a Helium Layer?

[YT2095]

after constantly filling up one of my daughters balloons about once every 2 weeks, I got to thinking about these Helium atoms and where they go.

obviously small enough to escape the balloon and probably the bedroon ceiling etc...

so they rise up through the air like a ping pong ball under water does.

they`re heavier than a vacuum (like that in space) so they would stop there after reaching a pressure equilibrium.

 

so do we have a thin Helium Layer around the Earth?

[Royston]

This is just a guess, but I would imagine the helium would escape past the ozone layer and would be ionized due to the level of radiation...for your theory to work I think there would have to be a sufficent amount of helium (a lot more than we have in our atmosphere) and less radiation, to create the equilibrium you're describing.

 

I really am guessing though, maybe somebody more knowledgeable knows better.

[insane_alien]

the helium atoms velocity can easily exceed the escape velocity of earth so will evapourate away into the 'vacuum' of space.

[YT2095]

so it`s a bit like the ping pong ball under water that will actualy Leave the water surface and "jump" and inch or 2 into the air?

[Klaynos]

into the air and keep going if they're greater than the escape velocity....

[Royston]

Yeah...I was thinking of early atmospheres when I posted, but the proto-planets were more massive and so obviously had stronger gravity trapping helium and hydrogen.

 

I think solar winds had something to do with the change in atmosphere as well IIRC.

[YT2095]

so over the millions of years earth has existed, How do we still have Any Helium on the planet at all?

 

it`s not like it forms compounds like Hydrogen does.

[Royston]

It's trapped within the earth itself, released through volcanism et.c

[insane_alien]

YT, radioactive decay. specifically alpha decay.

[YT2095]

well I`ve actualy wondered about this myself, HOW do we "Catch" it, also if we take for instance Am241, it makes Helium nuclei, so how much would you need to keep a balloon filled?

[Royston]

YT, radioactive decay. specifically alpha decay.

 

Gah, I can't wait to start studying again...there's so much I need to refresh my memory on.

[insane_alien]

well I`ve actualy wondered about this myself, HOW do we "Catch" it, also if we take for instance Am241, it makes Helium nuclei, so how much would you need to keep a balloon filled?

 

calculate the number of helium atoms escaping the balloon per second then get a source with the same number of bequerels in activity. preferably more so it lasts longer, although it may pop.

[YT2095]

37KBq per slug output.

however, How does one calculate the "escapage"?

[insane_alien]

umm... take the volume that escapes over a day or so then work out the mol value. then use that to calculate the number of atoms per second. accurate it won't be but its better than nothing.

[Bluenoise]

Yep yep it goes running out into space to never again be seen by us. The majority of the helium we get right now is a by product of fossile fule extration. It probably seeps into the oil from rocks. Radioactive decay can replenish it.