On the horizon
The 'ice cube' telescope
Construction is under way for a telescope whose "mirror" will be buried more than a mile beneath the South Pole ice cap. Dubbed IceCube, because its array of detectors covers a cubic kilometer of ice, this telescope is designed to study the high-energy variety of the ghostlike subatomic particles known as neutrinos.
Traveling to Earth virtually unobstructed, high-energy neutrinos serve as windows back through time, and should provide new insight into questions about the nature of dark matter, the origin of cosmic rays, and other cosmic issues. In the past few weeks, the first IceCube cable was lowered down into a hole drilled through the Antarctic ice using jets of hot water. The cable carries 60 digital optical modules that should enable IceCube to pick out the rare signal of a neutrino colliding with a molecule of water. Plans call for a total of 4,200 modules to be put in place over the next five years.
Sleep helps young birds master the art of song, but it takes time for them to get in voice, according to a study published this week in the journal Nature.
The study examined the effect of sleep on song learning in young zebra finches. Individuals of this species are active in the daytime, do not sing in darkness, and develop their song between one and three months after hatching. Surprisingly, instead of showing gradual improvement in which they might wake up each day and "pick up where they left off" in their vocal abilities, many of the birds displayed dramatic degradation in the quality of their songs. However, the quality of these birds' songs improved after intense morning rehearsal to the point where by the end of each new day, their singing was indeed better than the day before.
The study also found that birds that learn to sing better than others - at the end of their three months of rehearsal - actually awaken from sleep as poorer singers than their ultimately less tuneful counterparts.
It's been 75 years since the discovery of Pluto, but it remains a mystery. Perhaps it will reveal some of its secrets in another 10 years when a space probe gets close enough for a good look.
Pluto was quickly heralded as the ninth planet in the solar system when it was spotted Feb. 18, 1930, by a young amateur astronomer. It still holds that title today, if somewhat tenuously. "It's a misbehaved planet if you want to think about it as a planet," said Neil deGrasse Tyson, director of New York's Hayden Planetarium.
Complicating the debate is that there is no official definition for a planet. Setting standards like size limits or orbital patterns potentially invites other objects to get tagged with the "planet" label.
A survey of the oceans has confirmed the startling finding, first reported two years ago, that commercial fishing has wiped out 90 percent of large predatory fish in the past 50 years.
The new survey - reported in the current issue of Royal Society Proceedings B in Britain - encompasses twice as many studies and examines ecosystems not previously assessed. If anything, the plight of predatory fish is worse than the earlier data indicated, wrote Ransom Myers of Dalhousie University, who wrote both surveys. "Industrial fisheries have changed marine ecosystems in fundamental ways. Current fishing mortalities projected into the future could lead to the extinction of certain sensitive species of sharks and other large predators at the top of the food web."
