Some planets have many moons. Others don’t have any. Our Earth has only one. That’s why we call it just “The Moon.”
Humans have had a lot of questions about our . Fortunately, science has helped to answer them. Astronauts also helped when they landed on the Moon in 1969. So, let’s start... at the beginning.
Where Did the Moon Come From?
Most scientists agree. They believe two planets smashed into each other about 4.5 billion years ago. One was the very young Earth. The other was a smaller planet called Theia. The force of the crash broke off huge pieces of rocks. And those later formed the Moon.
For a long time, people thought Theia just hit the edge of the Earth. A recent study says this is not true. Edward Young was the author. “The Moon was formed by a violent, head-on between the early Earth and ... Theia,” he wrote.
Astronauts brought back rocks and pebbles from the Moon. Scientists studied the from those rocks. Then they compared the results with rocks on Earth. “We don’t see any difference,” explained Young. That proved to him that Earth and the Moon came from the same object — caused by a direct hit.
What if Theia had missed Earth? “We may well have not had a Moon,” Young said.
Why Does the Moon Have Craters and Dark Spots?
The Moon is covered in craters. Asteroids and meteorites caused them by crashing into the surface. When space rocks hit the Earth’s atmosphere, most burn up. Our Moon doesn’t have an atmosphere. Also, the Moon isn’t very active, so volcanoes don’t cover up the craters. Plus, there is no weather to wear them down. So the craters can stay intact.
The Moon also has huge dark areas. Many people think they see a face of a man in the shapes. For years, scientists thought an asteroid had created the “man in the Moon.” Scientist Maria Zuber studies this from Cambridge, Massachusetts. She said it wasn’t a space rock. Instead, it was probably a huge volcano!
Zuber studied a giant dark region of the Moon called Oceanus Procellarum. She used data from a pair of spaceships. Zuber noticed that the dark area was not the right shape for an asteroid crash. If an asteroid hit the Moon, it would make a crater in the shape of a circle. But the area’s shape was a rectangle!
Zuber said volcanoes flooded the Moon with lava. This happened about 4 billion years ago. “The flooding occurred due to a large plume beneath the Moon,” she explained. A plume is a glob of liquid rock inside the Earth or a moon.
Why Do We See Only One Side of the Moon?
The Moon rotates, or turns, as it flies around the Earth. Yet we can see only one side. Why? The Moon rotates at the same speed that it rotates around the Earth! So, we always see the same side from our planet.
There is no “dark” side of the Moon. Both halves get the same sunlight! Scientists call the two sides the “near side” and the “far side.” The Video shows the far side of the Moon!
Updated July 18, 2019, 5:01 P.M. (ET)
By Russell Kahn (Russ)
