Emily Lakdawalla Reports on the Latest Planetary Science

Episode Summary

Executive Summary: This episode of Planetary Radio recaps major planetary science results from recent conferences in South Africa and France. Bill Nye highlights international collaboration and space-agency growth, while Emily Lakdawalla details new findings on Vesta, comet Hartley 2, Phobos, Mercury, and Saturn’s giant storm. Bruce Betts closes with skywatching updates, space history, and a trivia contest.

Main Topics: International Astronautical Congress and global space cooperation: Bill Nye describes the South Africa meeting as a multinational forum where scientists, agency leaders, and the Planetary Society discussed astronaut health, nuclear propulsion, climate responsibility, and the importance of efficient use of resources. He also praises South Africa’s new space agency, SANSA. DPS/EPSC conference science highlights: Emily Lakdawalla summarizes the flood of new results presented at the combined Division for Planetary Sciences and European Planetary Science Conference in France, emphasizing how much is still preliminary but rapidly advancing across multiple worlds. Vesta’s complex geology: Scientists presented crater counts and terrain analysis showing Vesta has a long and complicated geologic history, with different-aged hemispheres, layered impacts, and landslides, making it more Earth-like in its geological complexity than expected. Hartley 2 and comet composition differences: Hartley 2’s two lobes appear to have distinct compositions, especially in carbon dioxide content, suggesting it may be a contact binary assembled from separately formed materials rather than a single homogeneous body. Phobos grooves, impacts, and small-body populations: Mars Express imaging of Phobos suggests its grooves may be secondary impact structures from Mars impacts, and related talks on Lutetia and Steins indicate there may be more asteroids in the 5-100 meter size range than previously estimated. Mercury’s topography and gravity revealed by MESSENGER: MESSENGER’s early orbital data showed Mercury’s northern lowlands, enormous lava plains, hidden topographic rise, and gravity anomalies such as Caloris Basin, dramatically improving knowledge of the planet’s geology. Saturn’s 2010-2011 giant storm observed by amateurs and Cassini: A massive Saturn storm was first spotted by amateur astronomers, tracked globally, and later studied by Cassini. It produced intense lightning, wrapped around the planet, split, and vanished after about eight months.

Key Arguments: Space exploration is a shared international endeavor that benefits from cooperation among agencies and nations, as shown at the IAC. Studying astronaut physiology, including mitochondria and exercise needs, is essential for long-duration human spaceflight. South Africa’s new space agency is a positive sign of growing global participation in space science. Vesta’s geology is complex enough to warrant comparison with terrestrial planets, despite its small size. Hartley 2 likely formed from two separate bodies or materials, as indicated by different compositions in each lobe. Phobos grooves are plausibly explained by secondary impact debris from Mars rather than only internal fracturing. Mercury’s geology is far more active and diverse than previously recognized, with major volcanic and gravitational features. Amateur astronomers remain crucial contributors to professional planetary science, especially for monitoring large-scale planetary weather like Saturn’s storms.

Data Points: International Astronautical Congress: Annual meeting of the International Astronautical Federation - Bill Nye describes the conference in South Africa South African space agency: SANSA - Nye notes South Africa has started its own national space agency Phobos groove sets: About a dozen - Presentation suggesting the grooves formed from rare events since capture Hartley 2 lobes: Two distinct compositions - One lobe richer in carbon dioxide than the other MESSENGER laser altimetry points: More than 6 million measurements - Emily explains the topographic mapping of Mercury MESSENGER laser pulses: 3.5 million pulses - Altimeter data collection over Mercury’s surface Mercury lava coverage: About 6% of the surface - Northern lowland floodplain of lava identified by topography Mercury elevation of lava plains: About 2 km below mean elevation - Describes the northern volcanic lowland Saturn storm duration: About 7-8 months - The storm began in early December 2010 and disappeared in mid-June Saturn storm count since 1903: 6 - Emily says this was the sixth such event observed since 1903 ASTRO history: Shenzhou 5 launched in 2003 - Bruce Betts’ space history segment Supersonic flight milestone: 1947 - First official supersonic flight by Glamorous Glennis Apollo 7 launch: 1968 - Bruce Betts references the return of Apollo to crewed flight Random space fact: 16 moons larger than Ceres - Bruce’s trivia segment

Pivotal Quotes: "Space exploration brings out the best in us, and it is always good to talk to you." — Bill Nye: Closing remarks about the value of international space cooperation "The topography is beautiful. It shows us, for instance, that there is a northern lowland on Mercury." — Emily Lakdawalla: Discussion of MESSENGER’s new Mercury topographic results "It was amateurs who first notified people about the storm." — Emily Lakdawalla: Explanation of how Saturn’s giant storm was discovered and tracked

Implications: The episode shows planetary science advancing quickly through new missions, international collaboration, and citizen science. Mercury, Phobos, and Vesta are revealing unexpected histories, while amateurs remain vital for tracking planetary weather and transient events.