The first river otter seen in the city in decades has become a local celebrity -- and harbinger of cleaner water.

A rapt crowd followed a trail of bubbles that zipped over the surface of a seaside pond in the ruins of a 19th century bath in San Francisco.

San Francisco's newest star - the first river otter seen in the city in decades - surfaced its whiskery head furtively, a mouth full of sea grass. The crowd oohed as large waves pounded rocks just offshore, a briny smell and chill in the air.

The otter ducked back under water and took the sea grass underneath a concrete remnant of the historic baths, where the animal was building a nest.

"We came here to see the baths and this was just a bonus," said Eliza Durkin, who brought her son Jonathan to the site for a school project on historic places.

Beyond tourists, the otter has mystified and delighted conservationists, who are piecing together clues to figure out how he got there. The whiskery creature was first spotted by birdwatchers in September and has since settled into the City by the Bay.

River otters once thrived in the San Francisco Bay area, but development, hunting and environmental pollution in the 19th and 20th centuries has taken its toll on the once thriving local population.

The creatures are a living barometer of water quality - if it's bad they cannot thrive. But new populations being seen north and east of San Francisco are giving hope to conservationists that years of environmental regulations and new technologies are making a difference.

Pipeline spills caused by flooding and riverbed erosion dumped 2.4 million gallons of crude oil and other hazardous liquids into U.S. waterways over the past two decades, according to a new report from federal regulators.

The Department of Transportation report to Congress was crafted in response to a 2011 spill into Montana's Yellowstone River. The spill highlighted gaps in federal pipeline rules that require lines to be buried just 4 feet below riverbeds - scant cover that can quickly be scoured away by floodwaters.

The Associated Press obtained the report this week before its public release.

Regulators found flood-related pipeline spills since 1993 in California, Texas, Iowa, Louisiana, Montana, Nebraska, South Dakota and Kentucky. Of the 2.4 million gallons of oil, gasoline, propane and other hazardous liquids released, less than 300,000 gallons were recovered.

There is a lot of excitement about Comet ISON, which might become a very bright comet, visible across the globe, by the end of 2013. But, before that happens, a second comet might become visible to the eye alone around the time it is closest to the sun in March of 2013. The Pan-STARRS telescope in Hawaii discovered this comet in June 2011. Since comets carry the names of their discoverers, it has been designated C/2011 L4 (PANSTARRS). Only the largest telescopes on Earth could glimpse Comet PANSTARRS when it was first discovered, but amateurs telescopes began to pick it up by May 2012. By October 2012, its surrounding coma was seen to be large and fine at an estimated 75,000 miles (120,000 kilometers) wide. In March 2013, by some estimates, this comet should get as bright as Venus, but do remember that comets are notoriously difficult to predict. As comet-hunter David Levy once famously said:

Comets are like cats; they have tails, and they do precisely what they want.

Colossal magnetized fountains of gamma-ray-emitting gas are spewing from the center of our Milky Way galaxy, researchers say.

The amount of magnetic energy contained in these geyser-like outflows "corresponds to the energy liberated by about a million supernova explosions - that is a lot!" study lead author Ettore Carretti, an astrophysicist at the Commonwealth Scientific and Industrial Research Organization in Australia, told SPACE.com.

These outflows could help solve mysteries concerning the magnetic field of the Milky Way galaxy, Carretti added.

Radiation in space might harm the brains of astronauts in deep space by accelerating the development of Alzheimer's disease, a new study on mice suggests.

The research reveals another risk that manned deep-space missions to places such as Mars or the asteroids could pose, scientists added.

"This study shows for the first time that exposure to radiation levels equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer's disease," study author Kerry O'Banion, a neuroscientist at the University of Rochester Medical Center, said in a statement.

Absolute zero is often thought to be the coldest temperature possible. But now researchers show they can achieve even lower temperatures for a strange realm of "negative temperatures."

Oddly, another way to look at these negative temperatures is to consider them hotter than infinity, researchers added.

This unusual advance could lead to new engines that could technically be more than 100 percent efficient, and shed light on mysteries such as dark energy, the mysterious substance that is apparently pulling our universe apart.

An object's temperature is a measure of how much its atoms move - the colder an object is, the slower the atoms are. At the physically impossible-to-reach temperature of zero kelvin, or minus 459.67 degrees Fahrenheit (minus 273.15 degrees Celsius), atoms would stop moving. As such, nothing can be colder than absolute zero on the Kelvin scale.

The U.S. military is already using, or fast developing, a wide range of technologies meant to give troops what California Polytechnic State University researcher Patrick Lin calls "mutant powers." Greater strength and endurance. Superior cognition. Better teamwork. Fearlessness.

But the risk, ethics and policy issues arising out of these so-called "military human enhancements" - including drugs, special nutrition, electroshock, gene therapy and robotic implants and prostheses - are poorly understood, Lin and his colleagues Maxwell Mehlman and Keith Abney posit in a new report for The Greenwall Foundation (.pdf), scheduled for wide release tomorrow. In other words, we better think long and hard before we unleash our army of super soldiers.

If we don't, we could find ourselves in big trouble down the road. Among the nightmare scenarios: Botched enhancements could harm the very soldiers they're meant to help and spawn pricey lawsuits. Tweaked troopers could run afoul of international law, potentially sparking a diplomatic crisis every time the U.S. deploys troops overseas. And poorly planned enhancements could provoke disproportionate responses by America's enemies, resulting in a potentially devastating arms race.

Back at the beginning of December NASA and NOAA unveiled some of the marvelous new visible light imagery of Earth at night at the American Geophysical Union (AGU) meeting in San Francisco. There was so much new and exciting in these images that I didn't manage to get around to highlighting one of my favorites: seeing Earth illuminated by moonlight.

Astronomers have used the ALMA telescope to get their first glimpse of a fascinating stage of star formation in which planets forming around a young star are helping the star itself continue to grow, resolving a longstanding mystery. The young system, about 450 light-years from Earth, is revealing its complex gravitational dance to the ever-sharpening vision of the Atacama Large Millimeter/submillimeter Array (ALMA), scheduled for completion this year.

As young stars gather material from their surrounding clouds of gas and dust, the incoming material forms a flat, spinning disk around the star. Planets begin as small clumps within that disk that, through their gravitational pull, add to their mass. As the planets pull in more material, they also leave a wake in their trail that clears out a gap in the disk. Such gaps have been observed in the dust disks surrounding a number of still-forming solar systems.

During this process, the star also continues to grow more massive, leading to the question of how material can get through the gap cleared by the protoplanets and onto the star.

"This has been a bit of a mystery, but now we have found a process that allows the star to continue to grow despite the gap," said Simon Casassus, of the University of Chile and the Millennium Nucleus for Protoplanetary Disks, who led an international research team.

First, the scientists found that the gap is not empty, but is filled by thin, tenuous gas, as shown by ALMA detection of carbon monoxide. "Whereas dust is severely depleted within the gap, some residual gas remains," said Gerrit van der Plas, of the University of Chile. "This agrees with predictions for gap clearing by a planetary-mass body," he added.

Here's a pretty cool interactive map made by Brandon Martin-Anderson showing, according to census data, every single person in the United States and Canada. The map uses the 2010 US census and the 2011 Canadian census, for a total of 341,817,095.

But interestingly, there are no other visual aids--no landmarks, no borders, no rivers or lakes. So if you want to find yourself, you'll have to go by population groups, which gets pretty difficult as you zoom further in. Unless you live in Nunavut or something.

Source: BMander