September 14, 2009 - Just Passing Through
Just Passing Through NASA’s third and final High Energy Astronomical Observatory (HEAO-3) was launched thirty years ago this week. HEAO-3 carried a cryogenic gamma-ray spectrometer, which functioned for about five months. A direct descendent of the HEAO-3 is the Chandra X-Ray Observatory, which also studies high-energy phenomena but at slightly longer wavelengths. When Chandra observed the colliding galaxies in the Bullet Cluster, it showed that the bullet-shaped pink lump at the bottom is the hot gas from one galaxy cluster, which passed through the hot gas from the other, larger cluster during the collision. Blue areas show where most of the mass of the clusters exists. That they are separate from the visible matter (in pink) gives credence to the existence of dark matter.
Image credit: X-ray: NASA/CXC/M.Markevitch et al; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.
September 14-20, 2009
Holidays - Sky Events - Space History
Moon at perigee
Venus 3° north of Moon
Uranus at opposition
Saturn in conjunction with Sun
Rosh Hashanah begins at sunset
Mercury in inferior conjunction
Venus 0.5° north of Regulus