Jean-Marie Prival
  • Member for 1 year, 6 months
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  • Clermont-Ferrand, France
How do we get to know the total mass of an atmosphere?
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25 votes

There is a simple$^*$ way to know the total mass of the atmosphere: measuring the pressure it exerts on the surface, which necessarily integrate all of the atmosphere above ground level. If you take ...

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When was the last volcanic eruption on Mars?
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14 votes

Berman and Hartman (2002) dated some lava flows of the Athabasca–Marte Valles system at < 20 Ma (mega-annum). Later, Vaucher et al. (2009) dated lava flows of the same region, finding ages even ...

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Is there convection in Mars' mantle?
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8 votes

There are several ways to look at this. One rather simple way is to compute the Rayleigh number of Mars' mantle. The Rayleigh number is a dimensionless number defined as: $Ra = \dfrac{\rho g \alpha \...

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What caused these strange craters on Hyperion?
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7 votes

According to Thomas et al. (2007), these craters are not unusually deep: It is unlikely that unusual crater depths significantly enhance the sponge-like appearance. Crater depth-to-diameter ratios ...

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Where was this photo of Nancy Grace Roman taken, what is the display shown?
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6 votes

Her Wikipedia page also includes this picture (public domain), where she wears the same dress, and where a similar display can be seen in the background: Roman sits at the control console for the ...

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What if a global killer hit Mars?
5 votes

A partial answer to this part: Would any volcanoes erupt? At a local scale (i.e., close to the impact), such an asteroid could melt the rock, see impactite. But this is not volcanism stricto sensu, ...

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Could ancient tectonic activity on Mars be due to it having oceans of sulphuric acid?
5 votes

First, tectonic activity have not ceased on Mars, although the planet is in a "stagnant lid" stage, which represents the last stage before a body becomes tectonically dead. See the answer to ...

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What are the white reflections on Ceres?
5 votes

Several papers with data from the Dawn spacecraft have just been published. Among them, Fresh emplacement of hydrated sodium chloride on Ceres from ascending salty fluids focuses on the composition of ...

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Are there any Hubble images of Polymele available?
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4 votes

HST Proposal 15144, entitled "Deep Search for Satellites Around the Lucy Mission Targets", has a data page with 24 Hubble images of Polymele (you need to go to page 2 of 2 of the table). An ...

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How was a rock on the surface of asteroid 101955 Bennu first observed from Earth (Benben Saxum)?
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4 votes

I think it is the "boulder" discovered by Nolan et al. (2013). They used radar images from two ground-based observatories, from two different passes, to perform shape modeling: The radar ...

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What other definitions for a planet were proposed?
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4 votes

The IAU website has this draft definition of "planet" and "plutons" page, published on 16 August 2006 in Prague. It says (emphasis mine): The world's astronomers, under the ...

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Age of Occator Crater
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3 votes

Five years have passed, and several papers have been published about this. The latest, Neesemann et al. (2019), compiles previous results and propose a new age estimate. Or rather estimates, because ...

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What's the difference between a crater and a basin?
3 votes

The French version of the Wikipedia article has a "nomenclature" section, absent from the English version. It says: Lorsque l'énergie cinétique de l'impacteur est suffisante pour atteindre ...

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Are the Venusian "continents" likely to have existed before the global resurfacing event?
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3 votes

Ishtar Terra belongs to the tessera type of terrain, "one of the most tectonically deformed types of terrain on Venus", representing ~7.3 % of Venus' surface (Ivanov & Head 2011, Global ...

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Fixed star-like light appears for a second or two - is there a way to find out what it was?
2 votes

How can I go about finding out whether others saw it as well, and what it was? I can't say for the "what was it?" part, but there is actually a way to answer the first part of your question....

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Catalogue of black holes
2 votes

The Wikipedia list given by @NeutronCat in a comment contains this external link. This compilation by Wm. Robert Johnston has not been updated since 2004, but contains both stellar and supermassive ...

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Is early life required for life?
1 votes

Maybe he was thinking about the Great Oxidation Event? It was produced by early life forms (such as cyanobacteria) and, even if it caused an extinction at the time, it is thought that it allowed ...

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What are the most recent minerals modified by water found to date on Mars?
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1 votes

If you have access, I would recommend you to read Carter et al. (2013). It is a compilation of all occurrences of hydrous minerals that have been detected on Mars by spectrometers OMEGA (Mars Express/...

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