Science & TechnologyS


Meteor

Dark Ages: Did a comet impact cause global catastrophe around 500 A.D.?

Richard A. Lovett
National Geographic News
Wed, 03 Feb 2010 11:04 UTC
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© Detlev van Ravenswaay, Astrofoto, Peter Arnold Images, PhotolibraryAn asteroid hurtles toward Earth in an artist's rendering.
Double impact may have caused tsunami, global cooling

Pieces of a giant asteroid or comet that broke apart over Earth may have crashed off Australia about 1,500 years ago, says a scientist who has found evidence of the possible impact craters.

Satellite measurements of the Gulf of Carpentaria (see map) revealed tiny changes in sea level that are signs of impact craters on the seabed below, according to new research by marine geophysicist Dallas Abbott.

Based on the satellite data, one crater should be about 11 miles (18 kilometers) wide, while the other should be 7.4 miles (12 kilometers) wide.

For years Abbott, of Columbia University's Lamont-Doherty Earth Observatory, has argued that V-shaped sand dunes along the gulf coast are evidence of a tsunami triggered by an impact.

"These dunes are like arrows that point toward their source," Abbott said. In this case, the dunes converge on a single point in the gulf - the same spot where Abbott found the two sea-surface depressions.

The new work is the latest among several clues linking a major impact event to an episode of global cooling that affected crop harvests from A.D. 536 to 545, Abbott contends.

According to the theory, material thrown high into the atmosphere by the Carpentaria strike probably triggered the cooling, which has been pinpointed in tree-ring data from Asia and Europe.

What's more, around the same time the Roman Empire was falling apart in Europe, Aborigines in Australia may have witnessed and recorded the double impact, she said.

Comment: For an in-depth study, read Laura Knight-Jadczyk's review of New Light on the Black Death: The Cosmic Connection.

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Cell Phone

7 Gadgets That Changed the World

Stephanie Pappas
TechNewsDaily
Sat, 06 Feb 2010 09:26 UTC
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© Unknown
Companies like to call their new gadgets revolutionary. Amazon did it when it introduced its Kindle e-book reader in 2007, and Apple CEO Steve Jobs used the word often last week while unveiling his company's new iPad - a tablet computer that also doubles as an e-reader. Jobs even threw in a "magical" here and there when describing the device.

Corporations aren't the only ones predicting that the digitization of books will bring great change. Take author and journalist Steven Johnson, who's Kindle moved him to envision a paperless future:
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Chalkboard

Scientists ID a Protein That Splices and Dices Genes


Science Daily
Fri, 05 Feb 2010 17:59 UTC
A novel finding offers a clue as to how genes can have what you might call multiple personalities.

The research was recently described online in the journal Science by teams from the National Cancer Institute, The University of Texas Health Science Center at San Antonio and the University of Toronto.

Genes are long strings of DNA letters, but they can be cut and spliced to make different proteins, something like the word "Saskatchewan" can have its middle cut out to leave the word "Swan," its front, middle and end deleted to leave the word "skate," or its front and back chopped off to make the word "chew."
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Chalkboard

First Measurement of Energy Released from a Virus During Infection


Science Daily
Fri, 05 Feb 2010 17:45 UTC
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© Carnegie Mellon University3D reconstruction of bacteriophage lambda with (left) and without (right) DNA.
Within a virus's tiny exterior is a store of energy waiting to be unleashed. When the virus encounters a host cell, this pent-up energy is released, propelling the viral DNA into the cell and turning it into a virus factory. For the first time, Carnegie Mellon University physicist Alex Evilevitch has directly measured the energy associated with the expulsion of viral DNA, a pivotal discovery toward fully understanding the physical mechanisms that control viral infection and designing drugs to interfere with the process.

"We are studying the physics of viruses, not the biology of viruses," said Evilevitch, associate professor of physics in the Mellon College of Science at Carnegie Mellon. "By treating viruses as physical objects, we can identify physical properties and mechanisms of infection that are common to a variety of viruses, regardless of their biological makeup, which could lead to the development of broad spectrum antiviral drugs."

Current antiviral medications are highly specialized. They target molecules essential to the replication cycle of specific viruses, such as HIV or influenza, limiting the drugs' use to specific diseases. Additionally, viruses mutate over time and may become less susceptible to the medication. Evilevitch's work in the burgeoning field of physical virology stands to provide tools for the rational design of less-specialized antiviral drugs that will have the ability to treat a broad range of viruses by interrupting the release of viral genomes into cells.
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Saturn

How the face of Pluto changed in just two years (do you think they can blame it on global warming?)


UK Daily Mail
Fri, 05 Feb 2010 16:01 UTC
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© AFP/Getty ImagesChanging face: Scientists are baffled after new images of the surface of dwarf planet Pluto show it has become 20 per cent more red
Nasa scientists have been left stunned after detailed images of the surface of Pluto reveal it has dramatically changed colour over just a two-year period.

The Hubble Telescope captured the images, which are the most detailed and dramatic ever taken of the distant dwarf planet.

They revealed that the cosmic body, demoted from full planet status in 2006, is significantly redder than it has been for the past several decades.

The photos show a mottled world with a yellow-orange hut, but astronomers say it is 20 per cent more red than it used to be. At the same time its illuminated northern hemisphere is getting brighter, while the southern hemisphere has darkened.
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Meteor

Did an Asteroid Strike in Australia Plunge Anglo-Saxon England into a Mini Ice-Age?

Claire Bates
Mail Online
Thu, 04 Feb 2010 19:05 UTC
Asteroid
© Mail OnlineA veil of dust thrown up by an asteroid 2,000ft across may have caused a mini ice-age in 535AD
In the mid-sixth century, Europe and Asia experienced the most severe and protracted episode of cooling of the last 2,000 years.

Sources from the time refer to widespread crop failures and famines as the unseasonal weather took hold. The Gaelic Irish Annals recorded 'a failure of bread' from 536 to 539AD.

Tree ring analysis by Mike Baillie from Queen's University in Belfast also suggested a cool period. He found the Irish oak showed abnormally little growth in 536 and 542. This phenomenon was noted in trees in Sweden and Finland as well.
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Info

Youth who self-identify as gay, lesbian or bisexual at higher suicide risk


Physorg.com
Fri, 05 Feb 2010 13:31 UTC
Mental health professionals have long-known that gay, lesbian and bisexual (GLB) teens face significantly elevated risks of mental health problems, including suicidal thoughts and suicidal attempts. However, a group of McGill University researchers in Montreal has now come to the conclusion that self-identity is the crucial risk-factor, rather than actual sexual behaviours. Their results were published in February in the Journal of the American Academy of Child & Adolescent Psychiatry.

The researchers administered a detailed, anonymous questionnaire to nearly 1,900 students in 14 Montreal-area high schools, and found that those teens who self-identified as gay, lesbian or bisexual, or who were unsure of their sexual identity, were indeed at higher risk for suicidal ideation and attempts. However, teens who had same-sex attractions or sexual experiences - but thought of themselves as heterosexual - were at no greater risk than the population at large. Perhaps surprisingly, but consistent with previous studies, the majority of teens with same-sex sexual attraction or experience considered themselves to be heterosexual.
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Radar

Imagining The Fate Of Data After The Apocalypse

Alasdair Wilkins
io9
Fri, 05 Feb 2010 12:00 UTC
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© Unknown
If modern civilization collapsed, could the survivors hope to rebuild using our massive stores of data? Unless we can come up with something way more permanent to put them on in the near future, we probably shouldn't bank on it.

A recent article by Tom Simonite and Michael Le Page in New Scientist tackles this question by positing a minor cataclysm: something bad enough to tear apart civilization as we know it, but not quite enough to kill off humans entirely. Candidates include a pandemic, a financial collapse that would make 2008's pale in comparison, a severe natural disaster, or just the slow accumulation of decay in society's foundations.
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Bulb

First Germanium Laser

Larry Hardesty
MIT News
Thu, 04 Feb 2010 10:00 UTC
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© Christine Daniloff
New results from MIT's Electronic Materials Research Group bring us closer to computers that use light instead of electricity to move data.

MIT researchers have demonstrated the first laser built from germanium that can produce wavelengths of light useful for optical communication. It's also the first germanium laser to operate at room temperature. Unlike the materials typically used in lasers, germanium is easy to incorporate into existing processes for manufacturing silicon chips. So the result could prove an important step toward computers that move data - and maybe even perform calculations - using light instead of electricity. But more fundamentally, the researchers have shown that, contrary to prior belief, a class of materials called indirect-band-gap semiconductors can yield practical lasers.

As chips' computational capacity increases, they need higher-bandwidth connections to send data to memory. But conventional electrical connections will soon become impractical, because they'll require too much power to transport data at ever higher rates. Transmitting data with lasers - devices that concentrate light into a narrow, powerful beam - could be much more power-efficient, but it requires a cheap way to integrate optical and electronic components on silicon chips.
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Clock

NIST's Second "Quantum Logic Clock" Based on Aluminum Ion is Now World's Most Precise Clock

Laura Ost
National Institute of Standards and Technology (NIST)
Thu, 04 Feb 2010 19:08 UTC
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© J. Burrus/NISTNIST postdoctoral researcher James Chin-wen Chou with the world's most precise clock, based on the vibrations of a single aluminum ion (electrically charged atom). The ion is trapped inside the metal cylinder (center right).
Clock keeps time to 1 second in 3.7 billion years

Boulder - Physicists at the National Institute of Standards and Technology (NIST) have built an enhanced version of an experimental atomic clock based on a single aluminum atom that is now the world's most precise clock, more than twice as precise as the previous pacesetter based on a mercury atom.

The new aluminum clock would neither gain nor lose one second in about 3.7 billion years, according to measurements to be reported in Physical Review Letters.

The new clock is the second version of NIST's "quantum logic clock," so called because it borrows the logical processing used for atoms storing data in experimental quantum computing, another major focus of the same NIST research group. (The logic process is described here.) The second version of the logic clock offers more than twice the precision of the original.
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