Physicists Find New Evidence For Helium 'Rain' On Saturn (sciencemag.org)

sciencehabit writes: Using one of the world's most powerful lasers, physicists have found experimental evidence for Saturn's helium 'rain,' a phenomenon in which a mixture of liquid hydrogen and helium separates like oil and water, sending droplets of helium deep in the planet's atmosphere. The results show the range of blistering temperatures and crushing pressures at which this takes place. But they also suggest that a helium rain could also fall on Jupiter, where such behavior was almost completely unexpected.

Comments

Don't try this at home

[Anonymous Coward]

Millot says it took about 5 years and 300 laser shots to sketch out the phase transition across temperatures between 3000 and 20,000 kelvins and pressures between 30 and 300 gigapascals.

That's not what I expected when I read about "rain" - the helium "rain" apparently falls through an "atmosphere" of metallic hydrogen.

Re:Don't try this at home

[Rei]

It would have to be far, far colder to support liquid helium at normal atmospheric pressures.

An interesting possibility that I've pondered is that if you have a very distant body (no relevant stellar heat input), small enough to not have relevant internal heat, which is losing helium to a tidally locked partner, it would be experiencing evaporative cooling to below the cosmic microwave background... to the point that the helium becomes a superfluid. My calculations show that you don't need some sort of extreme helium loss rate because radiative heat exhange with the cosmic microwave background is so incredibly slow. That would be an incredibly bizarre world to see...

Further in the future, the cosmic microwave background will drop below helium's triple point, and superfluid He4 will become common in the universe :)