Space 'CaCa"?

Did You Know?" Daily Discovery

Estimates vary, but the U.S. Geological Survey reports at least 1,000 million grams, or roughly 1,000 tons of material and debris enters the atmosphere every year from outer space and makes its way to Earth's surface.

ain't that "HOT SHI(F)T " or not....? =)

Wikipedia Moves into Top 10

Wikipedia Moves into Top 10

As a seminal benchmark, Wikipedia's move into the top ten U.S. websites underscores the power and validity of the Web 2.0 principle: people are the algorithm. The volunteer-powered content of the online encyclopedia, with its more than 5 million articles in more than 200 languages, is now the largest single source of knowledge in history. Wikipedia is already ranked in the top ten list of most popular Web sites globally, has been quickly gaining popularity in the U.S. It's also the world's fourth most recognzied brand.

In January of last year, Wikipedia sites ranked in the 33rd spot with 18.3 million unique visitors. By July, it had climbed to the 18th spot on the list with 28.1 million unique visitors, and in November it ranked 12th with 39.1 million unique visitors, according to comScore.

 

FROM ICEHOUSE TO HOTHOUSE....

FROM ICEHOUSE TO HOTHOUSE:

MELTING ICE AND RISING CARBON DIOXIDE CAUSED CLIMATE SHIFT

Three hundred million years ago, Earth's climate shifted dramatically from icehouse to hothouse, with major environmental consequences. That shift was the result of both rising atmospheric carbon dioxide concentrations and the melting of vast ice sheets, new research by University of Michigan paleoclimatologist Christopher Poulsen shows.

Poulsen will discuss his findings in a symposium titled "Geosystems: Climate Lessons from Earth's Last Great Icehouse" at the annual meeting of the American Association for the Advancement of Science in San Francisco.

The changes occurred during the period of Earth's history when the continents were consolidated into a single supercontinent, Pangaea. Toward the end of the Paleozoic Era, tropical regions of Pangaea became much warmer and drier, winds in the region shifted direction, and tropical flora drastically changed. At the same time, atmospheric carbon dioxide increased and the enormous ice sheets that blanketed Gondwana---the landmass that eventually broke up to become present-day South America, Africa, Antarctica, India and Australia---began disappearing.

"There's lots of evidence for large changes in climate and vegetation, but there's been no clear hypothesis for why those changes occurred," said Poulsen, who is an assistant professor of geological sciences. A few notions have been floating around: some researchers have suggested that the uplifting or erosion of mountain chains might have caused the climate shift; others think the motion of the plates that make up Earth's outer layer played a role. But Poulsen had a different idea. "I wondered whether the melting of the Gondwana ice sheets and/or the rise in atmospheric carbon dioxide could explain these documented climate and vegetation changes," he said.

Poulsen and coworkers used theoretical climate models to experiment with different combinations of carbon dioxide concentrations and glaciation.

"The modeling simulations showed that as Gondwana deglaciated and carbon dioxide rose, the tropics became more arid and the vegetation was fried and replaced with desert," Poulsen said. "Our results also showed that deglaciation and rising carbon dioxide contributed about equally to the observed climate and vegetation changes."

In addition, the model, which relied on estimates of carbon dioxide concentrations, produced more warming than geological evidence actually indicates. This may suggest that carbon dioxide didn't rise quite as much as has been estimated, Poulsen said.

Poulsen is cautious about applying his conclusions to current climate concerns.

"The climate change I'm studying happened a long time ago, so you have to be a little careful, but certainly this work shows there is a very strong connection between carbon dioxide increase and warming," he said. "Another interesting aspect is that for a long time people have thought that the tropics aren't really susceptible to large climate changes. This work shows that the tropics are susceptible."

article- http://umich.edu/~newsinfo/