Wednesday, December 22, 2010
Tuesday, December 7, 2010
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Thursday, December 2, 2010
Number of stars grossly underestimated
Starry, starry, starry night: Star count may triple
The universe may glitter with far more stars than even Carl Sagan imagined when he rhapsodized about billions upon billions. A new study suggests there are a mind-blowing 300 sextillion of them, or three times as many as scientists previously calculated. That is a 3 followed by 23 zeros. Or 3 trillion times 100 billion.
The estimate, contained in a study published online Wednesday in the journal Nature, is based on findings that there are many more red dwarf stars — the most common star in the universe — than once thought.
But the research goes deeper than that. The study by Yale University astronomer Pieter van Dokkum and Harvard astrophysicist Charlie Conroy questions a key assumption that astronomers often use: that most galaxies have the same properties as our Milky Way. And that conclusion is deeply unsettling to astronomers who want a more orderly cosmos.
When scientists previously estimated the total number of stars, they assumed that all galaxies had the same ratio of dwarf stars as the Milky Way, which is spiral-shaped. Much of our understanding of the universe is based on observations made inside our own galaxy and then extrapolated to other galaxies.
But about one-third of the galaxies in the universe are elliptical, not spiral, and van Dokkum found they aren't really made up the same way as ours.
Using the Keck telescope in Hawaii, van Dokkum and a colleague gazed into eight distant, elliptical galaxies and looked at their hard-to-differentiate light signatures. The scientists calculated that elliptical galaxies have more red dwarf stars than predicted. A lot more.
"We're seeing 10 or 20 times more stars than we expected," van Dokkum said.
Generally scientists believe there are 100 billion to a trillion galaxies in the universe. And each galaxy — the Milky Way included — was thought to have 100 billion to a trillion stars. Sagan, the Cornell University scientist and best-selling author who was often impersonated by comedians as saying "billions and billions," usually said there were 100 billion galaxies, each with 100 billion stars.
Van Dokkum's work takes these numbers and adjusts them. That's because some of those galaxies — the elliptical ones, which account for about a third of all galaxies — have as many as 1 trillion to 10 trillion stars, not a measly 100 billion. When van Dokkum and Conroy crunched the incredibly big numbers, they found that it tripled the estimate of stars in the universe from 100 sextillion to 300 sextillion.
That's a huge number to grasp, even for astronomers who are used to dealing in light years and trillions, Conroy said.
"It's fun because it gets you thinking about these large numbers," Conroy said. Conroy looked up how many cells are in the average human body — 50 trillion or so — and multiplied that by the 6 billion people on Earth. And he came up with about 300 sextillion.
So the number of stars in the universe "is equal to all the cells in the humans on Earth ” a kind of funny coincidence," Conroy said.
For the past month, astronomers have been buzzing about van Dokkum's findings, and many aren't too happy about them, said astronomer Richard Ellis of the California Institute of Technology. Read full story
Tuesday, November 30, 2010
Thunderstorm approaches Bill Snyder
Storm develops over skies of Bangkok on eve
Eye of Hurricane Earl is seen
Storm clouds carrying heavy rain
Grave markers are silhouetted
Thursday, November 25, 2010
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Wednesday, November 24, 2010
Sunday, November 14, 2010
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Wednesday, November 10, 2010
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Sunday, November 7, 2010
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Friday, November 5, 2010
The Eye Of the Peacock Mantis Shrimp
The peacock mantis shrimp, found on Australia's great barrier reef, is equipped with the most complex eyesight in the animal kingdom. It really is exceptional says Dr.Nicholas Roberts, outperforming anything we humans have so far been able to create.
Consider this: The peacock mantis shrimp can perceive polarized light and process it in ways that humans cannot do. Polarized light waves may travel along a straight line or rotate in a corkscrew motion. Unlike other creatures, this mantis shrimp not only sees polarized light in both its straight-line and corkscrew forms but is also able to convert the light from the one form to the other. This gives the shrimp enhanced vision.
DVD players work in a similar way. To process information, the DVD player must convert polarized light aimed at disc into a corkscrew motion and then change it back into a straight-line format. However, the peacock mantis shrimp goes to a step further. While a standard DVD player only converts red light or in higher-resolution player, blue light - the shrimp's eye can convert light in all colors of the visible spectrum.
Researchers believe that using the peacock mantis shrimp's eye as a model. Engineers could develop a DVD player that plays disc with far more information that today's DVDs. "What's particularly exciting is how beautifully simple it is," says Roberts. "It works much, much better than any attempts that we've made to construct a device.
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