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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…
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 …
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…
Snow precipitation on Mars driven by cloud-induced night-time convection
Montmessin, Franck; Hinson, David P.; Forget, François +4 more
Although it contains less water vapour than Earth's atmosphere, the Martian atmosphere hosts clouds. These clouds, composed of water-ice particles, influence the global transport of water vapour and the seasonal variations of ice deposits. However, the influence of water-ice clouds on local weather is unclear: it is thought that Martian clouds are…
Groundwater activity on Mars and implications for a deep biosphere
Michalski, Joseph R.; Niles, Paul B.; Cuadros, Javier +3 more
By the time eukaryotic life or photosynthesis evolved on Earth, the martian surface had become extremely inhospitable, but the subsurface of Mars could potentially have contained a vast microbial biosphere. Crustal fluids may have welled up from the subsurface to alter and cement surface sediments, potentially preserving clues to subsurface habita…
Transport-driven formation of a polar ozone layer on Mars
Montmessin, Franck; Lefèvre, Franck
Since the seasonal and spatial distribution of ozone on Mars was detected by the ultraviolet spectrometer onboard the spacecraft Mariner 7, our understanding has evolved considerably thanks to parallel efforts in observations and modelling. At low-to-mid latitudes, martian ozone is distributed vertically in two main layers, a near-surface layer an…