VLT’s lasers firing off into the night sky above the Atacama desert

This photograph captures the Unit Telescope 4 of ESO’s Very Large Telescope, located in Chile’s Atacama Desert, and its four-laser system which is used to excite sodium atoms in the atmosphere. When sodium atoms are excited, they emit light that the VLT can pick up and use to correct for the effect that our atmosphere has on starlight as it passes through. It’s this advanced system (called “adaptive optics”), combined with the excellent dark conditions of the Atacama desert, that allows the VLT to obtain extremely sharp images of the Universe.