"Astronomers have stumbled across a serendipitous cosmic alignment: two galaxies, billions of light-years apart but perfectly in line as viewed from Earth so that they act like a compound lens, gravitationally bending light and magnifying a distant cosmic beacon behind them. Some of the light from the beacon—a luminous giant black hole known as a quasar—follows a zigzag path around the two galaxies.
Besides producing an unusual light show, this first known double lens will enable accurate readings of the expansion rate of the universe, known as the Hubble constant, the team reports in a preprint posted on arXiv on 8 November. “That’s the real power of these lensed quasars: to shine a light on whether the expansion rate of the universe is consistent with the cosmological model or not,” says cosmologist Thomas Collett of the University of Portsmouth."
-Daniel Clery
Add comment
Comments