An outbreak of smallpox was the furthest thing from historian Dr. Paul Levengood's mind when his staff at the Virginia Historical Society put together an exhibit of "bizarre bits" that were added to the society's collection since its founding in 1831, The Wall Street Journal reported Thursday.

There was Confederate president Jefferson Davis's cigar, confiscated by Union troops. There was a fungus carving of Robert E. Lee on his horse, Traveller, and a wreath made of human hair.

Then someone mentioned a letter, handwritten and dated 1876, with what appeared to be a smallpox scab pinned inside -- light brown, about the size of a pencil eraser and crumbling.

The scab got the attention of the Centers for Disease Control and Prevention (CDC), home to one of the world's two known caches of live smallpox viruses.

Alerted by a government scientist in Maryland who was concerned that the scab might transmit infection, the agency dispatched two CDC representatives to Richmond. They donned disposable surgical gowns and gloves, lifted the scab from a display case, sealed it in bio-bags inside a red cooler and whisked it back to a high-security lab deep within the CDC's Atlanta headquarters.

The atmosphere is more than just the air above us. It's 5 layers protect us. Ed has more in this Weather 101.

An Amazonian tribe has no abstract concept of time, say researchers.

The Amondawa lacks the linguistic structures that relate time and space - as in our idea of, for example, "working through the night".

The study, in Language and Cognition, shows that while the Amondawa recognise events occuring in time, it does not exist as a separate concept.

The idea is a controversial one, and further study will bear out if it is also true among other Amazon languages.

The Amondawa were first contacted by the outside world in 1986, and now researchers from the University of Portsmouth and the Federal University of Rondonia in Brazil have begun to analyse the idea of time as it appears in Amondawa language.

"We're really not saying these are a 'people without time' or 'outside time'," said Chris Sinha, a professor of psychology of language at the University of Portsmouth.

"Amondawa people, like any other people, can talk about events and sequences of events," he told BBC News.

"What we don't find is a notion of time as being independent of the events which are occurring; they don't have a notion of time which is something the events occur in."

The Amondawa language has no word for "time", or indeed of time periods such as "month" or "year".

A new study suggests the Milky Way doesn't need a makeover: It's already just about perfect.

Astronomers base that assertion on their discovery of a vast section of a spiral, star-forming arm at the Milky Way's outskirts. The finding suggests that the galaxy is a rare beauty with an uncommon symmetry -- one half of the Milky Way is essentially the mirror image of the other half.

Thomas Dame and Patrick Thaddeus of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., say the structure they've discovered is most likely the outer extension of the Scutum-Centaurus arm from the inner galaxy. The finding suggests that Scutum-Centaurus wraps all the way around the Milky Way, making it a symmetric counterpart to the galaxy's other major star-forming arm, Perseus.

The two arms appear to extend from opposite ends of the galaxy's central, bar-shaped cluster of stars, each winding around the galaxy, the researchers note in an upcoming issue of Astrophysical Journal Letters.

Dame found evidence for the new structure while reviewing galactic data on atomic hydrogen gas, which radiates at a radio wavelength of 21 centimeters. After tracing the extension of the arm in the 21-centimeter radio emission, "I was in the unique position of being able to walk up two flights of stairs to the roof of my building [at Harvard] and search for carbon monoxide emissions from molecular clouds using the CfA 1.2-meter radio telescope," says Dame. Molecular gas clouds contain the raw material for making stars.

Although "doomsday" is quite unlikely from one day to the next, a humanity-exterminating event could strike at any moment. It could happen suddenly in the form of a giant, non-catalogued asteroid, or more slowly through the spread of a mutated or never-before-encountered monster virus.

Rest assured, however, that doomsday will not be a foretold supernatural event falling on a pre-selected, arbitrary date, such as tomorrow, May 21, 2011, despite the claims of a fringe Christian broadcaster in California. (Ditto for the 2012 Mayan calendar hoopla.)

But should doomsday come, and the planet were to become uninhabitable, what might humanity do to survive?

In the short term, with the end of days nigh, the outlook is bleak. Although the concept of a last-resort, fleeing-for-the-stars planetary evacuation has been given thought, it has not received any dedicated action.

Gaining knowledge of how to preserve our civilization down the eons has been a lesser-cited rationale for further advancing human spaceflight abilities. As theoretical physicist Stephen Hawking put it to Big Think last year, "our only chance of long-term survival is not to remain inward-looking on planet Earth, but to spread out into space."

Toxic chemicals are accumulating in the bodies of dolphins and whales, according to two new studies, and concentrations tend to be highest in the most populated and developed areas.

The findings are not necessarily surprising. Scientists have known for years that the blubber of marine predators harbors pollutants. Still, the new studies offer the most extensive evidence yet that dolphins and whales can be sentinels for environmental contamination. By documenting levels of chemicals in blubber, scientists can now start to gauge the effects of those chemicals on the animals' health and behavior.

The research may also help illuminate potential threats to human health. Dolphins, in particular, eat the same fish we do. So, finding lots of chemicals in a particular geographic pod can signal areas that may not be safe for fishing.

"Dolphins are a nice barometer in some ways for understanding contamination of the immediate environment," said John Kucklick, a research biologist at the National Institute of Standards and Technology in Charleston, S.C.

A fresh analysis of a fossil found in the 1970s suggests that the family trees for crocodiles, birds and dinosaurs diverged earlier than some may have thought.

The study represents the latest chapter in a long-running debate over the relationships between dinosaurs and the ancestors of two dissimilar types of modern-day creatures - crocs and birds.

Paleontologists have traced the ancestry of all three groups to a category of common ancestors called archosaurs. The archosaurs and their cousins lived around the time of Earth's deadliest die-off, the Permian-Triassic extinction, around 252 million years ago. Teasing out the details of the archosaurs' family tree is key to understanding how birds, dinosaurs and crocodiles are linked.

"This is one of the most interesting evolutionary questions in paleontology: the origin of birds in the broadest sense," Spencer G. Lucas, curator of paleontology at the New Mexico Museum of Natural History, told me today. "If you take crocodiles, birds and dinosaurs, how do you think that evolutionary tree came together?"

Most experts say birds could actually be considered the modern-day descendants of dinosaurs, while a relative few insist that dinosaurs were more closely related to crocodiles.

A new tool to look at the universe debuted Thursday, with the installation of the Alpha Magnetic Spectrometer, nicknamed AMS, on the International Space Station.

With a large powerful magnet, AMS samples from the stream of cosmic rays flying through space and processes them through a series of detectors to determine particle energy, electrical charge and position. Over time, physicists expect the mountain of data to shed light on dark matter, antimatter and other phenomena that are impervious to traditional telescopes. The 600-member science team, headed by Nobel laureate Samuel Ting with the Massachusetts Institute of Technology, plans to take things slow.

With a pricetag of about $2 billion and a multinational team from 60 research organizations, AMS took 17 years to come together. The effort was nearly derailed after the 2003 Columbia accident when NASA took away its ride on the shuttle. "This isn't going to happen again, so it's important to do this very, very systematically," Ting said Thursday.

The best views yet of a giant, once-in-a-generation storm on Saturn are now emerging, revealing how such tempests disrupt the ringed planet and create hot spots and cold vortexes, researchers say.

These findings could shed new light on the behavior of giant planets orbiting both alien stars and our sun. [Photo of Saturn's huge storm]

The atmosphere of Saturn normally appears calm, but about once per Saturn year - equal to about 30 Earth years - the giant world is gripped by a titanic storm as spring comes to its northern hemisphere. The current monster Saturn storm erupted last Dec. 5.

"This disturbance in the northern hemisphere of Saturn has created a gigantic, violent and complex eruption of bright cloud material, which has spread to encircle the entire planet," said researcher Leigh Fletcher, a planetary scientist at the University of Oxford in England.

An exploding star spotted in 2005 defies the curent theories and observations. The theory of how it ignited could explain something unexpected: Why we have calcium in our bones. Astronomers have reported a whole new type of supernova, which seems to spew out calcium and titanium. While most reports focused on the calcium, it's the titanium that's really interesting - the finding could negate ongoing efforts to find signs of dark matter at the center of the Milky Way.

The team of astronomers, led by Hagai Perets, at the Harvard-Smithsonian Center for Astrophysics, and Avishay Gal-Yam of the Weizmann Institute of Science in Rehovot, Israel, presented evidence that supernova SN 2005E is distinct from the two main classes of supernovae: Type Ia supernovae, thought to be old, white dwarf stars that accrete matter from a companion until they undergo a thermonuclear explosion that blows them apart entirely; and Type Ib/c or Type II supernovae, thought to be hot, massive and short-lived stars that explode and leave behind black holes or neutron stars.