Friday, March 21, 2008

Venus's atmosphere

Real Climate has an interesting post on Venus's atmosphere, highlighting results from ESA's Venus Express spacecraft. How long does a day on Venus last? The sidereal day is 243 Earth days long (longer than Venus's year of 225 Earth days), but the solar day is 117 Earth days. Confused? Go read the post, as it has one of the clearest explanations of the different types of day that I can remember reading.

The image is of Venus Express's launch in 2005 from Baikonur on a a Russian Soyuz-Fregat.

Tuesday, March 11, 2008

I hold with those who favor fire

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
-- Fire and Ice by Robert Frost.

On an appropriately catastrophysical note, Dennis Ovverbye at the NYT has a nice article on the latest forecast for Earth's future.

Monday, March 10, 2008

The Milky Way's spiral arms and climate change

Do astronomical objects influence Earth's climate? This is a fascinating question that never seems to get robustly answered, and often seems to be misused by global climate change denialists. The latest salvo - spiral arm crossings - is discussed over at Real Climate.

I wasn't aware the spiral arm pattern speeds were so ill-determined.

The image of a current model for the spiral arm structure of our own Milky Way galaxy, taken from an excellent web page from the Canadian Galactic Plane Survey (CGPS) - go there for more information.