Black holes pepper our universe, but like their name implies, most are invisible — until something happens to change that. That something is often material flowing into the black hole. And in March 2018, one such previously invisible black hole flared to life when a flood of matter fell inward, allowing astronomers to spot and track the event, ultimately mapping out the region close to a black hole in finer detail than ever before.

That work, published January 9 in Nature, was led b