Dr. Mahbub Khan :
We the citizens of this panet Earth have seen the actual picture of a Black Hole last month on April 10, 2019. The whole world came together in order to do this monumental task. This pioneering science work was done with an amazing collaboration of over 200 scientists of 60 different institutes from 16 different countries of 6 continents. They worked for over a decade to do this as the EHT Collaboration team. A picture of the Black Hole and a picture of the 200+ scientists who did this spectacular piece of work are given here right below.
Picture of the Super-massive Black-Hole with a mass of 6.5 billion times that of our Sun, which is located at the center of the massive galaxy, called M87 (Messier 87) near the Virgo Galaxy Cluster that is 55 million light years away from our planet Earth. Light year is the distance light travels in one year which is about 6 trillion miles or 10 trillion kilometers. Light travels at the speed of 186,000 miles per second which is known as the highest possible speed in the universe. In the picture of the Black-Hole we can see that one side of the donut looks brighter than the other. That is because the materials around the Black-Hole are orbitting around the Black-Hole and so the materials on one side that are coming towards us are giving the brighter part of the donut and the materials on the other side are moving away from us.giving the relatively less-bright part of the donut area.
Picture shows the EHT team, where the team project is called the EHT (Event Horizon Telescope) Collaboration. The Event-Horizon name comes from the boundary around a black hole wherefrom even light cannot escape. The radius of the Event Horizon is called the Schwarzschild Radius, and light cannot escape from inside it.
The question is:
1) what is a Black Hole any way?
2) why do we need so many people from so many different places of the world to take this picture? Any one can take a picture of the sun and moon and planets and stars with an iPhone easily. So, what is the big deal here?
1) what is a Black Hole any way?
Black Hole concept is actually not very difficult. Black hole is made up of huge amounts of matter squeezed into a small area, (NASA), creating a massive gravitational field which draws in everything around it, including light. The question is how are we going to see it if the light can not come out of it? Here is the explanation: Black Hole has a way of super-heating the material around it and also warping the space-time. Material accumulates around black holes, is heated to billions of degrees and reaches nearly the speed of light. Light bends around the gravity of the black hole, which creates the photon ring seen in the image. The imaging methods that the EHT team used to capture the photo revealed that the supermassive black hole has a ring-like structure and a shadow, which is represented by a dark central region.
Black Hole has been one of the most fascinating objects of modern sciences. Black Holes are created by a process that starts with the death of big stars through the Supernova explosion when it reaches the nuclear fusion limit at the level of Iron (Fe) in its core. That becomes the limit of the nuclear fusion process because Iron has the highest binding energy per nucleon and so, the star can no longer get advantage of the E = mc2 process to save itself from the attack by the gravitation. So, at that point the gravitational collapse becomes so intense that the atomic electrons and protons merge to become neutrons and the entire star becomes a neutron star. At that stage, if the neutron star is massive enough then it will go through further gravitational collapse to transform into a Black Hole. Black Holes can combine to make more massive Black Holes. There are billions of galaxies in the universe and each of the galaxies are assumed to have a Black Hole at its center.
Here is a diagram and description of the Regions of a Black Hole:
Accretion Disk: Large outer disk of gas dust and cosmic materials, in the shape of a doughnut, that moves around the black hole.
Ergosphere: Region surrounding the black hole, where energy can still escape, objects are in orbit.
Photon Sphere: Region where light has been deflected and is now in orbit around the black hole. The radius of the Photon Sphere is 1.5 times the radius of the Event Horizon.
Event Horizon: Invisible Sphere where anything that falls inward can never escape, because the escape velocity exceeds the speed of light. Since no object can reach the velocity of light, as derived from the Theory of Relativity, no object can escape as it inwardly crosses the Event Horizon. The radius of the Event Horizon is given by the Schwarzschild radius formula for Rs:
Rs = 2 G M / c2 where G is the universal gravitational constant, M is the mass of the black hole and c is the speed of light.
Singularity: The deepest central point of a black hole where the force of gravity is infinitely strong and the density reaches the theoretical value of infinity.
Let us see what would happen to our Sun and to our solar system if a black hole passed by our galactic neighborhood?
Well, that will cause the dooms day for us for sure. The force of gravity of a black hole is so strong that the tidal force would deform the Sun into an oval shape and then it would break it apart and consume it, together with all the planets, as you can see the representation below.
Time contraction (not dilation) near a black hole: The equations of General relativity show that if a person in a space ship entered into an orbit around a black hole, at a safe distance, for example for one year, then when coming back to the Earth, at the time of arrival he/she would notice that more than 100 years have passed here. To go to a black hole and then come back to the Earth is like traveling to the future. The closer you go to black hole, the greater the force of gravity and the greater is the time contraction with respect to us here on Earth. If you were to cross the Event Horizon, the point of no return, the time inside the black hole would stop with respect to us here on Earth.
T (Earth) = T (Near Black Hole) / v ( 1 – 2GM/rc2)
T (Earth) = Time as measured on Earth
T (Near Black Hole) = Time as measured near a black hole at a distance r, greater than the Schwarzschild radius Rs.
What would happen to a person going near a black hole?
If a person or an object were to fall into a black hole, the force of gravity is so strong that it would be stretched like chewing gum, it would make it like a thin spaghetti, that we call spaghettification, as displayed in the picture below.
2) why do we need so many people from so many different places of the world to take this picture? Any one can take a picture of the sun and moon and planets and stars with an iPhone easily. So, what is such a big deal here?
That is because this supermassive Black-Hole of massive Galaxy M87 is located far away from us (55 million light years) and the light signal intensity is extremely small. So, a camera is needed which has an aperture of the size of this whole Earth. The iPhone does not have that. The exposure time was also needed to be long to collect adequate amount of signal. So, 8 different Radio telescopes were placed in 8 different locations of the Earth and as the Earth was spinning, it was simulating the Earth-size aperture. The 8 different Radio telescopes were collecting signals that were synchronized among the 8 telescopes by atomic clock. To make sure these observations were truly simultaneous, and to see the same wavefront of light as it landed on each telescope, they used extremely precise atomic clocks at each of the telescopes. The telescope array collected 5,000 trillion bytes of data over two weeks, which was processed through supercomputers so that the scientists could retrieve the images. All the respective measurements from each station were taken in hard disks (too much data to transfer through the Internet) and combined at MIT and at the Max Planck Institute in Germany for independent processing and verification. Once combined special mathematical algorithms were used with a supercomputer to extract the image.
Here are two of the 8 EHT telescopes that were used in Spain and South Pole
You can see some further details of this EHT project at the following link, where 4 scientists have also given a video presentation about this EHT project. This viseo was done before the Black-Hole picture release on April 10, but it is still very informative video about this exciting EHT project picturing Black-Hole.
We the citizens of this panet Earth have seen the actual picture of a Black Hole last month on April 10, 2019. The whole world came together in order to do this monumental task. This pioneering science work was done with an amazing collaboration of over 200 scientists of 60 different institutes from 16 different countries of 6 continents. They worked for over a decade to do this as the EHT Collaboration team. A picture of the Black Hole and a picture of the 200+ scientists who did this spectacular piece of work are given here right below.
Picture of the Super-massive Black-Hole with a mass of 6.5 billion times that of our Sun, which is located at the center of the massive galaxy, called M87 (Messier 87) near the Virgo Galaxy Cluster that is 55 million light years away from our planet Earth. Light year is the distance light travels in one year which is about 6 trillion miles or 10 trillion kilometers. Light travels at the speed of 186,000 miles per second which is known as the highest possible speed in the universe. In the picture of the Black-Hole we can see that one side of the donut looks brighter than the other. That is because the materials around the Black-Hole are orbitting around the Black-Hole and so the materials on one side that are coming towards us are giving the brighter part of the donut and the materials on the other side are moving away from us.giving the relatively less-bright part of the donut area.
Picture shows the EHT team, where the team project is called the EHT (Event Horizon Telescope) Collaboration. The Event-Horizon name comes from the boundary around a black hole wherefrom even light cannot escape. The radius of the Event Horizon is called the Schwarzschild Radius, and light cannot escape from inside it.
The question is:
1) what is a Black Hole any way?
2) why do we need so many people from so many different places of the world to take this picture? Any one can take a picture of the sun and moon and planets and stars with an iPhone easily. So, what is the big deal here?
1) what is a Black Hole any way?
Black Hole concept is actually not very difficult. Black hole is made up of huge amounts of matter squeezed into a small area, (NASA), creating a massive gravitational field which draws in everything around it, including light. The question is how are we going to see it if the light can not come out of it? Here is the explanation: Black Hole has a way of super-heating the material around it and also warping the space-time. Material accumulates around black holes, is heated to billions of degrees and reaches nearly the speed of light. Light bends around the gravity of the black hole, which creates the photon ring seen in the image. The imaging methods that the EHT team used to capture the photo revealed that the supermassive black hole has a ring-like structure and a shadow, which is represented by a dark central region.
Black Hole has been one of the most fascinating objects of modern sciences. Black Holes are created by a process that starts with the death of big stars through the Supernova explosion when it reaches the nuclear fusion limit at the level of Iron (Fe) in its core. That becomes the limit of the nuclear fusion process because Iron has the highest binding energy per nucleon and so, the star can no longer get advantage of the E = mc2 process to save itself from the attack by the gravitation. So, at that point the gravitational collapse becomes so intense that the atomic electrons and protons merge to become neutrons and the entire star becomes a neutron star. At that stage, if the neutron star is massive enough then it will go through further gravitational collapse to transform into a Black Hole. Black Holes can combine to make more massive Black Holes. There are billions of galaxies in the universe and each of the galaxies are assumed to have a Black Hole at its center.
Here is a diagram and description of the Regions of a Black Hole:
Accretion Disk: Large outer disk of gas dust and cosmic materials, in the shape of a doughnut, that moves around the black hole.
Ergosphere: Region surrounding the black hole, where energy can still escape, objects are in orbit.
Photon Sphere: Region where light has been deflected and is now in orbit around the black hole. The radius of the Photon Sphere is 1.5 times the radius of the Event Horizon.
Event Horizon: Invisible Sphere where anything that falls inward can never escape, because the escape velocity exceeds the speed of light. Since no object can reach the velocity of light, as derived from the Theory of Relativity, no object can escape as it inwardly crosses the Event Horizon. The radius of the Event Horizon is given by the Schwarzschild radius formula for Rs:
Rs = 2 G M / c2 where G is the universal gravitational constant, M is the mass of the black hole and c is the speed of light.
Singularity: The deepest central point of a black hole where the force of gravity is infinitely strong and the density reaches the theoretical value of infinity.
Let us see what would happen to our Sun and to our solar system if a black hole passed by our galactic neighborhood?
Well, that will cause the dooms day for us for sure. The force of gravity of a black hole is so strong that the tidal force would deform the Sun into an oval shape and then it would break it apart and consume it, together with all the planets, as you can see the representation below.
Time contraction (not dilation) near a black hole: The equations of General relativity show that if a person in a space ship entered into an orbit around a black hole, at a safe distance, for example for one year, then when coming back to the Earth, at the time of arrival he/she would notice that more than 100 years have passed here. To go to a black hole and then come back to the Earth is like traveling to the future. The closer you go to black hole, the greater the force of gravity and the greater is the time contraction with respect to us here on Earth. If you were to cross the Event Horizon, the point of no return, the time inside the black hole would stop with respect to us here on Earth.
T (Earth) = T (Near Black Hole) / v ( 1 – 2GM/rc2)
T (Earth) = Time as measured on Earth
T (Near Black Hole) = Time as measured near a black hole at a distance r, greater than the Schwarzschild radius Rs.
What would happen to a person going near a black hole?
If a person or an object were to fall into a black hole, the force of gravity is so strong that it would be stretched like chewing gum, it would make it like a thin spaghetti, that we call spaghettification, as displayed in the picture below.
2) why do we need so many people from so many different places of the world to take this picture? Any one can take a picture of the sun and moon and planets and stars with an iPhone easily. So, what is such a big deal here?
That is because this supermassive Black-Hole of massive Galaxy M87 is located far away from us (55 million light years) and the light signal intensity is extremely small. So, a camera is needed which has an aperture of the size of this whole Earth. The iPhone does not have that. The exposure time was also needed to be long to collect adequate amount of signal. So, 8 different Radio telescopes were placed in 8 different locations of the Earth and as the Earth was spinning, it was simulating the Earth-size aperture. The 8 different Radio telescopes were collecting signals that were synchronized among the 8 telescopes by atomic clock. To make sure these observations were truly simultaneous, and to see the same wavefront of light as it landed on each telescope, they used extremely precise atomic clocks at each of the telescopes. The telescope array collected 5,000 trillion bytes of data over two weeks, which was processed through supercomputers so that the scientists could retrieve the images. All the respective measurements from each station were taken in hard disks (too much data to transfer through the Internet) and combined at MIT and at the Max Planck Institute in Germany for independent processing and verification. Once combined special mathematical algorithms were used with a supercomputer to extract the image.
Here are two of the 8 EHT telescopes that were used in Spain and South Pole
You can see some further details of this EHT project at the following link, where 4 scientists have also given a video presentation about this EHT project. This viseo was done before the Black-Hole picture release on April 10, but it is still very informative video about this exciting EHT project picturing Black-Hole.
(https:/youtu.be/1EZi0SZ4L2I
If you want to understand the Black Hole and some other Big Bang Sciences that are presented in a very easy way then you can watch my video presentation here at the following link:
https:/www.youtube.com/watch?v=3dEtHHwd920&feature=youtu.be
References: Dr. Miguel Moreno – Former NASA Scientist, Jack Guy of CNN, Astronomy by OpenStax, Horizons – Exploring the Universe by Seeds and Backman.
(Dr. Mahbub Khan writes from California, USA).)
