Three years ago, scientists used a telescope the size of Earth to produce the first-ever image of a black hole.

The Event Horizon Telescope (EHT) has now produced images of two supermassive black holes: the one in the center of a galaxy called M87 and the one at the center of our own galaxy, the Milky Way.

"The two images appear very similar to us when we gaze at them in the sky," Feryal Özel, an astrophysicist at the University of Arizona and a member of EHT's science council, said during a news conference held by the National Science Foundation on Thursday (May 12) to unveil the new image of Sagittarius A* in the Milky Way.

Sagittarius A* in photos: The Milky Way's monster black hole discovery in images.

In particular, the two black holes differ in how difficult it is to image material moving around its boundary, or event horizon.

This black hole is farther away from Earth, of course, but it's also much larger, and material moves around its event horizon at a more leisurely pace.

"Material swirls around M87* over the course of many days," Vincent Fish, an astrophysicist at the Massachusetts Institute of Technology's Haystack Observatory and a member of EHT's science council, said during the news conference.

The Milky Way's supermassive black hole, dubbed Sagittarius A*, is less cooperative.

Katie Bouman, a computer scientist at the California Institute of Technology and co-lead of the EHT Imaging Working Group, said during the news conference that when the independent imaging teams that formed to analyze the M87* results compared their first takes at an image, they were more or less the same.

Although the material surrounding Sagittarius A* is moving around the event horizon inconveniently fast, our supermassive black hole nonetheless offers a much tamer environment near its surface than M87* does.

"If Sagittarius A* were a person, it would consume a single grain of rice every million years," Michael Johnson, an astrophysicist at the Harvard/Smithsonian Center for Astrophysics and member of the EHT science council, said during the news conference.

"Sagittarius A* is giving us a view into the much more standard state of black holes: quiet and quiescent," Johnson said.

"When we look at the heart of each black hole, we find a bright ring surrounding the black hole shadow," Özel said

"Space-time, the fabric of the universe, wraps around black holes in exactly the same way, regardless of their mass or what surrounds them," Özel said