What happened to this galaxy’s dark matter?

Back in 2018, astronomers used Hubble to observe a relatively nearby galaxy and found it presented a baffling mystery: It appeared to have little or no dark matter.

This was so weird they decided to follow up to make sure their results made sense. So they took more Hubble observations — a lot more — and the mystery only deepened. It appears to have even less dark matter than they originally thought.

This is unexpected, and bizarre. Why doesn’t this galaxy have a feature pretty much every other...