Astronomers working on the Event Horizon Telescope project have received visual evidence for the first time that the ring of plasma around the black hole M87 *, which was presented to the public in 2019, is rotating and experiencing turbulent changes. New, but less detailed images of the giant object are reported in an article published in The Astrophysical Journal.
Researchers observed M87 *, located 55 million light-years from Earth, back in 2009-2012, when sufficient data was not yet collected to obtain an image. However, with subsequent processing, carried out after the publication of the main image, the scientists were able to reveal that the plasma ring was changing its brightness. The very shadow of the black hole, located in the center of the ring, did not change in size, which confirms the nature of the object.
The ring is made of dust and gas that swirl and fall into a black hole as part of an accretion disk, and the uneven brightness is a consequence of the Doppler effect, predicted by Einstein's theory of general relativity. The part of the disk that moves in the direction of the observer appears brighter, and the part that moves away appears dimmer. However, the fact that the bright part moved in the ring indicates turbulence in the flow.
According to scientists, not all theoretical models of accretion allow for such a strong fluctuation. The phenomenon itself could be caused by the influence of a magnetic field or a mismatch between the angular momentum of the black hole and the accretion flux. Further observations will lead to more detailed images of the black hole.
