Astronomers working on the Event Horizon Telescope (EHT) project, which set out to capture the first ever image of a black hole, are scheduled to make a “groundbreaking” announcement on April 10 — and speculation is mounting as to what precisely will be unveiled.
Dong Lai is a professor of astronomy at Cornell University and an expert on black holes. He is not involved with the project, but predicts the EHT team will reveal an image of a black hole at the center of the Milky Way galaxy, as well as an image of a black hole at the center of nearby galaxy M87.
“My guess is EHT will produce an image of the supermassive black hole at the center of the Milky Way galaxy and also an image of one at the center of the nearby galaxy M87. More precisely, these are images of radiating hot gas orbiting very close to the black hole. The strong gravity — the ‘event horizon’ — of black holes creates a dark shadow with a distinct shape where no light can be seen.
“The black hole shadow was first studied and computed more than 40 years ago by Jim Bardeen in the U.S. and by Jean-Pierre Luminet in France. These days all astrophysicists believe the existence of black holes at the center of galaxies and many of their properties as predicted by general relativity. So I don’t expect EHT will reveal any surprises.
“Nevertheless, it will be very nice and gratifying to see the black hole shadows directly. This is very challenging because the images are heavily blurred by the interstellar gas. The EHT team is to be congratulated for overcoming many technical challenges to achieve the goal of imaging black holes.”