Harvard scientists lead team revealing black hole – Harvard Gazette

To collect the data used in the black hole image, Doeleman said, the team gathered information from six locations — Antarctica, Chile, Mexico, Hawaii, Arizona, and Spain. By combining data from multiple places, researchers were able to build a system powerful enough to peer into the heart of a black hole. “The EHT observations require measurements of light received from M87 every nanosecond in order to properly sample the incoming high-frequency radio waves,” said Daniel Palumbo, a Harvard graduate student at the CfA. “We capture and freeze that light locally at each telescope. Storing that information requires hundreds of terabytes of space, shipped around the globe for later combination by a supercomputer. High-quality data from a wide array of telescopes let us form images that we trust.” Doeleman said the credit for the feat must be shared by the dozens of astronomers, postdoctoral fellows, graduate students, and undergraduates who worked for years to make it happen. “The group here is tremendous,” he said. “The group at the Harvard-Smithsonian Center for Astrophysics (CfA) and the Black Hole Initiative at Harvard … they’re the backbone of the entire effort. They are shouldering all the burden and they have risen to a monumental challenge. We have a great, wonderful team of people here and around the world that brought us to this point, and when I saw that first full image, I just said, ‘This is it.’” “A black hole, if you looked at it naked … would be invisible. It’s nature’s most amazing invisibility cloak.” — Sheperd Doeleman, director of the EHT Doeleman said EHT researchers were split into four independent teams to analyze the data gathered by the telescopes, each of which produced nearly identical images. “That’s when we knew we had something,” he said. “Then all the teams came together to refine these techniques. … So we were doing new things throughout this whole project.” But when it comes to imaging a black hole, simply building a bigger dish — even a planet-size one — wasn’t enough. To even reach the EHT telescopes, photons born near the black hole must have a wavelength short enough to be able to escape from the super-heated soup of the circle of gas and dust that collect around a black hole, known as an accretion disk, travel millions of light-years through the interstellar medium, and pass through Earth’s atmosphere. The magic number needed to pull it off, Doeleman said, was 1.3 millimeters. “At 1.3 millimeters, everything just works,” he said. “All these things have to happen — we need cosmic sources that are this size. We need wavelengths of light that can see through all this. And we need the Earth to be the right size … so we can resolve this. Did we hit the lottery or what?” In the future, Doeleman said, the team should be able to increase the images’ resolution by capturing shorter wavelengths and building ever-larger telescopes. “In fact, we’ve just put in our first space proposal … to explore putting telescopes in orbit,” he said. “In theory, we could put something far enough away from Earth so we could get a diameter larger than Earth. We do have some tricks up our sleeve … and we’re thinking those things could happen over the next decade, and we would be able to sharpen our capabilities even more.” For now, though, Doeleman said it’s hard to overstate the significance of the first image of a black hole, if only because of the host of new questions it will allow astronomers and physicists to ask. “Today’s result represents the end of years of hard work by the EHT team, but it’s really just the beginning,” said Andrew Chael, a Harvard graduate student at the CfA. “Using these images and future observations we will be able to not only test general relativity in a new, extreme environment, but we will also be able to learn more about how supermassive black holes interact with whole galaxies, especially how magnetic fields can extract energy from the black hole and launch huge jets out to enormous scales like we see in M87. The next few years will be an incredibly exciting time in black hole physics and astrophysics.” Aside from the scientific discoveries made possible by the work of the EHT, Doeleman believes the project is awe-inspiring just by its nature. “For my money, there’s the wonder of it,” he said. “The fact is that we’re just blobs of protoplasm living on a planet that’s just the right size, with just the right wavelength of light, and we made radio telescopes that can image a supermassive black hole 50 million light-years away, that’s incredible. And it’s not only incredible because we can do it, but it’s incredible because the very nature of a black hole is that it’s unseeable, and here we are seeing the unseeable.”

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