Star Points for May, 2008; by Curtis Roelle Mercury: Messenger of Gods Mercury, the nearest of the four terrestrial planets to the sun, orbits our star once every 88 days. With regard to our own planet, Mercury is the third closest to us after Venus and Mars. Mercury's distance from the earth varies from 48 to 139 million miles. The planet has not been visited by a spacecraft since Mariner 10 flew past it three times in 1974 and 1975. But that changed this year when NASA's MESSENGER mission (MErcury Surface, Space ENvironment, Geochemistry, and Ranging) buzzed Mercury at an altitude of only 124 miles in January. Imagery taken during the flyby encounter has revealed portions of the surface hidden from Mariner 10's cameras. It's been a long trip since MESSENGER's launch in August 2004. In a game of planetary billiards MESSENGER has performed gravity- assisted flybys of the earth (August 2005) and Venus (October 2006 and June 2007) in order to gain energy and optimize fuel expenditure. MESSENGER isn't through making bank shots yet. Additional Mercury flybys are planned for this October and in September 2009. If the mission goes according to plan, MESSENGER will finally enter orbit around Mercury in March 2011. MESSENGER was built for NASA in Maryland at The Johns Hopkins University Applied Physics Laboratory (JHU-APL) in Laurel. The Mission Operations Center (MOC) is also located at JHU-APL. The program web site is http://messenger.jhuapl.edu/. The planet Mercury was named after the mythological Roman god of science, patron of travelers, and messenger to the gods. One reason for this could have been because Mercury quickly appears and disappears from our view. Its proximity to the sun means the planet spends precious little time in the night sky. When placed for viewing Mercury must be observed in twilight either shortly after sunset or before sunrise. Luckily, May provides an excellent time to view Mercury in the evening sky after sunset. Mercury remains at least 10 degrees above the west-northwestern horizon 45 minutes after sunset between May 6-18 according to Sky & Telescope magazine (http://www.skyandtelescope.com/). The sun sets at 08:07 p.m. on the 6th and at 08:19 p.m. on the 18th. By the way, 10 degrees is about the width of your fist when your arm is outstretched. Weather permitting, The Westminster Astronomical Society (WASI) will hold a public star party, complete with telescopes, at Bear Branch Nature Center (BBNC) in Carroll County on Friday, May 9. The western horizon at BBNC is fairly, low making it a good place for trying to see Mercury shortly after the 07:30 p.m. planetarium show ends. The star party is free. Carroll County Parks charges $2 per person for the planetarium show, and reservations are recommended.