The Last 30 Days in Astronomy

APR – 23 – 2007 • STEREO sees Soundly • The STEREO spacecraft was launched in October of 2006. But these twin observatories took about half of a year to be far enough apart to realize the mission’s goals – taking three dimensional pictures of the sun. Now the first 3D images are available. http://www.nasa.gov/mission_pages/stereo/main/index.html

APR – 24 – 2007 • Potentially Habitable Planet • A planet, named Gliese 581c, is the first exoplanet discovered that appears to be habitable. A few facts about the planet are contained in the name. The Gliese stars are red dwarfs so it cannot be far away. In fact, Gliese 581 is one of the 100 closest known stars (actually less than 21 light years distant). The letter c indicates that at least one other planet has already been found around this star. And the habitable zone around a red dwarf must be much closer to the star than Earth is to the sun. Indeed, this planet has a “year” that lasts 13 days. http://www.washingtonpost.com/wp-dyn/content/article/2007/04/24/AR2007042401470.html

MAY – 03 – 2007 • Mercury’s Liquid Inner Shell • When Mariner 10 zoomed by Mercury in 1974 – 75 it discovered a magnetic field. This was unexpected because one of the prerequisites for a planetary magnetic field is a molten core. Mercury’s core was thought to be solid simply because it is too small to have not cooled off by now. Recent radar observations show that at least the outer core, a shell around the solid core, is still molten. This in turn may indicate the presence of sulfur in this part of Mercury – a kind of antifreeze that lowers the freezing point of iron. http://www.nasa.gov/vision/universe/solarsystem/mercury-20070503.html

MAY – 07 – 2007 • Brightest Supernova • The largest supernova ever detected was found in 2006. SN 2006gy is 100 times more energetic than a typical supernova. But for some reason NASA chose May 7 to announce this discovery which has been reported in various journals earlier. http://www.nasa.gov/vision/universe/features/chandra_bright_supernova.html

MAY – 08 – 2007 • Phoenix at the Cape • The Phoenix spacecraft is now at Cape Canaveral undergoing final testing before the August 3 launch. The Phoenix will actually go digging for water on a Martian arctic plain. http://www.nasa.gov/mission_pages/mars/news/phoenix-20070508.html

MAY – 09 – 2007 • Hot Jupiter Temperature Mapped • A total of 250,000 data points from HD 189733b were mapped by the infrared telescope Spitzer. This planets completes an orbit in 2.2 days and is the closest planet found thus far. The temperature readings range from 1,200 degrees Fahrenheit (on the dark side) to 1,700 degrees (on the sunlit side). http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20070509.html