Blackhole

The strangest, most mysterious, and most powerful thing in this universe is the black hole. Black holes can swallow any star. Blackholes contain powerful jets that propel matter away at almost the speed of light. The first idea of ​​a black hole comes from mathematical equations. Which was a mathematical puzzle for that time. Albert Einstein never acknowledged that things like black holes could actually exist. For many years people did not want to believe that there could be anything like a black hole, because a black hole is a concept that cannot be seen, where no formula of physics works. Where any object is lost forever which is the complete opposite of reality.

About Blackhole

However, over time we have come to know that black holes actually exist but what is this black hole or black hole really? How do we know for sure that a black hole exists, how black holes or supermassive black holes are formed, and what effect do black holes have on us? What is a black hole? Many of us think that a black hole is a sphere-shaped object. But no, a black hole is a sphere-shaped space. There is nothing completely empty. However, black holes have very strong gravity. According to Einstein’s general relativity, mass causes space to bend and this causes the force of gravity to be felt. Now, according to General Relativity’s formula, if there is a huge mass of objects in a very small space, then the curvature of space there will be extreme.

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As a result, it was not known what solution could be found from the general relativity formula to the question of what would happen to an object if it fell at that extreme curvature. But in 1915, just a week after the publication of General Relativity, Carl Schwerschild solved the problem. Karl Schwarzschild mathematically showed that if the mass of an object of massive mass, such as the full mass of a star, were brought to a single point, the curvature of space-time would be extreme, and any object, even light, would disappear if it exceeded a certain limit of curvature of this extreme space-time. Becomes. That is, if an object of any mass could be compressed in a space that is small enough, there would be something called what we now call a black hole, and we would call an event horizon if an object crossed that boundary would never return.

About Blackhole

The funny thing here is that Albert Einstein, whose theory was predicting something like a black hole, couldn’t believe that there could be such a thing! Now the question is how the black hole is created? As we all know, the future of any star depends on its mass. Our Sun will also become White Dwarf in the future. Stars that are heavier than our Sun will become neutron stars in the future, and stars that are at least 10 times heavier than our Sun will become black holes at the end of their life cycle. The source of energy for any star is nuclear fusion. The energy created by the nuclear fusion reaction causes the outer layer of stars to expand. But again gravity causes that expansion to subside, leaving a star in a stable state. Thus, once the stars run out of energy, they stars have no energy left to work against gravity. As a result, very powerful gravity tends to compress the entire star towards its center. When the giant star compresses along the center, a huge explosion occurs at one stage. As a result, matter spreads around the outer layer of matter, called supernovae.

About Blackhole

Now the greater the mass of the star, the stronger the gravity. As a result, if the mass of the star is sufficient, the gravity will be so strong that it will become uncontrollable. This causes the entire mass of the star center to merge into an infinitely small point. The result is a new black hole. Now the question is, how do we know for sure that there is a black hole that cannot be seen, from which nothing comes back? Suppose a very high voltage cricket match is going on between Bangladesh and India at Mirpur Stadium. You are out of the stadium, now you can easily guess from the scene outside the stadium i.e. the busyness and activities of the people that there must be a very important match going on inside the stadium. Similarly, although not directly visible in the black hole, it is easy to guess from the environment around the black hole that there is a black hole in that place.

About Blackhole

A very small fraction of the electromagnetic spectrum we see with the naked eye is only 0.0035 percent. If we think of this electromagnetic spectrum as long as the Padma Bridge, we can see with our naked eyes only 21 centimeters of this bridge. This side of the spectrum includes radio waves, microwaves, infrared radiation and ultraviolet, X-rays, and gamma-rays. Since 1931, radio waves and X-rays have added a new dimension to astronomy in deep space viewing. But still did not notice anything related to the black hole. However, they see many high-powered X-rays in deep space. Finally, in 1970, Paul Murdin noticed a strange thing. About half of the stars we see in the sky are binary stars. Two stars are called binary stars if they keep moving due to gravity.

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Paul Murdin sees only one of the binary stars in a certain direction in the sky, the other star is not visible. Only X-rays are emitted from the space of the other star. Paul Murdin then calculated a draft to determine the mass of this invisible object from which X-rays were emanating. If the mass of this invisible object is three times the mass of the Sun, then that object must be a black hole. Paul Murdin estimates that the mass of that invisible object is about 5 to 6 times the mass of the Sun. He then published a paper on the subject, claiming that it was probably a black hole. But even then, scientists weren’t sure if what Paul Murdin called a black hole was really a black hole! It will take another 20 years for that to happen. Because to determine the exact mass of that invisible object, it is necessary to determine the distance correctly.

About Blackhole

Finally, using the Parallax method in 1990, the distance to that invisible object was found to be 6000 light-years, and it is estimated that the mass of that invisible object is about 15 times the mass of the Sun. Eventually, everyone was convinced that the invisible object was a black hole and that it was the first man-made black hole to be named Cygnus X-1. However, in 2021 the distance of Cygnus X-1 was revealed by measuring more precisely. According to 2021 data, the distance of Cygnus X-1 from the Sun is 6070 light-years and the mass is about 21 Solar mass and the radius of the event horizon of this black hole is about 44 kilometers. Now looking at this Cygnus X-1, you can see that it has an accretion disk around it. This accretion disk is actually hot gas and dust that surrounds the event horizon of a black hole. Looking at the image of the black hole, it seems that this accretion disk may have one or two in the black hole, one is on the side and the other is on the top. But that is not the case with the one we see on the surface. This is mainly due to gravitational lacing.

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However, as the black hole consumes the gas and dust of this accretion disk, the gas and dust of the accretion disk revolve around the event horizon at high speed. When a lot of water comes out through a hole, it causes a rotation like the one above. However, the gas and dust in the accretion disk rotate at about 50% of the speed of light. As a result, they collide, causing their temperature to rise to about a million degrees. The result is a high-powered X-ray, and this X-ray was originally seen by Paul Murdin through an X-ray telescope. This Cygnus X-1 black hole is constantly engulfing the star. Thus Cygnus X-1 will one day completely swallow its binary star. Another mystery about the Cygnus X-1 is its huge and powerful jets. Which is located perpendicular to the accretion disk of the black hole. What causes these jets to emit huge amounts of particles and radiation from a black hole is still unknown.

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Through these jets, particles and radiation are scattering far away from the black hole at speeds close to the speed of light, which is really a huge mystery. Since Cygnus X-1, many black holes have been detected one by one, and scientists estimate that our Milky Way galaxy alone could contain 1 to 100 million black holes. However, after detecting Cygnus X-1, another huge surprise awaited the scientists. After the discovery of the radio telescope, scientists found some mysterious hotspots in deep space. These hotspots looked a lot like stars. Scientists have seen these hotspots through radio signals. As a result, they are named QUASI-Stellar radio sources abbreviated QUASARS.

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Scientists weren’t sure if these QUASARS were actually them, but astronomers analyzed the electromagnetic spectrum from these hotspots. But the electromagnetic spectrum coming from these hotspots was not understood by scientists. However, later scientists realized that this electromagnetic spectrum was actually pointing to hydrogen. But the spectrum of hydrogen is shifting to a much lower frequency. This means that QUASARS are constantly moving away from each other at huge speeds, and scientists then wonder how the constantly moving object is showing so much. QUASAR, which is 200 million light-years away, emits about 1 trillion suns of energy per second. But how could it be possible to create such huge energy, scientists could not match the equation of such huge energy in any way.

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There is no way that chemical energy or nuclear energy can be such a huge source of energy. So where does so much energy come from, the answer is one and that is gravity. In our day-to-day life, we ​​know or feel gravity as a very weak force. But if you consolidate massive mass into infinitely small points, the power of gravity there will be unimaginable. Scientists were then convinced that these hotspots were actually one huge black hole and that such a huge brightness was being created from the accretion disk rotating around all these huge black holes. One of these black holes at the center of QUASARS is actually a supermassive black hole. Whose mass are millions of times the mass of the sun? The mass of Cygnus X-1 is only 21 times the mass of the Sun. But the supermassive black holes in QUASARS are tens of millions of times the mass of the Sun, and all of these supermassive black holes are basically at the center of a galaxy.

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Then there is the question of whether there is a supermassive black hole in the center of our Milky Way galaxy. If there is, how can we understand that it is easy to study the center of another galaxy. But it is very difficult to verify certain information about the center of the Milky Way galaxy. Because the diameter of our Milky Way galaxy is one million light-years. But its thickness is only 1000 light-years. The center of the Milky Way galaxy is 27,000 light-years from Earth. Now between the center of the Earth and the Milky Way galaxy are millions of stars, dust, gas, and so on. As a result, the light from the center of the Milky Way galaxy will be obstructed in many ways. As a result, it is almost impossible to capture a serpent image of the center of the galaxy. In 1990, astronomers undertook a project to find out if there really was a supermassive black hole at the center of the Milky Way galaxy. But then there is another problem with the previous problem. That is the Earth’s atmosphere, because of the Earth’s atmosphere, any image of space becomes wavy.