The Moon has no atmosphere and no liquid water at its surface, so it has nowind or weather at all. On the lunar surface, there is no protection from the Sun’srays, and no ability to retain heat like the greenhouse effect on Earth. Temperatureson the moon range from about 253 degrees Fahrenheit (123 degrees Celsius) to–387 degrees Fahrenheit (–233 degrees Celsius). The Moon’s surface is covered withrocks, mountains, craters, and vast low plains called maria (“seas”).What is theMoon made of?Though the full Moon sometimes looks very much like a wheel of bleu or Stiltoncheese, it is actually covered with rocks, boulders, craters, and a layer of charcoal-colored soil. The charcoal-colored soil consists primarily of pulverized rocky andglassy fragments, and is up to several meters deep. Two main types of rock havebeen found on the moon: basalt, which is hardened lava, and breccia, which is soiland rock fragments that have melted together. Elements found in moon rocksinclude aluminum, calcium, iron, magnesium, titanium, potassium, and phospho-rus. Unlike iron-rich Earth, the Moon appears not to have much metallic content.Howfar awayis theMoon?On average, the Moon is about 238,000 miles (384,000 kilometers) away fromEarth. This value was measured quite accurately by the ancient Greek astronomerHipparchus, who lived in the second centuryB.C.E. Today, laser rangefinders havebeen used to measure a very precise value.Howwas ourMoon formed?The formation of the Moon was a great scientific mystery for many years. It was oncethought that Earth and the Moon might have formed simultaneously as two separateobjects, bound together by their mutual gravitational pull. This was shown to beunlikely after scientists proved that the two objects have very different compositions.Another idea suggested that Earth’s Moon formed elsewhere, and was later capturedinto Earth’s orbit as it went by Earth’s gravitational influence. The major problemwith this scenario is that Earth and the Moon are relatively close in size; gravitation-al capture is very, very unlikely, unless one object is many times larger than the other.Within the past few decades, scientists have shown that the most likely scenarioof how the Moon formed involves the collision of two planetary bodies. Billions of178How much would I weigh on the Moon?The gravitational acceleration at the surface of the Moon is about one-sixththat of Earth. So if you weigh 150 pounds on Earth, you would weigh just25 pounds on the Moon. Your mass, on the other hand, would remain un-changed whether you were on Earth or on the Moon.
