Early Earth's chlorine blown away by giant impacts
|Element has long puzzled scientists because modern levels are so low
By Erin Wayman
Earthlings may owe a debt of gratitude to the enormous miniplanets that smashed into the planet in its youth. Such collisions might have knocked away much of the supply of chlorine concentrated on the planet’s surface, geochemists propose. Had that loss not occurred, the world’s oceans would have been too salty for complex life to thrive, they suggest.
The scenario may explain why Mars, which suffered fewer large impacts, may have more than twice as much chlorine as Earth does, the researchers report April 16 in Earth and Planetary Science Letters.
“The story seems to hang together pretty well,” says James Brenan, a geologist at the University of Toronto who wasn’t involved in the study. “Life, probably over a fairly long time, might have been able to adapt to this environment, though certainly things would be different than today.”
One snag is that the idea is “a very difficult thing to test,” says geochemist Ray Burgess of the University of Manchester in England.
Einstein's gravity theory passes toughest test yet
|Astronomy & Space
A strange stellar pair nearly 7,000 light-years from Earth has provided physicists with a unique cosmic laboratory for studying the nature of gravity. The extremely strong gravity of a massive neutron star in orbit with a companion white dwarf star puts competing theories of gravity to a test more stringent than any available before. Once again, Albert Einstein's General Theory of Relativity, published in 1915, comes out on top.
At some point, however, scientists expect Einstein's model to be invalid under extreme conditions. General Relativity, for example, is incompatible with quantum theory. Physicists hope to find an alternate description of gravity that would eliminate that incompatibility.
A newly-discovered pulsar -- a spinning neutron star with twice the mass of the Sun -- and its white-dwarf companion, orbiting each other once every two and a half hours, has put gravitational theories to the most extreme test yet. Observations of the system, dubbed PSR J0348+0432, produced results consistent with the predictions of General Relativity.
Campaigners call for ban on "killer robots"
|By Li-mei Hoang
(Reuters) - Machines with the ability to attack targets without any human intervention must be banned before they are developed for use on the battlefield, campaigners against "killer robots" urged on Tuesday.
The weapons, which could be ready for use within the next 20 years, would breach a moral and ethical boundary that should never be crossed, said Nobel Laureate Jody Williams, of the "Campaign To Stop Killer Robots".
"If war is reduced to weapons attacking without human beings in control, it is going to be civilians who are going to bear the brunt of warfare," said Williams, who won the 1997 peace prize for her work on banning landmines.
Weapons such as remotely piloted drones are already used by some armed forces and companies are working on developing systems with a greater level of autonomy in flight and operation.
"We already have a certain amount of autonomy," said Noel Sharkey, professor of Artificial Intelligence and Robotics at the University of Sheffield.
"I think we are already there. If you asked me to go and make an autonomous killer robot today, I could do it. I could have you one here in a few days," he told reporters.
Google Transparency Report Shows Increase In Government Removal Requests
Google released its Transparency Report for the last six months of 2012 this week. The report shows an increase in requests from governments to remove content, much of it videos on YouTube. Google’s legal director Susan Infantino went over the highlights of the report in a post on the company’s official blog.
From July to December 2012, Google received 2,285 government requests to remove 24,179 pieces of content. That’s up from 1,811 requests to remove 18,070 pieces of content the search giant received in the first six months of last year.
“As we’ve gathered and released more data over time, it’s become increasingly clear that the scope of government attempts to censor content on Google services has grown. In more places than ever, we’ve been asked by governments to remove political content that people post on our services. In this particular time period, we received court orders in several countries to remove blog posts criticizing government officials or their associates,” the post said.
Brazil was one of the governments where there was an increase in removal requests. Google received 697 requests from Brazil. Of those, 640 were court orders. While many of these were likely submitted in groups, Infantino estimates Google received an average of 3.5 court orders per day during this time period from Brazil alone. Brazil submitted 191 requests in the first half of 2012, far fewer submissions.
So far, the great tit has coped with climate change
|Its food supply out of sync, a European bird has escaped population decline – for now
By Susan Milius
Though climate change has knocked little birds called great tits out of sync with their chicks’ food supply, the birds are maintaining their population numbers, a new study finds. But the way the tits cope may give them only a temporary reprieve.
“It’s buying them time,” says ecologist Tom Reed of the Netherlands Institute of Ecology in Wageningen.
Warmer springs mean that the peak food demands for Parus major chicks come later than the annual burst of local caterpillars. With less food, fewer young survive to leave their nests, Reed reports. However, the smaller resulting cohort of fledglings faces less competition for winter nuts and other resources. So a greater percentage of the youngsters survive through the winter than previously did, and — so far — this survival uptick has kept the study population from shrinking, Reed and an international team report in the April 26 Science.
These “quite acrobatic little birds” are close relatives of North America’s chickadees, Reed says. Decades ago, researchers set out nest boxes in a Dutch national park, and great tits readily moved in, forming a manageable study population.
EPA: Tar Sands Pipelines Should Be Held To Different Standards
Up until now, pipelines that carry tar sands oil have been treated just like pipelines that carry any other oil. But the Environmental Protection Agency now says that should change. That's because when tar sands oil spills, it can be next to impossible to clean up.
The agency made this argument in its evaluation of the State Department's environmental review of the Keystone XL pipeline project, which, if approved, would carry heavy crude from Alberta, Canada, to refineries in the United States.
The urges the State Department to set special standards to prevent Keystone from spilling, and make sure any spills that happen are rapidly contained.
The EPA says it has learned about the additional risks of tar sands spills from a cleanup of a into Michigan's Kalamazoo River that has dragged out nearly three years and cost more than $1 billion. A lot of the heavy crude sank to the bottom and hasn't biodegraded.
Circumcision changes penis biology
|Altered mix of microbes might reduce susceptibility to viral infections
By Nathan Seppa
Uncircumcised men harbor more bacteria around the head of the penis than do circumcised men, and the mix of microbial species is decidedly different in the two groups, researchers find.
Whether these changes in microbial numbers and diversity explain why circumcised men are less likely to get infected with HIV remains unclear. But the findings identify previously unknown differences that exist between a warm, moist environment under the foreskin and the comparatively dry surfaces found on circumcised men.
“It’s a very promising line of research,” says Robert Bailey, a biologist and epidemiologist at the University of Illinois at Chicago, who wasn’t part of the study team. “But it’s far from really providing the story on the mechanism for the increased risk of HIV infection through the foreskin.”
The report, which appears April 16 in mBio, finds that when the foreskin is removed from the head of the penis, resident microbes become exposed to oxygen and many bacteria flee the scene.
West Virginia Ranks As Most Stressed Out State
The state with the most tobacco smokers in the US has also polled in as the state with the most people who are stressed out, according to Gallup.
A new poll by Gallup found West Virginia ranked as the state that is most stressed out. The Mountain State is not only home to the highest percentage of adult smokers, 27 percent, but it is also a state where 47.1 percent of its population is stressed out.
Next to West Virginia in the survey was Rhode Island, clocking in not far behind at 46.3 percent of its population admitting to wanting to pull their hair out. Filling out the rest of the top five states are Kentucky, Utah and Massachusetts.
Gallup said the state-level data is based on daily surveys conducted from January through December 2012, including more than 350,000 interviews. It said it has been measuring daily stress in its tracking survey since 2008. Stress levels were statistically unchanged in 2012 compared with 2011, according to the surveyor.
The survey found Hawaii remained the least likely state in the US to have people who say they felt stressed on any given day in 2012. The Aloha State only has 32.1 percent of its population saying they are stressed out on a given day. Next to Hawaii in the survey was Louisiana at 37.6 percent, followed by Mississippi, Iowa and Wyoming.
National Air And Space Museum Trophy Won By Curiosity Team
|NASA’s Jet Propulsion Laboratory
The team in charge of successfully landing NASA’s Mars rover Curiosity, managed by NASA’s Jet Propulsion Laboratory, Pasadena, Calif., received the Smithsonian National Air and Space Museum’s highest group honor at a dinner in Washington on Wednesday night, April 24. The 2013 Trophy for Current Achievement honors outstanding achievements in the fields of aerospace science and technology.
The Mars Science Laboratory Project built and operates the rover Curiosity, which has been investigating past and current environments in Gale Crater on the Red Planet since its dramatic sky-crane landing in August 2012. The rover has 10 science instruments to investigate whether an area within Gale Crater ever has offered an environment favorable for microbial life.
JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA’s Science Mission Directorate in Washington.
Meteorite Smashes Through Roof Of Connecticut Resident
According to local news reports, officials at Yale Peabody Museum confirmed that a meteorite struck a private residence in Wolcott, Connecticut last week.
Police in the area received a call from local resident Larry Beck just before 10:30 a.m. Saturday morning, who said a baseball-sized rock crashed through the ceiling in his kitchen, local CBS affiliate WFSB reported.
“It sounded like a gunshot but it was a louder bang,” Beck told WFSB. “We looked up and saw the ceiling coming down and broke away the sheet rock in the dining room.”
He had heard the rock crash through his home on Friday night but assumed a joint or rafter in his house had been broken. It wasn’t until Saturday morning when he went up to his attic that he saw the damage that the space rock caused.
“For this to crash through asphalt shingles, the roof, smash copper pipe, crack a ceiling, it was moving very quickly,” Wolcott Police Chief Edward Stephens told WFSB.
How a Fake Island Landed on Google Earth
|Megan Gannon, News Editor
Last year, a group of Australian researchers "undiscovered" an island the size of Manhattan in the South Pacific.
A mysterious place called Sandy Island had popped up on maps, northwest of New Caledonia. It even showed up as a black polygon on Google Earth. But when scientists sailed there last November, they found open water instead of solid ground.
In an obituary for the island published this month, the researchers explained why the phantom landmass had been included on some maps for more than a century, pointing to some human errors and a possible pumice raft.
Sandy Island was first recorded by the whaling ship Velocity in 1876 and first mentioned on a British Admiralty chart in 1908. But future expeditions failed to find the island, and it was removed from some official hydrographic charts by the 1970s.
However, the errant island stuck on some maps and then crept into digital databases like the widely used World Vector Shoreline Database, which was developed by the U.S. military.