Amateur Astronomers on the Lookout for Near Earth Objects

Episode Summary

Executive Summary: This Planetary Radio episode spotlights amateur astronomers helping track near-Earth objects through Shoemaker NEO grants, explains why several icy moons may hide subsurface oceans, and gives a sky-watching update on Venus, Saturn, Jupiter, Mars, and space history. It mixes public-safety science, observational astronomy, and a trivia contest with practical observing tips and outreach.

Main Topics: Shoemaker NEO Grants and amateur asteroid tracking: James McGahy and Peter Burtwistle describe how Planetary Society grants upgraded their observatories, making it easier to find, confirm, and measure near-Earth objects and comets. Why near-Earth object monitoring matters: The guests explain that asteroid/comet follow-up helps determine orbits, sizes, and potential Earth impact risk, underscoring the planetary defense value of amateur contributions. Subsurface oceans on icy moons: Emily Lochtawala answers a listener question about Europa and extends the discussion to Ganymede, Callisto, and other icy worlds that may harbor hidden oceans. Current space headlines: The show covers Atlantis docking with the ISS, Hubble’s final servicing mission date, and new high-resolution Mars Reconnaissance Orbiter images from HiRISE. What’s Up sky guide and trivia: Bruce Betts highlights visible planets, a Venus-Saturn close approach, a space-history anniversary, and the weekly mineral trivia contest. Planetary Society outreach and membership: A promotional segment encourages listeners to support the Planetary Society and its mission-related public engagement efforts.

Key Arguments: Amateur astronomers are crucial partners in near-Earth object discovery and follow-up, especially for faint, fast-moving targets that surveys flag but do not fully characterize. Automating telescope movement and improving cameras dramatically increases observing efficiency and the number of measurable astrometric positions. Asteroid occultations provide a more accurate way to estimate asteroid size than brightness-based assumptions because they create a measurable chord across the object. Evidence for oceans on Europa, Ganymede, and Callisto comes from Galileo’s magnetic-field measurements, but direct proof still requires a dedicated mission. If Jupiter’s larger icy moons have oceans, similar bodies elsewhere in the solar system likely do too, including Titan, Rhea, Titania, Oberon, Triton, and possibly Pluto, Eris, and Sedna. Planetary defense and scientific curiosity are linked: tracking NEOs helps protect Earth while also preserving the enjoyment and beauty of observing the sky.

Data Points: Shoemaker NEO grants awarded: 29 - Total grants mentioned as having been made by the Planetary Society. New Shoemaker NEO recipients announced: 7 - A new group of awardees was just announced. James McGahy astrometric measurements: 5,676+ - Past count of near-Earth asteroid measurements; he says he has likely made more since then. Peter Burtwistle astrometric positions: 7,400+ - Positions on file from his observations. James McGahy comets misidentified as NEOs: 43 - Objects initially thought to be near-Earth asteroids that turned out to be comets. Peter Burtwistle NEO confirmations: 61 - Near-Earth object confirmations credited to him in recent years. Grasslands Observatory telescope size: 62 cm / 24.5 inches - James McGahy’s larger telescope upgraded with grant support. Great Shefford Observatory telescope size: 16 inches - Peter Burtwistle’s telescope after replacing a 12-inch instrument. Image download time reduced: Up to 50 seconds to near-instant with upgrades - Peter describes the camera improvement enabled by the grant. HiRISE data volume: 1.7 terabytes - Amount of data behind the Mars Reconnaissance Orbiter’s sharpest Martian snapshots. Atlantis ISS mission duration: 11 days - Planned duration of the shuttle mission to the International Space Station. Hubble servicing mission date: September 10, 2008 - Target launch date for Atlantis on the final Hubble repair mission. Venus-Saturn close approach: Less than 1 degree - Bruce Betts notes the planets will appear very close on June 30 and July 1. Valentina Tereshkova spaceflight year: 1963 - Used in the space-history segment. Mariner 5 launch year: 1967 - Anniversary noted in the What's Up segment. Observer question context: Europa, Ganymede, Callisto - Icy moons discussed as likely ocean worlds.

Pivotal Quotes: "We really do have to think about it in the sense of trying to find and then analyze the orbital characteristics of these objects simply because they are such a danger, potential danger to the Earth if one were to hit the Earth." — James McGahey: Explaining why near-Earth object tracking is important. "The discovery that there may be an ocean underneath Europa's bright icy surface was one of the biggest surprises from the Galileo mission to Jupiter." — Emily Lochtawala: Answering whether Europa is the only moon with an ocean. "Venus and Saturn coming snuggling soon." — Bruce Betts: Describing the upcoming planetary conjunction in the sky guide.

Implications: The episode reinforces that small observatories and amateur astronomers can make meaningful contributions to planetary defense and discovery. It also shows that ocean worlds remain a major target for future missions, with public engagement helping sustain interest and support.