Observing the image of the very first picture ever taken of a black hole would be like listening to a song played on a broken piano, says famed research Katie Bouman.
Katie Bouman became a worldwide celebrity in April for her key role in creating the first ever black hole image, a technological achievement that earned her an invitation to the US Congress on Thursday.
With obvious pleasure, the smiling postdoctoral fellow at the Harvard Smithsonian Astrophysics Center patiently explained the lengthy process culminating in the publication, on April 10, of this blurry photograph of an orange halo around a black disc, the image of the heart of the galaxy Messier 87.
As the galaxy is 55 million light-years away, “the ring is incredibly small in the sky,” she explained. It was “like the size of an orange on the surface of the moon, seen from the Earth”.
The laws of physics would have forced humans to create a telescope the size of the Earth to see it. Hence the idea of the Event Horizon telescope (EHT), an international collaboration that includes a dozen radio telescopes and observatories around the globe, from Europe to the South Pole, through Chile and Hawaii. By combining them, astronomers have, for a few observations, a virtual telescope of the size of the globe.
But because of the limited number of locations, the telescopes recorded only certain frequencies and left holes.
“As an analogy, imagine that the data taken by the EHT are the notes of a song: each piece of data corresponds to a note of the song. Observing the black hole with the Event Horizon telescope is like listening to a song played on a piano where half of the keys are broken,” explained the scientist.
It was therefore necessary to fill the holes to reconstruct the image of the black hole.
“In the same way that your brain is able to recognize a song played on a broken piano if there is a sufficient number of intact keys, we are able to create algorithms to reconstruct the missing information of the EHT in order to reveal the image of the black hole,” she said.
The final result has been verified by four independent teams around the world. The four images produced varied slightly but had the same basic structure. “To see these images for the first time was extraordinary, one of the happiest memories of my life,” said Katie Bouman.
She took advantage of the audition to pay tribute to the many people who contributed to the project: students, PhD students and post-docs.
“Like black holes, the contributions of many early-stage scientists often go unnoticed,” said the former PhD student at the Massachusetts Institute of Technology (MIT).