Space and Physics

Event Horizon Telescope To Begin Most Detailed Observation Of A Black Hole in April


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockFeb 17 2017, 17:31 UTC


The ambitious Event Horizon Telescope is ready to start its operation and in just a few months an international group of astronomers might see the most detailed look yet at a black hole.


The target is Sagittarius A* (pronounced ‘A’-star), the supermassive black hole at the center of the Milky Way. This incredible task can only be achieved by linking nine radio telescopes across the globe and making them act as a single Earth-size telescope.

"There's great excitement. We've been fashioning our virtual telescope for almost two decades now, and in April we're going to make the observations that we think have the first real chance of bringing a black hole's event horizon into focus," project leader Sheperd Doeleman from the Harvard-Smithsonian Center for Astrophysics told BBC News.

The team hopes it could get a successful observation between April 5 and April 14, finally providing a direct view of what the edge of a black hole looks like. Since not even light can escape black holes, they cannot be seen directly, so the researchers will be looking at the event horizon – the region that separates the black hole from the rest of the universe.

Gas and stars and material orbit around the black hole before being sucked in and radio waves give a great chance to see that gas. Also, radio waves allow astronomers to use interferometry, a clever trick to get high-resolution images.


It’s possible to combine the data from different radio telescopes into a single image, and the further they are apart, the higher the resolution. The telescopes used in the project are located in the US, Chile, Spain, and even the South Pole, providing an unprecedented resolution.

And high resolution is required if we want to see Sagittarius A*. Although it weighs 4 million Suns, it is "just" 44 million kilometers (27 million miles) in diameter. And being 26,000 light-years away from Earth gives it the apparent size in the sky similar to a CD on the surface of the Moon from Earth.

According to the equations of general relativity, the team should be seeing light fringing against a dark feature.


"Now, it could be that we will see something different," Doeleman continued. "As I've said before, it's never a good idea to bet against Einstein, but if we did see something that was very different from what we expect we would have to reassess the theory of gravity. I don't expect that is going to happen, but anything could happen and that's the beauty of it."

[H/t: BBC News]

Space and Physics
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