Sundials on Mars?
DB: This is Earth and Sky. Dave Dorais in Seattle asks, “Have you heard about the sundials on the Mars Rovers?”
JB: We have, Dave. Actually, Seattle is home base for the mind behind the Martian sundial project. In 1998, science educator Bill Nye – that’s Bill Nye the Science Guy – noticed that part of a camera carried by the Rovers was shaped like one kind of sundial. Nye worked with the scientists to make this piece of equipment serve double–duty as a sundial on Mars – what they’re calling a “Marsdial.”
DB: These Martian sundials tell solar time at their location, just as sundials do on Earth. Each Marsdial’s central post casts a shadow marking the sun’s position in the Martian sky. On Mars, this central post is slightly off–center to reflect the shape of Mars’ orbit around the sun, which is less circular than that of Earth. The first Marsdial reached Mars on January 3, on NASA’s Mars Rover called Spirit . . .
JB: . . . and the second arrived on Opportunity three weeks later. The Rovers’ main cameras have captured many Marsdial images, showing solar time at two different landing sites on Mars. The Marsdials represent simple, ancient, earthly technology tied into the sophisticated technology that lets us visit Mars.
DB: For links to Marsdial images, come to today’s show at earthsky.org. Thanks for your question, Dave. And with thanks to the National Science Foundation, we’re Block and Byrd for Earth and Sky.
Links:
Mars Exploration Rover Mission (NASA’s Jet Propulsion Lab)
NASA’s Mars Exploration Program (NASA’s Jet Propulsion Lab)
Red Rover Goes to Mars: Marsdials
Athena Mars Exploration Rovers: Marsdial (Cornell University)
The Planetary Society – The Marsdial: A Sundial for the Red Planet
The Planetary Society: The Earthdial Project
North American Sundial Society (NASS)
“”Sundials””:http://www.hps.cam.ac.uk/starry/sundials.html at the Department of History and Philosophy of Science, University of Cambridge, U.K.
De Zonnewijzerkring (Dutch Sundial Society)
British Sundial Society (BSS)
Mayall, R. Newton, and Margaret W. Mayall. 2000. Sundials: Their Construction and Use, New York: Dover.
Rohr, Rene R. J. 1996. Sundials: History, Theory, and Practice, New York: Dover.
Stoneman, Milton. 1982. Easy–to–Make Wooden Sundials, New York: Dover.
Waugh, Albert E. 1973. Sundials: Their Theory and Construction, New York: Dover.
References:
Dr. Woodruff
Sullivan University of Washington
Seattle, Washington, USA
Emily Lakdawalla
The Planetary Society
Pasadena, California, USA
