(Img. eso1907a) First Image of a Black Hole: Credit: EHT Collaboration. Source: European Southern Observatory.
The Event Horizon Telescope (EHT) — a planet-scale array of eight ground-based radio telescopes forged through international collaboration — was designed to capture images of a black hole. In coordinated press conferences across the globe, EHT researchers revealed that they succeeded, unveiling the first direct visual evidence of the supermassive black hole in the centre of Messier 87 and its shadow. The shadow of a black hole seen here is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across. While this may sound large, this ring is only about 40 microarcseconds across — equivalent to measuring the length of a credit card on the surface of the Moon. Although the telescopes making up the EHT are not physically connected, they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations. These observations were collected at a wavelength of 1.3 mm during a 2017 global campaign. Each telescope of the EHT produced enormous amounts of data – roughly 350 terabytes per day – which was stored on high-performance helium-filled hard drives. These data were flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration.
I find this image intriguing, because a supercomputer made it possible to process data, that was measured for a period of time in order to gather information about something we cannot see and was able to visualize the circumstances that a black hole has in one single image. So we don’t see the black hole itself, but the shadow it is casting.
The image above is a publication tiff 4k image from the full size original tiff file provided the European Southern Observatory (ESO). As in the image description mentioned, it is created by a huge amount of data, that is transformed by supercomputers into an image. The black hole is an infinite small point in space where a huge amount of mass is located. It’s gravity is so intense, that even light cannot get out. This state is called singularity.
How does a singularity influence time? When we cannot detect or measure what is in that black hole, does that mean, that there is no time? The black hole is a state in space time. So it must have a time for itself. Maybe the time in the blackhole is the time it lasts in space before it vanishes.
When scientists observe the universe they usually do it with telescopes. Telescopes exist probably since 1608 when the Dutch eyeglass maker Hans Lippershey registered a patent. Those telescopes, that are used to observe the universe, record various frequencies and wavelengths, the so called electromagnetic radiation. The radiation travels in a vacuum with the fastest speed possible in the universe, the speed of light (299,792,458 meters per second).
The black hole in the picture above is located in the Messier 87 galaxy, named after Charles Messier, who discovered it in 1781. The galaxy is 54 million light-years away from Earth.
This means, that the light travels 54 million years across the universe until we can detect it on planet Earth. The distance between two points in the universe is measured with a property of the electromagnetic spectrum. This is possible because light moves through space. When we know the distance light travels in a specific time, we can use it to measure distances.
Relation time & photography
In this case it took a team of more than 200 researchers and several years of research to collect all the data. Innovative algorithms and connecting the world’s radio observatories were needed in order to achieve this image.
Not to forget that the light of the hot matter around the black hole had to travel for 55 millions of light-years through the universe to the Earth in oder to by detected by the telescopes. For making this image, a lot of time had to pass by.
Of course all images are dependent on time. A picture „captures“ a fraction of time on film or stores it as a digital file to be interpreted as an image after processing. Without time there would be nothing, and nothing to be photographed. We photograph the past, when we take a picture in a moment in time, the moment already has vanished into oblivion. Just the picture remains, from the past to the present and maybe to the future.


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Garner, Rob: Messier 87, National Aeronautics and Space Administration, 2017, https://www.nasa.gov/feature/goddard/2017/messier-87,  (accessed 17th March 2021).

Kasprak, Alex: Space Place in a Snap: What Is a Black Hole?, Jet Propulsion Laboratory, California Institute of Technology, 2013, https://www.jpl.nasa.gov/edu/learn/video/space-place-in-a-snap-what-is-a-black-hole/ (accessed 17th March 2021).

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