Milky Way Black Holes Could Be Rotating at Their Limit

At the core of our Galaxy lies an extraordinary rotating entity: a black hole that appears to be spinning near its maximum velocity.

Michael Jansen from Radboud University in the Netherlands and his team investigated black holes in the center of the Milky Way, specifically Sagittarius A*, utilizing data gathered by a collective network known as the Event Horizon Telescope (EHT). To tackle the intricacies of the data, they opted for artificial intelligence methods.

Initially, they simulated approximately one million black holes using established mathematical models, a computational endeavor that necessitated millions of hours on supercomputers. These simulations served as training data for a type of AI known as neural networks, enabling them to assess the properties of black holes based on empirical observations. Subsequently, they fed the AI with data on Sagittarius A* collected by the EHT throughout 2017.

The AI determined that Sagittarius A* is rotating at 80-90% of its theoretical maximum speed. It also indicated to the researchers that none of the currently available magnetic field models adequately describe the characteristics of this black hole, highlighting the need for additional mathematical modeling. Janssen notes that earlier studies had merely narrowed down the potential characteristics of Sagittarius A*, such as its rotation speed and surrounding magnetic fields, while this new methodology has refined those estimates.

Dimitrios Psaltis from Georgia Tech in Atlanta remarked that some of the findings were unexpectedly counterintuitive. Previous analyses had not clarified whether black hole spins could be accurately discerned from EHT data.

While earlier research suggested that Sagittarius A* might be spinning at significant speeds,
Mizuno Yuishi from Zhejiang University in Shanghai, China, noted that there is still room for enhancement in the computational models applied in this new analysis. “Our theoretical model is still not perfect,” he acknowledged.

However, both Mizuno and Psaltis agree that integrating AI into the study of exotic cosmic entities like black holes is increasingly essential. “We possess a wealth of data and numerous models, and we require a contemporary approach to merge the two,” Psaltis states. “This is precisely where machine learning proves to be transformative.”

Yet, this integration presents unique challenges, as AI work necessitates verification to mitigate potential inaccuracies and errors in subsequent analysis.

Janssen and his team have conducted numerous verification checks, including testing the AI with specially designed simulation data. They are also evaluating data from subsequent EHT operations and will be analyzing new findings from observatory results, he explains.