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Science Notes / Astronomy, ornithology

A new look at solar wind

Voyager 1 is nearing the edge of the solar system and continuing to prove theorists wrong about solar wind -- the massive outflow of particles produced by the sun. The tiny spacecraft, launched 33 years ago, is now 10.8 billion miles from Earth and has reached the region of the solar system where the hot ionized gas, or plasma, emitted by the sun is ramming into the cold gas and dust of interstellar space and changing direction, curling around to envelope the solar system in a giant cloud called the heliosphere.

As a result, the solar wind is no longer going in the same direction as Voyager, but virtually perpendicular to it, and the spacecraft is actually measuring a small inward speed of the ionized gas, said Edward Stone, the Voyager 1 project scientist.

Researchers first detected that inward speed in June, when Voyager was about 10.6 billion miles from Earth, but have taken measurements for another four months to ensure that they had not simply encountered an area of localized turbulence, said Tom Krimigis of the Jet Propulsion Laboratory in La Canada Flintridge, Calif.

Once the solar wind crashes into the interstellar medium and circles back in the heliosphere, it eventually forms a giant tail like a comet before dissipating into the void, Stone said.

-- Los Angeles Times


Early bird gets the girl

With a little assistance from streetlights, the early bird catches the female's favor. Light pollution may give certain male songbirds a reproductive edge, according to German scientists who have been studying small birds called blue tits.

The scientists found that males living near roads illuminated by streetlights along the edges of a forest were more successful at mating with more than one female than those living in the heart of the forest. Because the natural light-dark cycle affects behavior, researchers hypothesized that the streetlights advanced the start of dawn singing in males living near them. Females nesting deep in the forest would hear the early-rising crooners and leave their social partners for dawn trysts.

"The blue tit is our long-term model species for our work on the evolution of promiscuity," said Bart Kempenaers, the lead author of the study, which was published in Current Biology. Although blue tits are socially monogamous, males often have offspring with other females.

Researchers from the Max Planck Institute for Ornithology in Seewiesen, Germany, measured lamp position and light intensity. They also put recorders in the trees to listen to dawn songs.

Male blue tits residing within about 50 yards of a light began singing an average of three minutes earlier than their forest peers, and they were twice as likely to sire offspring with females that were not their social partners.

-- Washington Post

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