An 80-million-year-old dinosaur fossil unearthed in the Gobi Desert of Mongolia demonstrates that miniaturization, long thought to be a hallmark of bird origins and a necessary precursor of flight, occurred progressively in primitive dinosaurs.

The find, described in the September 7 issue of the journal Science, is made up of the fossilized bones of a new dinosaur the researchers have named Mahakala, and includes portions of its skull, forelimb and hindlimb, as well as much of the vertebral column.

Mahakala is an early evolutionary offshoot of the group of carnivorous dinosaurs known as dromaeosaurids that also includes the agile, sickle-clawed Velociraptor made famous in the 1993 movie Jurassic Park.

Bog mummies are 2000-year-old mummies from the Iron Age that were preserved with amazing detail by the peat bogs of Europe.

Physical anthropologists draw conclusions from the eerily preserved hair, leathery skin and other features in the mummies that emerge from the bogs. In the Iron Age, from approximately 500BC to 500AD, people were often cremated, leading experts to believe that mummies preserved by the bogs were usually those who met their demise through particularly violent means or were used as sacrifices.

Bears don't rub trees because their backs are itchy. Dr Owen Nevin of the University of Cumbria states that adult male grizzly bears use so-called “rub trees” as a way to communicate with each other while looking for breeding females, and that this behavior could help reduce battles between the bears.

Many theories have been advanced as to why bears rub trees: some thought females might rub trees as they came into oestrous, and others that bears might be giving their backs a good scratch to get rid of parasites or pick up sap to act as insect repellent.

By 1763, the world of Cherokee Indians in the Southeastern U.S. was in tatters. The French and Indian War had wracked the sprawling Cherokee settlements that stretched from the headwaters of the Savannah River in South Carolina and Georgia to the Overhills towns in eastern Tennessee.

Though 75 years would pass before the Trail of Tears would banish the remnants of the nation west to Oklahoma, the tribe watched hopelessly as much of its history rapidly faded.

Researchers have long wondered why the Cherokee settled where they did, building clusters of small towns in fertile river valleys in mostly mountainous areas.

Scientists have also studied why the society collapsed with such relative speed as the eighteenth century unfolded.

252 million years ago a mass extinction of cataclysmic proportions occurred and the world was changed forever. Prior to that, ocean life was diverse and clam-like organisms called brachiopods dominated. After the extinction little else existed and a different kind of clam-like organism, called a bivalve, took over.

Why did it happen?

The Aurigid meteor shower peaked on September 1, originating from C/1911 N1 Kiess, or comet Kiess, a long-period comet that takes about 2000 years to orbit the Sun. It was discovered in 1935 by Carl Kiess.

As Earth passes through the dust comet Kiess left behind 2000 years ago, meteoroids, or shooting stars, rain upon Earth. They burn up in the atmosphere at very high velocities, about 67 km/s, creating the meteor shower.

The Aurigids get their name from the constellation Auriga, because if you look up in the sky, this is where the shooting stars seem to come from. The dust trail of comet Kiess will not be crossed again in this manner for 70 years.