The first picture of black hole
On the night of 10th April 2019, I was on social media and was thrilled to see the picture of the black hole. I felt happy because the screen of the invisible object was unveiled. I stared for a while. The greatness of Einstein's theory of relativity proved again. I couldn't help but thank that man. Who told the unknown facts of black holes by calculating mathematically complex theoretical equations. The event horizon of the black hole, and the light ring, all caught my eye. However, today we will learn about the mystery of the first picture of a black hole.
This image of a black hole is not a photograph, but a combination of data from several powerful telescopes around the world. Which has been used to create many scientific techniques and models. And the main controller behind all these is the data observed by the telescope. For this reason, the created image is not a simulation.
The images of black holes that we have seen before are just computer simulations of various theoretical and mathematical models.
Since April 2016, scientists have been working to create a black hole's first image by building a global network of telescopes. Firstly, they had started capturing the image of Sagittarius A black hole in the center of the Milkyway Galaxy. It is 4.3 times heavier and 30 times bigger in size than the sun and the distance from Earth is about 26,000 light-years. Far from our scenery. The visual reflection of this black hole is like a picture of an orange on the moon seen from the Earth. As a result, scientists failed to produce a sharp, clear picture of Sagittarius A. So, they are looking for a nearby black hole to observe that will have a much higher mass, diameter, and radioactive radiation. Finally, they fixed a black hole for observation in the center of the M7 galaxy, 5 billion times heavier compared to the Sun, 2,000 times larger than Sagittarius A, and 55 million light-years away from the Earth. Although it is far from Sagittarius A, its mass and diameter are much higher.
Image: M6 Galaxy Center (image source: Wikipedia)
Integrated telescopes collect 5,000 trillion bytes of data in just five days. This data is equivalent to a 50,000-year-old MP3 file or the lifetime selfie data of 40,000 people.
But due to the ecliptic motion of the earth, atmospheric clouds, cosmic radiation, huge distances, and dust clouds in the M7 galaxy, a data gap is created in the observed data. Mathematical analysis and research are carried out on the data for about two years. Data gaps are filled with prevailing mathematical algorithms. But conventional mathematical algorithms could not adequately fill the data gap. So the limitations of the conventional algorithm system were eliminated by inventing new algorithm models compatible with the project components. Dr. Katie Bowman is a 29-year-old MIT graduate computer scientist who has developed new algorithms that process terabyte data in telescopes and eliminate data gaps. And she made himself a part of history at a very young age.
The image of the black hole is created by filling all the data gaps. Finally, on April 10, a picture of a very heavy black hole in the M7 Galaxy Center came to the world's attention. The image is real proof of the existence of a black hole. In the center of this image the black part with a round light ring. One side of this light ring is quite bright. The Messiah 6 galaxy, or M7 galaxy, is located in a cluster of galaxies called the Virgo galaxy cluster. Eventually, what seemed impossible to us came to the fore.
Image: Image of the first black hole. (image source: event horizon telescope collaboration)
Event Horizon Telescope (EHT) is a combination of 6 telescope systems used to take pictures of black holes. 200 researchers from 59 institutes in 20 countries have worked for more than a decade. The name of this project is Event Horizon.
The extent of the boundary from which light and radiation cannot return is called the event horizon of a black hole.
Scientists have integrated a total of eight telescopes from around the world to take pictures of black holes. This adjustment is made using very long baseline interferometry (VLBI) following the European Southern Observatory. Here interferometry is the arrangement of several telescopes through which telescopes act as a single unit to take very good quality pictures of cosmic objects (planets, stars, supernovae, nebulae, galaxies, etc.). And this combination very effectively creates a virtual telescope equal to Earth. This combination can be called the global combination of telescopes.
Figure: Global coordinate or interferometry of Event Horizon Telescope
(image source: exemrace)
The figure shows these eight telescopes with their locations.
The main magic in the appearance of the first image of a black hole is the unique telescope adjustment system.
Integrated telescopes collect 5,000 trillion bytes of data in just five days. This data is equivalent to 50,000 years of MP3 files or 40,000 human lifetime selfie data. Scientists create images by processing this data with a spectro-computer. It takes 200 researchers 2 years to do this. Details of telescope observations were published in six series of papers in The Astrophysical Journal Papers. These journals detailed the project. Paper 2 discusses the integration of the Event Horizon Telescope (EHT), the development of technology using existing facilities, and instrumentation, the creation of fine detection systems, and the creation of unique imaging techniques through the integration of telescopes. Paper-3 discusses the use of strict validity principles for data collection, data processing, algorithm calibration, and selection of suitable data for analysis.
Paper-4 discusses the process & approach of image reconstruction. The imaging algorithm has been tested for several months, with rigorous evaluation of conventional imaging algorithms and new algorithm techniques suitable for EHT instruments and synthetic data set analysis. Thus the final image of the black hole has become clear.
Paper-5 explains the magnification (accretion) and high-velocity radiation (jet radiation) of a black hole by analyzing images and data using General Relativistic Magneto Hydro Dynamic (GRMHD) simulation and an advanced ray detector system. Paper-6 compares model adaptations and simulations with data. From the black hole's image, the size-structure of the light ring, the mass of the black hole, the nature of the black hole, and the effect of the surrounding space on time have been extracted. Finally, the essence of Paper 2-6 has been described in Paper-1.
Therefore, the image of a black hole is only a few kilobytes, but it has been synthesized from a few thousand terabytes of data.
Sources: IOPScience, CNN, Space.com, Event Horizon Telescope, National Geographic, Science News for Students.
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