Scattered Clouds and Fog...On Mars

Episode Summary

Executive Summary: This Planetary Radio episode centers on Mars weather and mission legacy: Emily Lakdawalla reflects on Spirit’s end and its iconic summit on Husband Hill, Bill Nye connects extreme Earth weather to climate monitoring and satellites, and Mark Lemon discusses Phoenix’s surprising discoveries of clouds, fog, and perchlorates on Mars. The show closes with night-sky highlights, an OSIRIS-REx update, and a trivia contest.

Main Topics: Spirit rover’s end and legacy: Emily Lakdawalla mourns Spirit’s mission-ending silence while celebrating its most memorable achievement: reaching Husband Hill and revealing a new Martian vista. Phoenix lander’s Martian weather discoveries: Mark Lemon explains how Phoenix observed ice fog, clouds, dust, and even possible snowfall using the Surface Stereo Imager and laser experiments. Mars habitability and perchlorates: The conversation emphasizes Phoenix’s lasting scientific impact, especially the discovery of perchlorates and what they may mean for past habitability and Viking-era mysteries. Earth weather extremes and climate monitoring: Bill Nye discusses floods, tornadoes, atmospheric moisture increases, and warming, arguing that satellites and Earth observation are essential to understanding climate. Upcoming exploration and mission continuity: The episode looks ahead to Curiosity, continued Mars science, and OSIRIS-REx, highlighting ongoing public engagement and future sample return exploration. Night sky, eclipse, and trivia segment: Bruce Betts gives viewing advice for Saturn, Jupiter, Venus, Mars, Mercury, and eclipses, and the show wraps with a trivia contest and listener participation.

Key Arguments: Spirit’s mission was emotionally significant because it exceeded expectations and produced a landmark summit view from Husband Hill. Phoenix demonstrated that Mars is dynamically atmospheric, with clouds, fog, dust devils, and likely ice precipitation, not just a static desert. The Surface Stereo Imager was crucial not only for science but for mission operations, terrain mapping, and guiding the robotic arm. Perchlorates may be one of Phoenix’s most important discoveries because they could explain oxidants seen by Viking and affect interpretations of Martian chemistry and habitability. Bill Nye argues that increased atmospheric water vapor and warming are measurable trends, and satellites are essential tools for understanding and responding to climate change. Public participation in missions like OSIRIS-REx helps build support for exploration and brings science directly to audiences.

Data Points: Spirit mission duration beyond plan: Spirit survived far longer than originally intended - Emily Lakdawalla reflects on the rover’s unexpected longevity and emotional farewell Mars atmospheric moisture increase: about 4% more moisture than a decade ago - Bill Nye cites satellite/space-assets observations about Earth’s atmosphere Global warming trend: 0.7°C (0.69°C), about 1°F warmer than a decade ago - Bill Nye discusses recent climate change measurements Earth’s heat input: 1 quintillion kilowatt hours or 60 quadrillion BTUs per year - Bill Nye uses this figure to emphasize the scale of energy affecting climate Phoenix images captured: about 30,000 individual images - Mark Lemon summarizes the SSI camera’s output during the Phoenix mission OSIRIS-REx launch date: 2016 - Bruce Betts announces the asteroid sample-return mission schedule OSIRIS-REx sample return: 2023 - Bruce Betts describes the planned timeline for returning asteroid samples Catalina Sky Survey discoveries in 2010: 602 near-Earth objects - Bruce Betts answers the trivia question about the most productive asteroid survey Membership size: nearly 100,000 members - Planetary Society membership promotion during the program Phoenix mission duration: five months of round-the-clock data gathering - Mark Lemon describes Phoenix’s operational period near Mars’ North Pole

Pivotal Quotes: "it’s all over now but the crying" — Emily Lakdawalla: Emily describes her emotional reaction to Spirit’s end "Spirit summited Husband Hill for the first time and got her first look down into the plains of Gusev Crater below her" — Emily Lakdawalla: Her favorite memory of Spirit’s mission "Mars is Earth-like in a lot of interesting ways. Spectacular sunsets, we see a cloudy sky, we see fog." — Mark Lemon: Mark explains the significance of Phoenix’s atmospheric observations

Implications: Listeners come away with a stronger sense that Mars is climatically active and scientifically rich, while Earth’s weather and climate demand sustained observation. The episode also reinforces that future exploration will depend on public support, mission data reuse, and long-term scientific follow-up.