WANNA PEEP AT A BLACK HOLE?

By-Malav Agrawal

Many of us have seen the movie Interstellar and were fascinated by the black hole shown as a big, white, bright ring. But that was an artist’s stimulation. What actually does a black hole look like, and how do we look at something that we can’t see?

If you move out of the glimpse of the city lights on a clear and dark night, you might get a stunning view of our spiraling Milky Way Galaxy and if you were able to zoom past millions and millions of stars and cosmological stuff 26000 light years in, towards the centre of our galaxy, you might see that bright interstellar ring. Scientists have been

observing the stars near the center of our Galaxy for many years and by predicting the motion of these giants,it seems that the only thing possible so small and massive enough to keep these celestial objects in motion is ablack hole.The Theory of Relativity predictedthe

existence of black holes and itwould be so cool to take a photograph of a black hole.It would not only give us our very first glimpse of a black hole but also a chance to prove those equations right.So how to see something that’s by definition impossible to see?

If you are able to see close enough you would be able to see a bright ring around the black hole caused by the gravitational lensing of the

hotplasma.But seeingsomethingthat far fromEarthis just like seeing an orange on the surface of the moon from earth. And due to an effect called diffraction, it all comes down to a simple equation that tells that

the smaller we want to see,the larger we need to build a telescope and crunching those numbers down,we would require to build a telescope as big as the size of earth to see that ring around the black hole.Building a single dish telescope the size of earth is a herculean task. So what we do instead is to make a bunch of powerful telescopes, Called The Event Horizon Telescopes located on various positions of

the globe, coordinated by a cesium atomic clock, working together

precisely.

So how does it work?Suppose the earth to be a giant disco ball(that

would make a great party) made up of small mirrors, each mirror

receiving and reflecting light. Suppose some of its mirror breaks down, but still, others continue to work unaffected. And as the Earth rotates

and completes its course around the sun through the Cosmos, different

mirrors get a chance to cover the positions of the broken ones in the

journey. So what if we could combine those images together at different

locations and different times to get a single picture of what we need,a

BLACK HOLE. So we have some big telescopes on various locations on

earth and as the earth moves and rotates, different telescopes get

chance to view the center of our Galaxy from various locations,

inclinations, and lines of sight. And all these telescopes work in perfect

coordination guided by an atomic clock (with an accuracy up to 10-14

decimal places, or 1 second in 1,400,000 years!!).What we need is to

combine all those pictures into a single picture so that we can get a

picture of a black hole.

So in short, what we need for a black hole picture is-

-A blackhole;

-Some telescopes working together;

-And an algorithm to combine those results.

Well,now the wait’s over!!!

First computer generated Image of a black hole.

Each white dot was made one at a time based off measurement of

light.

Credits- Katie Bowman (Ted Talks)