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The detection of flat rotation curves in galaxies and the "missing mass" in clusters of galaxies have left astronomers with two main possibilites - either the universe is filled with particles that have yet to be directly detected or the standard theory of gravity fails at large scales. Although there is growing observational evidence for dark matter, there are very few tests of gravity on scales > 10 AU. One such test comes from the analysis of the Pioneer 10 and 11 spacecrafts' tracking data. Both of these spacecraft show an unmodeled deceleration of approximately 8.7 x 10^{-10} m/s^2 beginning about 10 AUs from the Sun. If this anomoly cannot be explained by spacecraft systematics, it will represent a serious challenge to our standard theory of gravity. To test the veracity of the "Pioneer Anomoly" as a gravitational perturbation, we have analyzed the astrometric data of m inor planets in the outer solar system for evidence of orbital perturbations.. In this talk, we will discuss the results of this analysis, along with the challenges of using planets and minor planet tracking data to probe gravity. We will also discuss how future surveys such as the LSST can place tight limits on any deviation from classical theories of gravity at distances between 20 AU and 100 AU from the Sun.
Colloquia are usually preceded by coffee and followed by an informal reception (both in room CSS 0254). Anyone interested in having lunch or talking with the speaker should contact either of the colloquium coordinators (see below). The hour immediately after lunch will normally be reserved for the speaker to talk to graduate students. Students are urged to contact the coordinator to arrange this.
Request colloquia announcements by e-mail:
coll-request@astro.umd.edu
Colloquium Organizer:
Andrew Wilson (301) 405-1519
Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.
Parking for visitors is available in the Cashier-Attended Parking Lot at the intersection of Paint Branch & Technology Drive. It is a 5-10 minute walk from the parking lot to the Computer & Space Sciences building.
There are a limited number of parking meters in Lot DD; there are no parking meters in Parking Garage 2. Parking at non-metered spaces in Lot DD and PG2 is free after 4 pm and on weekends.
More information is available from the Department of Campus Parking.
Department of Astronomy, University of Maryland College Park, MD 20742-2421 Phone: (301) 405-3001 FAX: (301) 314-9067 Comments and questions may be directed to webmaster@astro.umd.edu
This page was automatically generated on:
05-Mar-2008.
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