Summer is well under way in the southern half of Neptune’s largest moon, but this means that the air is full of methane (natural gas) and the temperature is a nightmarish -235°C.

Scientists using the Very Large Telescope (VLT) at the European Southern Observatory (ESO) have carried out the first ever infrared analysis of the atmosphere on Triton. They found that Triton has seasons just like Earth, but they change much more slowly. Since Neptune takes 165 years to orbit the sun, a season on Triton lasts for just over 40 years.

Most of Triton’s atmosphere is made up of nitrogen, just like here on Earth. The methane and carbon monoxide that is present are also very important for the conditions on Triton.

These are the best measurements of Triton’s atmosphere since the Voyager 2 probe flew past it in 1989.