• Question: How cold is Neptune?

    Asked by Lottie_C_DJS to Stephen on 14 Mar 2017.
    • Photo: Stephen Pulker

      Stephen Pulker answered on 14 Mar 2017:

      Neptune is about 2.7 billion miles away from Earth (2,700,000,000); you would have to drive from London to Edinburgh 8.4 million times to cover the same distance; in a car traveling at 70 mph (motorway speed) it would take you 4,400 years to make the journey; it takes light approximately 4hrs !!! So Neptune is verrrry far away. As such it is verrrry cold . . . at the surface it is estimated to be -220 degrees Celsius (only about 50 degrees Celsius above the absolute lowest possible temperature -273.15 degrees Celsius). However, due to its immense size and the immense pressures that will exist within it, near the core this temperature will rise to about +7000 degrees Celsius. So how hot or cold you felt would depend on where you were in the atmosphere.