Does every element decay?

[Toadie]

I know when thinking about radioactive decay, unstable isotopes are what come to mind. But out of curiosity (and I really have no education on the matter, if you couldn't tell), would any given matter decay into pure radiation in theory, if given an extremely vast period of time?

[insane_alien]

unknown. protons might decay but we have not been able to measure it which sets an extremely high lower bound on the halflife.

 

if they do decay, then eventually everything will become electromagnetic radiation.

 

if they don't then stuff will hang around until its swallowed by a black hole.

[SH3RL0CK]

unknown. protons might decay but we have not been able to measure it which sets an extremely high lower bound on the halflife.

 

if they do decay, then eventually everything will become electromagnetic radiation.

 

if they don't then stuff will hang around until its swallowed by a black hole.

 

 

But don't black holes themselves decay via Hawking radiation?

[insane_alien]

yes, but hawking radiation is a whole slew of particles and photons so there would still be matter about unless the mater released actually decays in and of itself.

[timo]

I think that according to current knowledge (both on elementary particles and on bound states) the answer is "no". Electrons don't decay. Protons don't do so in a measurable way. Even if they did I am not sure if that implied that all nuclei decay. Free neutrons do decay but iron nuclei (which are said to contain neutrons) don't.

[Horza2002]

In principle yes they will...most atoms do decay evetnually....although some of them take 1,000,000s years!

[Mr Skeptic]

There are 80 elements that have at least one stable isotope, and 256 isotopes appear to be stable, though some of them are predicted to have a mode of decay. Every element has radioactive isotopes for sure, even hydrogen. A neutron by itself is also radioactive.

 

Some theories require that protons decay, in which case all atoms will eventually decay. If so, the half-life would be more than the age of the universe.

 

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

[louis wu]

yes, but hawking radiation is a whole slew of particles and photons so there would still be matter about unless the mater released actually decays in and of itself.

Surely in Hawking radiation the emitted particle has an even chance of being an anti-particle; so emitted particles are primed to change to radiation at their first collision, eventually leaving the universe without matter.

[rogerxd45]

In principle yes they will...most atoms do decay evetnually....although some of them take 1,000,000s years!

 

well some radioactive elements have half lives MUCH longer then 1 million years.

 

Se-82 is said to have a halflife of 1.08x10-20 so that would be

108,000,000,000,000,000,000 Years!

[jdurg]

Don't forget Bismuth. It was once thought that Bismuth was the last element with a stable isotope, but they have found that the isotope that was once thought to be stable is actually radioactive with a half-life that is in the order of BILLIONS upon BILLIONS of years.

[rogerxd45]

Don't forget Bismuth. It was once thought that Bismuth was the last element with a stable isotope, but they have found that the isotope that was once thought to be stable is actually radioactive with a half-life that is in the order of BILLIONS upon BILLIONS of years.

 

i forgot about that one

 

i believe it wasnt until 2003 that they figured that out.

 

does anyone know the actual halflife of bismuth

[insane_alien]

19+/- 2 *10^ 18 years according to wiki.