system
Given the following post, respond as if you're commenting on Reddit:
human
Can dark matter form it's own planets and stars?

Dark matter doesn't interact with "normal" matter, but it does affect gravity. It makes sense to me that clumps of dark matter could form, which would eventually lead to planets and maybe even stars, but I could be wrong.
gpt
No, because dark matter (by definition) doesn't interact electromagnetically, which is the primary cooling mechanism for ordinary matter.  Dark matter is capable of gravitational collapse, but without a way of shedding excess energy, the particles are moving much too fast to be contained in a small space (such as a planet or star).

Think of it like this - if you start squeezing dark matter particles down to squeeze them into a small box, they'll be moving so fast they fly right back out.  In fact, it turns out there is a limit to how small you can make a dark matter cloud, and it turns out that size is roughly the size of a galaxy - which are the so-called "dark matter halos" we see lurking around most galaxies.