system
Given the following post, respond as if you're commenting on Reddit:
human
What radioactive element takes the longest time to decay into something stable? How long is that?

My younger brother asked this, and I'm having trouble finding the answer through google. Any help, please?
gpt
It's hard to say, because after a certain point, the accuracy of our equipment is exceeded, and we need to run century-long experiments with the most sensitive of detectors to prove it. Otherwise, scientists are just relying upon mathematical models, which have their own error bars.

Tellurium-128 is worth mentioning, though. It has the longest *confirmed* half-life, at 2.2*10^^24 years. That's two trillion trillion years.

^^128 Te decays to ^^128 Xe which is considered stable.