SAO Weekly Updates http://www.cfa.harvard.edu//sao/su/ SAO Weekly Updates en-us Seven Billion Year-Old Galaxies http://www.cfa.harvard.edu/sao/su/2008/su200832.html August 06, 2008: As modern telescopes peer more and more deeply into the universe, they are seeing older and older galaxies. The Sun's Magnetic Field http://www.cfa.harvard.edu/sao/su/2008/su200831.html July 30, 2008: Solar flares, prominences, and so-called coronal mass ejections are three different manifestations of stored magnetic energy near the sun's surface being released in sudden eruptions. Radio Beacons in the Early Universe http://www.cfa.harvard.edu/sao/su/2008/su200830.html July 23, 2008: Radio galaxies are cosmic beacons, with the brightest ones beaming nearly a trillion solar-luminosities of radiation into space at radio wavelengths. Reflecting on Planets http://www.cfa.harvard.edu/sao/su/2008/su200829.html July 16, 2008: Mars, Jupiter, and all the other planets and asteroids in the night sky that are visible to us can be seen because they reflect sunlight. Looking Out for Near Earth Objects http://www.cfa.harvard.edu/sao/su/2008/su200828.html July 09, 2008: Near Earth Objects (NEOs) are small solar system bodies that are infamous because their orbits take them near earth's orbit; sometimes they pass dangerously close to the earth or even collide with it. The North Star http://www.cfa.harvard.edu/sao/su/2008/su200827.html July 02, 2008: Polaris, the North Star, is not only renowned as a reliable beacon for early navigators. Objects Both Hot and Cold http://www.cfa.harvard.edu/sao/su/2008/su200826.html June 25, 2008: The sun's photosphere is hot, about 6000 kelvin, and so the sun emits about 70% of its light in the visible portion of the electromagnetic spectrum, and about one-quarter in the infrared. Trans-Neptunian Objects http://www.cfa.harvard.edu/sao/su/2008/su200825.html June 18, 2008: The sun's family of planets, including the Earth, as well as its other companions like comets, all formed from a disk of material that was present in the early days of the solar system. Gamma Rays from a Binary Star http://www.cfa.harvard.edu/sao/su/2008/su200824.html June 11, 2008: Gamma-rays are the most energetic known form of light (that is, of electromagnetic radiation). Cosmic Rays ... Still Mysterious http://www.cfa.harvard.edu/sao/su/2008/su200823.html June 04, 2008: Cosmic rays are very rapidly moving nuclear particles that impact the earth from space, and generally originate from well beyond the solar system. Milkomeda, Our Future Home http://www.cfa.harvard.edu/sao/su/2008/su200822.html May 28, 2008: Galaxies frequently collide with one another, leaving evidence for their stupendous interactions nearly everywhere in the sky. A Shocking Discovery http://www.cfa.harvard.edu/sao/su/2008/su200821.html May 21, 2008: The complex sequence of events that lead to star formation, processes once thought to involve just the simple coalescence of material under the influence of gravity, continues to amaze and surprise astronomers. Saturn's Weather http://www.cfa.harvard.edu/sao/su/2008/su200820.html May 14, 2008: The Earth is not the only planet whose atmosphere experiences seasonal weather changes. The Orion Nebula Star Cluster http://www.cfa.harvard.edu/sao/su/2008/su200819.html May 07, 2008: Most stars form in clusters, sometimes with ten thousand or more stars packed into a volume smaller than a few light-years in radius. Cold but Luminous http://www.cfa.harvard.edu/sao/su/2008/su200818.html April 30, 2008: Over the past two decades astronomers have come to realize that many galaxies are fabulously luminous -- some are more than a thousand times brighter than our Milky Way.