A black hole is very strange and outlandish, so those scientists that studied black holes for years realized that they might also exist in real life. They are created from collapsed, massive stars, and they are dense so that nothing will have the ability to escape from their gravitational pulls, which includes the light too.
Such holes also mess with space-time badly, so scientists were wondering for a long time: How black wholes look? Using the help of the so-called Event Horizon Telescope, we are probably about to see one; however, if we return to 1979, a person called Jean-Pierre Luminet has created the primary ‘image’ with the use of an early and old-fashioned computer, and lots of India ink and math.
A lot of people have a problem to imagine black holes, but that is because, by definition, black holes do not emit any radiation or light. Fortunately, there are some larger of them which are close to different stars, and they suck their matter away, which is something that can be seen by astronomers.
In his e-Luminesciences blog, Luminet wrote:
As [gases from stars] fall towards the black hole, it becomes hotter and hotter and begins to emit radiation. This is a good source of light: the accretion rings shine and illuminate the central black hole.
One distinctive feature that black holes have is their ‘event horizon’ limit, which is the point from which light and matter never return. At the outer edge of the black hole, the materials are pulled in from the nearby stars of the ‘accretion disk’ which is shown as Interstellar shown below, which as two different bright and perpendicular disks. However, that is simply an illusion – just one disk exists on the equator, and the light is bent upward by the extreme gravity of the black hole.
The image of Luminet describes other significant phenomena which Interstellar does not show. The first thing is that the light and the energy which are near the black hole’s edge are stronger, while weaker when farther out. The second thing is the Einstein and Doppler effects, which appear as a result of the rotation of the accretion disk, and which can make the light to appear brighter on the one of the side, which depends on the direction of spinning.
In the image of Luminet, the direction of that accretion disk is counter-clockwise, so the light of the disk can approach the viewer on the left, while receding on the right, in that way making the left-hand side to look much brighter.
As a result of this, black holes are brighter in their center and also left, just like it is shown in the image of Luminet. He said:
A realistic image must show a strong asymmetry of the disk's brightness so that one side is far brighter and the other is far dimmer.
He also calculated everything from 1979 with the use of the IBM 7040 mainframe, which is a transistor computer from earlier with punch cards. This machine generated some isolines for the image of Luminet, which have been directly translatable as smooth curves with the use of drawing software which was available during that time.
In order to create his final image, Luminet relied on the second passion he had, and that was the art. With the use of numerical data coming from that same computer, Luminet started drawing directly on a negative paper using black India ink, putting dots densely at the places where the stimulation has shows brighter light. He said:
Next, I took the negative of my negative to get the positive, the black points becoming white and the white background becoming black.
What resulted from this was an image which still exists and is even closer than anything else to reality, even closer than CGI which was done by the whiz kid of Interstellar. Moreover, the subsequent computer simulations which were created by the NASA Goddard, together with others, still represents these identical defining elements – the thin ‘photon ring’ in the middle, Einstein and Doppler-shifted light, together with a dual accretion disk which is caused by the gravitational lensing.
Image Credit: Jean-Pierre Luminet
