system
Given the following post, respond as if you're commenting on Reddit:
human
Why does an object become radioactive when in proximity to a radiation source?

My understanding is that when you have a radioactive material, e.g. Uranium, it decays which causes it to emit high energy particles, i.e. ionizing radiation. But say for example you leave a piece of clothing next to said Uranium for some time, the clothing will then become a radiation source itself. 

So how does this work? Is the piece of clothing now decaying as well? Or are the high energy particles emitted from the uranium somehow getting trapped in the piece of clothing and then being re-emitted? 

Thanks!
gpt
Ignoring contamination since that’s not what you’re asking about, there can also be *activation*, where the material itself is made radioactive by radiation.

Any type of radiation, at sufficiently high energies, can induce nuclear reactions in matter, and the products of those nuclear reactions are not necessarily stable in general.

So you’re producing radioactive nuclei inside the object, which then decay and emit more radiation.

However under most circumstances, the only type of radiation where this is really a concern is with neutrons.