An illustration of heavily-curved spacetime, outside the event horizon of a black hole. As you get closer and closer to the mass’s location, space becomes more severely curved, eventually leading to a location from within which even light cannot escape: the event horizon. The radius of that location is set by the mass of the black hole, the speed of light, and the laws of General Relativity alone. (PIXABAY USER JOHNSONMARTIN)

This Is What We Know About Black Holes In Advance Of The Event Horizon Telescope’s First Image

We’ve never seen an image of a black hole’s event horizon before. Here’s what we’re expecting, based on what we already know.

For hundreds of years, physicists have hypothesized that the Universe should contain black holes. If enough matter is gathered into a small enough volume of space, the gravitational pull will be so strong that nothing in the Universe — no particles, no antiparticles, not even light itself — can escape. They are predicted by both Newton’s and Einstein’s theories of gravity, and astrophysicists have observed many candidate objects that are consistent with black holes and no other explanations.

But we’ve never seen the event horizon before: the characteristic signature unique to black holes, of the dark region where nothing can escape. On April 10, 2019, the Event Horizon Telescope collaboration will release their first-ever image of such an event horizon. Here’s what we know right now, on the eve of this monumental discovery.

The black hole at the center of the Milky Way, along with the actual, physical size of the Event Horizon pictured in white. The visual extent of darkness will appear to be 250–300% as large as the event horizon itself. (UTE KRAUS, PHYSICS EDUCATION GROUP KRAUS, UNIVERSITÄT HILDESHEIM; BACKGROUND: AXEL MELLINGER)