system
Given the following post, respond as if you're commenting on Reddit:
human
If a radioactive isotope is accelerated near c, will the decay slow down or remain the same relative to observer?

I would assume the decay would slow down, but the more I think on it, the less I'm confident.
gpt
It will be slower.
For example, when cosmic rays hit the atmosphere, they can produce muons. A muon is more or less like an big electron and its lifetime is only 2 µs.
So if you don't consider the time dilation, a muon cannot travel more than 2 µs times 300000 km/s = 0.6 km. So you wouldn't expect them to reach the ground. But they do.

From our point of view, they live longer than 2 µs. From their point of view, they live 2 µs but the length of the atmosphere is contracted.