Monday, 19 October 2009

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Exoplanets Galore! 32 Alien Planets Discovered, Including Super-Earths

Posted: 19 Oct 2009 11:12 AM PDT


Thirty-two new alien orbs have just been added to the growing list of exoplanets, including several that qualify as "super-Earths," meaning they have a mass only a few times that of our planet and could potentially harbor Earth-like environments.

In the past five years, the High Accuracy Radial Velocity Planet Searcher, a special exoplanet-hunting device attached to a 3.6-meter telescope in La Silla, Chile, has spotted more than 75 alien planets, including 24 of the 28 known exoplanets with a mass less than 20 times that of Earth.

Given the high frequency of low-mass planets discovered by HARPS, the researchers think between 39 and 58 percent of solar-type stars host a planet with a mass of less than 50 Earth-masses.

"These findings consolidate the results of simulations of planet formation predicting a large population of super-Earths," astrophysicist Stephane Udry of Geneva University wrote in an email to "The formation models furthermore predict an even larger population of Earth-mass planets, providing solid scientific justifications for the development of ambitious programs (in space and on the ground) to look for those Earth-type planets."

Udry's announcement of the HARPS team's findings Monday at an exoplanet conference in Portugal marks the end of the first phase of HARPS research, and scientists say the project has been even more successful than they originally expected.

The HARPS instrument detects hidden exoplanets by looking for stellar "wobble," or a slight change in the radial velocity of potential host stars. The high-precision spectrograph can pick up even tiny fluctuations in a star's radial velocity — differences in speed of as little as 2.2 miles per hour — which are caused by the gravitational pull of a nearby planet.

The HARPS scientists focused their exoplanet-hunting efforts on certain kinds of stars, including stars similar to our sun and those with low mass (called Mdwarfs) or low metal content.

"By targeting M dwarfs and harnessing the precision of HARPS, we have been able to search for exoplanets in the mass and temperature regime of super-Earths," co-author Xavier Bonfils of the Joseph Fourier University in France said in a press release, "some even close to or inside the habitable zone around the star."

Image: Artist's impression of Gliese 667C, a six Earth-mass exoplanet that circulates around its low-mass host star at a distance only 1/20th of the Earth-Sun distance. The host star is a companion to two other low-mass stars, which are seen here in the distance. ESO/L. Calçada

See Also:

Follow us on Twitter @wiredscience, and on Facebook.

Self-Steered Tractors and UAVs: Future Farming Is (Finally) Now

Posted: 19 Oct 2009 10:47 AM PDT


It was 1903 when Robert Blair's great-grandfather began farming the dry ridge overlooking the Clearwater River near Lewiston, Idaho. In 2001, when Blair took the reins, the farm's books were still kept by hand. Now, he's deployed a set of DARPA-like technologies including unmanned aerial vehicles and self-steering tractors.

"In six years, I went from just having a cell phone to my tractor driving itself and having a small airplane flying and landing itself on a farm," Blair said.

The new precision farmers are hacking together a way of making food in which the virtual and physical worlds are so tightly bound that having his tractor steered by GPS-guidance with inch-level accuracy is ho-hum. Autosteering of farm machinery has exploded over the past several years, according to an annual survey by Purdue University's Center for Food and Agricultural Business. In 2004, just five-percent of agricultural retail outlets offered autosteering. In 2008, more than half did.

In a 2009 issue of Precision Farmer Magazine, Montana wheat farmer Steven Swank described the benefits of a souped-up GPS called "real-time kinematic" satellite navigation.

"RTK is so much more relaxing. It allows you to multi-task, and that me to spend more time with my family," Montana wheat farmer Steven Swank told . "I even watched a DVD in the cab with my daughter recently."

Blair, at 40, is a leader of this next generation of farmers who are adapting the precision dreams of the 90s to the realities of the soil and the history of their acreage. People dreamed of vastly reducing pesticide and fertilizer usage by applying just the right amount to each plant, but the variable-rate technologies have been only patchily adopted. Instead, a new crop of younger growers has adopted something like augmented reality. Data draped over their land guides their tractors and their decision-making.

"The big story is the generational shift going on right now. The younger people are starting to get a hold of these farms and they have a much different attitude to technology," said Joe Russo, president of the agriculture technology company, ZeDX. "They Twitter, they got smartphones, they're always on the computer. Precision ag is gonna ride that wave."

Farmers have adopted autosteer, especially, because it's made them money. By eliminating the slop-space that even the best farm machinery operators needed, it allows them to put more rows in their fields, effectively increasing their per-acre yields. For high-value crops, it was an obvious technology to adopt.

"The pay back was so much more than variable rate ever was that it was a no-brainer," said Paul Schrimpf, who's been covering precision agriculture for the magazine CropLife.

Blair wants to push the envelope further, though. He's leading a charge to adapt unmanned aerial vehicles — like the Predator Drones zipping across Afghanistan — to the task of crop surveillance. In true maker fashion, he's not waiting for the technology to be delivered to him. He's founded a company and built a prototype of his UAV that uses an off-the-shelf digital camera to take photos of his farm.

The images it produces aren't just pretty pictures, they can be converted into data that can be used in water, fertilizer, and pesticide decision-making.


Based on the color data captured by the CCD, Blair can obtain a value called the normalized differential vegetative index, which he can use to find patterns in his fields.

"Now we have a numeric value and we can write an algorithm to find different things," Blair explained. " Is a stressed crop showing a different value than one that's healthy?"

Farmers like Blair have antecedents in the farmer-scientists of the Green Revolution, but ever-cheaper information technology has let them map the data to their land with ever greater resolution. Blair is slowly turning the vast, uncontrolled experiment that is his farm into a living laboratory that also happens to make money.

Cockroaches Use Earth’s Magnetic Field to Steer

Posted: 19 Oct 2009 09:49 AM PDT


Just as birds guide their migratory journeys by sensing Earth's magnetic field, so do cockroaches use geomagnetic detection as they scurry across your kitchen floor.

To reveal the mechanisms of cockroach navigation, Czech researchers first placed roaches inside an artificial magnetic field. As they rotated the field, the cockroaches followed.

In itself, this wasn't surprising: Scientists know that cockroaches, like many insects, can detect magnetic fields. But they weren't sure if cockroaches have "mapping" cells in which minute variations in Earth's geomagnetic field cause pairs of quantum-entangled electrons to spin in different ways, or "compass" cells in which embedded iron particles respond to geomagnetic tugs.

When the researchers flooded the roaches with radio waves known to disrupt electron-paired compass cells, the cockroaches no longer followed the turning field. They apparently use a map to steer. And as cockroaches have been around for 350 million years, the mapping system could be widespread in the insect world.

"Insects may be equipped with the same magnetoreception as the birds," wrote the researchers in a paper published Friday in the Journal of Experimental Biology.

As for why cockroaches need such sophisticated magnetoreception, that remains a mystery. But at least one explanation can, unfortunately, be ruled out: They don't use their map to go south for the winter.

Image: Flickr/liangjinjian

See Also:

Citation: "Radio frequency magnetic fields disrupt magnetoreception in American cockroach." By Martin Vácha, Tereza Puzová and Markéta Kvícalová. Journal of Experimental Biology, Vol. 212 Issue 21, November 1, 2009.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecosystem and planetary tipping points.