THE WOODLANDS, Tex. -- Mercury is a world of extremes. Daytime temperature on the planet closest to the sun can soar as high as 400 degrees Celsius near the equator, hot enough to melt lead. When day turns to night, the planet's surface temperature plunges to below -150 degrees C.
But some places on Mercury are slightly more stable. Inside polar craters on the diminutive planet are regions that never see the light of day, shaded as they are by their crater rims. The temperature there remains cold throughout the Mercury day -- and during the Mercury year. Now … Read more