Or, how to make a telescope as large as the world

This is it. The first image that has ever been taken of any black hole.

And  maybe it doesn’t look spectacular at first, but consider this: not only  is this black hole is about 55 million light years away from us, but  black holes are invisible by their very nature! (This is because their  gravitational pull is so strong that not even light can escape them.)

Which is why, for many years, astronomers thought that an image of a black hole would be impossible to get.

They were wrong.

In  theory, we can’t take a picture of a black hole because it just isn’t  possible to take an image of something that doesn’t emit or reflect  light.

Take  a closer look, though. What you see in the picture is not the black  hole itself, but a disk around it. You’ll see black space, a ring of  fire, and then more black within.

That’s the black hole.

In this picture, the black hole isn’t visible — and shouldn’t be, if our laws of physics are correct.

The ring itself exists because of a phenomenon in which a star comes too close to the black hole and gets sucked into it.

Due  to the enormous amount of gravitational force exerted by the black  hole, the star gets pulled in until all that remains is the ring. The  ring is called the accretion disk, and it’s the most obvious part of the  image taken.

But  it won’t be around forever: the black hole continues to exert it’s  pull, and after a period of time, this ring will get eaten up as well.

The story begins with a small team of innovators and ends with a telescope that is unlike anything the world has ever seen.

Although  there have been major advances in telescope technology lately, there is  no single telescope on earth that can take a picture of a black hole.  They’re just too small to do so!

In  theory, to have that kind of resolution, you would need a telescope the  size of planet Earth, and obviously, that isn’t possible. To solve this  problem, they hit upon an idea that was truly innovative: if one  telescope couldn’t do the job then perhaps many would.

As it turns out, they were right.

The  team used a global network of dishes to simulate a telescope of this  size. Twelve radio-telescopes stationed at different points across the  world were kept in sync with powerful atomic clocks. Each telescope  collected and recorded radio waves coming from near the black hole. This  data was then combined using supercomputers to create the image of the  black hole.

This program included the support of many countries and was named the Event Horizon Telescope or EHT.

This black hole is actually what’s called a supermassive black hole that lives in the centre of the Messier 87 galaxy. It’s about 7 billion times as massive as our Sun. That’s colossal compared even to other supermassive black holes.

The  most important part of this photo is where there is no light, that dark  circle in the centre which measures to about 25 billion miles across.  That’s the actual black hole.

And at its edge is the place known as the event horizon, the  point of no return. Once you cross the event horizon, the black hole’s  gravity is so strong that you cannot escape. Not you, not the fastest  spacecraft, not even the fastest thing in the universe: light.

Many,  many things needed to be just right in order to capture this image,  enough that it might be considered a miracle. The light travelled for  about 55 million light years, without getting absorbed by gas or  particle. Only a small fraction of the radio waves that hit the outer  atmosphere actually end up reaching the surface, as most of them get  absorbed or reflected. And for these waves to get received by the EHT,  the weather needed to be good and clear at every one of the 12  telescopes, including the one in Antarctica.

This is the first picture of a black hole ever taken, but it certainly isn’t the last.

As  after this first success, the team of EHT Scientists has started  examining other black holes, in hopes to further our understandings on  the black holes.

The team has now turned the giant camera towards another black hole named the Sagittarius A*. This black hole is the one present at the center of our own galaxy, the Milky Way. We believe that its images will be released soon.

With these images of black holes, we can understand more about their properties and answer currently unanswered questions like:

Why are they present at the centre of galaxies?
Why do they vomit massive streams of subatomic particles into space?
How exactly do they affect the space-time fabric around them?

And, what effect might they one day have on us?

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