Anti Helium

[Jon P. Inghram]

According to the Wikipedia article it mixes very slowly with the atmosphere. There just aren't any natural processes known that remove from the atmosphere, so in theory it just builds up slowly without going away.

[KRSESQ]

I should think that this stuff would just escape down the nearest floor drain and get dispersed in the sewer lines, or mixed into the water at the treatment plant. Or, eventually it would disperse into the soil, would it not?

Never was much good at fluid dynamics, except for making tidal waves in the bathtub.

Kevin

[Brian Ellis]

No, like all gases it diffuses. If heavy gases did not diffuse, CFCs, which are also heavy, would never reach the ozone layer, would they? As SF6 is insoluble in water, it would never rain out, nor be absorbed/adsorbed by soil. It could be adsorbed by certain grades of carbon. It is subject to neither atmospheric hydrolysis nor photolysis.

As a rough guide, a release of any such heavy gas will be almost homogeneously distributed round the earth at the latitude of release and within 1500 m altitude within 2 weeks (this will also be weather-driven to some extent). It will be homogeneous throughout the hemisphere of release, up to the tropopause (usually 8000-16000 m) within a little over one year. It will be homogeneously distributed through both hemispheres and into the stratosphere within about 14 years. By 'homogeneous', I mean that the ratio of the gas molecules to other gas molecules (notably N2 and O2) will be substantially constant at all pressures.

The gravitational force of individual gas molecules is far too small, compared with the intramolecular force exerted by the thermal movement of all molecules.

Exact analogy: take a beaker of water in a constant temperature chamber and drop in a crystal of, say, potassium permanganate. Cover the beaker to prevent air currents from disturbing the surface. You will see the crystal dissolving and forming a purple layer at the bottom. Leave it for the time it takes (a few days) and you will see the water will become homogeneously pink, right to the top, despite KMnO4 being much heavier than water.