Experts think a big crash created the Moon!
Experts think a big crash created the Moon!

The Science of Our Moon

Learn some fun facts about Earth’s only natural satellite!

Some planets have many moons. Others don’t have any at all. Our Earth has just one. That’s why we call it simply “The Moon.”

Humans have been looking up at the Moon since, well, ever since there have been humans! And we’ve had a lot of questions about it. Fortunately, science has been able to answer many of them. Astronauts helped when they first landed on the Moon on July 20, 1969.

So, let’s answer three big questions about our Moon. We can start... at the beginning.

Where Did the Moon Come From?
Experts can’t be sure how the Earth got its satellite. No one was there to see it happen! But most scientists agree on the basic idea. They believe two planets smashed into each other about 4.5 billion years ago. One was the very young Earth. The other was a slightly smaller planet called Theia. The force of the crash broke off huge pieces of rocks, which later formed the Moon.

For a long time, people thought Theia hit just the edge of the Earth. A recent study says this is not true. “The Moon was formed by a violent, head-on collision between the early Earth and ... Theia,” wrote author Edward Young.

Moon rocks helped develop this idea. From 1969 to 1972, astronauts brought back 842 pounds (382 kg) of rocks and pebbles from the Moon. Scientists studied the chemicals from those rocks. Then they compared the results with rocks from Hawaii and Arizona. “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.

But what if Theia had missed Earth? “We may well have not had a Moon,” Young told News-O-Matic. “Venus, for example, is in many ways like Earth,” he explained. “Yet it does not have a moon.”

“It is fun to look up at the Moon,” added the scientist, “and realize it is there because of a giant impact between planets as they were forming.”

Why Does the Moon Have Craters and Dark Spots?
The Earth and Moon look very, very different. Why in the world is that? Well, there are a few reasons.

First of all, the Moon is covered in craters. Millions of asteroids and smaller meteorites caused them by crashing into the surface. When space rocks hit the Earth’s atmosphere, most of them burn up in the air. Our Moon doesn’t have an atmosphere. That means it isn’t protected. The Moon also 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 for billions of years.

The surface of the Moon is also covered with 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 published a paper about this from Cambridge, Massachusetts. She said it wasn’t a space rock slamming the surface. Instead, it was probably a huge volcano!

Zuber studied a giant dark area of the Moon called Oceanus Procellarum. She used data from a pair of spaceships, named GRAIL, which flew by the Moon in 2012. 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 told News-O-Matic that volcanoes flooded the Moon with lava. That happened about 4 billion years ago. “The volcanic 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 when we look up we can see only one side. Why? The answer is that the Moon rotates at the same speed that it rotates around the Earth! So, we always see the same side from our planet.

Some people call the other part the “dark side of the Moon.” But the truth is that there is no “dark” side. Both halves get the same amount of sunlight! Scientists call the two sides the “near side” and the “far side.” Watch the Video to see how that far side of the Moon looks as it passes in front of the Earth.

Updated July 18, 2019, 5:02 P.M. (ET)
By Russell Kahn (Russ)

Experts think a big crash created the Moon!
Experts think a big crash created the Moon!

Some planets have many moons. Others don’t have any at all. Our Earth has just one. That’s why we call it simply “The Moon.”

Humans have been looking up at the Moon since, well, ever since there have been humans! And we’ve had a lot of questions about it. Fortunately, science has been able to answer many of them. Astronauts helped when they first landed on the Moon on July 20, 1969.

So, let’s answer three big questions about our Moon. We can start... at the beginning.

Where Did the Moon Come From?
Experts can’t be sure how the Earth got its satellite. No one was there to see it happen! But most scientists agree on the basic idea. They believe two planets smashed into each other about 4.5 billion years ago. One was the very young Earth. The other was a slightly smaller planet called Theia. The force of the crash broke off huge pieces of rocks, which later formed the Moon.

For a long time, people thought Theia hit just the edge of the Earth. A recent study says this is not true. “The Moon was formed by a violent, head-on collision between the early Earth and ... Theia,” wrote author Edward Young.

Moon rocks helped develop this idea. From 1969 to 1972, astronauts brought back 842 pounds (382 kg) of rocks and pebbles from the Moon. Scientists studied the chemicals from those rocks. Then they compared the results with rocks from Hawaii and Arizona. “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.

But what if Theia had missed Earth? “We may well have not had a Moon,” Young told News-O-Matic. “Venus, for example, is in many ways like Earth,” he explained. “Yet it does not have a moon.”

“It is fun to look up at the Moon,” added the scientist, “and realize it is there because of a giant impact between planets as they were forming.”

Why Does the Moon Have Craters and Dark Spots?
The Earth and Moon look very, very different. Why in the world is that? Well, there are a few reasons.

First of all, the Moon is covered in craters. Millions of asteroids and smaller meteorites caused them by crashing into the surface. When space rocks hit the Earth’s atmosphere, most of them burn up in the air. Our Moon doesn’t have an atmosphere. That means it isn’t protected. The Moon also 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 for billions of years.

The surface of the Moon is also covered with 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 published a paper about this from Cambridge, Massachusetts. She said it wasn’t a space rock slamming the surface. Instead, it was probably a huge volcano!

Zuber studied a giant dark area of the Moon called Oceanus Procellarum. She used data from a pair of spaceships, named GRAIL, which flew by the Moon in 2012. 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 told News-O-Matic that volcanoes flooded the Moon with lava. That happened about 4 billion years ago. “The volcanic 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 when we look up we can see only one side. Why? The answer is that the Moon rotates at the same speed that it rotates around the Earth! So, we always see the same side from our planet.

Some people call the other part the “dark side of the Moon.” But the truth is that there is no “dark” side. Both halves get the same amount of sunlight! Scientists call the two sides the “near side” and the “far side.” Watch the Video to see how that far side of the Moon looks as it passes in front of the Earth.

Updated July 18, 2019, 5:02 P.M. (ET)
By Russell Kahn (Russ)

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