Science & Medicine

Radar guns might spot suicide bombers

Santa Cruz, Calif. -- Radar guns used by police to spot speeding motorists could help identify suicide bombers by detecting the wiring in an explosive vest, U.S. researchers say.

A police radar gun fires pulses at a car and measures the shift of the reflected signal to calculate its velocity, but the strength and polarization of the reflected signal -- the "radar cross section" -- can provide additional information about the size and shape of the reflecting object and the material from which it is made, NewScientist.com reported.

Two researchers in California decided to see if the wiring in a suicide vest would alter the radar cross section of a bomber enough to allow a radar gun to pick him or her out in a crowd.

Galaxy-forming collision recreated

Paris -- Andromeda, the nearest spiral galaxy to our Milky Way, was born from the collision of two smaller galaxies, an international team of astronomers says.

The researchers conducted a computer simulation of how Andromeda has evolved over time, and the results suggest the two galaxies collided around 9 billion years ago and became permanently fused in the present Andromeda galaxy about 5.5 billion years ago, the BBC reported.

While astronomers can detect galaxies at the very edge of the universe, there is still much that is unknown about those in our immediate neighborhood, known as the Local Group of galaxies, team leader Francois Hammer of the Paris Observatory says.

Humans saving Britain's barn owls

London -- British barn owls are becoming increasingly dependent on humans, with three-quarters of the country's owls living in man-made nest boxes, conservationists say.

The barn owl population has been boosted by nest box installation programs, but the birds are now largely reliant on such measures, the BBC reported.

The British people have become the barn owls' custodians, the U.K.-based World Owl Trust says.

And without the nest boxes and other ongoing conservation efforts, the once-common birds could become increasingly rare, the group
says.

Between the 1930s and 1980s, their numbers fell from 12,000 breeding pairs to approximately 4,000, a 70-percent decline.

Jupiter's 'disappearing' stripe returning

Pasadena, Calif. -- NASA images show one of Jupiter's stripes that "disappeared" last spring is returning, revealing clues about the planet's winds and clouds, U.S. scientists say.

Amateur astronomers noticed earlier this year that a long-existing standing dark-brown stripe on the planet known as the South Equatorial Belt had turned white, NASA said.

Telescopes in Hawaii including NASA's Infrared Telescope Facility and instruments at the W.M. Keck Observatory and the Gemini Observatory suggest the vanished dark stripe is making a comeback.

Oxygen detected on Saturn moon

Pasadena, Calif. -- NASA's Cassini space probe orbiting Saturn has found evidence of an atmosphere on Rhea, one of the ringed planet's moons, U.S. researchers say.

The spacecraft has detected a very thin atmosphere containing oxygen and carbon dioxide around the icy moon, a NASA release said Friday.

This marks the first instance of a spacecraft directly capturing molecules of an oxygen atmosphere -- admittedly a very thin one -- at a world other than Earth, scientists said.

The formation of oxygen and carbon dioxide, as detected on Rhea, could possibly drive complex chemistry on the surfaces of many icy bodies in the universe, researchers say.

Ancient Egyptian lake as big as Lake Erie

Washington -- A dry, sand-covered region of Egypt was home 100,000 years ago to a lake as large as one of the Great Lakes, U.S. researchers say.

Radar images taken from the space shuttle confirm that a lake wider than Lake Erie once existed a few hundred miles west of the Nile River, ScienceNews.org reported.

From the time it first appeared about 250,000 years ago, the lake in Egypt's Tushka region would have grown and shrunk periodically until finally drying up about 80,000 years ago, researchers say.

After dinosaurs, mammals went supersized

Albuquerque -- When dinosaurs disappeared, the world's mammal species went on a growth binge and then hit an upper limit, all at about the same time, U.S. researchers say.

Scientists at the University of New Mexico making a survey of big-mammal body size found mammal groups around the world tended to give rise to giant species at about the same time, ScienceNews.org reported Thursday.

Such supersizing took about 20 million years after the disappearance of the dinosaurs, paleoecologist Felisa A. Smith says.

The few mammal species that survived the catastrophe that wiped out dinosaurs started small, "about the size of a baseball, certainly not as big as a football," Smith says.

China lags in scientific literacy

Beijing -- China is 20 years behind developed countries when it comes to scientific literacy but is gaining, a survey published Sunday indicates.

The China Association for Science and Technology said only 3.27 percent of Chinese have basic scientific literacy, Xinhua reported. That is up sharply from 1.6 percent in 2005 and 2.25 percent in 2007, said Ren Fujun, director of the China Research Institute for Science Popularization, which conducted the survey.

Yang Wenzhi, a science popularization director with the association, said the low literacy level stems from the country's slow development prior to the 1980s and poor quality education in the past.

Elephant trunk inspires robot arm

Esslingen, Germany -- German researchers say they've developed a robotic arm that uses an elephant's trunk as its inspiration to create a strong yet bendable appendage.

German automation company Festo, which developed the Bionic Handling Assistant, says it could safely operate around people in tight quarters in homes, schools and medical rehabilitation centers, LiveScience.com reported.

Rather than the metal skeletal bars and tubes that comprise conventional robotic arms, Festo's arm relies on the sequential inflation of tiny air bladders to accomplish movement.

The bladders line the interior of the arm like inflatable vertebrae, running the length of the arm in two rows.

Laser can make marks inside glass

Paris -- Borrowing a laser technology developed for space, a Belgian company says can inscribe marks in glass without cracking, heating or leaving any external marks.

Trackinside uses a low-impact laser to inscribe serial numbers inside, rather than on the surface, of glass used in medical syringes, ampules, perfume vials and drink bottles.

"It's the only technology that can mark glass without damaging it," Managing Director Jean Michel Mestrez said.

The technology was developed in Belgium as a process to etch lenses and mirrors for use in space telescopes and measuring equipment, a European Space Agency release said.

It works much like the laser used in eye surgery, which beams energy through the surface of the eye to make incisions deep below.

Gravity wave project takes important step

Pasadena, Calif. -- U.S. scientists say they're one step closer to "hearing" gravity waves, the ripples in space and time predicted by Albert Einstein in the early 20th century.

Engineers at NASA's Jet Propulsion Laboratory have tested a system of lasers intended for a space mission called the Laser Interferometer Space Antenna, or LISA, NASA said in a release Tuesday.

The goal of the mission is to detect the subtle, whisper-like signals of gravitational waves, which have yet to be directly observed.

The JPL test has reached a significant milestone, demonstrating that noise, or random fluctuations, in the system's laser beams can be hushed enough to allow the detection of the subtle and elusive waves.

Study: Flexible scales make speedy sharks

Birmingham, Ala. -- Flexible scales on the bodies of sharks make them peerless predators by allowing them to change directions while moving at full speed, U.S. researchers say.

Researchers at the University of Alabama say this evolutionary feature means the scales can control water flow separation across the creatures' bodies, LiveScience.com reported.

Flow separation is an issue in systems such as aircraft design, explains UA researcher Amy Lang, because it tends to cause vortices that impede speed and stability.