The skeletons of two dozen children killed in an ancient mass sacrifice have been found in a tomb at a construction site in Mexico.

The find reveals new details about the ancient Toltec civilization and adds to an ongoing debate over ritualistic killing in historic Mesoamerica.

Construction crews unearthed the burial chamber this spring near the town of Tula, the ancient Toltec capital, 50 miles (80 kilometers) north of Mexico City.

The chamber contained 24 skeletons of children believed to have been sacrificed between A.D. 950 and 1150, according to Luis Gamboa, an archaeologist at Mexico's National Institute of Anthropology and History.

All but one of the children were between 5 to 15 years of age, and they were likely killed as an offering to the Toltec rain god Tlaloc, Gamboa said.

The long-running controversy about the origins of the Etruscan people appears to be very close to being settled once and for all, a geneticist will tell the annual conference of the European Society of Human Genetics today. Professor Alberto Piazza, from the University of Turin, Italy, will say that there is overwhelming evidence that the Etruscans, whose brilliant civilisation flourished 3000 years ago in what is now Tuscany, were settlers from old Anatolia (now in southern Turkey).

Etruscan culture was very advanced and quite different from other known Italian cultures that flourished at the same time, and highly influential in the development of Roman civilisation. Its origins have been debated by archaeologists, historians and linguists since time immemorial. Three main theories have emerged: that the Etruscans came from Anatolia, Southern Turkey, as propounded by the Greek historian Herotodus; that they were indigenous to the region and developed from the Iron Age Villanovan society, as suggested by another Greek historian, Dionysius of Halicarnassus; or that they originated from Northern Europe.

Now modern genetic techniques have given scientists the tools to answer this puzzle. Professor Piazza and his colleagues set out to study genetic samples from three present-day Italian populations living in Murlo, Volterra, and Casentino in Tuscany, central Italy. "We already knew that people living in this area were genetically different from those in the surrounding regions", he says. "Murlo and Volterra are among the most archaeologically important Etruscan sites in a region of Tuscany also known for having Etruscan-derived place names and local dialects. The Casentino valley sample was taken from an area bordering the area where Etruscan influence has been preserved."

Streams of hot gas swirling around Saturn have been traced to two icy moons previously thought to be geologically dead worlds.

The finding, detailed in the June 14 issue of the journal Nature, suggests Saturn's satellites Tethys and Dione might be volcanically active after all.

Known as plasma, the gas is composed of negatively charged electrons and positively charged ions, which are atoms with one or more electrons missing. After being ejected from the moons, the charged particles become trapped inside the magnetic field surrounding Saturn, called the magnetosphere.

A great escape

The particles remain trapped only temporarily, however, because Saturn spins so fast about its axis-a day there is only 10 hours and 46 minutes long-that it drags its magnetosphere and the trapped plasma inside it rapidly through space.

It's the cry of farmers when city folk visit: "Shut the bloody gate."

After three years of research, Australian scientists have come up with a solution to keeping the animals in - the virtual fence.

"It's like an electric fence, except it's invisible," Andrew Fisher, leader of a research team at the CSIRO's Livestock Industries division in Armidale, said yesterday.

A farmer would create the virtual fence by mapping out the proposed boundary using a computer linked to a satellite global positioning system.

The livestock to be fenced in would wear battery-powered collars around their necks. If a cow, for example, wandered within a metre or two of the virtual fence the collar, fitted with a GPS chip, would emit a warning hum. If the cow ignored the sound and crossed the line it would receive a mild electric shock, less powerful than those used by electric fences.

A rocket carrying an intelligence-gathering payload for the Pentagon suffered a technical problem after its launch, officials said. But they were confident Saturday that its secretive mission would be performed.

The Atlas V rocket launched Friday morning, hauling a payload from the National Reconnaissance Office, a division of the Department of Defense that builds and operates spy satellites.

Australian and US scientists successfully launched a supersonic scramjet engine at an Outback test range Friday, as they work on a device that could revolutionize air travel.

The researchers said a rocket carrying the scramjet reached speeds of mach 10 -- ten times the speed of sound -- after blasting off at the Woomera range in South Australia Friday.

The eagle screams, And with pale beak tears corpses. . . . Mountains dash together, Heroes go the way to Hel, And heaven is rent in twain. . . . All men abandon their homesteads When the warder of Midgard In wrath slays the serpent. The sun grows dark, The earth sinks into the sea, The bright stars From heaven vanish; Fire rages, Heat blazes, And high flames play 'Gainst heaven itself" R.B. Anderson, "Norse Mythology," 1875

NASA seems to spend a lot of time looking for and thinking of ways to divert errant asteroids that might possibly hit earth. However, they keep reassuring the public that the probability of actually being hit by an asteroid is extremely small. So why all the attention?

An irregularly-shaped space rock nearly 4 m in length and 1.5 to 2.3 m across has entered Earth's gravitational field claimed an amateur astronomer.

''The rock,named 6RIODB9, suddenly entered our planet's gravitational field on June 12 and is slowly making revolutions along the Earth. On June 17, it will be at a distance of nearly 203,000 km from our planet. A similar 'rock' was observed in September 2006 by The University of Arizona's Catalina Sky Survey,'' said Dr Ram S Shrivastava.

Plants on extrasolar planets resembling Earth could be as black as these eggplants. Scientists who speculate on plant life and what might constitute photosynthesis "out there" say that plant color depends on the size and light intensity that the planet feeds off from its star, or sun, as well as the extrasolar planet's atmospheric chemistry.

HOUSTON - Russian space officials said Friday they were considering moving up the launch of a Russian cargo ship as cosmonauts aboard the international space station struggled for a second day to reboot failed computers controlling the orbiting outpost's orientation.