Meteors May Masquerade as Lightning in the Atmosphere of Venus

Abstract

Lightning in the atmosphere of Venus is either ubiquitous, rare, or non‐existent, depending on how one interprets diverse observations. Quantifying when and where, or even if lightning occurs would provide novel information about Venus’s atmospheric dynamics and chemistry. Lightning is also a potential risk to future missions, which could float in the cloud layers (∼50–70 km above the surface) for up to an Earth‐year. Over decades, spacecraft and ground‐based telescopes have searched for lightning at Venus using many instruments, including magnetometers, radios, and optical cameras. Two optical surveys (from the Akatsuki orbiter and the 61‐inch telescope on Mt. Bigelow, Arizona) observed several flashes at 777 nm (the unresolved triplet emission lines of excited atomic oxygen) that have been attributed to lightning. This conclusion is based, in part, on the statistical unlikelihood of so many meteors producing such energetic flashes, based in turn on the presumption that a low fraction (< 1%) of a meteor’s optical energy is emitted at 777 nm. We use observations of terrestrial meteors and analogue experiments to show that a much higher conversion factor (∼5–10%) should be expected. Therefore, we calculate that smaller, more numerous meteoroids could have caused the observed flashes. Lightning is likely too rare to pose a hazard to missions that pass through or dwell in the clouds of Venus. Likewise, small meteoroids burn up at altitudes of ∼100 km, roughly twice as high above the surface as the clouds, and also would not pose a hazard.

Production and Reactions of Organic Molecules in Clouds of Venus

“…If these abundances are representative of average Venus atmospheric NO abundances, then NO chemistry will provide the most stringent limit on the concentration of gas phase HCHO produced at the top of the clouds. However, it was suggested that lightning, the only known source of NO in the clouds of Venus, might be absent . The details of the atmospheric chemistry can be found in the SI (SI 1.7).…”

Non‐Lightning‐Generated Whistler Waves in Near‐Venus Space

“…The existence and occurrence rate of lightning on Venus is hotly debated (e.g., Blaske et al., 2022; Gurnett et al., 2001; Hansell et al., 1995; Ksanfomaliti, 1980; Lorenz, 2018; Russell et al., 2007; Strangeway, 1992). One major piece of evidence used as indication of Venusian lighting are whistler‐mode waves in the ionosphere and induced magnetosphere (e.g., Hart et al., 2022; Russell et al., 2007, 2013; Scarf et al., 1980).…”

A Review of Infrasound and Seismic Observations of Sample Return Capsules since the End of the Apollo Era in Anticipation of the OSIRIS-REx Arrival

“…In this pursuit, the study of shock phenomena assumes paramount significance. The examination of shockwaves on Earth and other planetary bodies, such as Venus [110][111][112] and Mars [113][114][115], is essential for elucidating fundamental aspects of impact phenomena, planetary geophysics, and atmospheric dynamics. The utilization of infrasound sensing allows us to study the signatures of shockwaves, thus facilitating a more comprehensive understanding of the underlying physical processes, and characterization of the objects that generate them.…”