During last night's celebration at the Jet Propulsion Laboratory of ten years of the Mars Exploration Rovers, mission principal investigator Steve Squyres shared several stories about the exploration and discoveries made by the rovers Spirit and Opportunity since they landed on Mars in 2004.

An intriguing recent mystery is a strange rock that suddenly appeared in photos from the Opportunity rover in a spot where photos taken just 12 sols earlier there was no rock.

"One of the things I like to say is that Mars keeps throwing new things at us," Squyres deadpanned.

• U.S. scientists believe the genetic overlap observed between some modern dogs and wolves is the result of interbreeding after dog domestication

• University of Chicago researchers said their study reflects a more complicated history of how canines came to be domesticated

Dogs and wolves evolved from a common ancestor between 11,000 and 34,000 years ago, according to new research.

U.S. scientists said that part of the genetic overlap observed between some modern dogs and wolves is the result of interbreeding after dog domestication and not a direct line of descent from one group of wolves.

They believe their research reflects a more complicated history than the popular story that early farmers adopted a few docile, friendly wolves that later became our modern canine companions.

"There are strange things done in the midnight sun," poet Robert Service wrote. He was referring to the Klondike gold rush, but he could have been referring to the Arctic atmosphere, the strangeness of which continues to confound and concern scientists.

In separate studies published this week, research teams working in Barrow, Alaska announced two discoveries about the polar air: an unexpected process for depositing mercury pollution to land and sea, and the highest levels of molecular chlorine ever detected.

The chlorine finding, published in Nature Geoscience, is simply weird - it's too early to conclude what it means for the environment on a broader scale.

But the mercury finding, , is worrisome. Mercury is a potent neurotoxin that enters the atmosphere through coal-burning power plants and other industries, and can be carried far from its original source. When it enters an ecosystem, bacteria can transform it into highly toxic methylmercury and that builds up in wildlife; in humans, it has a host of harmful effects including neurological damage to babies in the womb.

The twin papers are another indication that the Arctic remains an enigma, especially as it changes in response to global warming.

"There's a lot left to learn - not just about the Arctic atmosphere but about atmosphere, ocean, sea ice, land, and snow," said Kimberly Strong, an Arctic expert and atmospheric physicist at the University of Toronto who was not involved in either research team.

"We're really just starting to pull together all the bits of the puzzle, and these two studies are contributing to that."

Both of the studies relate to a peculiar process that is one of the strangest things done in the midnight sun, at least when it comes to atmospheric chemistry. More than 20 years ago, scientists discovered that something weird was happening to mercury and ozone levels in the High Arctic air in springtime: in space of just hours they would suddenly disappear, only to return again hours later.

Goodness gracious, a great ball of lightning seen in China offers the first evidence in nature that the elusive glowing orbs form thanks to vaporised dirt.

Anecdotes about ball lightning stretch back for centuries, but the phenomenon has been hard to study as the balls are unpredictable - and when they do materialise, they last for mere seconds.

Lacking detailed observations, explanations have ranged from electrically charged meteorites to hallucinations induced by magnetism during storms.

In 2012, Jianyong Cen and his colleagues at Northwestern Normal University in Lanzhou, China, were observing a thunderstorm in Qinghai, China with video cameras and spectrographs.

Purely by chance, they recorded a ball lightning event. When a bolt struck the ground, a glowing ball about 5 metres wide rose up and travelled about 15 metres, disappearing after 1.6 seconds.

The spectrograph revealed that the main elements in the ball were the same as those found in the soil: silicon, iron and calcium. The observations support a theory for making ball lightning put forth in 2000 by John Abrahamson at the University of Canterbury in New Zealand.

Aging pipelines under the streets of Washington, D.C., are to blame for nearly 6,000 natural gas leaks, including 12 that could have caused dangerous explosions, a new study finds.

Researchers from Duke University and Boston University mapped 1,500 road miles (2,400 kilometers) of underground infrastructure that delivers fuel to power homes and businesses in the nation's capital. Using a high-precision device to detect methane - the chief component of natural gas - the scientists discovered more than 5,893 natural gas leaks throughout the city.

The scientists also found some manholes with methane concentrations nearly 10 times greater than the threshold at which explosions can occur.

"Repairing these leaks will improve air quality, increase consumer health and safety, and save money," study lead author Robert Jackson, a professor of environmental sciences at Duke University, said in a statement.

"Pipeline safety has been improving over the last two decades. Now is the time to make it even better."

After their initial findings, the researchers reported the leaks to city authorities. Yet, four months later, nine leaks were still found to be emitting dangerous levels of methane, Jackson said.

"Finding the leaks a second time, four months after we first reported them, was really surprising," he said.

Cbet nr. 3783, issued on 2014, January 16, announces the discovery of an apparently asteroidal object (discovery magnitude ~18.1) by Cristovao Jacques, Eduardo Pimentel, and Joao Ribeiro de Barros on CCD images obtained on Jan. 12.0 UT with a 0.45-m f/2.9 reflector of the Southern Observatory for Near Earth Research (SONEAR) at Oliveira, Brazil. The object has been found to show cometary appearance by CCD astrometrists elsewhere and then also by Jacques et al. The new comet has been designated C/2014 A4 (SONEAR).

We performed follow-up measurements of this object, while it was still on the neocp.
Stacking of 19 unfiltered exposures, 90-sec each, obtained remotely from MPC code Q62 (iTelescope, Siding Spring) on 2014, January 13.4 through a 0.50-m f/6.8 astrograph + CCD, shows that this object is a comet: small coma nearly 5 arcsec in diameter with a hint of elongation toward North-East.

We observed the object again on January 14.5: stacking of 25 R-filtered exposures, 30-sec each, obtained remotely from MPC code E10 (Faulkes Telescope South) on 2014, January 14.5 through a 2.0-m f/10.0 Ritchey-Chretien + CCD (operated by Las Cumbres Observatory Global Telescope Network), shows that this object is a comet: diffuse coma nearly 8 arcsec in diameter slightly elongated toward North-East

The millions of proteins in humans and other living things vibrate in different patterns like the strings on a violin or the pipes of an organ, according to a new study in Nature Communications.

Scientists have long suspected that proteins vibrate in such a manner, but now they have the high tech means to prove that this really happens.

The research team, from the University at Buffalo and Hauptman-Woodward Medical Research Institute, found that the vibrations persist in molecules like the "ringing of a bell," lead author and UB physics professor Andrea Markelz said in a press release.

We are not consciously aware of these non-stop vibrations. (Can you imagine what it would be like if we were?)

But it's fascinating to think that a veritable symphony of vibrations plays on in us and in other species.

The tiny motions enable proteins to change shape quickly so they can readily bind to other proteins, a process that is necessary for the body to perform critical biological functions like absorbing oxygen, repairing cells and replicating DNA, Markelz explained.

She added that the research opens the door to a whole new way of studying the basic cellular processes that enable life.

"People have been trying to measure these vibrations in proteins for many, many years, since the 1960s," Markelz said.

Here's a chance to have your name on a spacecraft that will eventually spend its time orbiting the sun.

NASA is inviting people around the world to submit their names to be etched on a microchip aboard the OSIRIS-REx spacecraft, which will first travel to an asteroid in 2016.

OSIRIS-REx will use a vision system provided by Canada.

The space probe will spend more than two years at the 500-metre-wide asteroid, named Bennu.

Its main mission is to collect at least 60 grams of material from Bennu's surface and return it to Earth in 2023 in a sample return capsule.

Anyone wishing to participate in "Messages to Bennu!" should submit their name online no later than Sept. 30 at: http://planetary.org/bennu

After a person submits their name, they will be able to download and print a certificate documenting their participation in the OSIRIS-REx mission.

Once the capsule with the sample deploys, the spacecraft will be placed into a long-term orbit around the sun, along with the microchip and every name on it.

NASA says the OSIRIS-REx science mission will help identify the population of potentially hazardous near-Earth objects, as well as those suitable for asteroid exploration missions.

U.S. President Barack Obama has indicated that his goal is to send humans to an asteroid by 2025.

Source: The Canadian Press

It's well known that identical twins are not totally identical - they can, usually, be told apart, after all. But up to now it has been almost impossible to distinguish their DNA. It's claimed that a new test can do it quickly and affordably, however - and this could help police solve a number of crimes.

At the end of 2012, six women were raped in Marseille, in the south of France. Evidence, including DNA, led police to not one, but two suspects - identical twins Elwin and Yohan. Their surname was not revealed. When asked to identify the attacker, victims recognised the twins but couldn't say which one had assaulted them.

Police are struggling to work out which one to prosecute. They have been holding the brothers in custody since February - each twin says he didn't carry out the attacks, but neither is blaming the other.

When the twins were arrested, media reports said tests to determine who to charge with the crimes would be prohibitively expensive, but that looks set to change. Scientists specialising in genomic research at the Eurofins laboratory in Ebersberg, Germany, say they can now help in cases like this.

The human genome consists of a three-billion-letter code," says Georg Gradl, their next-generation sequencing expert. "If the body is growing, or an embryo is developing, then all the three billion letters have to be copied.

"During this copying process in the body there are 'typos' happening," says Gradl, referring to slight mutations.

In standard DNA tests only a tiny fraction of the code is analysed - enough to differentiate between two average people, but not identical twins.

In a finding that overturns the conventional view that large old trees are unproductive, scientists have determined that for most species, the biggest trees increase their growth rates and sequester more carbon as they age.

In a letter published today in the journal Nature, an international research group reports that 97 percent of 403 tropical and temperate species grow more quickly the older they get. The study was led by Nate L. Stephenson of the U.S. Geological Survey Western Ecological Research Center. Three Oregon State University researchers are co-authors: Mark Harmon and Rob Pabst of the College of Forestry and Duncan Thomas of the College of Agricultural Sciences.

The researchers reviewed records from studies on six continents. Their conclusions are based on repeated measurements of 673,046 individual trees, some going back more than 80 years.

This study would not have been possible, Harmon said, without long-term records of individual tree growth. "It was remarkable how we were able to examine this question on a global level, thanks to the sustained efforts of many programs and individuals."

Extraordinary growth of some species, such as Australian mountain ash -- also known as eucalyptus -- (Eucalyptus regnans), and the coast redwood (Sequoia sempervirens) is not limited to a few species, the researchers said. "Rather, rapid growth in giant trees is the global norm and can exceed 600 kg (1,300 pounds) per year in the largest individuals," they wrote.