Download Fun Facts About the Moon Size and more Study notes Astrophysics in PDF only on Docsity! Fun Facts About the Moon Size: With a diameter of 2,159 miles (3,475 kilometers), the Moon is just 1/4 the size of Earth. Distance from Earth: The Moon's average distance from Earth is 238,000 miles (383,500 km). Orbit around Earth: It takes the Moon 27.3 Earth days to revolve around our planet one time. Rotation: The Moon spins on its axis once every 27.3 Earth days. Surface: The Moon's surface is covered with craters, mountain ranges, rilles (long narrow channels), and lava plains. The vast, dark regions we see on the Moon's surface are called maria, or seas. They are actually very large, smooth lava beds. The bright, light areas on the Moon's surface are called highlands. The Moon is covered with a solid, rocky crust about 500 miles (800 km) thick. Underneath the crust, scientists think there is a partially molten zone that leads to a small core of iron. Craters on the Moon come in a wide variety of sizes. The largest crater measures 1,600 miles (2,575 km) across, while the smallest is the size of a pinprick. Atmosphere: The Moon has no long-lasting, significant atmosphere, so the footprints left by Apollo astronauts will last a long time. Temperature: The mean daytime temperature is 225°F (107°C), while the mean nighttime tempera- ture is –243° (–153° C). Escape velocity: To escape the Moon's gravity, you need to travel 5,200 miles (8,400 km) per hour, compared to 25,000 miles (40,200 km) per hour necessary to escape Earth's gravity. Earth's gravity is six times greater than the Moon's. Other information: Roughly 842 pounds (382 kilograms) of Moon rock and soil were brought back to Earth aboard the Apollo spacecraft. Brief Explanation of the Moon Phases The Sun always illuminates the half of the Moon facing the Sun (except during lunar eclipses, when the Moon passes through the Earth's shadow). When the Sun and Moon are on opposite sides of the Earth, the Moon appears "full" to us, a bright, round disk. When the Moon is between the Earth and the Sun, it appears dark, a "new" Moon. In between, the moon's illuminated surface appears to grow (wax) to full, then decreases (wanes) to the next new Moon. The edge of the shadow (the terminator) is always curved, being an oblique view of a circle, giving the Moon its familiar crescent shape. New Moon Waxing Crescent First Quarter Waxing Gibbous Full Moon Waning Gibbous Last Quarter Waning Crescent Have you seen these lunar features?
