Black holes are dubbed “black” because their inescapable tug of gravity on light renders them invisible to the naked eye. Scientists can, however, look at the distorted spacetime around a black hole to determine its size and rotation. In many cases, black holes, also surround themselves in superheated clouds of spinning material that warps like a “carnival mirror” when viewed. In this new NASA animation, the US space agency demonstrated how the gravitational warping distorts our views of black holes.
NASA’s Francis Reddy said: “The visualisation simulates the appearance of a black hole where inflating 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.”
In the animation and the embedded images below, the black hole itself sits in the centre of the dark sphere or shadow.
All light that falls towards a black hole’s event horizon – its point of no return – it is trapped and cannot escape.
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The swirling gases travelling close to the event horizon are travelling at near the speed of light.
Gases farther away from the black hole are slightly slower.
The difference in speeds between the “lanes” produces the darker and brighter streaks of light in the gas.
However, because everything is distorted by gravity, the image we see depends on our viewing angle.
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Mr Reddy said: “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.”
In the regions closest to the black hole, the bending of light is so intense we can see the underside of the accretion disk.
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The warping creates an illusion of the disk outlining the black hole, beyond its shadow and event horizon.
A single bright ring sits inside of the shadow region and it is known as the photon ring.
The photon ring is composed of multiple images of the accretion disk and its light orbits the black hole many times before it escapes towards us.
The dark region below the photon ring is the black hole’s shadow – an area twice the size of the event horizon.
Jeremy Schnittman from NASA’s Goddard Space Flight Center, who generated the black hole animations, said: “Simulations and movies like these really help us visualise what Einstein meant when he said that gravity warps the fabric of space and time.
“Until very recently, these visualisations were limited to our imagination and computer programs.
“I never thought that it would be possible to see a real black hole.”
The first-ever image of a black hole’s shadow was caught by the Event Horizon Telescope team on April 10 this year.