"Every cloud has a silver lining." The saying is fairly well-known, but I was musing on it while staring through a cloud bank, and I started to wonder: What kind of hellhole would a planet have to be to have clouds made out of literal silver vapor?

The first thing that comes to mind is that for silver to become a vapor, the planet would have to be unsurvivably hot. It would also need an atmosphere composed of gaseous elements heavier than silver, for that silver to have any buoyancy. Already this planet is totally unsurvivable for all imaginable carbon-based life forms, but how much worse would it actually be? Is such a planet even physically possible? And what kind of insane conditions would it contain if it were?

  • $\begingroup$ No need to look beyond the solar system, metal snows on Venus $\endgroup$
    – user6760
    Nov 23 '16 at 8:10

It wouldn't have to be a hellhole. A few ideas:

  1. The silver particles could be very fine. According to this document from the IFC, particles need only be a certain proportion below the average size of molecules in a gas to remain suspended. In fact, this is a health problem worldwide (think asbestos, aerosolized bioweapons, etc).

  2. Silver atoms could be bonded with other elements that makes their combined density lighter than the atmosphere, or distributed in a kind of aerogel that causes them to float.

  3. Silver could be plentiful within liquids covering the surface of the planet, and could be strongly electro-magnetically attracted to those molecules, such that when it vaporizes into clouds they have a reflective, shiny appearance.

  • 1
    $\begingroup$ I disagree with the "bonded with other elements" as generally these molecules have different characteristics; that's like saying we have hydrogen rain on Earth because water contains hydrogen. The particle suspension is clever however! $\endgroup$
    – Zxyrra
    Nov 23 '16 at 7:25
  • $\begingroup$ @Zxyrra Thanks for the feedback, I'll try to improve that section. Also thanks for the compliment! My first post; not sure how this works yet. :) $\endgroup$
    – dynrepsys
    Nov 23 '16 at 13:05
  • $\begingroup$ And who are the IFC, and what are their relevant credentials here? Don't just point at a random document and assume that everyone is familiar with the organization publishing it; explain why it is relevant and why we should trust it to be accurate. Especially in answers to questions tagged science-based. $\endgroup$
    – user
    Nov 23 '16 at 13:36

This is ~Plausible

The densest planet we've seen is 55 Cancri e - a tidally locked, massive ball of something orbiting extremely close to its star. This planet will help provide us with some evidence that silver clouds are possible.

Silver as a Gas
At the substellar point of 55 Cancri e - that is, the point directly below the sun, or the middle of the tidally locked face - temperatures reach about 4760.33 °F (2626.85 °C). The boiling point of silver is 3,924°F (2,162 °C), so silver here may very well be gaseous. Alternatively, temperatures may be lower, as Dynrepsys noted, if fine particles are suspended - although I'm not sure what would cause that.

Silver Floating at a ~Specific Height (Not just dispersed)
The "floating in denser substances" part may not need to be true here. Silver is strongly diamagnetic - meaning strong magnetic forces will repel it. With a strong enough magnetic field, it may be able to ~plausibly~ float in the air.

Strong Magnetic Field Existence
Iron is considered to be necessary for magnetic field formation - but it is significantly less dense than silver, meaning silver would probably sink to the core of the planet during formation if iron would. Therefore, silver in the atmosphere would have to come from either volcanic activity - silver geysers - or meteor bombardments.

  • $\begingroup$ Any ideas why it would be silver in particular, and not some other element? $\endgroup$
    – Kys
    Nov 23 '16 at 17:53

Scientifily there are a number of ways, such as the aforementioned silver dust clouds, but more likely it would be quick silver vapor then actual vaporised silver. Gaseous mercury, to be clear.

  • $\begingroup$ Sorry, I'm looking for conditions that would produce actual silver (Ag) clouds. $\endgroup$ Nov 29 '16 at 5:11

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