Last year, using the exoplanets discovered by the Kepler space telescope as a guide, astronomers took a statistical stab at estimating the number of exoplanets that exist in our galaxy. They came up with at least 50 billion alien worlds.

Today, astronomers from the Space Telescope Science Institute (STScI) in Baltimore, Md., and the PLANET (Probing Lensing Anomalies NETwork) collaboration have taken their own stab at the "galactic exoplanetary estimate" and think there are at least 100 billion worlds knocking around the Milky Way.

Why has the estimate doubled? The key difference here are the methods used to detect alien worlds orbiting distant stars.

The Kepler space telescope watches the same patch of sky -- containing around 100,000 stars -- and waits for slight "dips" in starlight brightness. This dip occurs when an exoplanet passes in front of its parent star, thereby blocking a tiny fraction of light from view.

A new index assessing the vulnerability of the world's stocks of weapons-grade nuclear material produces some surprising results.

The Nuclear Threat Initiative, a respected non-proliferation think tank, and the Economic Intelligence Unit have produced a new ranking system to assess the security of the world's scattered stocks of weapons-grade uranium and plutonium.

The NTI Nuclear Materials Security Index is meant to be a measure of how vulnerable those stocks are to theft by terrorists or criminal groups. It is also intended to provide a baseline for assessing progress in locking those stockpiles up, ahead of the next Nuclear Security Summit, due in Seoul at the end of March.

The authors insist this is about establishing an objective view of the work still to be done to meet Barack Obama's ambitious goal to secure the global stockpiles by 2014. This is not about "naming and shaming" they insist. But if you publish a list comparisons are going to be made.

New "Eco-Bulbs" originally scheduled to become mandatory January 1, 2012 have been pushed back to October. On the horizon however are "Bio-Bulbs"

As late-night workers and long-distance travelers already know, shifting time zones or work periods throws the body's natural clock out of whack.

Even regular folks often find it nearly impossible to get a restful sleep for several hours after sitting under bright lights after the sun has gone down (some call it the Fenway Park phenomena).

Now a Florida inventor is testing a new LED bio-bulb that could regulate the body's circadian rhythm by helping control the production of melatonin, the body's sleep hormone that tells us when it's nighttime.

A 47-million-year-old primate may have been a fashionista of sorts, as new analysis of the fossil suggests it sported grooming claws.

Besides helping the primate rake through its fur, particularly in hard-to-reach spots, the grooming claw presents a puzzle of sorts for scientists studying the relationship between a group that includes humans, apes and monkeys, and the family that includes lemurs.

That's because the primate is the first extinct North American primate with a toe bone showing features associated with the presence of both nails and a grooming claw.

Traditionally, it's thought that primates with a toe attachment called a grooming claw were more closely related to lemurs, which are primates like us but are considered more primitive and part of a different family than great apes (including humans) and monkeys. In lemurs, the claw is located on the second toe.

So where does this newly examined specimen fit in? It was "either in the process of evolving a nail and becoming more like humans, apes and monkeys, or in the process of evolving a more lemurlike claw," study researcher Doug Boyer, of Brooklyn College of New York, said in a statement.

Here in Austin, Texas, attendees at the American Astronomical Society meeting are buzzing about the discovery of a possible supernova in the irregular galaxy NGC 3239 by amateurs Bob Moore, Jack Newton, and Tim Puckett.

The supernova showed up in this unfiltered CCD image that the trio took during an automated observing run on January 7th with a 16-inch (40-cm) reflector in Portal, Arizona. At that time the putative supernova was at magnitude 14.6; Puckett confirmed it at 14.4 the next day with the same scope. The most recent value is 13.9, and it might continue to brighten before the explosion reaches its peak.

Several professional astronomers at the meeting have already started putting out e-mails and calls for spectroscopic observations. They hope to catch the supernova early and gain important information about what kind of explosion it is and, perhaps, what its progenitor was. Nothing shows up at this position in images taken by Puckett two weeks ago - at least, nothing brighter than magnitude 19.

When David Carroll wanted to find a way to make low-cost solar panels, he discovered he needed look no further than his own backyard.

In a weedy part of his Winston-Salem lot, pokeweed grows in wild, red-caned riot. Birds love the purple berries, and soon, so did Carroll. Because with pokeberries, the Wake Forest University scientist believes he's found a key to supplying electricity to parts of the developing world.

One Friday last year, Carroll, director of the Center for Nanotechnology and Molecular Materials at Wake Forest, was meeting with his students, brainstorming ways to get solar power to impoverished communities.

Traditional silicon solar panels are great, they agreed. But to make them, you need costly materials and a high-tech factory.

"We were sitting around thinking about the problem of how do you make it really, really cheap - and you can't get around the fact that (if you do), it's not going to be a very good solar cell. So it has to be very cheap to be worth it," Carroll recalled.

Natural dyes from plants rich in compounds called flavonoids can produce electrical current when sandwiched between the layers of a solar cell, in the spot where silicon would normally go.

The signs of aging show up in our genes as the protective caps on the ends of packets of our DNA, called chromosomes, gradually wear away over time.

Now, scientists have found that the length of these caps, called telomeres, measured early in life can predict life span.

Using 99 zebra finches, a small bird also popular as a pet, a team of researchers in the United Kingdom measured the lengths of the telomeres found in the birds' red blood cells over the course of their lives.

They found the length of the telomeres at the first measurement, made 25 days after the birds hatched, was the strongest predictor of how long the birds actually lived.

In addition, the birds with the longest telomeres early in life, and throughout the study, were the ones most likely to live into old age, up to 8.7 years old - a "ripe old age" for a finch, said study researcher Britt Heidinger, a postdoctoral researcher at the University of Glasgow.

For relatively long-lived vertebrates, such as zebra finches and humans, aging and telomere loss appear to go hand-in-hand. And while it seems reasonable that telomere length early on could predict life span in humans, too, it's not yet certain, since no similar study has been completed in humans, according to Heidinger.

Extracting DNA from a museum collection of jellied autopsied brains dating back to the 1890s may give researchers a new take on the study mental disorders

Among the bloodletting boxes, ether inhalers, kangaroo-tendon sutures and other artifacts stored at the Indiana Medical History Museum in Indianapolis are hundreds of scuffed-up canning jars full of dingy yellow liquid and chunks of human brains.

Until the late 1960s the museum was the pathology department of the Central Indiana Hospital for the Insane. The bits of brain in the jars were collected during patient autopsies performed between 1896 and 1938. Most of the jars sat on a shelf until the summer of 2010, when Indiana University School of Medicine pathologist George Sandusky began popping off the lids.

Frustrated by a dearth of postmortem brain donations from people with mental illness, Sandusky - who is on the board of directors at the museum - seized the chance to search this neglected collection for genes that contribute to mental disorders.

In an effort to make data storage more cost-effective, a group of researchers from National Tsing Hua University in Taiwan and the Karlsruhe Institute of Technology in Germany have created a DNA-based memory device that is "write-once-read-many-times" (WORM), and that uses ultraviolet (UV) light to make it possible to encode information. The device, described in a paper accepted to the AIP's Applied Physics Letters, consists of a thin film of salmon DNA that has been embedded with silver nanoparticles and then sandwiched between two electrodes. Shining UV light on the system enables a light-triggered synthesis process that causes the silver atoms to cluster into nano-sized particles, and readies the system for data encoding. In some cases, using DNA may be less expensive to process into memory devices than using traditional, inorganic materials like silicon, the researchers say.

At 2:46 pm on a Friday afternoon in March last year, residents in the prefecture of Fukushima in Japan were jolted by a magnitude 9.0 earthquake centered off the Pacific coast at a depth of approx 15 miles. Almost immediately, three of the six reactors which were in operation at that moment in the Fukushima Daiichi nuclear power plant - located on the eastern shore of Honshu Island - automatically shut down as a result of the shaking.

The plant automatically switched to its backup diesel-fueled generators to supply the uninterrupted electric power required to keep the plant's reactors cooled. Approximately one hour later, a 46 foot tall tsunami wave swept over the seawall between the Fukushima plant and the Pacific Ocean, flooding and disabling the backup generators and washing away their fuel tanks. The seawall had been designed to withstand a 19 foot wave and was considered sufficient to protect the plant from the worst possible tsunami that could ever happen.

We know now that within days, fuel rods in three of the reactors melted and breached the reactor containment structures designed to keep radioactive material from escaping into the environment, though nothing of the sort was revealed at the time. We are still not certain how much airborne radioactive contamination escaped.

There were violent explosions and multiple fires at the plant which some observers now indicate were far more serious than how they were initially portrayed. There were, and continue to be, unspecified large releases of extremely contaminated water into the Pacific Ocean, but no data on what the results of that might be. It took several months for TEPCO, the Japanese utility company running the plant, to publicly admit the severity of the accident. There have been repeated 'explanations' that downplayed, understated or outright ignored the risks to the public and hid the reality of what was actually happening at any given time.