12/2/2009



Titan's Ontario Lacus: Smoothness Constraints from Cassini RADAR



Lauren Wye, Department of Electrical Engineering, Stanford University

The Cassini spacecraft has been orbiting Saturn since 2004, with frequent flybys of the largest moon Titan. With its thick atmosphere rich in nitrogen and hydrocarbons, it was once thought that Titan was covered in a global ocean of methane. Cassini optical and microwave imaging instruments have since revealed a world with a solid surface, strikingly similar in physical appearance to Earth, complete with lakes of liquid methane/ethane in the polar regions. Cassini RADAR altimetry data collected on the 49th flyby of Titan (2008 December 21) over Ontario Lacus, the largest lake in the south polar region, show signatures of a specular reflection so strong that it saturated the radar receiver. From the specular echo strength, which declines exponentially with increasing surface height variance, we are able to constrain the rms surface height variation to be less than 3 mm over the 100m-wide Fresnel zone. Lauren Wye will review her analysis of this data and the implications for wind speeds and surface material properties.



- Slides

1. David Morrison: Mission to a Potentially Threatening Asteroid
2. Laura T. Iraci: Laboratory Studies of Water Ice Cloud formation under Martian Conditions
3. Jeffrey Van Cleve: The Race to Detect the First Earth-sized Planet
4. Ron Greeley: Surface modifications by winds on Earth, Mars, Venus, and Titan
5. JoAnne Hewett: The Hunt for Hidden Dimensions
6. Franck Marchis: Multiple Asteroid Systems: New Techniques to Study New Worlds
7. Interstellar and Early Solar System Organics in Samples from Comet Wild 2
8. Ross A. Beyer: Google Earth, now with Mars!
9. Jeffrey Scargle: Tools for Probing the Universe
10. Richard Muller: Discovery of Strong Cycles in Fossil Diversity
11. Rachel Mastrapa: Weathering on Icy Satellites: Probing the Near Surface Using Infrared Spectroscopy
12. John McCarthy: Convergent evolution of our own and extra-terrestrial intelligence
13. Jasper Halekas: The Dynamic Lunar Environment
14. Tom Abel: First Things in the Universe
15. Julie Chittenden: Experimental determination of the effect of salts, regolith, and wind
16. Philip Russell: Aerosol particle roles in climate change
17. Edwin Kite: True Polar Wander and Climate on Late Hesperian/Amazonian Mars
18. Robert Landis: NEOs Ho!! The Asteroid Option
19. Terry Fong: Field Testing of Utility Robots for Lunar Surface Operations
20. Mikhail Kreslavsky: Geological record of recent climate change on Mars
21. Amos Nur: Apocolypse: Earthquakes, Archeology and the the Wrath of God
22. Robert Lillis: Death of the Martian Dynamo
23. Brian Jeffs: Progress in phased array feed development for radio astronomy
24. Ray Kurzweil: The Implications of the Law of Accelerating Returns for the Search for ETI
25. The impact and recovery of asteroid 2008 TC3
26. Dr. Beth Ann Hockey: How to Speak to Your Computer
27. Janice Bishop: The Surface of Mars
28. John Balboni: How do You Qualify Heat Shields on Earth?
29. Kevin Zahnle: Earth After the Moon-forming Impact
30. Dave Brain: Atmospheric Escape and Aurora on Mars
31. Michael Carr: Mars - The Water Story and Prospects for Life
32. Risa Wechsler: Connecting Galaxies, Halos, and Star Formation Rates Across Cosmic Time
33. Natalie Batalha: Kepler's First Peek
34. Darlene Lim: Pavilion Lake - Diving Deep to Get Us to the Moon and Mars
35. Paul Kalas: HST Imaging of Fomalhaut
36. Reid Parsons: Where is Mars' Ice?
37. Markus Aschwanden: Solar Flares and Coronal Mass Ejections Observed with STEREO
38. Nathan Bramall: Detecting Organics Using Fluorescence Spectroscopy
39. Dr. Stefan Funk: Fermi-LAT Observing the Universe With High-Energy Gamma-Ray Eyes
40. Special Panel: LCROSS Mission - The First Results of the Impact
41. Elmar Fuchs: The Inner Structure of a Floating Water Bridge
42. Ben Zuckerman: The Search for Intelligent Life in the Universe - Some Great Challenges for SETI
43. David Hollenbach: Water, Molecular Oxygen and Ice in Star-Forming Molecular Clouds
44. Linda Spilker: The Rings of Saturn as seen by Cassini CIRS
45. Claudio Maccone: Deep Space Flight and Communications
46. Lauren Wye: Titan's Ontario Lacus
47. Steven S. Vogt: Finding Planets Around Nearby Stars
48. Gerry Harp: Exploring Alternative SETI Search Algorithms with the ATA

The colloquiums are free and open to the public, and run from noon to 1 pm on Wednesdays at the SETI Institute, 515 N. Whisman Road, Mountain View, California.