Astronomers from the University of Leicester have discovered mysterious changes in the temperature of ice giant Neptune, the solar system's most distant planet.

Based on observations covering the past 17 years the scientists detected a consistent drop in the planet's temperature which has suddenly been interrupted by dramatic warming at its south pole.

Thermal-infrared images taken between 2003 and 2018 show the planet cooling by about eight degrees Celsius - until, at the end of that cycle, the temperature at its south pole shot up by about 11 degrees Celsius.