New answers tagged planetary-science
3
Yes. If something softer than talc or harder than diamond shows up, the new low or high point changes the scale itself by extends the spectrum but the relative positions of everything else remain unchanged.
The answer would still be Yes if it were an absolute scale, such as temperature. The freezing and boiling points of water might vary in different ...
2
The way Mohs hardness scale works (in essence), is that if something can scratch talc (which has a hardness of 1), but not gypsum (which has a hardness of 2), then it will be assigned a number between 1 and 2. Since graphite has a hardness of 1.5, if the material you're testing is able to scratch graphite, then it will be assigned something between 1.5 and 2....
6
Yes, for the simple reason that it is a scale of hardness rather than a classification of minerals: the minerals serve only as exemplars of hardness at various places on the scale.
11
1. Diamond. Its hardness is legendary. That it appears in liquid form on Uranus or Neptune hasn't been directly measured (no recent probes), but lab measurements in 2009 and 2010 of diamond's phase diagram still haven't been contested to claim that diamond can't be liquid there. On the contrary, in 2017 a process was demonstrated of converting diamond ...
18
Yes, but with a couple modifications.
On some planets, notably Venus within our Solar Systen, different conditions from those on Earth, especially temperature, can affect mineral hardness. Pyrite is indeed pyrite, but at 400+°C on the surface of Venus it may have a different hardness versus 20°C on Earth. Thus a distinction must be made between hardness ...
19
Yes, because for the vast majority of minerals you can find in space, they are the same as those you can find (or synthesize) on Earth. A pyrite in space is a pyrite just like on Earth. A wollastonite in space is no different than a wollastonite on Earth.
Nearly all space minerals are present on Earth, but the converse is not at all true--plate tectonics, ...
4
We don't need to invoke sulfuric acid or sulfur oxides. Even at relatively low partial pressures and temperatures close to those found on the surface of Venus, carbon dioxide alone can oxidize iron. Thus we need a metal more robust than common steel to avoid being corroded on Venus. See for example Ref. 1, which studies the impact of carbon dioxide on ...
3
Recently, I answered this question. I came to know that descent probes also provided some evidence for thin aerosol layers near the surface. It is written that:
A recent reanalysis of Venera-13, -14 descent probe spectrophotometer data found a sharp decrease of light levels at 1–2
km altitude, interpreted as indicating a detached layer of aerosols of
...
2
The first asteroid (Ceres) was discovered on 1801. Initial studies on asteroids were primarily on positional parameters and nature of orbit. The first ever attempt on predicting the composition of asteroids was done by Watson et.al. on 1941 but due to limited technology and knowledge, the findings were found to be inconclusive. In the 1950s, with the ...
5
TAI conceptually is time measured by a perfect atomic clock running exactly at the geoid. There are some issues with this concept:
A perfect atomic clock does not exist.
Older and presumably less accurate atomic clocks are regularly replaced with newer and presumably more accurate atomic clocks.
Few, if any, atomic clocks are at sea level.
Mean sea level is ...
2
Converting my comments to provisional answer.
"Saturn's Small Inner Satellites: Clues to Their Origins" by C. Porco et al. - this article in Science is paywalled, too, but pictures from the article are accessible with captions, as well as tables.
From table there (mass and density):
mass (× 10^19 g) ρ (g/cm^-3)
Pan 0....
1
One possible downside is that the low pressure dome, over the course of its lifetime, possibly does not produce enough consumables to outweight its construction cost.
Construction on Mars is expensive. Having a supply chain for consumables to Mars is also expensive. The base likely needs a supply chain anyway since all consumables presumably can't be ...
answered Sep 29 at 6:34
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