While radio observations on Uranus began in the 1960s, this initial GAVRT campaign began during the summer of 2002. Uranus experienced seasonal changes as it approached its equinox in 2007. The Uranus Campaign is a collaboration of observations of the planet that include the Hubble Space Telescope, the W.M. Keck Observatory, Lowell Observatory, NASA's Infrared Telescope Facility, the Very Large Array (VLA), and GAVRT Program. The VLA and the GAVRT students are contributing the radio measurements. GAVRT observations will help determine the nature of seasonal change in Uranus' deep atmosphere. These studies of Uranus and its seasons will continue for years as one year on Uranus is equal to 84 Earth years!
Active Galactic Nuclei (AGN) is a term that refers to galaxies that have excess visible light coming from their nuclei beyond the sum total of visible light from all their central stars. More luminous AGN are called quasars where the nucleus often outshines the host galaxy! The present model is that the excess light is generated by supermassive black holes (millions to billions of times the mass of our sun) that are at the centers of many galaxies. Black holes themselves don't generate any light since by definition a black hole is an object that has a high mass concentrated in a small volume (called the event horizon) where the escape velocity is the speed of light. Since nothing can travel faster than the speed of light, no light escapes the black hole.
The region around a black hole outside the event horizon is different. As gas falls toward the black hole, it heats up and starts emitting a lot of light. This is thermally generated light very much like when a piece of iron is heated and starts glowing red. This heated gas is called the accretion disk.
In this campaign, we will take measurements of the radio light and the infrared light and see whether the ratio of the non-thermal radiation (radio) to thermal radiation (IR) is related to the mass of the supermassive black hole. The Spitzer Space Telescope will image the AGN in the 3.6 to 8um range and that will be compared to data gathered by the GAVRT students in the S and X radio bands.
The LCROSS (Lunar CRater Observation and Sensing Satellite) Mission is designed to impact the Moon's South Pole to search for water ice beneath its permanently-shadowed craters. The search for water is very important to the possibility of future human activities on the Moon. LCROSS will make the first definitive measurements for water within a very cold crater. Using a suite of instruments, including infrared and visible spectrometers and cameras, LCROSS will be able to identify the presence of water or other constituents in the impact ejecta cloud. The plume should be visible to small optical telescopes on Earth. It is scheduled to launch on March 2nd, 2009 and be in the accurate orbital plane for impact in late 2009.