This blog provides commentary on interesting geological events occurring around the world in the context of my own work. This work is, broadly, geological fluid dynamics. The events that I highlight here are those that resonate with my professional life and ideas, and my goal is to interpret them in the context of ideas I've developed in my research. The blog does not represent any particular research agenda. It is written on a personal basis and does not seek to represent the University of Illinois, where I am a professor of geology and physics. Enjoy Geology in Motion! I would be glad to be alerted to geologic events of interest to post here! I hope that this blog can provide current event materials that will make geology come alive.

Banner image is by Ludie Cochrane..

Susan Kieffer can be contacted at s1kieffer at gmail.com

Wednesday, July 13, 2011

Happy New Year, Neptune!!

Neptune. It's blue appearance is due to traces
of methane in its atmosphere. The spots, like
the spots in Jupiter's atmosphere, indicate active
weather patterns.
 NASA Hubble Space Telescope photo.
Amidst all of the dismal stories on CNN.com regarding the national debt ceiling, bombings in Mombai, scandal in the British news media, there's a bit of joy in the Happy Birthday, Neptune, story!

Neptune is the farthest planet from the Sun, the fourth-largest planet by diameter, and has 17 times the mass of the Earth. It is about 30 times the distance from the sun as the earth.  It was discovered on September 23, 1846 and was the first planet found because of a mathematical prediction. Alexis Bouvard, a French astronomer could not predict the orbit of Uranus accurately without invoking a gravitational perturbation by an unknown planet.  It was subsequently observed by Johann Galle, and shortly after, it's largest moon, Triton, was discovered as well.  (When Voyager 2 flew by Triton in 1989, its instruments detected erupting geysers on the surface, see reference below.) It has the strongest sustained winds of any planet in the solar system, a record of 2100 km/hour (583 m/s).

Why "Happy Birthday?"  Neptune's "year" is 164.8 Earth years, so only now has Neptune returned to the same spot in its orbit as it had when it was discovered in September, 1846. Neptune has four seasons, like earth, but each season lasts about 41 Earth years.

References on Triton's geysers:

Soderblom, L.A., Becker, T.L., Brown, R.H., Cook II, A.F., Hansen, C.J., Kirk, R.L., Kieffer, S.W., Shoemaker, E.M. and Johnson, T., Triton's geyser-like plumes: discovery and basic characterization, Science, v. 250, pp.410-415, 1990. PDF
Kirk, R.L., Soderblom, L.A., Brown, R.H., Kieffer, Susan W., and Kargel, J.S., Triton's eruptive plumes: discovery, characteristics, and models, in Neptune and Triton, ed. D. Cruikshank, University of Arizona Press, 949-989, 1995.

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