Why don't transuranic elements occur in nature?

[chilehed]

Or is it just that they don't occur in our solar system? We make them in reactors, and if stars are just big energetic reactors...? I can understand how we'd not be able to find the short half-life stuff even if it had originally been around, but that doesn't explain the absence of plutonium in nature.

 

My kid's getting to where his questions go beyond my mechanical engineering background as well as anything I recall reading in the past.

 

He's also wondering: if you got shocked by a charge of protons, would it feel like an electric shock? I told him my guess is that if you could get some at a low enough energy it might, but free protons take a bit of energy to make so as a practical matter if you got zapped by them and could feel it then you'd be dead pretty quickly.

 

Thoughts?

Thanks.

[[Tycho?]]

You must be confused about something for your first point. Transuranic elements dont occur in nature (in quantities large enough to detect) because of their short half-lives. I assume that some plutonium is created in supernovae, which is where all elements heavier than iron are created. But the plutonium would decay quite quickly, and so by the time earth formed and humans started walking around looking for radioactive elements, any plutonium formed originally had been gone for a very, very long time.

 

About the proton shock im not so sure. It would feel like an electric shock, indeed there is a type of lightning that works via the movement of positive charges. I dont know about the practical part of this however.

[Gilded]

(http://en.wikipedia.org/wiki/Plutonium)

 

"The most stable isotope is 244Pu, with a half-life of about 80 million years, long enough to be found in extremely small quantities in nature."

 

Uranium-235 for instance, has a half-life of about 700 million years and is somewhat scarce in nature (only around 0.7% of natural uranium is U-235). Compared to Pu-239's half-life of 24,110 years this pretty much explains why you can't dig your weapon plutonium from the ground.

[swansont]

Or is it just that they don't occur in our solar system? We make them in reactors, and if stars are just big energetic reactors...?

 

The reactions are endothermic, which means they can't occur spontaneously. You'd get them in supernovae, where there is a lot of energy around. Stars, in the normal course of burning, don't give you anything heavier than iron.

[chilehed]

You must be confused about something for your first point.

Wouldn't be the first time...

 

 

Thanks, guys. Sounds pretty much like I thought, except I thought that Pu had a much longer half-life.