On Wednesday, April 10th, the world will finally view a real-life picture of a black hole.
The world’s leading astronomers will hold six major press conferences simultaneously to show the world the results of the Event Horizon Telescope (EHT). The Event Horizon Telescope is a huge international project built for one purpose: to capture a picture of a black hole. The EHT is unlike anything ever built; instead of being a giant telescope that would collapse, it is a bunch of observatories.
This is a huge deal to the scientific community because black holes are among a number of otherworldly elements we cannot see. While others have piqued our curiosity like dark matter and dark energy, none have sparked a flame in mankind like black holes. From Albert Einstein to Stephen Hawking, scientists everywhere have been puzzled by the phenomenon that is a black hole. But finally, on Wednesday we will see what a true black hole looks like. Even though humans have never seen a black hole, we do know a few things about them. Scientists first came up with black holes in the 1700s, but it has been the last 50 years where we have made the most progress. Scientists have figured out that every black hole has a kind of point of no return or the event horizon. The event horizon isn’t a physical thing but really the point where nothing can escape. If something is inside the event horizon, it can’t escape because it would need to travel faster than the speed of light.
At its center, a black hole has a singularity, or a point of infinite density. The distance between the singularity and the event horizon is the radius of the black hole.
Scientists have built eight radio telescopes like the EHT across the world to take pictures of two different black holes. Astronomers prefer Sagittarius A, the black hole at the center of the Milky Way. Sagittarius A is four million times the mass of our sun and is approximately 44 million kilometers across. The other candidate is a huge black hole in the galaxy, M87. This black hole is 1,500 times more massive than Sagittarius A, but is a lot farther.
Scientists are excited about this because it is putting Einstein’s theory of general relativity to test. This theory has been tested before, like in 2015 when astrophysicists used gravitational wave detectors to track two black holes hitting each other. When the black holes collided, they merged, creating a unique signature that could be detected; this was predicted by general relativity. However, it has never been tested on such a grand scale as it will be when scientists see the black hole. This will be a huge step in physics as a whole.