Many people listen to the weather report on the radio before they head out the door in the morning so they can be prepared for the day to come. "We don't know how long the Dagwood-sandwich structure would exist. This structure represents a stable state, but various factors could mean the moon doesn't reach this stable state," Dr. Christophe Sotin said in a May 1, 2014 statement. Dr. Sotin is of the JPL. Astronomers have known for years that the temperatures of the lunar near-side are higher than those on the far-side. This is because the abundances of the heat- producing elements uranium and thorium are greater on the near-side than on the far-side. In addition, these higher temperatures are a consequence of the fact that most of the volcanic eruptions occurred on the lunar near-side.