Black holes and their supposedly never-ending enigma have had us running behind answers and have led to the formulation of convoluted theories with no definitive conclusions for decades now. While black holes have been described and studied with a purely theoretical structure in mind, it has proved to be extremely challenging to gather some visual evidence suggesting the true nature of its existence. In recent times
The Event Horizon Telescope, which involves 200 scientists in 20 countries claimed to have created a revolutionary technology to view this spectacle with commendable work spanning over a decade. This week, scientists unveiled the first-ever image of a black hole at the centre of the Messier 87 galaxy, about 55 million light-years away. Needless to say, this image rattled the minds of black hole enthusiasts and the general public alike with people all over the world attempting to make sense of the scattered pieces of information gathered over time and the visual data in hand now.
A deep black well in the centre of a bright ring of plasma and gas – a part of the conundrum unlocked. The image, however, received mixed responses from people. While some marvelled at the very idea of a picture of a black hole, some criticized the blurriness of the image. However, the true essence of the picture is not being
Two astrophysicists — Sheperd Doeleman, the project leader of the Event Horizon Telescope, and Katie Mack of North Carolina State University explain to us why this picture is so much more fascinating than it seems. To explain the significance from a scientific standpoint, they dissect the image and bring to notice factors which would slip the common mind expecting a picture right out of a Christopher Nolan movie.
THE DARK SPOT
Let us first talk about the dark spot in the center. While it may seem like an object, nothing and arguably, everything exists at that point. The “spot” at the center is a shadow, a portal leading out of our known universe. There is light in that spot but it is not for us to view. Confused already? Let us try to break it down. Essentially a black hole, as the name suggests, is black as it involves the physical rupture of a part of the fabric of space and time where it has collapsed in on itself to form a point of infinite density. Now that is some Doctor Who stuff right there! Scientifically though, this is what is referred to as a singularity. That single point has such strong gravity that as light approaches it, there’s a region beyond which nothing can escape its grasp. This region is called the event horizon.
Let us draw an interesting analogy to put things into perspective. Let us imagine a water body leading to a waterfall. The water body can be thought of as the known universe. A fish swimming about accidentally makes its way to the peak of the waterfall. At a certain point, the water is rushing so fast that the fish can’t escape by swimming in the other direction. Soon, it is inevitably gushing down the waterfall. The peak in this case can be analogous to a black hole. While the fish still exists, it is out of our sight and not observable to a person constricted to the horizontal dimension alone. However, just because we can’t see it, doesn’t mean it’s not out there somewhere. “When the matter and light get too close to the black hole, the black hole just swallows it up, it removes that light from the universe,” Mack says.
THE SURROUNDING RING
In the image, let us observe the ring surrounding the dark centre. Now, what might that be? While one might say it’s the event horizon, it actually is not. That boundary is known as the photon orbit, and its diameter is about 2.5 times larger than that of the event horizon. The light that travels beyond the photon orbit could potentially escape the black hole if something was to reflect it back. While the ring is shining through the darkness, there is something rather sinister about its existence. The brightness is due to matter being shredded to pieces succumbing to the black giant at unimaginably high temperatures in the order of billions.
If observed carefully, the ring is brighter at the bottom. The reason behind this is as byzantine as the phenomena itself. The brightness is actually because the light is moving towards us, a bit like the Doppler Effect. “And that tells us about how this material is rotating as it falls into the whirlpool,” Mack says. The light you do see in this image isn’t just coming from the sides of the black hole, it’s coming from behind it, from in front of it, from all directions. Space and time are so paradoxical, that some of the light orbits the black hole in a circle.
The telescopes used in the Event Horizon effort were radio telescopes. That indicates their sensitivity to radio frequencies on the electromagnetic spectrum alone. “The [material] around the black hole is transparent to radio waves, so we can see through all the hot gas trying to get through the event horizon,” Doeleman says. “Otherwise all we’d see would be some big blob.” To the average person out there, the photograph has been sadly reduced to nothing but an internet meme.
However, the monumental workforce and intellect behind the production of this rather impossible image are staggering. Let us briefly look into why it took scientists nearly a decade to visualize and capture this vista. There had to be some radiation emanating from the outskirts of the black hole, and it had to reach Earth without being blocked or deviated by a cosmic body. The Event Horizon team constructed a virtual telescope the size of the Earth to view that radiation.
Yes, you heard right, it was indeed the size of our planet. Eight observatories all over the world had to synchronize their atomic clocks to a terribly specific degree. We as humans seem to be entwined in a world of fantasy brought to life by technological marvels, with these stunning visuals brought to our humble homes to as small a device like a cell phone! While we have transcended across the fabric of imagination and stupendous portrayals of space and time travel, we don’t seem to appreciate a simplistic idea of the true miracles of the universe.
While the picture might not seem right out of your favourite fantastical sci-fi, it has packed in it, more mystic elements than what has been perceived. If we looked beyond the confines of our mind and embraced a more minimalistic outlook, we might just be able to see the impossibility of what has just been achieved. With impeccable collaboration, astonishing levels of patience and immense hard work, the scientists have brought to us a picture of the most paradoxical phenomena in existence, a potential portal to a different universe! If that doesn’t scream cool, we don’t know what will.
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