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Sunday, September 14, 2008

Mysterious Stellar Blast in the 1840s Was a “Supernova Imposter”

Eta CarinaeA remarkable stellar event that mesmerized astronomers in 1843 may have been a previously unknown kind of explosion, researchers say. That explosion, which made the star Eta Carinae one of the brightest in the Southern sky, could have been the precursor to the star’s expected explosion into a supernova.

Researchers began watching Eta Carinae after the star mysteriously brightened 1843, and astronomers in recent decades have photographed and studied the resulting cloud of gas and dust, known as the Homunculus Nebula, that billows away from the star. A farther-out faint shell of debris from an earlier explosion is also visible, probably dating from around 1,000 years ago. “Looking at other galaxies, astronomers have seen stars like Eta Carinae that get brighter, but not quite as bright as a real supernova,” said [lead researcher] Nathan Smith…. “We don’t know what they are. It’s an enduring mystery as to what can brighten a star that much without destroying it completely” [SPACE.com].

Astronomers previously believed that the bright clouds of gas were a result of solar winds pushing out the star’s outer layers, but the new study, published in Nature [subscription required], argues against that hypothesis. Smith discovered filaments of gas produced by the 1843 outburst that were traveling faster than the solar wind could have propelled them, suggesting that they’re the result of a powerful interior explosion. Unlike a wind-driven event, an explosion “implies that there is some sudden burst of energy deep inside the star,” Smith says. “It may be related to the rate of fuel consumption as a massive star nears the end of its life” [Science News].

Researchers had already observed non-fatal explosions on other late-stage stars. Sometimes called “supernova imposters,” the blasts are even less well understood than supernovae [National Geographic News]. Smith suggest that these events may be a natural step in the death of a star, in which it sheds some of its mass before the final supernova.

CleanTechnica Like this post? Subscribe to our RSS feed and stay up to date. Nanoflowers Could Lead to Superior Batteries

Flower-shaped nanoparticles, or “nanoflowers”, might lead to superior batteries in the near future. Chemist Gaoping Cao and colleagues report in the latest issue of Nano Letters that they are working on developing nanoflowers which could lead to longer battery life for cell phones, laptops, and more.

While nanoflowers are not new, Cao claims that previously discovered forms of the nanoparticle weren’t able to provide the longer battery life that will be necessary for electronics of the future.

In Cao’s study, scientists grew clusters of carbon nanotubes—each 50,000 times smaller than a strand of human hair—that have strong electrical conductivity. They then put manganese oxide on top of the nanotubes. The process resulted in dandelion-shaped nanoclusters that will ultimately lead to a battery system with a higher energy storage capacity, longer life, and greater efficiency that current batteries.

And while I would be happy to have a more self-sustaining laptop, perhaps the nanoflowers will have even more important uses— like keeping future plug-in hybrid vehicles running for longer.

More Cyclists on the Road Mean Fewer Accidents

It may seem counterintuitive, but according to a recent report more cyclists on the road mean fewer accidents involving cyclists and motor vehicles. I was convinced of this after spending some time living and cycling in Japan, but it’s always nice to have some real research to back up one’s personal hearsay.

This happens because as more cyclists hit the road, drivers are more aware of their presence. Not only are drivers looking out for cyclists, but as interaction between cars and bikes increase, drivers learn how to drive safely and respectfully around cyclists.

According to the University of New South Wales, who did the research:

“It’s a virtuous cycle,” says Dr Julie Hatfield, an injury expert from UNSW who address the seminar on September 5. “The likelihood that an individual cyclist will be struck by a motorist falls with increasing rate of bicycling in a community. And the safer cycling is perceived to be, the more people are prepared to cycle.”

Also, even more encouragingly, it doesn’t seem that cycling infrastructure is responsible for the change:

Experts say the effect is independent of improvements in cycling-friendly laws such as lower speed limits and better infrastructure, such as bike paths. Research has revealed the safety-in-numbers impact for cyclists in Australia, Denmark, the Netherlands, 14 European countries and 68 Californian cities.

So, if you’ve ever thought about getting out on a bicycle, consider this: you will be safest in communities with the most cyclists; your contribution will not only keep a car off the road, but will help make everyone safer.

Happy riding!