October 12, 2012
What is the Moon?
Hi I’m Emerald Robinson. In this “What Is” video we’ll take a look at the Earth’s only natural satellite, the Moon.
The Moon is called “The Moon” simply because nobody knew that any other moon existed until Galileo discovered Jupiter’s moons in 1610.
The Moon is the fifth largest planetary satellite in the solar system, with a diameter of 2159 miles; it’s roughly one-fourth the diameter of Earth. The Moon’s gravity is 1/6 of Earth’s, so if you weigh 120 lbs. on Earth, you would only weigh 20 lbs. on the Moon.
The Moon is nearly 239,000 miles away, close enough that its gravitational force influences the Earth’s tides.
The Moon rotates on its axis once for every orbit it makes around the Earth every 27.3 days. This means the same side of the Moon always faces the Earth.
Craters caused by impacts cover the landscape of the Moon. But the dark, solid areas of the Moon are flat regions of cooled lava from volcanic activity that stopped about 1.2 billion years ago. Those areas, called Maria, cover 16% of the Moon.
Earth’s Moon is widely believed to have formed when a Mars-sized object collided with the Earth over 4.5 billion years ago. The impact was so catastrophic that debris was kicked into orbit around earth, which led to the formation on the Moon.
The moon is the only object man has visited beyond Earth.