6 If you watch an object or a person slip into a black hole, no matter how long you watched, you would never actually see the object enter it due to time dilation.
The outermost boundary of the black hole is known as the “event horizon.” When seen from outside, nothing can be seen of the black hole beyond the event horizon. This horizon is a point of no return as beyond it, the gravitational pull is so intense that nothing can escape. When a person or an object approaches the black hole, for an outside observer, it appears to slow down as it approaches the event horizon. The object also appears to stretch and contort as if it is being viewed under a giant magnifying glass.
As the object reaches the event horizon, the observer would see it freeze as if someone had hit the pause button. The object would seem to remain motionless and plastered across the surface of the event horizon. The observer would realize that the object doesn’t quite pass through the horizon. As time goes by, the object would appear more and more red-shifted, and it would appear that the object would be reduced to ash before reaching the darkness of a black hole. (1, 2)
7 About 12 billion light-years away there exists a black hole that holds at least 140 trillion times the water in all of Earth’s oceans combined making it the largest known reservoir of water.
Concept illustration of a feeding black hole, similar to APM 08279+5255. Image credit: NASA/ESA
In 2011, two teams of astronomers discovered a black hole located more than 12 billion light-years away holding the largest reservoir of water. This black hole is a feeding black hole located in a quasar called “APM 08279+5255.” It is 20 billion times more massive than our Sun. It powers the quasar by consuming the surrounding disk of dust and gas. Occasionally, it belches out energy equivalent to a thousand-trillion Suns. This black hole is surrounded by water equivalent to 140 trillion times all the water in the world’s ocean. The water is present in a vaporized state spanning hundreds of light years.
The amount of water vapor and other gas such as carbon monoxide present in this quasar is enough to feed the black hole until it grows to about six times its current size. But this might not happen if some of the gas ends up condensing into stars or getting ejected by a quasar. (source)
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8 A black hole produces extremely powerful space winds blowing at 125 million kph restricting the formation of stars in the galaxy.
In 2016, astrophysicists at York University detected ultrafast, quasar winds swirling around a supermassive black hole, PDS 456. The winds were blowing at more than 200 million kilometers an hour, roughly, a quarter the speed of light. The speed of the wind is equivalent to a category 77 hurricane. It is occurring as spiraling matter, and the heat and light from the quasar blow it away from the black hole.
These space winds play an important part in galaxy formation. During the formation of galaxies, these winds push material such as dust and gas outwards deterring the creation of stars. In absence of these winds, there would be far more stars in big galaxies than they actually are. Also, these powerful winds regulate the growth of the black hole itself. (1, 2)
9 There exists a black hole in the Perseus Cluster that “sings.” It produces the lowest note in the universe to the tune of a B-flat that’s 57 octaves below middle C.
The Chandra X-ray Observatory detected sound waves in the Perseus Cluster. Image credit: NASA/CXC/IoA/A.Fabian et al
In the Perseus cluster of galaxies located 250 million light years away, there exists a supermassive black hole producing the lowest note ever recorded. The note was first recorded in 2002 using NASA’s Chandra X-ray Observatory. Among the observations, astronomers saw the presence of ripples in the gas filling the cluster. These ripples were the sound waves that traveled away from the cluster’s central black hole.
The pitch of the sound generated by this supermassive black hole is in the note of B-flat. But the note is 57 octaves lower than middle-C making it impossible for the human ear to hear it. Nonetheless, it is the lowest note ever detected from an object in the Universe. (source)
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10 On April 2019, scientists successfully captured the first image of a black hole located in the Messier 87 galaxy 55 million light years from Earth. Its event horizon is 3 million times the size of our planet which is larger than our entire solar system.
Since light cannot escape from black holes, it is almost impossible to photograph them. They are surrounded by glowing accretion disks of in-falling material due to which one can understand that the black part in the center of the disk is the black hole. Recently, scientists have achieved the impossible by actually photographing a black hole. The first picture of the black hole is the outcome of a series of processes. In April 2017, data was collected by the Event Horizon Telescope, a network of eight, radio telescopes. These telescopes were located from Antarctica to Spain and Chile. They picked up radiation from particles that swirl around the black hole at close to the speed of light.
Creating the black hole image was the tricky part. It involved the combined effort of more than 200 scientists. The result was released for public viewing in April 2019. The image shows a fuzzy, doughnut-shaped ring of gas and dust. This is the black hole’s accretion disc that feeds the black hole within. The crescent-like halo in the image is due to the particles in the side of the disc rotating towards Earth. It looks brighter as its particles are flung towards us faster. The dark shadow within is the edge of the event horizon. Beyond it, no light or matter can travel fast enough to escape the gravitational pull of the black hole.
The photographed black hole is located at the heart of the Messier 87 Galaxy located 55 million light-years from Earth. Scientists are trying to produce an image of the black hole in our Milky Way. (1, 2)
