Science & TechnologyS


Meteor

Did a Comet strike Neptune 200 years ago?

Eric Hand
Nature
Fri, 28 May 2010 12:26 UTC
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© NASA/JPLAn abundance of carbon monoxide in Neptune's atmosphere could be the result of a comet smash
Did a large, icy comet smash into Neptune two centuries ago? That's the picture that is emerging from the latest measurements of gases in the atmosphere of the giant blue planet.

At a meeting this week of the American Astronomical Society in Miami, Florida, Paul Hartogh, project scientist for the Herschel mission, the European Space Agency's infrared observatory satellite, described the mission's first results for the Solar System. These include measurements of abnormally high levels of carbon monoxide in Neptune's stratosphere - a possible trace of a comet impact.

Emmanuel Lellouch, an astronomer at the Paris Observatory, first published the idea five years ago, on the basis of far less certain measurements made by a 30-metre radio telescope on the mountain Pico Veleta in Spain[1]. "We are becoming more confident," says Lellouch, who is a co-author with Hartogh on a forthcoming paper concerning the Herschel results in the journal Astronomy & Astrophysics.
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Info

DNA replication... without life

Kate McAlpine
New Scientist
Thu, 27 May 2010 12:10 UTC
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© University of Delaware/JGI/DOEProviding a perfect setting for life to replicate
The precursor of life may have learned how to copy itself thanks to simple convection at the bottom of the ocean. Lab experiments reveal how DNA replication could have occurred in tiny pores around undersea vents.

One of the initial steps towards life was the first molecule capable of copying itself. In the open ocean of early Earth, strands of DNA and loose nucleotides would have been too diluted for replication to occur. So how did they do it?

Inside many undersea hydrothermal vents, magnesium-rich rocks react with sea water. Such reactions create a heat source that could drive miniature convection currents in nearby pores in the rock, claim Christof Mast and Dieter Braun of Ludwig Maximilian University of Munich, Germany. They propose that such convection could concentrate nucleotides, strands of DNA, and polymerase, providing a setting that would promote replication.

Sea water inside pores on or near a vent's chimney may undergo thermal convection because the water at the wall of the pore closest to the vent's heat source would be warmer than the water near the furthermost wall, say Mast and Braun. If the pore contained strands of DNA, nucleotides, and polymerase they would ride upward in the warm current. The DNA strands would also be "unzipped" in the heat, splitting into two strands that each serve as templates for eventual replication.

All these components would then tend to shift away from the rising warmer region. In air, particles typically shift into a colder current because they are more likely to be pushed away by warmer, more energetic molecules than those on the cooler, calmer side. The researchers reckon a similar process would occur in the fluid in the vents.
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Sherlock

Scientists Announce New Horned Dinosaur


PhysOrg
Fri, 28 May 2010 11:10 UTC
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© Luis ReyMedusaceratops
Michael J. Ryan, Ph.D., a scientist at The Cleveland Museum of Natural History, has announced the discovery of a new horned dinosaur, Medusaceratops lokii. Approximately 20 feet long and weighing more than 2 tons, the newly identified plant-eating dinosaur lived nearly 78 million years ago during the Late Cretaceous period in what is now Montana. Its identification marks the discovery of a new genus of horned dinosaur.

Ryan, curator and head of Vertebrate Paleontology at the Museum, published his findings on the new genus in the book, New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium, available from Indiana University Press. Ryan was the book's lead editor.

Medusaceratops belongs to the Chasmosaurinae subfamily of the horned dinosaur family Ceratopsidae. The other subfamily is Centrosaurinae. The specimen is the first Campanian-aged chasmosaurine-ceratopsid found in Montana. It is also the oldest known Chasmosaurine ceratopsid.

The new dinosaur was discovered in a bonebed on private land located along the Milk River in North Central Montana. Fossilized bones from the site were acquired by Canada Fossil, Inc., of Calgary, Alberta, in the mid-1990s.
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Info

Snails on speed shed light on how patholgical memories form in addicts

Jessica Hamzelou
New Scientist
Fri, 28 May 2010 12:04 UTC
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© Colin Milkins/GettyThis place reminds me of something
Pond snails make unlikely speed freaks. But dosing the gastropods on methamphetamine is helping us understand how certain "pathological memories" form in human addicts.

Meth users develop long-term memories of their highs, which is why the sight of places and people connected with a high can cause recovering addicts to relapse into taking the drug. "It's hard to get rid of those memories in addicts," says Barbara Sorg at Washington State University in Pullman. So potent is meth's effect on memory that, in low doses, the drug can be used as a "cognitive enhancer" in kids with attention-deficit hyperactivity disorder.

To probe the drug's effect on memory, Sorg's team placed pond snails in two pools of low-oxygen water, one of which was laced with meth. In low-oxygen conditions snails will surface and use their breathing tubes to access more oxygen. By poking the snails, Sorg's team trained them to associate using the tubes with an unpleasant experience, and so keep them shut. Only the snails on speed remembered their training the following morning, and in a separate experiment it took longer for them to "unlearn" the memory.
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Heart

Arizona man is first to take artificial heart home

Andy Coghlan
New Scientist
Thu, 27 May 2010 11:57 UTC
Charles Okeke, a 43-year-old father of three from Phoenix, Arizona, is the first person to leave hospital with a completely artificial heart. Since 3 May he has been home with his family, thanks to a backpack-sized device that is powerful enough to keep his artificial heart pumping while he awaits a donor heart. How does the heart work and what's next for synthetic organs? New Scientist provides some answers.

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Sun

Cosmic hit-and-runs create failed stars

Rachel Courtland
New Scientist
Thu, 27 May 2010 11:53 UTC
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© Ingo Thies, Pavel Kroupai and Simon P. Goodwin et alA snapshot of a circumstellar disc around a Sun-type star being perturbed by a close star-star encounter.
It's hit-and-run on a cosmic scale. Close encounters between swerving young stars might help spawn the brown dwarfs riddling the Milky Way.

Brown dwarfs are balls of gas whose mass is generally dozens of times that of Jupiter. Like stars, brown dwarfs are capable of fusing hydrogen atoms, but they are too lightweight to sustain the process.

The origin of these failed stars is a mystery. Brown dwarfs might form like their larger cousins, collapsing directly from turbulent gas clouds, or they might form in a similar way to planets, condensing out of the discs of gas girdling young stars.

Simulations had shown that instabilities in the disc of gas around an isolated young star can trigger the formation of brown dwarfs. Now Ingo Thies and Pavel Kroupa of the University of Bonn in Germany, and colleagues, have shown that the process can also take place in a more commonplace scenario, involving a crowded cluster of newborn stars.

In new simulations, the team found that young stars that zoom close enough to their siblings can destabilise the surrounding gas discs, allowing denser areas to collapse rapidly and form brown dwarf-sized objects.
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Magnify

Wind Vibrations Turned into Electricity

David Teeghman
Discovery News
Fri, 28 May 2010 09:40 UTC
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© Vibro-Wind Research Group
Wind turbines are a common sight along the highway in parts of the country with more space than people. But there aren't many wind turbines in heavily populated areas.

Cities have just as much wind as rural areas, but the space is less plentiful. To harness the wind energy in places without enough space for the 30-foot long blades of a wind turbine, researchers and students at Cornell University are working to harness wind vibrations for energy.

The idea is to make wind energy a possibility for people in every part of the country. Researchers want to bring wind energy from the farms to people's roofs, the way it's possible to install solar panels on your house.

It still takes a true altruist to install solar panels on their roofs, however. While the price of a kilowatt hour of wind energy has dropped steadily to prices that rival coal, the average price of a kilowatt hour of solar energy is still much higher.
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Yoda

Forbidden Science: Leading Louisiana wetlands scientist fired for speaking the truth about New Orleans levees


Brasscheck TV
Fri, 28 May 2010 07:59 UTC
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Sun

Solar Scientists Agree That the Sun's Recent Behavior Is Odd, but the Explanation Remains Elusive

John Matson
Scientific American
Thu, 27 May 2010 22:21 UTC
Sun Close up
© NASA/GSFC/AIASOLAR SURPRISES: An image from the new Solar Dynamics Observatory shows activity on the sun's surface; the solar cycle has proved difficult to accurately predict.
The most recent solar minimum was both long and pronounced. But why?

Miami, Florida - In very rough terms, the sun's activity ebbs and flows in an 11-year cycle, with flares, coronal mass ejections and other energetic phenomena peaking at what is called solar maximum and bottoming out at solar minimum. Sunspots, markers of magnetic activity on the sun's surface, provide a visual proxy to mark the cycle's evolution, appearing in droves at maximum and all but disappearing at minimum. But the behavior of our host star is not as predictable as all that - the most recent solar minimum was surprisingly deep and long, finally bottoming out around late 2008 or so.

Solar physicists here at the semiannual meeting of the American Astronomical Society this week offered a number of mechanisms to shed light on what has been happening on the sun of late, but conceded that the final answer - or more likely answers - remains opaque. Beyond scientific understanding, motivations for better solar weather forecasts include hopes to use them to safeguard against electrical grid disruptions, damage to Earth-orbiting satellites and threats to the health of space travelers posed by solar radiation flare-ups.
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Sun

Why NASA Keeps A Close Eye On Sun's Irradiance

Adam Voiland
Space Daily
Thu, 27 May 2010 19:58 UTC
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© NASA/Goddard/SORCEAlthough sunspots cause a decrease in irradiance they're accompanied by bright white blotches called faculae that cause an overall increase in solar irradiance.
For more than two centuries, scientists have wondered how much heat and light the sun expels, and whether this energy varies enough to change Earth's climate. In the absence of a good method for measuring the sun's output, the scientific conversation was often heavy with speculation.

By 1976, that began to change when Jack Eddy, a solar astronomer from Boulder, Colo., examined historical records of sunspots and published a seminal paper that showed some century-long variations in solar activity are connected with major climatic shifts.
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