The smallest pieces of nature—individual particles like electrons, for instance—are pretty much interchangeable. An electron is an electron is an electron, regardless of whether it’s stuck in a lab on Earth, bound to an atom in some chalky moon dust or shot out of an extragalactic black hole in a superheated jet. In practice, though, differences in energy, motion or location can make it easy to tell two electrons apart.
![](https://scx1.b-cdn.net/csz/news/tmb/2019/stretchedpho.jpg)
Source:
https://phys.org/news/2019-10-photons-recover-lost.html