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Geological evidence for multiple climate transitions on Early Mars
Kite, Edwin S.; Conway, Susan
Landforms and deposits observed on the Martian surface suggest that Mars' early climate supported rivers and lakes over a time span of more than a billion years. But, like Earth, which has over the past billion years experienced periods of global glaciations and hyperthermals, the climate history of Early Mars may have been intermittent. Here we s…
Evidence for transient morning water frost deposits on the Tharsis volcanoes of Mars
Vandaele, A. C.; Daerden, F.; Ristic, B. +27 more
The present-day water cycle on Mars has implications for habitability and future human exploration. Water ice clouds and water vapour have been detected above the Tharsis volcanic province, suggesting the active exchange of water between regolith and atmosphere. Here we report observational evidence for extensive transient morning frost deposits o…
The vertical structure of CO in the Martian atmosphere from the ExoMars Trace Gas Orbiter
Forget, F.; Montmessin, F.; Korablev, O. +11 more
Carbon monoxide (CO) is the main product of CO2 photolysis in the Martian atmosphere. Production of CO is balanced by its loss reaction with OH, which recycles CO into CO2. CO is therefore a sensitive tracer of the OH-catalysed chemistry that contributes to the stability of CO2 in the atmosphere of Mars. To date, C…
Intermittent warmth on young Mars
Mangold, Nicolas
Warm and wet conditions could have episodically punctuated a generally cold early climate on Mars, according to a multidisciplinary modelling approach that potentially solves a five-decade long debate regarding warm conditions on early Mars.
Valley formation on early Mars by subglacial and fluvial erosion
Osinski, Gordon R.; Grau Galofre, Anna; Jellinek, A. Mark
The southern highlands of Mars are dissected by hundreds of valley networks, which are evidence that water once sculpted the surface. Characterizing the mechanisms of valley incision may constrain early Mars climate and the search for ancient life. Previous interpretations of the geological record require precipitation and surface water runoff to …
Ross Ice Shelf response to climate driven by the tectonic imprint on seafloor bathymetry
Tinto, K. J.; Padman, L.; Siddoway, C. S. +28 more
Ocean melting has thinned Antarctica's ice shelves at an increasing rate over the past two decades, leading to loss of grounded ice. The Ross Ice Shelf is currently close to steady state but geological records indicate that it can disintegrate rapidly, which would accelerate grounded ice loss from catchments equivalent to 11.6 m of global sea leve…
Lunar soil hydration constrained by exospheric water liberated by meteoroid impacts
Stubbs, T. J.; Elphic, R. C.; Benna, M. +2 more
Analyses of samples from the Apollo missions suggest that the Moon formed devoid of native water. However, recent observations by Cassini, Deep Impact, Lunar Prospector and Chandrayaan-1 indicate the existence of an active water cycle on the Moon. Here we report observations of this water cycle, specifically detections of near-surface water releas…
Independent confirmation of a methane spike on Mars and a source region east of Gale Crater
Cardesín-Moinelo, Alejandro; Marín-Yaseli de la Parra, Julia; Aoki, Shohei +11 more
Reports of methane detection in the Martian atmosphere have been intensely debated. The presence of methane could enhance habitability and may even be a signature of life. However, no detection has been confirmed with independent measurements. Here, we report a firm detection of 15.5 ± 2.5 ppb by volume of methane in the Martian atmosphere above G…
A deep groundwater origin for recurring slope lineae on Mars
Heggy, Essam; Abotalib, Abotalib Z.
The recurring slope lineae on Mars have been hypothesized to originate from snow melting, deliquescence, dry flow or shallow groundwater. Except for the dry flow origin, these hypotheses imply the presence of surficial or near-surface volatiles, placing the exploration and characterization of potential habitable environments within the reach of ex…
Surface refreshing of Martian moon Phobos by orbital eccentricity-driven grain motion
Fujimoto, Masaki; Ballouz, Ronald-Louis; Baresi, Nicola +2 more
The surface of the Martian moon Phobos exhibits two distinct geologic units, red and blue, characterized by their spectral slopes. The provenance of these units is uncertain yet crucial to understanding the origin of the Martian moon and its interaction with the space environment. Here we present a combination of dynamical analyses and numerical s…