This famous black hole is getting darker

Four years ago, astronomers released the first-ever image of a black hole: a reddish, puffy circle of light surrounding an empty, dark hole in the center of the giant galaxy M87, located 55 million light-years away in the constellation Virgo.

The image showed what astronomers, and the rest of the people, had only been able to imagine: a celestial entity so massive that its gravity warped space-time, drawing matter, energy and even light into a bottomless vortex. The image was released on April 10, 2019 by an astronomer called the Event Horizon Telescope, named after the boundary of no return around the black hole.

Now, a subgroup of that team, led by Leah Medeiros of the Institute for Advanced Study in Princeton, NJ, has used artificial intelligence to reprocess and produce the original data. A greatly improved version of the image.

They say the new image will sharpen limitations on how well the black hole in M87 fits with Einstein’s general theory of relativity, which first predicted the existence of black holes. Dr. Medeiros and colleagues published the new image Thursday in Astrophysical Journal Letters.

Perhaps the image will join its 2019 predecessor in the photography collection of the Museum of Modern Art in New York. Both images are based on observations made in April 2017. The Event Horizon team effectively created an Earth-sized telescope by combining data from five radio telescopes as far away as Antarctica, France, Chile and Hawaii, using a technique called Very Long Baseline Interferometry.

The resulting tool was powerful enough to resolve details as small as an orange on the moon’s surface or a cosmic twinkle out of nowhere – with a mass of 6.5 billion suns – 55 million light-years away. But loopholes in the network have created uncertainty. “We used machine learning to fill in the gaps,” Dr. Medeiros said in an interview.

Her team trained the neural network to recognize the black hole by feeding an AI simulation of all kinds of black holes consistent with Einstein’s equations.

In the enhanced version, Dr. Medeiros said, the death cake — visible radiation from matter falling into the crater — is thinner than the original. And the empty spot in the center of the dough looks blacker and larger, reinforcing the idea that there really is a black hole out there.

The team is already analyzing the new image to get a better estimate of the mass of M87’s black hole, but they’re not yet ready to discuss it.

In the meantime, the work continues, with an even larger Event Horizon network. (Three new telescopes have been added.) Each April, when M87 and the center of our galaxy (home to an even smaller black hole) are viewed, the Earth-sized eye renews its gaze into the darkness.

“People at the telescopes,” Dr. Medeiros said.