We all know that the fearsome dinosaurs (and a host of other creatures) perished when a large meteor (size of a small city) slammed into Earth some 65 million years ago. The impact crater is widely believed to be the Chicxulub Crater, near the present-day village of Chicxulub on the Yucatan Peninsula. Scientists (Richard Muller and his graduate student, Robert Rohde, from UC Berkeley) are now reporting that such extinctions took place with surprising regularity. A painstaking computer model, going back 500 million years, suggests that (about) 70% of the earth species are destroyed every 62 million years or so.

Chicxulub Crater (Courtesy: UC Berkeley)The researchers analyzed data that cover the first and last known appearances of no fewer than 36,380 separate marine genera, including millions of species that once thrived in the world's seas, disappeared, and in many cases returned.
The explanations might include quirks of Solar Dynamics (some hidden solar cycle), a companion star to our sun (which might occassionally nudge the asteroids in the Oort Cloud), or even the solar system passing through the Galactic Plane (resulting in a higher chance of comet/asteroid impact). There is also the possibility of a Earth cycle that perhaps triggers volcanoes/earthquakes or other natural disasters.
Are we already due for another major extinction? Scientists do not know yet. It might be a long drawn phenomenon, or a quick culling. Take your pick.

Scientists have found conclusive proof that raptors (a form of bird-like, meat-eating dinosaur) once roamed the Southern Hemisphere. Researchers from the Ohio State University and Argentine Museum of Natural History have discovered 90 million old fossils of Neuquenraptor Argentinus in Patagonia (at the southern tip of South America). The findings were published in the current issue of the journal Nature.

Raptor Foot Fossil (Courtesy: Argentine Museum of Natural History) The bones were first discovered in 1996. However, it took this much time to clean up, match, and map all the bones against a database of other fossils, which finally allowed the scientists to identify the bones to that of a raptor. The raptor lived during the late Cretaceous period (146-65 million years ago: the last of the three periods in the Mesozoic era, which also includes the Jurassic and the Triassic periods). This was roughly during the famed Velociraptor immortalized in the movie Jurassic Park.
During this era, the earth only had two giant supercontinents: Gondwana (composed of South America, Africa, Antarctica, India, and Australia, and at one time Florida and part of southwest Europe), and Laurasia (composed of North America, Europe, and Asia), the two completely separated by an ancient ocean. Velociraptors and its cousins roamed the Laurasia, whereas the Argentine raptor lived in Gondwana. This is what makes this find so unique: it suggests that the raptors were split up before Gondwana and Laurasia separated, some 150 million years ago, during the late Jurassic period.
Until now, all the raptor fossils were discovered in the Laurasian landmass. This is the first time some fossil has been located in the Gondwanan mass, and this will allow scientists to compare the fossils from the two regions and form a more accurate picture of the fearsome lizards that once roamed the earth.

Today's is a light-hearted post :-).
This could be the next craze ;-). A group of scientists are offering a service to beam your calls directly to creatures from outer space. As reported by NewScientist, people can log on to the website TalkToAliens, dial a premium rate US number (1-900-226-0300) and have their call routed through a transmitter and sent into space through a 3.2-metre-wide dish in central Connecticut, US. The service is pitched as the World's First Intergalactic Communication System (designed by humans).

Can I take your order? (Courtesy: Round Lake Area Library)The service was launched on February 27, 2005, and will cost users $3.99 (32.21 Darsek, a Klingon currency) a minute. The antenna will not be aimed at stars with potential to harbor life. Instead, it will be tracked across the milky way galaxy (perhaps to ensure that a passing starship could get some on-board recreation). The power output of the antenna could be received at a distance of 2 light-years, using earth technology, but the scientists are perhaps reasonably sure alien technology would be more efficient.
Perhaps not surprisingly, the service has been a hit. Since the alien hotline was turned on, the site has fielded hundreds of calls, averaging about three minutes each. The company would not say how many of these could be from extra-terrestrials living on earth, just trying to call home.
Right now, the service is strictly one-way. But I still think text-messaging the aliens is a better idea.

Retroviruses are viruses that embed themselves in the chromosomes/DNA of a species. When they infect the sperm/egg cells, they also affect the future generations of the species. A retrovirus struck the ancestors of modern day chimpanzees and gorillas some 4 million years ago, but somehow the ancestors of humans (and other apes such as orangutans and gibbons) escaped from its effects. Researchers from University of Washington say that the virus might have affected the evolution of chimps and gorillas. The research appears in the April issue of the journal Public Library of Science-Biology, which is available online on March 1.

Primate Tree (Courtesy: Northern State University)The researchers were studying portions of the so-called junk DNA (DNA that is not used to encode proteins or do any other useful function), when they found several similarities between the chimpanzee and gorilla DNAs. The human DNA lacks those portions, and the scientists were interested to know why. They compared the junk DNA with the database of virus genomes, and discovered that it was the remnant of a retrovirus, a type of virus that copies its genetic information into the host's genome. The virus probably infected the ancestors of the gorilla and chimpanzee. During this time, ancestors of humans were also living in Africa, but either they were far away from the affected region, or were not susceptible to the virus. Either way, it was perhaps a close call! Since retroviruses have the tendency to alter genetic sequences, if that had happened to our direct ancestor, there might not have been any of us today!
Several copies of the virus was found in the chimp/gorilla DNA, suggesting that the virus was at least partly successful in wiping out parts of these populations. Somehow the populations survived, but might have gone through a major period of culling, which perhaps reduced the genetic diversity in both species.

The Hubble telescope normally needs three gyroscopes to function properly. Due to budgetary/safety concerns, NASA has decided to bring Hubble down. Gyroscopes are used to prevent the telescope from tossing and tumbling in space. Currently, Hubble has four (functioning) gyros, and the fear was that if two were incapacitated (The gyros regularly break down, and astronauts have already replaced them twice), Hubble would not work any more, and efforts will not be made to fix it. Now it looks like Hubble can perhaps work even on two gyroscopes.

Hubble Space Telescope (Courtesy: Space Telescope Science Institute)Engineers at NASA have now developed software that would allow the telescope to run on only two gyros, leaving two on standby. The first full-scale test was conducted from 20 to 23 February. The fear was that with two gyros, the pictures will be blurred. But the tests found that the results are almost indistinguishable. This new setup will allow Hubble to stay up in orbit, possible till 2008! And we will keep getting the amazing pictures we all love so much :-):-).

How does a galaxy die? Either the stars burn out and the galaxy fades into oblivion, or the stupendous gravitational forces inside and outside the galaxy slowly rips it apart. This is what is about (well, in a billion years or so) to happen to NGC 1427A. According to HubbleSite, this irregular galaxy is under the gravitational grasp of a large gang of galaxies, called the Fornax cluster. Our poor galaxy is plunging headlong into this cluster at 600 kilometers per second.

NGC 1427A (Courtesy: HubbleSite)The shock waves generated due to the high speeds (the leading edge of the galaxy is compressing the interstellar gas in the Fornax cluster, resulting in high pressure regions) is causing a tremendous rate of stellar growth in this galaxy, especially the birth of new blue stars. This pressure wave is also responsible for the beautiful arrowhead outline of the galaxy which is over 20,000 light years long, and about 62 million light years away.

Update: Robot arm loses to human (here).

Six years ago, Dr. Yoseph Bar-Cohen, a physicist at NASA's Jet Propulsion Laboratory (JPL) issued a unique challenge: build a robotic arm using artificial muscles that could arm wrestle a human. The results of that challenge will be determined next week, when three such robotic arms will "step into the ring" to compete against a 17- year-old high school student. The ultimate goal is to win against the strongest human on Earth.

An artist's concept of electroactive polymers (Courtesy: NASA)The goal originally was to jump-start research in electroactive polymers, also known as artificial muscles. If the robotic arm wins, it will open doors for many engineering technologies in medicine, military defense and even entertainment. Electroactive polymers are simple, lightweight strips of highly flexible plastic that bend or stretch when put into contact with chemicals or electricity. They are quiet and shatterproof and can be used to imitate human muscle movements.
The three artificial arms and their teams come from around the world. Researchers from New Mexico and Switzerland built arms made of plastics and polymers. A group of students from Virginia Tech University in Blacksburg, Virginia will also test their arm invention made of gel fibers and electrochemical cells.
For more information about the competition, visit here.