The Event Horizon Telescope (EHT) collaboration has uncovered the reason why the stunning image of the M87* black hole features a ring that appears slightly elliptical rather than a perfect circle. The distortion – ranging from 2% to 20% – is attributed to turbulent plasma swirling near the black hole’s event horizon.
This insight is based on a new study, “Origin of the ring ellipticity in the black hole images of M87”, published in Astronomy & Astrophysics. Researchers used the current resolution of the EHT to analyze how inhomogeneities in the plasma flow distort the ring’s shape. These findings enhance our understanding of black hole environments and enrich the striking imagery first captured in 2017.
Read the full press release.
Image compares simulations and observations of black hole M87*. While gravity alone would distort the ring by less than 2%, EHT data show an 8% squish—likely caused by turbulent plasma, not gravity or spin. Credit: Rohan Dahale (IAA-CSIC), Ilje Cho (KASI/Yonsei University)