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Tuesday, 22 August 2017

Colliding black holes inside a computer

When we see a picture of scientists in lab or at a research centre, we notice that there are computers everywhere. And we think that they use these computers to analyze the data from the experiments in particle physics or cosmology. But there are lots of other things that are done with the aid of these computers, like landing of a rover, communication with a satellite orbiting mars, etc. 

SpaceX/Dragon CRS-12 Launches to the International Space Station

I was curious how physicists, cosmologists, and mathematicians use computers to solve problems. Like how the simulations of colliding black holes or galaxies is produced. How can it reveal something which has not happened yet? Like how our sun will explode at the end of its life and become a white dwarf.

The stars we see at night are just a small part of our galaxy. And our closest star, the sun can be seen throughout the day.

But how a black hole looks like?

We know that the planets are illuminated by star. Similarly Black holes are illuminated by the accretion disc surrounding them. So how does a black hole look like with its accretion disc? 

First computer images of the appearance of a black hole surrounded by an accretion disc were obtained by J.P. Luminet in 1979.

He had to produce the final image by hand using the numerical data.

blogs.nature.com

Almost 38 years have passed since then. 
So now we should have a real picture of black holes, right?

But still we do not have one.

Although the simulations of black hole have become more beautiful and precise, and Luminet’s original work has now been done with a computer and shows 3D model of similar picture he created with his own hands.

And the black hole Gargantua in the movie INTERSTELLAR with its distorted accretion disc due to gravitational lensing is also now a famous visualization of such black holes.

blogs.scientificamerican.com

But we do not have to be disappointed, because the Event Horizen Telescope, which is a large collection of telescopes, has started working on it and within few years we’ll see the first picture of a black hole!