Where on our planet do the greatest temperature gradients exist – over a distance of less than a meter?
The surface temperatures of the smaller planets and most moons in our solar system can exhibit tremendous differences over very short distances. This is because these bodies have very tenuous atmospheres, which allow the surface to quickly heat up when illuminated by the Sun and to quickly cool down when the Sun disappears from view. The gravity of objects like Mercury and our moon, for example, is not strong enough to have held onto any atmosphere that may have existed eons earlier. On these worlds, the temperature on the sunlit side may be 250 degrees F on the moon and perhaps 750 degrees F on Mercury – too hot to be suitable for life-forms on Earth. In contrast, on the dark side of the Mercury or even in areas of shadow during the day, the temperatures can be more than 150 degrees below zero F – too cold for most all life-forms that exist on our planet. During the daytime on Mercury, if you were traversing a crater near the north pole, the temperature sensor on your spacesuit or you
