The physics of losing Helium from the Earth - question

[GTrax]

Helium is seen to be "lighter" than air only when it is confined in a balloon or similar so as to be able to displace the heavier stuff around it.

Released loose, the atoms seem to mix with the air around very swiftly. I mean about 50 metres in 2 or 3 seconds, and then it seems to hang about steadily getting more dispersed, but still enough to make a vacuum leak detector howl, for maybe 20 minutes. Forgive the very casual approximate descriptions - this was not a real experiment!

There have been recent alleged "concerns" that helium is a non-renewable resource, countered by other accusations that this is hype intended to affect the share price and profits of helium-mining companies. As I understand it, Earth Helium is mostly derived from Radon gas decay.
http://amarillo.com/news/local-news/2010-09-13/helium-prices-jump-curb-debt"
http://www.mnn.com/earth-matters/wilderness-resources/stories/helium-crisis-spreads-around-the-world

So the question(s) ..
What exactly happens to released helium, party balloon or otherwise?
Does it drift up to "float "above the atmosphere, and get blown off into space?
Does it remain a "mixture" with air?

 

[rcgldr]

The main method of atmospheric escape on the Earth is due to a tiny portion of molecules at the fringes of the atmosphere that achieve escape velocity:

http://en.wikipedia.org/wiki/Atmospheric_escape

 

[D H]

So the question(s) ..
What exactly happens to released helium, party balloon or otherwise?
Does it drift up to "float "above the atmosphere, and get blown off into space?
Does it remain a "mixture" with air?

The troposphere is rather well-mixed. Higher layers of the atmosphere are not. The helium in that balloon will be mixed in with the other gases in the troposphere. While the tropopause is an inversion layer, some mixing of the gases in the lower and upper atmosphere still occurs. That helium will cross the tropopause eventually. Once it does, bye-bye (after a while). Above 75-100 miles altitude or so, the upper atmosphere becomes too tenuous to support fluid flow. Diffusion processes dominate in the upper atmosphere. The physics of this diffusion means that migration to the upper reaches of the atmosphere will be biased toward lighter constituents. The very top of the atmosphere, the exosphere, is almost all hydrogen.

 

[GTrax]

My thanks D H.
How we retain any of our atmosphere is, I suppose, closely related. Were it not for the magnetic field deflecting the main solar wind around the earth, I guess much of the atmosphere would be off into space. That there is a retained layer of Hydrogen up there is comforting. It is still with us, not just blown away, and it is even lighter than Helium!

 

[pmacias]

The physics behind the loss of helium from the Earth is a complex and ongoing topic of research. Helium is the second most abundant element in the universe, but on Earth, it is relatively rare and difficult to extract. As mentioned in the content, most of the Earth's helium is derived from the decay of radioactive elements such as uranium and thorium. This process produces helium gas that is trapped in underground natural gas deposits.

When helium is released into the atmosphere, it quickly rises due to its low density compared to air. However, it does not float above the atmosphere and get blown off into space. Instead, it becomes mixed with the surrounding air and is gradually dispersed throughout the atmosphere.

The rate at which helium is dispersed depends on a variety of factors such as wind patterns, temperature, and atmospheric conditions. In general, helium is a very light gas and can easily move through the atmosphere, but it is not completely immune to Earth's gravitational pull. This means that it will eventually settle back down to the surface, although this process can take a significant amount of time.

As for the concerns about helium being a non-renewable resource, there is some truth to this. While helium is constantly being produced through radioactive decay, it is not being produced at a rate that can keep up with our current consumption. This is why helium is often called a "fossil gas" and why its availability and price have become a concern in recent years.

In summary, when released into the atmosphere, helium becomes mixed with air and is gradually dispersed throughout the atmosphere. It does not float off into space, but it is also not completely renewable and its availability is a subject of ongoing research and concern.