Dark matter is only known by its effect on massive astronomical bodies, but has yet to be directly observed or even identified. A theory about what dark matter might be suggests that it could be a particle called an axion and that these could be detectable with laser-based experiments that already exist. These laser experiments are gravitational-wave observatories.
![](https://scx1.b-cdn.net/csz/news/tmb/2019/5d820f2ebb8fc.jpg)
Source:
https://phys.org/news/2019-09-dark-physicists-theorize-explore-nature.html