Wednesday, December 15, 2010
A NASA space probe dispatched 33 years ago for the first close-up studies of Jupiter and Saturn has entered the tail of the solar system, a place where the constant stream of charged particles flowing from the sun ebbs. This final phase of solar system exploration should last another four years, computer models show, though scientists overseeing the two Voyager spacecraft really don't know what to expect.
Voyager 1 is now about 10.8 billion miles from the sun, traveling in a region of space known as the heliosheath, a turbulent area between the sphere of space influenced by the sun and magnetic forces from interstellar space that lies beyond.
In June, Voyager 1 relayed data that showed it was no longer traveling amongst the outward flow of solar wind particles. Instead, the solar stream has turned a corner, literally, as it sweeps, like an exhaust, into the tail of the heliosheath.
Flying along at about 38,000 mph, Voyager 1 is continuing its beeline toward interstellar space. It is so far from Earth that radio signals, traveling at the speed of light, take 16 hours to reach the spacecraft.
Its twin, Voyager 2, is traveling at a more leisurely 35,000 mph and will leave the solar system in a southerly direction a few years after Voyager 1, traveling in a northerly path, becomes the first human-made object in interstellar space.
Scientists hope to have five years for studies beyond the solar system before Voyager 1's plutonium power source is depleted.
Posted by Discovery Student Adventures at 10:19 AM
Thursday, December 9, 2010
The filter-feeding strategy of blue whales, the largest animals on Earth, may explain their enormous size, according to a study that determined a single mouthful of food can contain 457,000 calories, or 240 times as much energy as they burn when grabbing that mouthful.
Blue and some other whale species eat by taking enormous mouthfuls of water and filtering out their meals, often tiny crustaceans called krill, using plates of baleen made of keratin, a protein found in hair, fingernails and feathers. A team of researchers led by Jeremy Goldbogen, who is now at the Scripps Institution of Oceanography, calculated the efficiency of eating this way.
Their math supports the long-standing assumption that baleen whales are much more efficient feeders than their smaller relatives, the toothed whales, which hunt down individual prey. The finding is detailed in the Journal of Experimental Biology.
Although the finding isn't a surprise, the baleen whales' efficiency is unprecedented in the animal kingdom, said study researcher Robert Shadwick, who studies animal biomechanics at the University of British Columbia.
"When they take a gulp of water, they are filling their mouths with the amount of water equal to their own body mass, so there is nothing that comes close to doing that," Shadwick told LiveScience.
These whales may eat an enormous quantity of food in a single gulp, but the effort is taxing. As the animals dive, they lunge into a school of krill and their mouths open to 80 degrees and inflate like a parachute as water gushes in. This creates a drag, slowing the whale. Whales can make up to six lunges in a dive, according to the researchers.
Posted by Discovery Student Adventures at 12:18 PM
Monday, December 6, 2010
You might not run faster or jump higher with shoes soled in new super rubber, but they could save your knees and eventually power your iPod. Japanese scientists have created a new kind of carbon-based rubber that can withstand extreme temperatures. This new super rubber could be used in everything from electricity-generating sneaker soles to spaceships traveling to distant moons.
"These properties are totally new and unique and have not previously been shown by any materials," said Ming Xu, a scientist at the National Institute of Advanced Industrial Science and Technology in Japan.
Like foam earplugs or ordinary rubber, the new carbon nanotube rubber is part of a class of materials known as viscoelastic materials. These are materials that can be twisted, punched, rolled, kicked, stretched and bent—yet return to their original shape.
Under everyday conditions these materials work just fine; they protect delicate eardrums from loud noises and help keep cars on the road. But if you freeze materials like foam ear plugs or rubber with liquid nitrogen or expose them to high heat, like the Japanese researchers did with their new super rubber, these everyday materials will either shatter on contact or melt away.
The new material doesn't shatter or melt, even under temperatures far, far beyond what rubber could endure.
The same goes for extremely cold temperatures. "Any rubber or polymer in general will become brittle" under very cold conditions and could break, said Gogotsi, "but the nanotube rubber will keep bouncing."
Posted by Discovery Student Adventures at 12:00 PM
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