What does the supermassive black hole at the center of the Milky Way look like? Early next year, we might find out. The Event Horizon Telescope—really a virtual telescope with an effective diameter of the Earth—has been pointing at Sagittarius A* for the last several years. Most researchers in the astrophysics community expect that its images, taken from telescopes all over the Earth, will show the telltale signs of a black hole: a bright swirl of light, produced by a disc of gases trapped in the black hole’s orbit, surrounding a black shadow at the center—the event horizon. This encloses the region of space where the black-hole singularity’s gravitational pull is too strong for light to escape.
By Jesse Stone | NAUTILUS
But George Chapline, a physicist at the Lawrence Livermore National Laboratory, doesn’t expect to see a black hole. He doesn’t believe they’re real. In 2005, he told Nature that “it’s a near certainty that black holes don’t exist” and—building on previous work he’d done with physics Nobel laureate Robert Laughlin—introduced an alternative model that he dubbed “dark energy stars.” Dark energy is a term physicists use to describe a peculiar kind of energy that appears to permeate the entire universe. It expands the fabric of spacetime itself, even as gravity attempts to bring objects closer together. Chapline believes that the immense energies in a collapsing star cause its protons and neutrons to decay into a gas of photons and other elementary particles, along with what he refers to as “droplets of vacuum energy.” These form a “condensed” phase of spacetime—much like a gas under enough pressure transitions to liquid—that has a much higher density of dark energy than the spacetime surrounding the star. This provides the pressure necessary to hold gravity at bay and prevent a singularity from forming. Without a singularity in spacetime, there is no black hole.
The idea has found no support in the astrophysical community—over the last decade, Chapline’s papers on this topic have garnered only single-digit citations. His most popular paper in particle physics, by contrast, has been cited over 600 times. But Chapline suspects his days of wandering in the scientific wilderness may soon be over. He believes that the Event Horizon Telescope will offer evidence that dark energy stars are real.