Astronomers use galaxy as a magnifying glass to see 12 billion years into the past
Astronomers have used the Atacama Large Millimeter/submillimeter Array (ALMA) in northern Chile to view a distant galaxy that looks a lot like our own Milky Way. While the galaxy doesn’t appear to have spiral arms like the Milky Way, it does feature a rotating disc and a cluster of stars packed around its center.
The array, one of the most expensive ground-based telescopes in operation, picked up light from a galaxy called SPT0418-47.
According to astronomers, the light from SPT0418-47 has taken more than 12 billion years to reach us, meaning what we are seeing now is a snapshot of what the galaxy and the universe looked like when it was just 1.4 billion years old.
Even with the most powerful telescopes we have, it is nearly impossible to see such distant galaxies as they appear small and faint. To get around this, the team used a nearby galaxy as a magnifying glass courtesy of an effect called gravitational lensing. With this technique, “the gravitational pull from the nearby galaxy distorts and bends the light from the distant galaxy, causing it to appear misshapen and magnified.”
The galaxy is surprisingly stable, too, which contradicts theories that virtually all galaxies were unstable and turbulent during the early days of the universe.
Simona Vegetti, a co-author on the research from the Max Planck Institute for Astrophysics, said the result “is quite unexpected and has important implications for how we think galaxies evolve.”