Like Earth, Neptune experiences seasons orbiting the sun. However, a Neptune season lasts about 40 years, and one year equals 165 Earth years. Neptune has been in the southern hemisphere since 2005, and astronomers have been eager to study temperature changes since the southern summer solstice.
- Neptune's moon dance In their orbit around the planet
they examined nearly 100 infrared thermal images of Neptune taken over a 17-year period with the help of telescopes, including the European Large Telescope (VLT). To put together the general trends of the planet's temperature in more detail than ever. These data show that despite the onset of summer in the Southern Hemisphere, most of the planet has gradually cooled over the past two decades. Neptune's average global temperature dropped by 8 degrees Celsius between 2003 and 2018.
Photos of Neptune between 2006 and 2020
Credit: ESO/M. Roman, NAOJ/Subaru/COMICS
Scientists were further surprised to discover the dramatic warming of Neptune's Antarctic during the last two years of their observatory. These data show an increase of 11 degrees Celsius from 2018 to 2020. Although Neptune's hot polar vortex has been known for years, this rapid warming has never been seen on the planet. "Our data cover less than half of Neptune's season, so no one expected to see big, rapid changes," he said.
They emit infrared light from a layer of Joe Neptune explored the stratosphere. This allowed the team to take a picture of Neptune's temperature and its changes over part of the planet's southern summer.
Neptune changes in infrared spectrum as a measure of
Credit: Michael Roman/NASA/JPL/Voyager-ISS/Justin Cowart.
About one-third of all images taken by the VLT Illustrator and VSIR are on the Atacama Desert in Chile. Due to the size of the mirror and the height, this telescope has a very high resolution and data quality and provides the clearest images of Neptune. The team also used data from NASA's Spitzer Space Telescope and images taken with the Southern Jamna Telescope in Chile, as well as the Subaru Telescope, the Coke Telescope and the North Jamna Telescope in Hawaii.
Neptune geometry and its face in the visible and infrared
spectrum in 2020; Antarctic warming is well known.
Credit: Michael Roman/NASA/ESA/STSci/M.H. Wong/L.A. Sromovsky/P.M. Fry
Because Neptune's temperature changes were so unexpected, astronomers still do not know what could have caused it. They could be due to chemical changes in Neptune's stratospheric chemistry or random patterns in the weather or even the solar cycle. Future ground-based telescopes, such as the Ultra-Large Telescope (ELT), can monitor temperature changes in more detail. The James Webb spacecraft will also present new unprecedented maps of Neptune's chemistry and atmosphere. "All of this points to a more complex picture of the planet's atmosphere and how it has changed over time." Gill