- Canadian Microbes Give Clues for Life on Icy Moons
- Reader Photo: Geminid Meteor Streaks Across the Everglades
- Video: Explosions Connected Across Sun’s Surface
- Leaked Memo Shows EPA Doubts About Bee-Killing Pesticide
Posted: 13 Dec 2010 05:09 PM PST
"Ultimately when we go to Europa, we'll want to be able to tell if there's any biological activity at all," astrobiologist Damhnait Gleeson of NASA's Jet Propulsion Laboratory told Wired.com here at the American Geophysical Union meeting Dec. 13.
Europa's thick water ice crust may hide a dark liquid ocean, making the moon a favorite candidate for finding life beyond Earth in the solar system. The icy surface is crisscrossed with sulfur-rich, rust-colored lines, which could be cracks in the ice where liquid from the ocean below pushed its way to the surface.
"These geologic features on Europa indicate a plumbing system, so material gets from the bottom to the top of the ice layer," Gleeson said.
If anything lives in the frigid subsurface brine, it could take in life-sustaining energy from chemicals brought down through the cracks, astronomers suspect. But to find these hardy bugs, astronomers need to know how to recognize them.
To get an idea of how sulfur-loving Europans might show signs of their presence, Gleeson and colleagues went to the most similar place on Earth: the Borup Fjord Pass in the Canadian arctic.
Pilots flying over the pass in the late 1990s noticed the ice was stained yellow with a pure form of elemental sulfur.
"It's so unusual to find ice and sulfur together on Earth," Gleeson said. "It's really not what you'd expect to see." On Earth, most pure sulfur reacts with oxygen to form the soft mineral gypsum. Finding so much elemental sulfur in Borup Fjord Pass suggested to Gleeson and colleagues that the supply of sulfur was being replenished, possibly by microbes. A trip to the site in 2006 confirmed their suspicions: The sulfur was built by microorganisms which derived energy from ripping electrons off another form of sulfur, sulfide.
Gleeson and colleagues brought the microbes back to the lab and let them grow on a diet of sulfide, then analyzed the elemental sulfur they produced. The researchers found that the microbe-built sulfur showed complicated sheets and filaments, structures that did not show up in microbe-free control samples.
"We can look at sulfur minerals that are formed by microorganisms, and we can tell they were formed by microorganisms," Gleeson said. The results may help design instruments for future missions to Europa, like the proposed Europa Jupiter System Mission.
For now, though, the best observations of Europa come from the Galileo spacecraft, which orbited Jupiter from 1995 to 2003. Gleeson and colleagues combined their fieldwork with observations of Borup Fjord from space, to help provide "ground truth" for observations of Europa from afar. But for Gleeson, these comparisons just highlight the need to actually go to Europa and start digging.
"What we can see from orbit is such a simple picture compared to the surface," Gleeson said. "From orbit it's just ice and sulfur. We really have to go deeper to understand the system."
Astrobiologist Kevin Hand of NASA's Jet Propulsion Lab, who also spoke at the AGU meeting, agreed. "Observations from orbit can provide compelling evidence for life, but not convincing evidence," he said. "To cross that threshold from compelling to convincing requires in-situ elements."
Images: 1) The Borup Fiord Pass at Ellesmere Island, Canada, where the snow is stained yellow by sulfur. 2) Sulfur-rich lines crisscross the surface of Jupiter's moon Europa. 3) Gypsum deposits mark a potential sulfur spring at Borup Fjord Pass. Gleeson et al. 2010/NASA
Posted: 13 Dec 2010 02:15 PM PST
An early arrival from the annual Geminid meteor shower burns bright in this stunning photo from Wired.com reader Chris Acuña. An artist and graphic designer in Miami, Acuña caught the shower's early warning shots Sunday night in Florida's Everglades.
"Even though it was not the peak, I was still able to catch a few streaks across the sky," Acuña wrote in an e-mail.
The shower peaks Monday night and early Tuesday (Dec. 13 and 14), but the International Meteor Organization reports that observers under dark skies are already seeing up to 40 meteors an hour.
If you take your camera out Monday night, send us your best shots. If we get enough good ones, we'll compile the best into a gallery.
Image: Chris Acuña
Posted: 13 Dec 2010 02:03 PM PST
SAN FRANCISCO — Dramatic explosions from the surface of the sun can link up across hundreds of thousands of miles. New views from three different NASA spacecraft show how near-simultaneous eruptions on opposite sides of the sun can connect through looping lines of magnetic force.
Solar scientists have suspected for decades that solar flares (sudden bursts of energy that erupt from sunspots) and coronal mass ejections (bubbles of gas threaded with lines of magnetic field that throw tons of solar plasma out into space when they explode) could be connected across great distances.
So-called sympathetic flares that went off one after another had been observed for 75 years. But how the flares could link together was a mystery.
New videos of a recent eruption that crossed nearly the entire sun could solve the puzzle. On August 1, a chain of more than a dozen flares and other eruptions cascaded across the surface of the sun. Much of the show was hidden from Earth, but it was all captured by NASA's Solar Dynamics Observatory (above) and twin STEREO spacecraft.
"We had to be beaten over the head, which is what the August events did," said Alan Title, a solar physicist at Lockheed Martin's Solar and Astrophysics Lab, here in a press conference at the American Geophysical Union meeting Dec. 13. "Once you see something like this, the things you saw in the past all fall into place."
Based on observations from SDO, Title and solar physicist Karel Schrijver of Lockheed Martin built a model of how lines of magnetic field changes on the sun from day to day. They found that a far-reaching network of magnetic field lines connected one region to another, even across the entire 860,000-mile diameter of the sun (video below).
"For years, solar physicists including ourselves have been looking for the cause of these explosions in the region that's exploding," Schrijver said. The new observations show that "we need to expand our view and look well beyond the region exploding."
When flares and coronal mass ejections erupt on the sun, they can blast Earth with bursts of X-rays and plasma that can shut down power grids, knock out satellites and make airplanes lose communication. Solar physicists are working to predict such damaging flares before they happen, but so far models have been built "by the seat of the pants," said Rodney Viereck of NOAA's Space Weather Prediction Center. The new global view of the sun could help improve space weather forecasting models.
"These observations have provided forecasters with more detail than they've ever had before," Viereck said.
Video: 1) Lockheed Martin's Solar and Astrophysics Laboratory 2) SDO/AIA
Posted: 13 Dec 2010 11:02 AM PST
Over the concerns of its own scientists, the Environmental Protection Agency continues to approve a controversial pesticide introduced to U.S. markets shortly before the honeybee collapse, according to documents leaked to a Colorado beekeeper.
The pesticide, called clothianidin, is manufactured by German agrochemical company Bayer, though it's actually banned in Germany. It's also banned in France, Italy and Slovenia. Those countries fear that clothianidin, which is designed to be absorbed by plant tissue and released in pollen and nectar to kill pests, is also dangerous to pollen- and nectar-eating bees that are critical to some plants' reproductive success.
In 2003, the EPA approved clothianidin for use in the United States. Since then, it's become widely used, with farmers purchasing $262 million worth of clothianidin last year. It's used on used on sugar beets, canola, soy, sunflowers, wheat and corn, the last a pollen-rich crop planted more widely than any other in the United States, and a dietary favorite of honeybees.
During this time, after several decades of gradual decline, honeybee colonies in the United States underwent widespread, massive collapses.
Up to one-third have now vanished, troubling farmers who rely on bees to fertilize $15 billion worth of U.S. crops and citizens who simply like bees. Though colony collapse disorder likely has many causes — from mites to bacteria to fungus to the physiological stresses and epidemiological risks of industrial beekeeping — pesticides are prime suspects, and the EPA's leaked documents (.pdf) are troubling.
The memo, obtained by Colorado beekeeper Tom Theobald and publicized by the Pesticide Action Network, was written in November by scientists from the EPA's Environmental Fate and Effects Division, who are considering Bayer's request to use clothianidin in cotton and mustard. They describe how a key Bayer safety study used by the EPA to justify its original clothianidin approvals, which were granted before the study was actually conducted, was sloppily designed and poorly run, making it a "supplemental" resource at best.
"Clothianidin's major risk concern is to non-target insects (that is, honey bees)," write the EFED researchers (.pdf). "Exposure through contaminated pollen and nectar and potential toxic effects therefore remain an uncertainty for pollinators."
According to the EPA's website, the clothianidin review has been moved back to 2012.
Image: Flickr/Jack Wolf.
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