Photographing a Black Hole

Using the EHT, scientists obtained an image of the black hole at the center of galaxy M87, outlined by emission from hot gas swirling around it under the influence of strong gravity near its event horizon.
Credit: Event Horizon Telescope collaboration et al.

A team of astronomers published the first photograph of a black hole. The “monster,” as they’ve called it, is 40 million kilometers across (about 3 million times the size of Earth), located at the center of a galaxy known as Messier 87, about 500 million trillion kilometers away.

The image was captured by a network of eight telescopes named Event Horizon Telescope (EHT), and assembled with an algorithm developed by young computer scientist Katie Bouman.

Dr. Eliot Quataert is the Director of the Theoretical Astrophysics Center at UC Berkeley and an Editorial Committee Member of the Annual Review of Astronomy and Astrophyics. His research focuses in part on black holes and galaxy formation. He spoke to Annual Reviews about this breakthrough.

What do you make of this announcement?

This is an incredibly exciting result. I was expecting something good but was even more amazed and impressed by the results than I had expected to be. It really is a testament to the hard work of hundreds of people over decades that we have been able to take this first real picture of what it looks like close to a black hole.

What new paths for research do you expect this will open?

The observations will continue to get better as the technology improves and new telescopes are added across the Earth, and maybe even in space. This will enable even better pictures of what the gas looks like close to a black hole. Over time, I think this will allow us to develop a better understanding of what is happening not only near the black holes that EHT can observe, but of all black holes across the Universe. This will impact a huge range of problems in astrophysics, from our understanding of how galaxies form and are affected by black holes to our understanding of the warped strong gravity very close to the event horizon of a black hole.

What articles can you recommend for readers who want to learn more about black hole research?

An older one, but famous, is “Black Hole Models for Active Galactic Nuclei,” by Martin J. Rees, in the 1984 Annual Review of Astronomy and Astrophysics.

Two recent ones on the role of black holes in galaxy formation are “The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe,” by Timothy Heckman and Philip Best, and “Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies,” by John Kormendy and Luis Ho, respectively in the 2014 and the 2013 volumes of the same journal.

We’ve made all three of these articles freely available for 30 days.