Find Expands Planet Search

Astronomers have turned up so many planets in nearby star systems in recent years that such discoveries are no longer big news.

But last week a team from the Harvard-Smithsonian Center for Astrophysics reported a leap forward in the field. They discovered the most distant such "extrasolar planet" ever found while also proving the effectiveness of a new technique that is expected to expand the planet search and improve the prospects for finding distant Earth-like worlds.

Planets outside the sun's family are incredibly difficult to detect, like searching for a moth in a powerful searchlight beam from hundreds of miles away. In the past, astronomers have relied heavily on an indirect method that measures the "wobble" induced in a star by the gravitational tug of the planet going around it.

The new technique watches for a planet to pass directly in front of the parent star, blocking a tiny fraction of the star's light -- like the same moth in the searchlight -- and causing a periodic dimming. Such measurements yield more information than other techniques about the size and nature of the planet.

The latest find, a planet about the size of Jupiter, is orbiting a star in the constellation Sagittarius, more than 30 times farther away than any known planet around a normal star and well outside Earth's local neighborhood. It orbits closer to its star than any other known planet, whipping around every 29 hours and getting baked to a temperature of 3,100 degrees Fahrenheit.

The climate is just right to form clouds of iron atoms, which produce showers of iron droplets.

Scientists have found a handful of such "hot" Jupiters among the 100 or so extrasolar planets detected to date, but they were surprised to find a planet so remarkably close to its star.

Previous techniques for planet searching are unable to detect planets much smaller than Neptune. But the new method, coupled with advanced instruments of the future, should detect Earth-size worlds. "We are at the leading edge of extrasolar planet research and we are getting closer and closer to finding new habitable worlds like our own," said team leader Dimitar Sasselov.

Eye of Newt, Saliva of Bat

Holy clotbusters, Robin. Could bats hold the secret to a new generation of stroke medications?

A compound isolated from the saliva of vampire bats shows promise as a treatment for the most common kind of stroke, researchers from Australia and Germany reported last week. Experiments have been conducted only in mice so far, and a number of obstacles could block the flight path from the bat cave to the dispensary. But if preliminary data hold true in further studies, then the bat spittle enzyme may prove safer and more effective than recombinant tissue plasminogen activator (rt-PA), the only approved treatment for strokes today.

The most common kind of stroke occurs when a clot lodges in a vessel supplying blood to the brain, cutting off circulation to that crucial organ.

Doctors often can dissolve the clot with rt-PA. But it's not a perfect drug. It's useful only if given within a few hours of the stroke, and there is mounting evidence that it may damage neurons in the process. (A less common kind of stroke occurs when a cranial blood vessel bursts, similarly depriving the brain of blood.)

In a series of tests in mouse brains, researchers compared the effects of rt-PA and DSPA, for Desmodus rotundus salivary plasminogen activator. Desmodus rotundus is the formal name of the blood-sucking vampire bat, which uses the salivary enzyme to keep blood flowing when it bites its prey. Tests indicated that DSPA is 200 times more potent than rt-PA, works three times longer than rt-PA, and is more specific in its action than rt-PA, suggesting it may cause less neuronal injury.

Others cautioned that the experimental methods used by the team offer only a rough simulation of a real stroke, and that mouse results often don't translate to humans. The researchers, some of whom have a financial interest in developing the compound, published their results in the Jan. 9 rapid-access issue of Stroke: Journal of the American Heart Association.

Gender and Self-Handicap

Psychologists have long noted that when some people confront a challenge, such as students facing a big exam, they resort to a perilous strategy: They refuse to study and instead watch a movie, go to a bar or do almost anything but hit the books.

Researchers call it self-handicapping. If the student does poorly on the exam, he can explain it away by saying that after all, he didn't prepare for it. If he does well, he can crow -- to himself and others -- that he is extraordinarily talented. Failure doesn't threaten his sense of competence, while success boosts his belief in his abilities.

What researchers didn't know is why men are more likely to go down this risky road than women.

Now, in research published this month in the Journal of Personality and Social Psychology, researchers at Indiana University in Bloomington say they have figured it out.

When groups of men and women were presented with case-studies of self-handicapping, women were more likely to see through the game, whether the self-handicapper was a man or a woman, and to question the person's ulterior motives. Besides, the researchers noted, "women have little respect for individuals who lack motivation and fail to put forth effort in important performance settings."

Men, on the other hand, were less likely "to ascribe negative motivations" to such individuals.

"This presents us with an interesting paradox," the researchers concluded. "Those individuals most inclined to engage in behavioral self-handicapping, [men] are less likely to attribute that motive to others."

Compiled from reports by staff writers Rick Weiss, Shankar Vedantam and Kathy Sawyer