First-Ever Photo of Milky Way's Black Hole Not Accurate, Scientists Claim

A trio of Japanese astronomers has challenged the accuracy of the first-ever image showing the supermassive black hole that lies at the heart of our galaxy. If confirmed, the findings of the researchers from the National Astronomical Observatory of Japan (NAOJ), published in the Monthly Notices of the Royal Astronomical Society, would indicate that the image may not be a true reflection of the black hole's appearance. The original image was released in 2022 by an international team known as the Event Horizon Telescope Collaboration (EHTC), which involves hundreds of scientists from around the world. It was created based on observations conducted in 2017 by a network of eight ground-based radio telescopes. The EHTC image of Sagittarius A*—the black hole at the center of the Milky Way—shows a dark, central region (the black hole's shadow) surrounded by a bright ring of light (called the accretion disk) that is the result of superheated gas being accelerated by extreme gravitational forces.

It should be noted that the image has been validated by many researchers. But the latest paper, led by Makoto Miyoshi with the NAOJ, paints a slightly different picture of what the black hole, located about 26,000 light-years away, may look like. In the latest study, which is based on a reanalysis of the EHTC data, Miyoshi and his colleagues argue that part of the black hole's appearance in the original image may actually be an artifact resulting from the process of its creation. "Our image is slightly elongated in the east-west direction, and the eastern half is brighter than the western half," Miyoshi said in a Royal Astronomical Society press release. "We hypothesize that the ring image resulted from errors during EHT's imaging analysis and that part of it was an artifact, rather than the actual astronomical structure." "At the same time, however, we confirm that the EHT array has the power to find black hole features that we could not see until now," Miyoshi told Newsweek. Newsweek contacted members of the EHTC, who provided a collective response from the consortium addressing the findings of the recent Miyoshi et al. paper, stating that it contains several "errors" in its analysis. "In 2022, the EHTC published the first image of the black hole in the Milky Way Galactic Center, Sagittarius A*. The image shows a ring-like structure with a central depression, consistent with the predictions of Einstein's theory of general relativity," the statement read. "The image was the result of multiple analyses... each with independent assumptions and associated systematics. These methods were extensively verified through simulations that mimicked the raw data in detail. The results were found to be consistent over two separate days of observations." "The EHTC welcomes critical, independent analysis and interpretation of our published results. We publish detailed descriptions of our methods as well as raw data, data products and analysis scripts to facilitate transparency, rigor and reproducibility. A recently published re-analysis [the Miyoshi et al. paper] claims to identify flaws in the EHTC analysis and provides a new image that differs from the EHTC result. EHTC experts find numerous errors in the M24 analysis... Additionally, EHTC experts find numerous mischaracterizations of EHTC methodologies and results."

"The EHTC stands behind its results. We look forward to publishing rigorous and thorough analyses of new observations with improved image fidelity that will further test the physics and astrophysics of black holes," the statement said. What Are Black Holes? Black holes are regions of space-time where gravity is so extreme that nothing, not even light, can escape. Most of the time, black holes form as the remnants of stars that died in cataclysmic cosmic explosions known as supernovas. At the center of a black hole lies the singularity—a point where gravity is predicted to be infinite and the laws of physics as we know them break down. Surrounding this is a region known as the event horizon—the boundary beyond which nothing can escape because of the extreme gravitational pull. The event horizon is named as such because it is impossible to observe any event taking place inside it. Supermassive black holes can have masses ranging from millions to billions of solar masses. Scientists believe that most large galaxies have supermassive black holes like Sagittarius A* at their centers. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about astronomy? Let us know via science@newsweek.com. Update 11/14/24, 10:03 a.m. ET: This article was updated with comment from Makoto Miyoshi and a statement provided by the Event Horizon Telescope Collaboration.

References

Miyoshi, M., Kato, Y., & Makino, J. (2024). An Independent Hybrid Imaging of Sgr A* from the Data in EHT 2017 Observations. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/stae1158 Event Horizon Telescope Collaboration (2022). First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way. The Astrophysical Journal Letters, 930(2), L12. https://doi.org/10.3847/2041-8213/ac6674