Astronomers have reconstructed multiple snapshots of the M87 black hole's activity, building on its landmark 2019 image. These offer a rare glimpse into the evolution of its famous "ring of light."
In April 2019, the Event Horizon Telescope (EHT) collaboration unveiled the first-ever image of a black hole: M87*, 6.5 billion times more massive than the Sun, at the center of the M87 galaxy, 53 million light-years away. This historic photo captured the black hole's shadow—the dark region where light cannot escape its immense gravity.
Encircling this cosmic giant, vast enough to swallow our Solar System, is a glowing ring of radiation from superheated gas orbiting at near-light speeds. The image reveals the ring brighter on its bottom half, forming a striking crescent shape.
EHT achieved this by combining data from eight radio telescopes worldwide via Very Long Baseline Interferometry (VLBI), creating a virtual telescope the size of Earth.
Yet the 2019 view was just one snapshot from a week of observations in April 2017. Recently, Harvard radio astronomer Maciek Wielgus and his team revisited earlier data to explore M87*'s prior appearances.
Leveraging vast archives unavailable for the original analysis, and enhanced by sophisticated mathematical models, they reconstructed detailed snapshots of M87* from 2009 to 2017. Here's the result:
No Hollywood blockbuster, but these findings carry immense scientific weight. Published in The Astrophysical Journal, the study shows M87*'s luminous ring oscillates over time. Upcoming campaigns will provide more snapshots to decode its behavior.
EHT data collection is limited to a narrow March-April window each year. The 2020 effort was halted by the COVID-19 pandemic, but the team planned a 2021 return with a 11-telescope array for sharper resolution. In the years ahead, smoother animations of this black hole could become reality.
