Science & TechnologyS


Telescope

New Research Suggests that Near-Earth Encounters can "Shake" Asteroids

Jen Hirsch
Massachusetts Institute of Technology
Wed, 20 Jan 2010 17:00 UTC
Cambridge, Massachusetts - For decades, astronomers have analyzed the impact that asteroids could have on Earth. New research by MIT Professor of Planetary Science Richard Binzel examines the opposite scenario: that Earth has considerable influence on asteroids - and from a distance much larger than previously thought. The finding helps answer an elusive, decades-long question about where most meteorites come from before they fall to Earth and also opens the door to a new field study of asteroid seismology.

By analyzing telescopic measurements of near-Earth asteroids (NEAs), or asteroids that come within 30 million miles of Earth, Binzel has determined that if an NEA travels within a certain range of Earth, roughly one-quarter of the distance between Earth and the moon, it can experience a "seismic shake" strong enough to bring fresh material called "regolith" to its surface. These rarely seen "fresh asteroids" have long interested astronomers because their spectral fingerprints, or how they reflect different wavelengths of light, match 80 percent of all meteorites that fall to Earth, according to a paper by Binzel appearing in the Jan. 21 issue of Nature. The paper suggests that Earth's gravitational pull and tidal forces create these seismic tremors.
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Info

Cave reveals Southwest's abrupt climate swings during Ice Age

Mari N. Jensen
University of Arizona
Wed, 20 Jan 2010 20:50 UTC
Image
© 2010 Stella Cousins.Sarah Truebe, a geosciences doctoral student at the University of Arizona, checks on an experiment that measures how fast cave formations grow in Arizona's Cave of the Bells.
Ice Age climate records from an Arizona stalagmite link the Southwest's winter precipitation to temperatures in the North Atlantic, according to new research.

The finding is the first to document that the abrupt changes in Ice Age climate known from Greenland also occurred in the southwestern U.S., said co-author Julia E. Cole of the University of Arizona in Tucson.

"It's a new picture of the climate in the Southwest during the last Ice Age," said Cole, a UA professor of geosciences. "When it was cold in Greenland, it was wet here, and when it was warm in Greenland, it was dry here."
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Einstein

The entropy force: a new direction for gravity

Martijn van Calmthout
New Scientist
Wed, 20 Jan 2010 18:07 UTC
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© SuperStock/GettyGravity keeps us tumbling back to Earth
Although gravity has been successfully described with laws devised by Isaac Newton and later Albert Einstein, we still don't know how the fundamental properties of the universe combine to create the phenomenon.

Now one theoretical physicist is proposing a radical new way to look at gravity. Erik Verlinde of the University of Amsterdam, the Netherlands, a prominent and internationally respected string theorist, argues that gravitational attraction could be the result of the way information about material objects is organised in space. If true, it could provide the fundamental explanation we have been seeking for decades.

Verlinde posted his paper to the pre-print physics archive earlier this month, and since then many physicists have greeted the proposal as promising. Nobel laureate and theoretical physicist Gerard 't Hooft of Utrecht University in the Netherlands stresses the ideas need development, but is impressed by Verlinde's approach. "[Unlike] many string theorists Erik is stressing real physical concepts like mass and force, not just fancy abstract mathematics," he says. "That's encouraging from my perspective as a physicist."
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Stop

Car-stopping electropulse cannon to demo 'next month

Lewis Page
The Register
Wed, 20 Jan 2010 13:39 UTC
Cig-lighter EMP blaster down to suitcase size, apparently

An old friend familiar to every tech buff and sci-fi fan - namely, the circuitry-addling electropulse blaster - has moved a large step closer to reality, according to reports. A vehicle mounted pulse weapon capable of stopping a (modern) car at 200m is to be demonstrated "next month", apparently.

Flight International has the story, uncovered while following up on a recent US Air Force request for an aircraft weapon capable of "disabling moving ground vehicles while minimising harm to occupants". The USAF is more than capable of stopping such vehicles at present, but its existing methods generally reduce the car or truck and its occupants to a few mangled scraps - not to mention destroying a large section of road and quite likely anything else in the general vicinity.

Just how the Air Force will proceed remains to be seen. However the US Marines have for some years been working with California firm Eureka Aerospace to produce an electromagnetic pulse (EMP, aka High Powered Microwave or HPM) weapon for this sort of task.
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Magnify

Scientists Find a Shared Gene in Dogs With Compulsive Behavior

Mark Derr
The New York Times
Wed, 20 Jan 2010 13:23 UTC
Scientists have linked a gene to compulsive behavior - in dogs.

Researchers studied Doberman pinschers that curled up into balls, sucking their flanks for hours at a time, and found that the afflicted dogs shared a gene. They describe their findings - the first such gene identified in dogs - in a short report this month in Molecular Psychiatry.

Dr. Nicholas Dodman, director of the animal behavior clinic at the Cummings School of Veterinary Medicine at Tufts University, in North Grafton, Mass., and the lead author of the report, said the findings had broad implications for compulsive disorders in people and animals.
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Better Earth

Solar system 'on fire' burned up Earth's carbon

David Shiga
New Scientist
Tue, 19 Jan 2010 11:58 UTC
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© Christian Miller/iStockNow where did all that carbon go?
Fire sweeping through the inner solar system may have scorched away much of the carbon from Earth and the other inner planets.

Though our planet supports carbon-based life, it has a mysterious carbon deficit. The element is thousands of times more abundant in comets in the outer solar system than on Earth, relative to the amount of silicon each body contains. The sun is similarly rich in carbon. "There really wasn't that much carbon that made it onto Earth compared to what was available," says Edwin Bergin of the University of Michigan in Ann Arbor.

The conventional explanation for the deficit argues that in the inner region of the dust disc where Earth formed, temperatures soared above 1800 kelvin, enough for carbon to boil away. But observations of developing solar systems suggest that at Earth's distance from the sun the temperature would be too cool to vaporise carbon dust.

Now a team of astronomers says that fire is to blame. Hot oxygen atoms in the dusty disc would have readily combined with carbon, burning it to produce carbon dioxide and other gases, say Jeong-Eun Lee of Sejong University in Seoul, South Korea, and colleagues, including Bergin, in a paper to appear in The Astrophysical Journal Letters (arxiv.org/abs/1001.0818). Any solid carbon in the inner solar system would have been destroyed within a few years, they calculate.
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Meteor

Preparing for an asteroid strike


New Scientist
Thu, 24 Sep 2009 10:47 UTC
Image
© Unknown
The sight of the solar system's biggest planet being battered by the broken remains of a comet in 1994 left a vivid reminder of our own planet's vulnerability. The scars that remained after the series of giant impacts on Jupiter were more prominent even than its great red spot, and remained visible for months.

This dramatic spectacle was enough to loosen government purse strings, and the funding has supported telescope surveys to hunt down asteroids that could wallop us. A decade and a half after comet Shoemaker-Levy 9 smashed into Jupiter, those surveys have catalogued more than 80 per cent of the near-Earth asteroids larger than 1 kilometre across.

Now we have seen the results of the first exercise ever to test plans for what to do if an asteroid is on collision course with Earth (see Asteroid attack: Putting Earth's defences to the test), and they do not inspire confidence. We still have a long way to go before we can say we are prepared for this cosmic threat.
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Display

The serfdom of crowds

Jaron Lanier
harpers.org
Wed, 20 Jan 2010 07:52 UTC
By Jaron Lanier, from You Are Not a Gadget, published in January by Knopf. Lanier, a computer scientist, popularized the term "virtual reality." His "Moving Beyond Muzak" was published in the March 1998 issue of Harper's Magazine.

The central faith embedded in Web technologies whereby users not only consume information but widely generate it is the idea that the Internet as a whole is coming alive and turning into a superhuman creature. The designs guided by this perverse kind of faith leave people in the shadows. Computers will soon get so big and fast, and the Internet so rich with information, that people will be obsolete, either left behind like the characters in Rapture novels or subsumed into some cyber-superhuman something. Silicon Valley culture has taken to enshrining this vague idea and spreading it the only way technologists can: in the design of software.

If you believe the distinction between the roles of people and of computers is starting to dissolve, you might express that - as some friends of mine at Microsoft once did - by designing features for a word processor that are supposed to know what you want - for example, when you want to start an outline within your document. You might have had the experience of Microsoft Word suddenly determining, at the wrong moment, that you are creating an indented outline. The real function of this feature isn't to make life easier for you. Instead, it promotes a new philosophy: that the computer is evolving into a life-form that can understand people better than people can understand themselves. If you believe this, then working for the benefit of the computing cloud over that of the individual puts you on the side of the angels.
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Telephone

Skype traffic soars, leaving old-school phone companies in the dust

Matthew Shaer
The Christian Science Monitor
Tue, 19 Jan 2010 18:28 UTC
First, a disclaimer: We are Skype users.

When it comes to calling relatives in far-flung locales, it's hard to beat the ease of Skype. It's free, usually pretty fast, and includes video, so we can see exactly what kind of sweater Uncle Frank is wearing to dinner. And according to the analytics firm TeleGeography, we're not alone.

In a paper released this week, TeleGeography reports that Skype experienced a 60 percent growth in user-to-user traffic last year. (Translation: When one Skype user chats directly with another Skype user, as opposed to using Skype to dial a regular old phone.) By the time analysts finish crunching the data, they expect Skype to have generated 54 billion minutes of international traffic in 2009, up from 33 billion minutes in 2008.
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Magnify

Stem cells get performance anxiety, don't work when watched

Casey Johnston
Nobel Intent
Tue, 12 Jan 2010 15:34 UTC
Image
© Unknown
Stem cells hold the promise of of healing injuries and defects in humans and animals, but scientists are still trying to determine the best way to get the stem cells to the defects, and how to optimize their healing effects once they're there. A recent study shows that stem cells can help with healing bone injuries, but they were indignant about being watched over their shoulders - attaching quantum dots to the stem cells for tracking purposes caused them to become less localized to the site they were applied to and to die off rather quickly.

Scientists know that providing stem cells to injured or damaged areas of the body can help them heal because of the stem cells' ability to develop into many different kinds of tissue. However, they are unsure of how delivery methods affect the ability of stem cells to function; for example, it is unclear whether a systemic introduction of stem cells might be more effective than applying them directly to the defective area.
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