Free Astronomy Magazine September-October 2022

28 SEPTEMBER-OCTOBER 2022 ASTRO PUBLISHING A n international team of as- tronomers have used ground- based telescopes, including the European Southern Observa- tory’s Very Large Telescope (ESO’s VLT), to track Neptune’s atmos- pheric temperatures over a 17-year period. They found a surprising drop in Neptune’s global temperatures Surprising changes in Neptune’s temperatures by ESO - Bárbara Ferreira T his composite shows thermal images of Neptune taken between 2006 and 2020. The first three images (2006, 2009, 2018) were taken with the VISIR in- strument on ESO’s Very Large Telescope while the 2020 image was captured by the COMICS instrument on the Subaru Telescope (VISIR wasn’t in operation in mid-late 2020 because of the pandemic). After the planet’s gradual cooling, the south pole appears to have become dramatically warmer in the past few years, as shown by a bright spot at the bottom of Neptune in the images from 2018 and 2020. [ESO/M. Roman, NAOJ/Subaru/COMICS]