This new visualization
of a black hole illustrates how its gravity distorts our view, warping its
surroundings as if seen in a carnival mirror. The visualization simulates the
appearance of a black hole where infalling matter has collected into a thin,
hot structure called an accretion disk. The black hole’s extreme gravity skews
light emitted by different regions of the disk, producing the misshapen
appearance.
Bright knots constantly form and dissipate in the disk as magnetic fields
wind and twist through the churning gas. Nearest the black hole, the gas orbits
at close to the speed of light, while the outer portions spin a bit more
slowly. This difference stretches and shears the bright knots, producing light
and dark lanes in the disk.
Viewed from the side, the disk looks brighter on the left than it does on
the right. Glowing gas on the left side of the disk moves toward us so fast
that the effects of Einstein’s relativity give it a boost in brightness; the
opposite happens on the right side, where gas moving away us becomes slightly
dimmer. This asymmetry disappears when we see the disk exactly face on because,
from that perspective, none of the material is moving along our line of sight.
Closest to the black hole, the gravitational light-bending becomes so
excessive that we can see the underside of the disk as a bright ring of light
seemingly outlining the black hole. This so-called “photon ring” is composed of
multiple rings, which grow progressively fainter and thinner, from light that
has circled the black hole two, three, or even more times before escaping to
reach our eyes. Because the black hole modeled in this visualization is
spherical, the photon ring looks nearly circular and identical from any viewing
angle. Inside the photon ring is the black hole’s shadow, an area roughly twice
the size of the event horizon — its point of no return.
Source: https://svs.gsfc.nasa.gov/13326
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