## How to take a picture of a black holeby: christian culp

"In the movie "Interstellar," we get an up-close look at a super massive black hole. Set against a backdrop of bright gas, the black hole's massive gravitational pull bends light into a ring. However, this isn't a real photograph, but a computer graphic rendering — an artistic interpretation of what a black hole might look like."

One thing predicted from this theory, black holes, still have not been directly observed. Hundred years ago, Albert Einstein first published his theory of general relativity. Although we have some idea as to what a black hole might look like, we've never actually taken a picture of one before. You might be surprised to know that that may soon change. We may be seeing our first picture of a black hole in the next couple years. Although I won't be able to show you a real picture of a black hole today, I'd like to give you a brief glimpse into the effort involved in getting that first picture.

So how does this even work? Remember if we want to see the black hole in the center of our galaxy, we need to build this impossibly large Earth-sized telescope? For just a second, let's pretend we could build a telescope the size of the Earth. This would be a little bit like turning the Earth into a giant spinning disco ball. Each individual mirror would collect light that we could then combine together to make a picture. However, now let's say we remove most of those mirrors so only a few remained. We could still try to combine this information together, but now there are a lot of holes. These remaining mirrors represent the locations where we have telescopes. This is an incredibly small number of measurements to make a picture from. But although we only collect light at a few telescope locations, as the Earth rotates, we get to see other new measurements. In other words, as the disco ball spins, those mirrors change locations and we get to observe different parts of the image. The imaging algorithms we develop fill in the missing gaps of the disco ball in order to reconstruct the underlying black hole image. If we had telescopes located everywhere on the globe — in other words, the entire disco ball — this would be trivial. However, we only see a few samples, and for that reason, there are an infinite number of possible images that are perfectly consistent with our telescope measurements. However, not all images are created equal. Some of those images look more like what we think of as images than others. And so, my role in helping to take the first image of a black hole is to design algorithms that find the most reasonable image that also fits the telescope measurements.

But of course, getting imaging ideas like this working would never have been possible without the amazing team of researchers that I have the privilege to work with. It still amazes me that although I began this project with no background in astrophysics, what we have achieved through this unique collaboration could result in the very first images of a black hole. But big projects like the Event Horizon Telescope are successful due to all the interdisciplinary expertise different people bring to the table. We're a melting pot of astronomers, physicists, mathematicians and engineers. This is what will make it soon possible to achieve something once thought impossible.

# Report Abuse

If you feel that this video content violates the Adobe Terms of Use, you may report this content by filling out this quick form.