Physicists in Israel have developed a new formula for predicting when clouds will spew forth rain. The trick, it seems, is all in the cloud turbulence. The more turbulence, the greater likelihood small droplets will smack into each other and form larger, heavier drops that fall to earth. Clouds are formed by warm water vapors rising to the sky. When a cloud cools, the vapors condense into droplets that increase in size and are eventually pulled back to earth by gravity, causing rain. Simple as this cycle may sound, when and where exactly the rain will fall is extremely difficult to predict.
Duke University chemists say they’ve come up with a way to grow carbon nanotubes — a.k.a. Buckytubes — that vary in size far less than those produced previously. The technique could help with the development of nanostructures with electronic properties reliable enough to use in molecular-sized circuits.
Until now, astronomers haven’t been able to offer a full explanation for why the Milky Way and other galaxies produce new stars at a relative snail’s pace. While they have known for decades that high turbulence keeps huge clouds of hydrogen gas from condensing into stars, they haven’t identified all the causes of the galactic perturbations. In a coming report researchers in San Diego say they have discovered that a well-known, but overlooked source of heating?regular outbursts of ultraviolet radiation from clusters of very large, bright stars?may play a significant role in keeping the Milky Way’s gas continually stirred up.
Using a common diabetes drug, researchers in Los Angeles have successfully treated pituitary tumors that cause a potentially life-threatening condition known as Cushing’s syndrome. The most common type of Cushing’s syndrome is caused by prolonged high-level exposure of a hormone called ACTH (adrenocorticotropin), which is secreted in excess by tumors of the pituitary gland, situated at the base of the brain and, which controls growth, metabolism and reproduction. Although the disorder is rare, it affects more women than men by a ratio of 5:1. Symptoms include weight gain with rounding of the face; increased fat in the neck; thinning skin; excess hair growth on the face neck, chest abdomen and thighs; muscle weakness and bone loss (osteoporosis); high blood sugar; diabetes; and high blood pressure.
A new moon of the planet Uranus has been discovered and confirmed by a team of astronomers at NASA’s Jet Propulsion Laboratory. This most-recently discovered natural satellite, named S/2001 U 1, brings the total number of confirmed uranian moons to 21. The new kid on the block — and five others like it — have very irregular, eccentric orbits that don’t share the same orbital plane as the larger moons of Uranus. Ranging in size from 10 to 20 kilometers, these moons are thought to be remnants of ancient collisions that occurred at the early stage of planetary formation.
Aluminum — one of nature’s best conductors of electricity conductors of electricity — may behave like a ceramic or a semiconductor in certain situations, according to an Ohio State University scientist and his colleagues. Among the findings that appear in the current issue of the journal Science: When it comes to forming tiny structures in computer chip circuits and nanotechnology, aluminum may endure mechanical stress more than 30 percent better than copper, which is normally considered to be the stiffer metal
New evidence from NASA’s Chandra X-ray Observatory challenges an alternative theory of gravity that eliminates the need for dark matter. The observation also narrows the field for competing forms of dark matter, the elusive material thought to be the dominant form of matter in the universe. An observation of the galaxy NGC 720 shows it is enveloped in a slightly flattened, or ellipsoidal cloud of hot gas that has an orientation different from that of the optical image of the galaxy. The flattening is too large to be explained by theories in which stars and gas are assumed to contain most of the mass in the galaxy. “The shape and orientation of the hot gas cloud require it to be confined by an egg-shaped dark matter halo,” said a researcher involved in the stoudy. “This means that dark matter is not just an illusion due to a shortcoming of the standard theory of gravity ? it is real.”
An extrasolar planet has been discovered using a new technique that will allow astronomers to detect planets no other current method can. Planets around other stars have been previously detected only by the effect they have on their parent star, limiting the observations to large, Jupiter-like planets and those in very tight orbits. The new method uses the patterns created in the dust surrounding a star to discern the presence of a planet that could be as small as Earth or in an orbit so wide that it would take hundreds of years to observe its effect on its star.
In case there was any doubt, researchers in — where else? — Los Angeles have determined that living near a freeway exposes you to a lot more pollution than if you lived further away. Specifically, a UCLA team found people who live, work or travel within 165 feet downwind of a major freeway or busy intersection are exposed to potentially hazardous particle concentrations up to 30 times greater than normal background levels.
Researchers say they’ve successfully tracked a star racing around a dark mass at the center of our Milky Way galaxy, offering strong support for the theory that a black hole is at the center of our little corner of space. Astronomers at the Max Planck Institute for Astrophysics tracked the orbit of the closest known star to the black hole candidate Sagittarius A*, a dark mass 3,000,000 times the mass of the sun. Following the star for 10 years, they found that it does indeed orbit Sagittarius A*. Approaching the black hole’s maw, the star reaches its highest velocity, whizzing past it at 5,000 kilometers per second.