Scientists have known for almost a century that the universe is expanding, meaning the distance between galaxies across the universe is becoming ever more vast every second. But exactly how fast space is stretching, a value known as the Hubble constant, has remained stubbornly elusive. Several recent studies that point to a nagging discrepancy between modern expansion measurements and predictions based on the universe as it was more than 13 billion years ago, as measured by the European Space Agency’s Planck satellite.
This past April, with an event that was as epic as the Apollo 11 landing on the Moon, the world viewed its first image of what had once been purely theoretical, a black hole at the heart of galaxy M87 the size of our solar system, and bigger, with the mass of six and a half billion suns that was captured by a lens the size of planet Earth and 4,000 times more powerful than the Hubble Space Telescope.
“The Hubble tension between the early and late universe may be the most exciting development in cosmology in decades,” said lead researcher and Nobel laureate Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University, about new Hubble Space Telescope data that suggest a faster expansion rate in the modern universe than expected, based on how the universe appeared more than 13 billion years ago strengthening the case that new theories may be needed to explain the forces that have shaped the cosmos.
“I don’t know how anyone can see the Hubble ‘Deep Field’ image and not feel like something else is going about its business out there,” writes Tracy K. Smith, U.S. poet laureate, whose father was an engineer on the Hubble Space Telescope.