Over the next 12 months, a group of astrophysicists hope to do something that has never been done before: observe the horizon of the central black hole in our galaxy. And that could have profound implications for our understanding of the Universe.
A black hole is a point in space where the gravitational attraction is so strong that even light can not escape. Albert Einstein predicted the existence of this phenomenon in his theory of general relativity, but so far no one has been able to observe one directly. The Event Horizon Telescope (EHT) project may soon change that. The EHT is a network of telescopes scattered throughout the world, which when combined could provide all the necessary components to capture the long-awaited image of a black hole, the most mysterious object in the universe.
“First, you need ultra-high magnification — the equivalent of being able to count the dimples on a golf ball in Los Angeles when you are sitting in New York,” said program director Sheperd Doeleman. “Then you need a way to see through the gas of the Milky Way and the hot gas that surrounds the black hole itself. This requires a telescope as big as the Earth. And that’s precisely where the telescope network comes into play,” he added.
The EHT team has, in a way, created a “virtual Earth-size telescope” that uses a network of individual radios scattered around the planet, says Doeleman. These telescopes have been synchronized and programmed to observe the same point in space – exactly at the same time – and record the radio waves that emanate from it. It all happened in April 2017 for five nights during which eight telescopes around the world simultaneously targeted Sagittarius A *, the supermassive black hole at the center of our galaxy, about 30,000 light-years from Earth.
With the data of the eight radio antennas now collected, the researchers are now continuing their analyzes in the hope of producing the first shot of this black hole. Not only will such an image prove that these objects do indeed exist, but it will also provide a new perspective on our Universe. “The impact of black holes on the universe is huge,” says the researcher. “Observing what is happening near the horizon will help us understand the Universe on a larger scale.”
In the future, researchers could take multiple images of a single black hole, spaced over time. This would allow scientists to determine whether Einstein’s theory of general relativity remains true at the black hole limit. So far, we have no guarantee of what we will see, but the whole team is now enthusiastic about the prospect of being at the origin of this unpublished image. The exact date of publication is unknown as the research team prefers to work carefully on the data already recorded.
However there is good reason to hope that the team will manage to capture a picture of a black hole in 2018, which would be a great first.