Planetary Climates

“Planetary Climates,” an illustrated presentation by Raymond E. Arvidson, will be featured at the April meeting of the Saint Louis Astronomical Society. The meeting will be held via Zoom online conference. Zoom access information will be posted on the Society’s website, www.slasonline.org. The event, cosponsored by NASA's Missouri Space Grant Consortium, is open to the public free of charge.

Venus, Earth, and Mars, the terrestrial planets, provide rather divergent examples of climatic evolution. Venus, with its dense carbon dioxide atmosphere, and consequent runaway greenhouse, has incredibly hot surface temperatures. Perhaps Venus never had oceans to absorb the carbon dioxide and make carbonate rocks such as limestone. Earth, on the other hand, is in the “habitable zone” with the right mix of volcanic gas emissions and solar radiation that keeps us on average above freezing. Mars, based on orbital and landed data (particularly from the Curiosity rover’s observations), once had the right combination of volcanic emissions and solar radiation to keep the surface above freezing. However, this climate only existed early in geologic time. We will explore what keeps a planet warm and wet, thus suitable for life, and what we expect to happen to Earth’s climate over the next century.

Raymond Arvidson is a Distinguished University Professor of Earth and Planetary Sciences at Washington University. His teaching and research are centered on current and past environments on the Earth, Mars, and Venus.  Dr. Arvidson has held key roles in numerous NASA planetary missions, including the Venus Magellan Radar Orbiter, the Mars Viking Lander Imaging System, the Mars Global Surveyor Orbiter, the Mars Reconnaissance Orbiter, and Mars robot rovers Spirit, Opportunity, and Curiosity. He is also the Director of the NASA Planetary Data System Geosciences Node, housed at Washington University. Professor Arvidson has received many teaching and research awards from the University, from NASA, and from several national geological societies.

The St. Louis Astronomical Society is an organization for individuals interested in astronomy and telescopes. The public is invited to attend its meetings, telescope observing sessions, and special events. For more information about Astronomical Society events, please visit  www.slasonline.org, or call 314- 962-9231.