Theory predicts the isotope’s radioactive decay has a half-life that surpasses the age of the universe “by many orders of magnitude,” but no evidence of the process has appeared until now.

An international team of physicists that includes three Rice University researchers – assistant professor Christopher Tunnell, visiting scientist Junji Naganoma and assistant research professor Petr Chaguine – have reported the first direct observation of two-neutrino double electron capture for xenon 124, the physical process by which it decays. Their paper appears this week in the journal Nature.

While most xenon isotopes have half-lives of less than 12 days, a few are thought to be exceptionally long-lived, and essentially stable. Xenon 124 is one of those, though researchers have estimated its half-life at 160 trillion years as it decays into tellurium 124. The universe is presumed to be merely 13 to 14 billion years old.

The new finding puts the half-life of Xenon 124 closer to 18 sextillion years. (For the record, that’s 18,000,000,000,000,000,000,000.) (1)

We look up to the universe.

We admire the cosmos in awe.

But the cosmos is nothing more than the shell.

What is in it, is important.

Even particles can outlive the universe.

What matters is what cannot.

One day we will discover how huge the cosmos really is.

One day we will know how tiny we actually are.

And only then, will we understand that we were wrong.

About how significant we are.

Especially because we are not…