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Would an impact event leave visible traces like impact basins, or could the entire surface melt and reform as it is today, as I suppose Earth did when the Moon formed? Could Venus have been a very different planet up until 0.3 billion years ago? How could one find out, what kind of investigation would be needed? Certainly giant impacts were fairly ...


4

The velocity required to escape the gravitational attraction of a massive body is given by the following equation: $$ v_{\mathrm{escape}} = \sqrt{\frac{2GM}{R}}$$ where $G$ is the gravitational constant ($G = 6.67 \times 10^{-11} \; \mathrm{Nm^{2} {kg}^{-2}}$), $M$ is the mass of the body from which you are escaping, and $R$ is its radius. Inputting the ...


4

Exoplanets are too far away to send satellites or to image them directly. So there is no way to go there and say: there it is a volcano. My guess is that we have to guess from what we know working in the solar system. And we might just get a statistical probability that the planet is active. I would say that there are two cases: If the planet is rocky and ...


4

No, it is not just a matter of migration. You need to take into account two facts. One is that (as experience shows) Io's own gravity is enough to avoid it breaking by tidal forces. It has been like that through all its history: Io could not have been formed if it started aggregating today, but it was formed at the same time Europa and Ganymede did: they ...


3

Reposting my own answer from Space Exploration on nearly identical question: The color dichotomy of Iapetus is due to the darker half, the Cassini Regio, being a result of the moon's accumulation of the dust in the Saturn's largest, yet extremely tenuous, diffuse dust ring called the Phoebe ring depositing onto the moon's leading hemisphere, while the ...


2

I would bet against lightning due to the very thin SO2 atmosphere; under normal conditions the pressure is 0.3 to 3 nbar, with plumes reaching 5 to 40 nbar. That does not sound like it could convey lightening. But given that the environment also has a lot of ionization there might also be all sorts of plasma and vacuum breakdown discharges. In short, I ...


2

Since this has gone unanswered, I'm going to give it a shot. Probably the answer is no. We know that on some moons, volcanic eruptions do send material into space. Enceladus for example, feeds Saturn's E-ring. It regularly shoots about 200 KG per second into space. The other highly volcanic moon in our solar system is Io which shoots material high ...


2

Source: JPL Article "The gravity anomalies along the border structures are interpreted as ancient, solidified, lava-flooded rifts that are now buried beneath the surface of the dark volcanic plains, or maria, on the near side of the moon." Because of the lava under Oceanus Procellarum, it's heavier/massive so it has a stronger gravitational pull than the ...


2

A younger lunar thermal history implies that the Moon was still undergoing a contraction and cooling process, which was initiated when it began accreting material together. Evidence has shown that the moon has no tectonic activity, so all geologic features are volcanic. The mare are a more recent example of this activity, and have been shown to have fairly ...


1

Is Io's orbit or rotation affected by its volcanism? The rotations of comets and asteroids are affected by outgassing volatilities. Io is very volcanically active. Does this give Io a varying orbit and a slow rotation? Jupiter's moon Io has a lot of volcanoes. A similar answer to your question is provided at Quora's question: "Could the eruptions of ...


1

There was once a very active argument over vulcanism on the Moon - with the distinguished amateur astronomers Patrick Moore and V. A. Firsoff the two leading advocates of vulcanism as having had a decisive impact on the Moon. The Apollo programme essentially settled this argument as far as craters were concerned - no serious figure seems to doubt these are ...


1

The grey areas are known as "maria" (singular:"mare") and they were formed from flood basalts. These are a type of volcano and they have formed on earth too, examples include the lake eruption on Iceland, and the Deccan traps, that played a role in the mass extinction 65 million years ago. On the moon, the flood basalt is old. About 3-4 billion years old, ...


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