Why is the Moon important to the Earth?
The regular daily and monthly phases of the Earth's only satellite, the Moon, have guided farmers for thousands of years. Its effect on Earth's tides, has also been charted by many cultures down through the ages. 70 spacecraft have been sent to the Moon. 12 astronauts have been on its surface and brought back 842 pounds of lunar rocks and soil to our planet.
The presence of the Earth`s satellite stabilizes our planet`s wobble. This has helped the planet to have a much more stable climate over billions of years, which may have affected the development and growth of life on Earth.
How did it get here?
Where did this satellite come from? It is believed that a Mars-sized body once collided with Earth and the debris from both Earth and the impacting body accumulated to form the Moon. Scientists believe that it was formed approximately 4.5 billion years ago (the age of the oldest collected lunar rocks). When it was formed, its outer layers melted under very high temperatures, forming the lunar crust, probably from a magma ocean.
Man in the moon
On the Earth, we see the same side of the Moon all the time because it rotates just once on its own axis in the same time that it goes once around Earth. We call that synchronous rotation. Patterns of dark and light features on the nearside look like a "Man in the Moon". The lighter parts are highlands. The dark parts are called maria. These are impact basins that were filled with dark lava between 4 and 2.5 billion years ago.
After that, the Earth`s satellite cooled down, and hasn`t changed, except for a steady stream of hits by meteorites and comets. Its surface is charcoal gray, with fine soil. This blanket is called the lunar regolith, a term for debris layers on planetary surfaces. The regolith is thin, ranging from about 2 meters on the youngest maria to 20 meters on the oldest surfaces in the highlands.
Eathquakes on our satellite
Unlike Earth, this satellite of ours doesn`t have moving crust plates or volcanoes. However, seismometers placed by the Apollo astronauts in the 1970s have recorded small quakes at depths of several hundred kilometers. The quakes are probably triggered by tides produced by Earth's gravitational pull. Small eruptions of gas have also been reported. Local magnetic areas have been detected around craters.
A surprising discovery from the tracking of the Lunar Orbiter in the 1960s revealed strong areas of high gravitational acceleration on parts of the surface.
In 1998, the Lunar Prospector spacecraft team reported finding water ice at both poles. This is probably from Comet impacts.
We still Have a lot to learn about our own satellite. It still has plenty of mysteries to be revealed.
More Moon resourcesPhases of the MoonLunar eclipse pagethe origin of the MoonClick here to return to the top of the moon page