Exoplanet Finder Debra Fischer

Episode Summary

Executive Summary: This episode of Planetary Radio focuses on the hunt for Earth-like exoplanets, highlighting Deborah Fisher’s work on FINES, a fiber-optic system intended to improve Doppler precision and help Kepler’s planet census. It also covers NASA microgravity research on salmonella, explains why Galileo’s Jupiter probe sent no images, and ends with skywatching, space history, and an exoplanet trivia contest.

Main Topics: FINES and the search for Earth-like exoplanets (Priority: 5/5): Deborah Fisher explains how a fiber-optic device plus tip-tilt stabilization could reduce spectrograph noise and push Doppler measurements toward the precision needed to detect Earth-mass planets. Kepler, Doppler precision, and complementary planet characterization (Priority: 5/5): The conversation frames Kepler as a size-finding census mission and ground-based Doppler follow-up as essential for determining planet masses and densities. Microgravity research on salmonella (Priority: 4/5): Bill Nye argues that research aboard the ISS may reveal ways to control bacterial virulence and mutation, with implications for antibiotic resistance and public health. Galileo probe Q&A (Priority: 3/5): Emily Lochtewala explains why the Galileo Jupiter probe could not return images: low bandwidth, short-lived descent, and no high-gain antenna. Skywatching and space history (Priority: 3/5): Bruce Betts provides the planet roundup, notes Mercury and Titan milestones, and mentions the exoplanet CoRoT-Exo-7 as an example of unusually small but extreme worlds. Planetary Society updates and trivia contest (Priority: 2/5): The episode promotes Planetary Society membership, announces contest results, and asks listeners to identify exoplanet discovery methods for a t-shirt prize.

Key Arguments: Current Doppler instruments can measure stellar reflex velocities to about 1–2 m/s, but detecting an Earth analog requires roughly 10 cm/s precision. The main limitation is instrumental light behavior inside the spectrograph; scrambling the light into a stable cone should improve modeling and precision. Fiber optics already improve stability in some European systems, suggesting FINES could help U.S. observers regain a technical edge. Kepler will determine planet sizes, but ground-based spectroscopy is needed to derive masses and densities, making the two approaches complementary. Microgravity experiments may be valuable not because they are intuitive, but because they can reveal unexpected ways to control pathogen virulence and mutation. The Galileo probe could not send images because atmospheric probes have limited power, short lifetimes, and low data rates, especially without steerable antennas.

Data Points: Exoplanets discovered by Fisher and Marcy: more than half of over 300 - Introductory framing of Deborah Fisher’s and Jeff Marcy’s contribution to exoplanet discovery. Stars with detected planets: about 10–15% - Fisher’s estimate of the fraction of stars found to have planets, noting detection bias. Jupiter’s reflex velocity on the Sun: about 12 meters per second - Used to compare stellar motion caused by Jupiter with what instruments can currently measure. Current Doppler precision: 1 to 2 meters per second - Fisher states present measurement capability for stellar wobble detection. Earth-like Doppler signature: 10 centimeters per second - Target precision needed to detect an Earth-mass planet via the Doppler method. Goal precision for FINES: half a meter per second - Fisher says the project aims to improve below 1 m/s and match or exceed Swiss performance. Kepler launch date: March 6 - Fisher references the recent launch of Kepler at the time of recording. Kepler follow-up time horizon: over the next three years - Expected period for a large yield of planets from the mission. Alpha Centauri observing cadence: 200 nights this year - Fisher describes her intense campaign to reduce noise through repeated observations. Galileo probe data rate: 128 bits per second - Used to explain why the probe could not transmit images during its descent. Galileo descent duration: about an hour - Time available for the probe to relay its science data to the orbiter. Huygens data rate: 8 kilobits per second - Compared to Galileo to show why Huygens could return small images from Titan. Huygens descent duration: more than 4 hours - Longer descent enabled image transmission from Titan. Close-approach distance of near-Earth object: 80,000 kilometers - Opening news item about a 15-meter object that passed unusually close to Earth. Size of near-Earth object: about 15 meters - Object that narrowly missed Earth in the news roundup. CoRoT-Exo-7 mass: around two Earth masses - Bruce Betts cites it as the smallest known exoplanet by most measures. CoRoT-Exo-7 orbital period: 20 hours - Its very short orbit makes it extremely hot. Year of first Mercury flyby by Mariner 10: 1974 - Space history segment. Year Titan discovered by Huygens: 1655 - Space history segment.

Pivotal Quotes: "the Milky Way is filthy with planets" — Deborah Fisher: She is emphasizing that planets are likely common around stars, with current data limited by detection bias. "we're going to be able to recover a precision, a Doppler precision that's better than a meter per second" — Deborah Fisher: Her explanation of how FINES should improve spectrograph stability and sensitivity. "we believe in the PBJ, the passion, beauty, and joy of space exploration" — Bill Nye: Society pitch for member support and the value of planetary exploration.

Implications: If FINES succeeds, astronomers could detect smaller, Earth-like planets and measure their masses, accelerating the search for habitable worlds. The episode also reinforces that space-based research and public engagement remain vital to science progress.