There are some computer problems so hard that computer scientists consider them out of reach. They label them “intractable” and move on.

But researchers at Cornell University, Ithaca, N.Y., have developed tools to solve such problems, at least in certain practical situations. Mostly their approach is to have the computer do what a human being might do: stop, go back and start over and try something different.

“Even though these problems are intractable in the worst ca

Researchers doing ultra-cold temperature physics may not have to wear parkas, but they are producing the coldest temperatures ever and exploring model quantum systems that might lead to more accurate clocks and gyroscopes, quantum computers and communications as well as a better understanding of quantum physics phenomena.

Nearly 80 years ago, Albert Einstein and Satyendra Nath Bose predicted that gases of atoms cooled down very close to absolute zero would behave in unison. In 1995,

Observing the edge of the famous Horsehead Nebula with the IRAM interferometer located on the Plateau de Bures (France), a team of French and Spanish astronomers discovered a large quantity of small hydrocarbon molecules. This is a surprise because the intense UV radiation illuminating the Nebula should destroy the small hydrocarbons near the edge. The astronomers suggest that these molecules might result from the fragmentation of giant molecules, called “polycyclic aromatic hydrocarbons” (PAH

Soon we may be able to fill the bath, turn the lights on and play our favourite CD without moving from our chair or pressing a button. Technology, developed by ESA for European spacecraft, is now being used to create small sensors that can make any flat surface – walls, windows or tables – interactive.

“The idea is to use an accelerometer to determine the exact position of touch on an object,” says Nicolas Delorme from Nodal Consultants, part of ESA’s Technology Transfer Prog

On February 1, 2005, the European Southern Observatory (ESO) has merged its two observatories, La Silla and Paranal, into one. This move will help Europe’s prime organisation for astronomy to better manage its many and diverse projects by deploying available resources more efficiently where and when they are needed. The merged observatory will be known as the La Silla Paranal Observatory.

Catherine Cesarsky, ESO’s Director General, comments the new development: “The me

Researchers at the University of Warwick’s Department of Physics have gained insight into the mysterious giant dark “tadpoles” that appear to swim towards the surface of the Sun during solar flares – enormous energy releases happening in the atmosphere of the Sun.

The tadpoles – colossal physical structures with dark heads and attendant wiggly tails that seem to swim sunwards against tides of hot matter being thrown away from the Sun during flares – have puzzled astrophys

The profusion of wireless communications in homes, in coffee shops and even on battlefields presents us with fantastic new conveniences — but also new security problems. Indiana University computer scientist Markus Jakobsson will discuss “stealth” attacks over wireless networks, which can disrupt communications and endanger personal information. One such attack is “denial of service,” in which devices are overloaded with so much incoming information they cease functioning properly.

A new security approach could improve safeguarding of credit card numbers, bank passwords and other sensitive information for those who surf the Internet using wireless connections, researchers told the annual meeting of the American Association for the Advancement of Science (AAAS)on Saturday.

The same protocol could be employed in many computer networks in which two computers, hand-held communication devices or network nodes need to simultaneously verify the identity of each o

For the last few years evidence that we are living on a very “weird” universe has been growing: the expansion of the universe is accelerating, and one theory proposed to account for this acceleration is what has been termed “dark energy.”

In order to find out what this mysterious energy really is, astronomers need to compare astrophysical observations that are at first sight completely unrelated. At a session on dark energy at the Annual Meeting of the American Association for

Distributed computing project to search for gravitational waves.

A new grassroots computing project dubbed Einstein@Home, which will let anyone with a personal computer contribute to cutting edge astrophysics research, will be officially announced at the annual meeting of the American Association for the Advancement of Science (AAAS) in Washington DC on Saturday, February 19. LIGO Laboratory Director Barry Barish of Caltech and Einstein@Home Principal Investigator Bruce Allen

Cassini-Huygens supplied new evidence about why Titan has an atmosphere, making it unique among all solar system moons, a University of Arizona planetary scientist says.

Scientists can infer from Cassini-Huygens results that Titan has ammonia, said Jonathan I. Lunine, an interdisciplinary scientist for the European Space Agency’s Huygens probe that landed on Titan last month. “I think what’s clear from the data is that Titan has accreted or acquired significant amounts

Astronomers around the world recorded late last year the brightest explosion ever of high-energy X-rays and gamma rays – a split-second flash from the other side of our galaxy that was strong enough to affect the Earth’s atmosphere.

The flash, called a soft gamma repeater flare, reached Earth on Dec. 27 and was detected by at least 15 satellites and spacecraft between Earth and Saturn, swamping most of their detectors. Some of the best observations were recorded by the Reuven

Advanced computational methods and supporting experiments, including work performed at the Department of Energy’s Oak Ridge National Laboratory, are giving scientists a better understanding of the nature and stability of superheavy nuclei and the heaviest elements that lie beyond the borders of the periodic table.

Nature magazine on Thursday published a review article that describes collaborative work by researchers at Oak Ridge National Laboratory and the University of Te

Earth is showered constantly by particles called muons that are created by cosmic rays, and clever scientists are finding ways to use them as probes of dense objects, including a massive pyramid in Mexico and volcanoes in Japan. American researchers also have proposed using the energetic particles to detect smuggled nuclear materials in vehicles and cargo containers.

Muons are formed when cosmic rays from deep space interact with the atmosphere. The particles, which strike earth&#1

A group led by astronomers from Ohio State University and the Technion-Israel Institute of Technology have measured the mass of a unique black hole, and determined that it is the smallest found so far.

Early results indicate that the black hole weighs in at less than a million times the mass of our sun -– which would make it as much as 100 times smaller than others of its type. To get their measurement, astronomers used NASA’s Hubble Space Telescope and a technique similar to Doppl

A team of scientists led by biophysicist Stuart Lindsay from the Biodesign Institute at Arizona State University have created the first reproducible single molecule negative differential resistor and in the process have developed a groundbreaking experimental technique that provides a “roadmap” for designing single molecule devices based on biochemistry.

The findings will be discussed in a presentation by Lindsay on February 18 at the American Association for the Advancement of S