Very Large Telescope finds Neptune warmest at south pole

William Atkins
Monday, 15 October 2007 00:25

Science - Space

Because it was found that Neptune is about ten degrees warmer—about -310 degree Fahrenheit [-190 degrees Celsius])—at the south pole than all other places on the planet, a big question has been solved: Why is there methane in the stratosphere?          

The temperature difference between the south pole and the rest of the planet is due to the fact that Neptune’s south pole is tilted toward the Sun—thus, allowing it to receive sunlight all of the time. The temperature difference also makes for some of the highest-velocity winds in the solar system—some reaching 1,240 miles (2,000 kilometers) per hour.

Thus, the south pole is warm enough for gaseous methane to climb from the lower to higher atmosphere, at least according to the first map that has been made of Neptune’s lower atmosphere with respect to temperature.

The average temperature was found by researchers using the Very Large Telescope, at the Southern Observatory in Paranal, Chile. The average temperature on Neptune is -328 degree Fahrenheit (-200 degrees Celsius).

The results of this first temperature map of the planet Neptune apears in the September 18, 2007 issue of Astronomy & Astrophysics.