Explanation:
What would it look like to circle a black hole?
If the
black hole was surrounded by a
swirling disk of glowing and accreting gas,
then the great gravity of the black hole would
deflect light
emitted by the disk to make it look very unusual.
The
featured animated video gives a visualization.
The video starts with you, the observer, looking toward the
black hole from just above the plane of the accretion disk.
Surrounding the central
black hole is a thin circular image of the orbiting disk that marks the position of the
photon sphere —
inside of which lies the black hole’s
event horizon.
Toward the left, parts of the large main image of the disk
appear brighter
as they move toward you.
As the video
continues, you loop over the
black hole, soon looking down from the top,
then passing through the disk plane on the far side,
then returning to your
original vantage point.
The accretion disk does some interesting
image inversions — but never appears flat.
Visualizations such as this are particularly relevant today as
black holes are
being imaged in
unprecedented detail by the
Event Horizon Telescope.