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LARGEST EXTRASOLAR PLANETARY SYSTEM DISCOVERED

A fifth planet has been discovered around a nearby star, making it the largest planetary system known outside our own. The planet appears to be a gas giant like Saturn, but scientists say any large moons it may have could potentially host life, since the planet lies in the "habitable" zone around its star, where liquid water can exist.

The planet was discovered around a star called 55 Cancri that is about 41 light years away from Earth and is slightly cooler and dimmer than our own Sun.

The 55 Cancri system was already known to include four other planets, including three giant planets that orbit the star closer than Mercury orbits the Sun. The fourth is four times as massive as Jupiter and orbits at about Jupiter's distance from the Sun.

All of those planets were discovered by the way their gravity tugs on the parent star, a technique called the radial-velocity method.

Now, astronomers have used the same method to discover a fifth planet that lies between the hot, close-in planets and the frigid distant one. The discovery was made by researchers led by Debra Fischer of San Francisco State University in California and Geoff Marcy of the University of California in Berkeley, both in the US.

The new planet, called 55 Cancri f, orbits the star at a distance of 117 million kilometres, about 8% farther than Venus is from our Sun, putting it in the right zone for liquid water to exist. Watch an animation of an imaginary journey from our solar system to 55 Cancri, with a tour of the five-planet system that ends at the newly discovered planet in the star's habitable zone.

Three New Exo-planets Discovered

These extra-solar planets were seen to pass in front of, or transit, their host star. Studying such planets outside of our Solar System allows scientists to investigate how planetary systems form. WASP is the first team to detect planets in both the Northern and Southern Hemisphere using this technique.

Exoplanet expert Dr. Pierre Maxted comments “The planets are known as ‘hot-Jupiters’ as they are similar to Jupiter but are so close to their parent star that they orbit it in less than two days. This means that these planets have a surface temperature of nearly 2000°C and so are unlikely to host life. But finding these planets is important as these stars could also host much smaller planets similar to Earth, although detecting these worlds will be much more difficult”.

The planets orbit around stars similar to our Sun that are located at a distance of 850 light-years away from the Earth. Two are in the constellation of Phoenix visible only from the Southern hemisphere, while the third is in the Northern constellation of Lyra. All three stars are too faint to be seen with the naked eye, but are easily detectable with a small telescope.

Dr Coel Hellier, of Keele University, comments "When we see a transit we can deduce the size and mass of the planet and also what it is made of, so we can use these planets to study how solar systems form."

WASP-4 and WASP-5 are the first planets discovered by the WASP project's cameras in South Africa, and were confirmed by a collaboration with Swiss and French astronomers. "These two are now the brightest transiting planets in the Southern hemisphere" said Dr Hellier. WASP-3 is the third planet that the team has found in the North, using the SuperWASP camera sited in the Canary Islands.

Using data produced by SuperWASP’s cameras, which monitor up to 400,000 stars every minute, the new extra-solar planets were discovered as they were seen to pass in front of their host star.

Explaining the discovery, Dr Don Pollacco of Queen’s University, Belfast, Astrophysics Research Centre said: “We take pictures of the sky and measure the brightness of stars. If a planet is going around one of these stars and it happens to pass across the face of that star, our cameras will pick up the light from the star getting a little fainter.

“Discoveries such as these open up a whole new area of astronomy. Such transiting planets are important because they are the only ones that can have their mass and size measured directly. Astronomers can determine what they are made of and armed with this information we can begin to understand how these solar systems were formed.”

The WASP project is the most ambitious project in the world designed to discover large planets. Funding for the project comes from the UK Universities and the Science and Technology Facilities Council.

As sophisticated as machines are today, they still cannot navigate an
automobile through crowded city streets as well as experienced human
drivers. But the Defense Advanced Research Projects Agency (DARPA) is
working to change that with an eye toward sending automated robotic
ground vehicles into battle to evacuate wounded soldiers, collect
reconnaissance and carry out other dangerous missions.
This weekend DARPA, the U.S. Department of Defense's central research
and development arm, will move closer to that goal when it hosts the
final round of its 2007 DARPA Urban Challenge, a competition testing
the driving prowess of experimental unmanned autos. The agency has
whittled the field down from 89 to 11 teams of gearheads, scientists
and students who will test their autonomous creations at the former
George Air Force Base in Victorville, Calif. The winner will drive away
with $2 million and those snagging second and third places will get $1
million and $500,000, respectively.
Unlike the DARPA Grand Challenges held in 2004 and 2005 in the Mojave Desert, this year's
competition tests whether a vehicle—which must run entirely on its own using a system of
sensors, global positioning systems and computers—can handle the types of driving conditions
that city dwellers face every day, such as changing lanes, merging onto roadways with
fast-moving traffic and traversing busy intersections. (Fortunately, they will not have to
contend with iPod-wearing pedestrians, cell phone–gabbing drivers or unpredictable cabbies.)

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IBM scientists have measured the distribution of electrical charges in tubes of carbon that measure less than 2 nanometers in diameter, 50,000 times thinner than a strand of human hair. This novel technique, which relies on the interactions between electrons and phonons, provides a detailed understanding of the electrical behavior of carbon nanotubes, a material that shows promise as a building block for much smaller, faster and lower power computer chips compared to today's conventional silicon transistors. Credit: IBM

IBM scientists have measured distribution of electrical charges in tubes of carbon that measure less than 2 nanometers in diameter, 50,000 times thinner than a strand of human hair. The technique provides a better understanding of the electrical behavior of carbon nanotubes, a material that could lead to smaller, faster and lower power computer chips.