Researchers have used machine learning to tighten up a previously released image of a black hole. As a result, the portrait of the black hole at the center of the galaxy Messier 87, over 53 million light years away from Earth, shows a thinner ring of light and matter surrounding its center in a report published today in The Astrophysical Journal Letters.The original images were captured in 2017 by the Event Horizon Telescope (EHT), a network of radio telescopes around Earth that combine to act as a planet-sized super-imaging tool. The initial picture looked like a “fuzzy donut,” as described by NPR, but researchers used a new method called PRIMO to reconstruct a more accurate image. PRIMO is “a novel dictionary-learning-based algorithm” that learns to “recover high-fidelity images even in the presence of sparse coverage” by training on generated simulations of over 30,000 black holes. In other words, it uses machine learning data based on what we know about the universe&rsq