At precisely 13:00 Universal Time today — 9 a.m. in the Eastern United States — scientists will hold simultaneous news conferences in Washington, D.C., Belgium, Denmark, Chile, Japan, China and Taiwan to reveal the long-awaited results of the Event Horizon Telescope. What everyone is expecting and hoping to see is the first direct image of a black hole.
The Event Horizon Telescope is a network of 10 radio telescopes on four continents that collectively operate like a single instrument nearly the size of the Earth. The scientists behind this mega-telescope boast that their ability to resolve objects in deep space is equivalent to being able to count the dimples on a golf ball in Los Angeles while standing in New York City.
An astronomical photograph of a black hole would represent a tremendous breakthrough for astrophysics and the culmination of a century of theoretical and observational labor. Even a generation or two ago, scientists weren’t entirely confident that black holes existed, because even though they looked plausible mathematically the observational evidence was indirect.
Few people have hated the idea of black holes more than the man who helped establish their existence: Albert Einstein. His celebrated general theory of relativity in 1915 described how matter can cause space and time — “spacetime” — to curve, much the way a bowling ball will dimple the surface of a trampoline. Gravity is the effect of that warping of the geometry of the cosmos. Physicists put it this way: “Matter tells space and time to curve. Space and time tell matter to move.”
Just months after Einstein’s equations were published, a German scientist, Karl Schwarzschild, tweaked Einstein’s equations and came up with a disconcerting conclusion. If an object was dense enough, he found, it would eventually punch through the universe’s fabric, creating a bottomless pit in spacetime known as a “singularity.”
These singularities — named “black holes” in the 1960s — are gravity wells so strong that, once you enter, you can’t turn back. The gravitational field of a black hole is so intense that not even light can escape the “event horizon,” the point of no return.