Peering through the cosmic dust and gas that shroud our galaxy, astronomers have crafted the most detailed infrared map of the Milky Way ever created, revealing a staggering 1.5 billion celestial objects. This monumental achievement, built upon 13 years of observations spanning 420 nights, provides an unparalleled glimpse into the vast and dynamic nature of our galactic home.
The map, a tapestry woven from 200,000 images captured by the European Southern Observatory’s (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) in Chile, showcases a diverse array of celestial bodies. Among these are countless stars, enigmatic brown dwarfs – celestial objects that fall between planets and stars – and free-floating planets, cast adrift in the vast expanse of space. Adding to this cosmic menagerie are hypervelocity stars, catapulted into interstellar space after encounters with the supermassive black hole at the heart of our galaxy.
To construct this groundbreaking map, astronomers employed the VISTA InfraRed CAMera (VIRCAM), an infrared instrument that pierces the obscuring veil of dust and gas, unveiling the infrared glow emanating from previously undetected sources. This allowed the telescope to discern the faint infrared light emanating from ‘failed stars,’ also known as brown dwarfs, as well as rogue planets, over hundreds of nights between 2010 and 2023.
The team’s meticulous approach extended beyond simply capturing images. By repeatedly observing the same regions of the sky, they were able to track the movement and brightness changes of objects over time. This painstaking process yielded a dataset of staggering proportions, covering an area of sky equivalent to the width of 8600 full moons and containing roughly ten times the number of objects than a previous map released by the same team in 2012.
This extraordinary map is a testament to the relentless pursuit of astronomical knowledge. As the team embarks on further exploration, they eagerly anticipate upgrades to VISTA and ESO’s Very Large Telescope, which will allow them to break incoming light into its component spectra. This will provide invaluable insights into the chemical composition of the newly discovered objects, enriching our understanding of the Milky Way and its inhabitants.
