Two Truths and a Lie!?

Hi everyone!

Today’s blog is a bit different than what I usually put out. I have short summaries of three planetary science articles below, two of which are actual, peer-reviewed articles and the remaining one is an imposter! Your task as a reader is to determine which one is the fake one. While I think that I’m slowly getting better at explaining ‘science’, made-up science is an entirely different story. I’ve tried my best to conceal the identity of the fake one, so here goes nothing…

Ejecta Thickness Distribution of the Schrodinger Basin on the Moon

This paper focuses on the ejecta deposit thickness for the Schrodinger basin on the Moon. The authors use data from LRO Wide Angle Camera (WAC), LOLA, and the Kaguya Terrain Camera. They estimate the ejecta thickness using crater morphometry on 16 partially filled pre-Schrodinger craters, all of which are located in lunar highlands.  In this article, they measure the outer and inner thicknesses of the ejecta. Here the outer thickness is equal to the difference between initial and current rim heights and the inner thickness is equal to the difference between initial and current rim-to-floor depths. They start by first obtaining the thickness distribution of Schrodinger’s ejecta deposits and then use that to derive the thickness distribution of ejecta as the ejecta deposits of a specific impact are a mixture of ejecta and the excavated local materials. Authors use three different previously proposed distinct ejecta thickness models to calculate these measurements using various parameters such as the transient cavity radius, ejecta volume, excavation volume, excavation depth, and the rim uplift. Based on their observations they conclude that ejecta thickness at the current Schrodinger basin rim is 704 m. They also claim that the previous (widely used) model significantly underestimated the ejecta thickness of the basin.

geomorphology of the Eberswalde Alluvial fan on Mars

This paper focuses on the geomorphology of the Eberswalde alluvial fan in the Erythraeum region of Mars, in a 65-km-diameter crater of the same name. In this article, the author is trying to determine whether this feature is an alluvial fan or a delta. To achieve that, they observe different lobes of the feature using data from Mars Global Surveyor (MGS), Mars Orbiter Camera (MOC), and the Mars Orbiter Laser Altimeter (MOLA) instruments. The author examines these lobes in terms of their cross-cutting relationship with one another, relative sinuosity, meander-belt width, and channel width. The authors review various previously established theories and factors that differentiate between an alluvial fan and a delta and then apply that knowledge to their own observation of the study area. For each lobe, they observe very low sinuosity and also find evidence of morphological features formed by pebbles and boulders of the debris flows on the surface. Additionally, they observe similar channel widths as seen in the alluvial fans on Earth. The author also mentions a lack of evidence suggesting deposition through flow into a standing body of water, based on the absence of floodplains in the region. Combining all these observations, the author concludes that the Eberswalde feature is more of an alluvial fan than a delta.

Materials and mechanisms involved in the formation of the Hollows on Mercury

This article is about an unusual landform on the surface of Mercury, known as ‘hollows’. These landforms are shallow, flat-floored, rimless depressions that are surrounded by bright deposits. In this study, the authors conduct a comprehensive survey of MESSENGER images in order to identify and map the areas where these hollows are present. The article mentions that these hollows occur globally but are rare in the high reflectance plains at higher northern latitudes. Their absence at high southern latitudes is explained to be an observational bias. The authors further analyze the occurrence of these hollows based on the latitudinal and longitudinal variations, geological settings such as inside and outside impact craters, and lastly their association with pyroclastic features. This article also analyzes the mechanisms behind their formation based on their locations on the surface. The results indicate a weak correlation between their occurrence and insolation. They observe a possible correlation with sub-surface heat sources, indicating a thermal control and thus claim sublimation as the primary hollow forming mechanism. The article also explains that the fact that these hollows mostly appear inside impact craters, is suggesting that the material containing these hollow-forming volatiles is being exposed from depth by large impacts. The authors do not observe any association of these hollows with volcanic plains. Lastly, they conclude that the low-reflectance material in which these hollows are formed had a volatile component, which then was lost and formed these hollows.

So… which one is an imposter? 😀

Until next time!

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