel, according to a study published Monday in the journal PNAS. The biologists on the team genetically modified a strain of bacteria that consumes hydrogen and produces isopropanol—the active ingredient in rubbing alcohol. In doing so, they successfully mimicked the natural process of photosynthesis—the way plants use energy from the sun to survive and grow.

 This makes two things possible that have always been serious challenges for alternative energy space—solar energy can be converted into a storable form of energy, and the hydrogen can generate a more easily used fuel.
To be sure, the bionic leaf developments are highly unlikely to replace fossil fuels such as oil and natural gas any time soon—especially as the prices of both are currently so low. But it could be a good supplemental source. 

"One idea Dan [Nocera] and I share, which might seem a little wacky, is personalized energy" that doesn't rely on the power grid, biochemist Pamela Silver, who participated in the study, told CNBC in a telephone interview. 
Typically, people's energy needs are met by central energy production facilities—they get their electricity from the power grid, which is fed by coal- or gas-burning power plants, or solar farms, for example. Silver said locally produced energy could be feasible in developing countries that lack stable energy infrastructure, or could even appeal to people who choose to live off the grid.

"Instead of having to buy and store fuel, you can have your bucket of bacteria in your backyard," Silver said. 

Besides, the experiment was an attempt at proof-of-concept—the scientists wanted to demonstrate what could be done, Silver said. Now that they have mastered this process, further possibilities can be explored.  

 "No insult to chemists, but biology is the best chemist there is, so we don't even know what we can make," said Silver. "We can make drugs, materials—we are just at the tip of the iceberg." 

The team hopes to develop many different kinds of bacteria that can produce all sorts of substances. That would mean, potentially at least, setting up the bionic leaf device and then plugging in whatever kind of bacteria might be needed at the moment.

For now, they want to increase the efficiency of the device, which is already much more efficient at photosynthesizing than plants are. Then they will focus on developing other kinds of bacteria to plug into the device.

"The uber goal, which is probably 20 years out," Silver said, "is converting the commodity industry away from petroleum."

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Planck telescope puts new datestamp on first stars

February 10, 2015 / / 0 Comments


Polarisation of the sky
Planck has mapped the delicate polarisation of the CMB across the entire sky



Excerpt from bbc.com

Scientists working on Europe's Planck satellite say the first stars lit up the Universe later than previously thought.

The team has made the most precise map of the "oldest light" in the cosmos.

Earlier observations of this radiation had suggested the first generation of stars were bursting into life by about 420 million years after the Big Bang.

Planck's data indicates this great ignition was well established by some 560 million years after it all began.

"This difference of 140 million years might not seem that significant in the context of the 13.8-billion-year history of the cosmos, but proportionately it's actually a very big change in our understanding of how certain key events progressed at the earliest epochs," said Prof George Efstathiou, one of the leaders of the Planck Science Collaboration.

Subtle signal

The assessment is based on studies of the "afterglow" of the Big Bang, the ancient light called the Cosmic Microwave Background (CMB), which still washes over the Earth today.
Prof George Efstathiou: "We don't need more complicated explanations"

The European Space Agency's (Esa) Planck satellite mapped this "fossil" between 2009 and 2013.

It contains a wealth of information about early conditions in the Universe, and can even be used to work out its age, shape and do an inventory of its contents.

Scientists can also probe it for very subtle "distortions" that tell them about any interactions the CMB has had on its way to us.

Forging elements

One of these would have been imprinted when the infant cosmos underwent a major environmental change known as re-ionisation.

Prof Richard McMahon: "The two sides of the bridge now join"
It is when the cooling neutral hydrogen gas that dominated the Universe in the aftermath of the Big Bang was then re-energised by the ignition of the first stars.

These hot giants would have burnt brilliant but brief lives, producing the very first heavy elements. But they would also have "fried" the neutral gas around them - ripping electrons off the hydrogen protons.

And it is the passage of the CMB through this maze of electrons and protons that would have resulted in it picking up a subtle polarisation.

ImpressionImpression: The first stars would have been unwieldy behemoths that burnt brief but brilliant lives


The Planck team has now analysed this polarisation in fine detail and determined it to have been generated at 560 million years after the Big Bang.

The American satellite WMAP, which operated in the 2000s, made the previous best estimate for the peak of re-ionisation at 420 million years. 

The problem with that number was that it sat at odds with Hubble Space Telescope observations of the early Universe.

Hubble could not find stars and galaxies in sufficient numbers to deliver the scale of environmental change at the time when WMAP suggested it was occurring.

Planck's new timing "effectively solves the conflict," commented Prof Richard McMahon from Cambridge University, UK.

"We had two groups of astronomers who were basically working on different sides of the problem. The Planck people came at it from the Big Bang side, while those of us who work on galaxies came at it from the 'now side'. 

"It's like a bridge being built over a river. The two sides do now join where previously we had a gap," he told BBC News.

That gap had prompted scientists to invoke complicated scenarios to initiate re-ionisation, including the possibility that there might have been an even earlier population of giant stars or energetic black holes. Such solutions are no longer needed.

No-one knows the exact timing of the very first individual stars. All Planck does is tell us when large numbers of these stars had gathered into galaxies of sufficient strength to alter the cosmic environment. 

By definition, this puts the ignition of the "founding stars" well before 560 million years after the Big Bang. Quite how far back in time, though, is uncertain. Perhaps, it was as early as 200 million years. It will be the job of the next generation of observatories like Hubble's successor, the James Webb Space Telescope, to try to find the answer.

JWSTBeing built now: The James Webb telescope will conduct a survey of the first galaxies and their stars
line
The history of the Universe

Graphic of the history of time
  • Planck's CMB studies indicate the Big Bang was 13.8bn years ago
  • The CMB itself can be thought of as the 'afterglow' of the Big Bang
  • It spreads across the cosmos some 380,000 years after the Big Bang
  • This is when the conditions cool to make neutral hydrogen atoms
  • The period before the first stars is often called the 'Dark Ages'
  • When the first stars ignite, they 'fry' the neutral gas around them
  • These giants also forge the first heavy elements in big explosions
  • 'First Light', or 'Cosmic Renaissance', is a key epoch in history
line

The new Planck result is contained in a raft of new papers just posted on the Esa website. 

These papers accompany the latest data release from the satellite that can now be used by the wider scientific community, not just collaboration members.
Dr Andrew Jaffe: "The simplest models for inflation are ruled out"
Two years ago, the data dump largely concerned interpretations of the CMB based on its temperature profile. It is the CMB's polarisation features that take centre-stage this time.
It was hoped that Planck might find direct evidence in the CMB's polarisation for inflation - the super-rapid expansion of space thought to have occurred just fractions of a second after the Big Bang. This has not been possible. But all the Planck data - temperature and polarisation information - is consistent with that theory, and the precision measurements mean new, tighter constraints have been put on the likely scale of the inflation signal, which other experiments continue to chase.
What is clear from the Planck investigation is that the simplest models for how the super-rapid expansion might have worked are probably no longer tenable, suggesting some exotic physics will eventually be needed to explain it.
"We're now being pushed into a parameter space we didn't expect to be in," said collaboration scientist Dr Andrew Jaffe from Imperial College, UK. "That's OK. We like interesting physics; that's why we're physicists, so there's no problem with that. It's just we had this naïve expectation that the simplest answer would be right, and sometimes it just isn't."

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