Summary: As we all know, and is explained in the text, dark matter is “a thing”, but we still don’t know much more about it than that it exists. Lately particle physicists have been getting excited about the possibility that dark matter consists of axions. I found these two recent review articles (February issue of Science Advances) to be very helpful.  They reminded me of particle physics that I had forgotten, caught me up on the arguments that particle physicists are making in favor of axion dark matter, and helped me understand the observational strategy to try to detect axions.  These are not articles for introductory astronomy students to read; they are written at far too high a level.  But they may be useful for busy astronomy teachers, who need a refresher about the issue---just in case this turns out to be the answer!

Articles:

What is it?  

How might we observe it?