It’s spring here in the Great Plains, and that means the temperature can swing from snowboot weather to shorts weather in 24 hours, with a dash of tornado in between. The chaos we see here, however, may be the normal outrage of a planet having to change seasons. A new analysis of Neptune shows: The ice giant’s global temperature dropped about 8 degrees Celsius between 2003 and 2012 at the start of Neptune’s summer… Then from 2018 to 2020, thermal images show that the planet’s south pole brightened dramatically, indicating a spike of 11 degrees C.

With its giant orbit, Neptune spends 165 years orbiting the Sun, and the span of years from 2003 to 2020 is the equivalent of about five weeks on Earth. Let’s call it “June”.

This is one of those stories where I have to admit, I read the papers and wonder why our life lessons from Earth aren’t applied to our expectations of other worlds. As the first author of the related paper in Planetary Science Journal, Naomi Rowe-Gurney, points out: We weren’t expecting any seasonal changes to happen in this short time period, because we’re not even seeing a full season. It’s all very strange and interesting.

As Neptune continues to orbit, we’ll get to watch the world settle into summer. Rowe-Gurney comments: We need to keep observing over the next 20 years to see a full season and see if something else changes. 

And then we’ll need 1,000 years or so to see how weird or not. That particular summer was in comparison to a Neptunian lifetime of summers.

More Information

New thermal maps of Neptune reveal surprising temperature swings (Science News)

“Subseasonal Variation in Neptune’s Mid-infrared Emission,” Michael T. Roman et al., 2022 April 11, The Planetary Science Journal