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A Curious Cold Layer In The Atmosphere Of Venus

October 1, 2012 Leave a comment

Credits: ESA/MPS, Katlenburg-Lindau, Germany

Venus Express has spied a surprisingly cold region high in the planet’s atmosphere that may be frigid enough for carbon dioxide to freeze out as ice or snow.

The planet Venus is well known for its thick, carbon dioxide atmosphere and oven-hot surface, and as a result is often portrayed as Earth’s inhospitable evil twin.

But in a new analysis based on five years of observations using ESA’s Venus Express, scientists have uncovered a very chilly layer at temperatures of around –175ºC in the atmosphere 125 km above the planet’s surface.

The curious cold layer is far frostier than any part of Earth’s atmosphere, for example, despite Venus being much closer to the Sun.

Full Story: http://www.esa.int/esaSC/SEMILCERI7H_index_0.html

Gone, With The Wind

October 1, 2012 Leave a comment

The case of the missing quasar gas clouds has been solved by a worldwide team of astronomers, and the answer is blowin’ in the wind.

“We know that many quasars have structures of fast-moving gas caught up in ‘quasar winds,’ and now we know that those structures can regularly disappear from view,” says Filiz Ak, a graduate student at Penn State and lead author of the paper. “But why is this happening?”

Quasars are powered by gas falling into supermassive black holes at the centers of galaxies. As the gas falls into the black hole, it heats up and gives off light. The gravitational force from the black hole is so strong, and is pulling so much gas, that the hot gas glows brighter than the entire surrounding galaxy.

What’s going on here? There are several possible explanations, but the simplest is that, in these quasars, gas clouds that we had seen previously are literally “gone with the wind” —the rotation of the quasar’s disk and wind have carried the clouds out of the line-of-sight between us and the quasar.

Full Story: http://www.sdss3.org/press/thewind.php