A meteor that exploded in the skies above Russia’s Ural Mountains was the largest since the Tunguska blast in Siberia in 1908 and released about 33 times the energy of the atomic bomb that destroyed Hiroshima.

Before hitting the Earth’s atmosphere yesterday, the object was about 17 meters (55 feet) and had a mass of about 10,000 tons, the U.S. National Aeronautics and Space Administration said in a statement.

The meteor, which hit 16 hours before an asteroid half the length of a football field hurtled past Earth, has prompted calls to be more vigilant about the risks of strikes from space. Every day, 100 tons of dust and sand-size particles enter the Earth’s atmosphere, most of which burns up.

“We would expect an event of this magnitude to occur once every 100 years on average,” Paul Chodas of NASA’s Near-Earth Object Program Office said in the statement about yesterday’s explosion. The Chelyabinsk meteor released 500 kilotons of energy when it disintegrated above the city of Chelyabinsk at about 9:20 a.m. local time, according to NASA.

Unrelated to asteroid 2012 DA14, which flew past by Earth safely, the Chelyabinsk meteor hit the atmosphere at a speed of 18 kilometers per second (40,000 miles per hour) and broke apart 15 kilometers to 25 kilometers above the Russian city, according to NASA.

Shock Wave

The shock wave from the meteor blew out in 3,700 buildings windows in and around Chelyabinsk, the regional government said in a statement. About 1,150 people sought medical attention, of whom more than 50 were hospitalized, the Health Ministry said.

Burning streaks lit up the sky in videos that were caught by drivers on dashboard cameras, broadcast on Russian television and posted on YouTube. The force destroyed a warehouse wall at the OAO Chelyabinsk Zinc Plant and disrupted service by Russia’s second-biggest mobile operator, OAO MegaFon.

A piece of the meteor probably hit a frozen lake about 80 kilometers (50 miles) west of Chelyabinsk, Vadim Kolesnik, an Interior Ministry official, said yesterday by phone. A hole 8 meters in diameter was found in the ice, national television channel Rossiya 24 reported. There are two other possible impact sites, he said.

Divers exploring the lake haven’t found any pieces of meteorite, Rossiya 24 reported today.

The Tunguska event, which was the most powerful natural explosion in the modern era, leveled about 800 square miles (2,100 square kilometers) of forest in Siberia, while leaving no crater, according to NASA. The asteroid that scientists say plowed into Earth about 66 million years ago, wiping out the dinosaurs, may have been about 6 miles in diameter.

A United Nations team met in Vienna this week to come up with recommendations on how best to track, and someday deflect or destroy, orbiting space rocks.

Read More »

Washington: Astronomers have identified "cosmic web stripping" as a new way of explaining the famous missing dwarf problem: the lack of observed dwarf galaxies compared with that predicted by the theory of cold dark matter and dark energy. 

High-precision observations over the last two decades have indicated that our universe consists of about 75 percent dark energy , 20 percent dark matter and 5 percent ordinary matter. 

Galaxies and matter in the universe clump in an intricate network of filaments and voids, known as the cosmic web. 

Computer experiments on massive supercomputers have shown that in such a universe a huge number of small "dwarf" galaxies weighing just one thousandth of the Milky Way should have formed in our cosmic neighborhood. Yet only a handful of these galaxies are observed orbiting around the Milky Way. The observed scarcity of dwarf galaxies is a major challenge to our understanding of galaxy formation. 

An international team of researchers has studied this issue within the Constrained Local Universe Simulations project (CLUES). The CLUES simulations use the observed positions and peculiar velocities of galaxies within 10,000,000 light-years of the Milky Way to accurately simulate the local environment of the Milky Way. 

"The main goal of this project is to simulate the evolution of the Local Group-the Andromeda and Milky Way galaxies and their low-mass neighbors-within their observed large scale environment", said Stefan Gottlober of the Leibniz Institute for Astrophysics Potsdam. 

Analyzing the CLUES simulations, the astronomers have now found that some of the far-out dwarf galaxies in the Local Group move with such high velocities with respect to the cosmic web that most of their gas can be stripped and effectively removed. 

They call this mechanism "cosmic web stripping", since it is the pancake and filamentary structure of the cosmos that is responsible for depleting the dwarfs' gas supply. 

"These dwarfs move so fast that even the weakest membranes of the cosmic web can rip off their gas", explained Alejandro Benitez Llambay, PhD student at the Instituto de Astronomia Teorica y Experimental of the Universidad Nacional de Cordoba in Argentina, and first author of the publication of this study. 

Without a large gas reservoir out of which to form stars, these dwarf galaxies should be so small and dim that they would be hardly be visible today. The missing dwarfs may simply be too faint to see. 

Read More »

Washington: Medical illustrators and neurological imaging experts have figured out how night-hunting owls can almost fully rotate their heads without damaging the delicate blood vessels in their necks and heads, and without cutting off blood supply to their brains. 

Combining angiography, CT scans and medical illustrations to examine the anatomy of a dozen of the big-eyed birds, the Johns Hopkins team, led by medical illustrator Fabian de Kok-Mercado, found four major biological adaptations designed to prevent injury from rotational head movements. 

"Until now, brain imaging specialists like me who deal with human injuries caused by trauma to arteries in the head and neck have always been puzzled as to why rapid, twisting head movements did not leave thousands of owls lying dead on the forest floor from stroke," says senior investigator and interventional neuroradiologist Philippe Gailloud, the journal Science reports. 

"The carotid and vertebral arteries in the neck of most animals -- including owls and humans -- are very fragile and highly susceptible to even minor tears of the vessel lining," adds Gailloud, associate professor of radiology at the Johns Hopkins University School of Medicine. 

Sudden gyrations of the head and neck in humans have been known to stretch and tear blood vessel linings, producing clots that can break off and cause a deadly embolism or stroke, according to a John Hawkins statement. 

Researchers say these injuries are commonplace, often resulting from whiplashing car accidents, but also after jarring roller coaster rides and chiropractic manipulations gone awry. 

The most striking findings came after researchers injected dye into the owls' arteries, mimicking blood flow, and manually turned the animals' heads. 

Blood vessels at the base of the head, just under the jaw bone, kept getting larger and larger, as more of the dye entered, and before the fluid pooled in reservoirs. This contrasted starkly with human anatomical ability, where arteries generally tend to get smaller and smaller, and do not balloon as they branch out. 

"Our in-depth study of owl anatomy resolves one of the many interesting neurovascular medical mysteries of how owls have adapted to handle extreme head rotations," says de Kok-Mercado, a scientific illustrator and animator at the Howard Hughes Medical Institute. 

Read More »

Russia will resume a long-dormant quest to explore the moon by sending an unmanned probe there in 2015, the head of the space agency was quoted as saying on Tuesday.

The craft, called Luna-Glob, or Moon-Globe, will be carried by the first rocket to blast off from a new facility that Russia is building in its far eastern Amur region, Roskosmos director Vladimir Popovkin said, according to the Interfax news agency.

"We will begin our exploration of the moon from there," he said of the new space centre that will decrease Russia's reliance of the Baikonur Cosmodrome in the ex-Soviet nation Kazakhstan, which it leases.

Russian space officials have said Luna-Glob would consist of an orbital module and a probe that would land on the moon and beam back information about samples it takes from the surface.

The Soviet Union got a jump on the United States in the Cold War space race, sending a probe to the moon in 1959 and putting the first person into space in 1961. But the United States first put a man on the moon in 1969 and Russia has not done so.

The last successful Soviet launch of a unmanned probe to the moon was in the 1970s, and Russia has suffered setbacks in its space program in recent years, including bungled satellite launches and the failure of a Mars probe in 2011.

A successful rocket launch on Tuesday put three military satellites in orbit, the Defense Ministry said.

Prime Minister Dmitry Medvedev approved a plan last month to spend 2.1 trillion roubles ($70 billion) on space industry development in 2013-2020, to pursue projects to explore the moon and Mars, among other things.

Read More »

London: In a new study, researchers have shed light on a peculiar tentacled marine creature that lived 520 million years ago. 

Experts thought that Cotyledion tylodes may have belonged to the jellyfish-like cnidarian group, but new anatomical evidence from the animal's fossilised remains suggests the species was an early member of the group of small marine organisms called entoprocts. 

Results of the study, by an international research team, suggest that entoprocts appeared earlier than previously thought. 

Entoprocts are small organisms that feed by straining food particles from water. 

Scientists analysed hundreds of Cotyledion tylodes fossils preserved in the Chengjiang fossil site in Yunnan province, China, dating from the Cambrian geological period (545 to 495 million years ago). 

To date, the only uncontested fossil entoproct comes from the Jurassic (205 to 142 million years ago). 

However this reinterpretation of Cotyledion tylodes as an entoproct places the fossil record of this group in the earlier Cambrian period. 

Some anatomical characteristics of Cotyledion tylodes are comparable to those of modern entoprocts, especially the presence of a U-shaped gut with a mouth and anus surrounded by a crown of tentacles. 

"This is... the first time to confirm that [Cotyledion tylodes] had a U-shaped gut accommodated in the calyx cavity," BBC quoted Zhifei Zhang from Northwest University, Xi'an city, Shaanxi Province, China, as saying. 

The bizarre-looking creature also had a goblet-shaped body with an upper cup-like cavity and lower elongated stalk, with which it "attached to exoskeletons of other organisms", Zhang explained.

Cotyledion tylodes was larger than extant entoprocts, measuring between 8mm and 56mm in height. Its body was covered in external, hardened structures called sclerites, which are not found on modern entoprocts. 

The "Cambrian explosion" saw the relatively sudden appearance of abundant life forms in the sea. 

Mr Zhang said that the team's reinterpretation of Cotyledion tylodes as belonging to the Entoprocta phylum adds further support to the idea that "nearly all the living phyla of animals suddenly appeared in the Cambrian". 

However, few fossil representatives of Lophotrochozoa (the superphylum containing the entoprocts group of animals) have been found in Cambrian fossil records. 

The study has been published in the journal Scientific Reports. 

Read More »