MOONSHIP PHOTOGRAPHED: NASA's LCROSS spacecraft was 480,000 km from Earth on Monday, June 29th, when Paul Mortfield of Sierra Remote Observatories in California photographed it passing by galaxy IC3808: movie. "Amateur astronomers with mid-sized telescopes should be able to capture LCROSS during its cruising orbits over the next several months before it hits the Moon," he says. "To find it, go to the JPL ephemeris generator and enter 'LCROSS' as the target body."
VOLCANIC SUNSETS: The plume of volcanic dust and sulfur dioxide that has caused so many pretty sunsets over the USA this week has crossed the Atlantic and reached Europe. "The purple color of the sky on June 30th was unbelievable," says Rafael Gallego, who sends this picture from Carrión de los Céspedes, Spain:
Similar reports are pouring in from France, England, Denmark, the Netherlands, Canada and many US states. Here's what to look for: When the sun goes down, delicate ripples of white appear over the western horizon. Then, as the twilight deepens, the sky turns a lovely shade of "volcanic lavender."
The source of the phenomenon is Russia's Sarychev Peak volcano. It erupted on June 12th, hurling massive plumes of sulfur dioxide (SO2) and other debris into the stratosphere. The white ripples that herald these sunsets are made of volcanic aerosols--a mixture of ash and sulfur compounds. Blue light scattered by fine volcanic aerosols combines with ordinary red sunset rays to produce the telltale lavender.
Earth-orbiting satellites are monitoring Sarychev's sulfur dioxide plume as it circumnavigates the globe at high latitudes, spreading the phenomenon from Russia to the USA to Europe and back again. All northern sky watchers should be alert for volcanic sunsets.
UPDATED: 2009 Sarychev Sunset Gallery
[See also: 2008 Kasatochi Sunset Photo Gallery]
ART OR SCIENCE? Researchers at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, have created an unprecedented 3D supercomputer model of a sunspot. The result is not only scientificially informative, but also a thing of beauty:
To create the virtual sunspot, researchers programmed NCAR's IBM bluefire supercomputer with the laws of magnetohydrodynamics, sprinkled in some ground-based observations of actual sunspots, and hit "go." The bluefire is capable of 76 trillion calculations per second; even so, the program took weeks to complete. The final model contains 1.8 billion points and covers a 3D domain 31,000 miles by 62,000 miles wide and 3,700 miles deep.
Physcists are now studying movies of the virtual sunspot to develop new insights into the dynamic behavior of these planet-sized behemoths. More than one onlooker has gasped in amazement when shown the surprisely lovely subsurface structure of the 'spot.
Is it art or science? You decide.
2009 Noctilucent Photo Gallery
[previous years: 2008, 2007, 2006, 2005, 2004, 2003]
Explore the Sunspot Cycle