: Argonne National Laboratory)

There are certain things in the Universe that, if you leave them alone for long enough, they’ll eventually decay away. Other things, no matter how long we wait, have never been observed to decay. This doesn’t necessarily mean that they’re truly stable, only that if they’re unstable, they live longer than a certain measurable limit. While a large number of the particles — both fundamental and composite — are known to be unstable, with some atomic nuclei being unstable but , some particles appear to be truly stable forever, from both observational and theoretical perspectives.

But are they truly, perfectly stable, destined never to decay even as the cosmic clock runs forward for all eternity? Or, if we could wait long enough, would we eventually see some or even all of those particles eventually decay away? And what about the simplest stable composite particle of all, the one at the heart of every atom: the proton? That’s what kilioopu wants to know, simply inquiring,

“I would be interested in a discussion about proton stability.”