Jean Pinegar, age 10, of Des Moines, Iowa, for her question:

WHICH PLANET WAS MADE FIRST?

Naturally, no human reporter was there to take notes when the planets were created. But as far as possible modern scientists have traced back the fabulous story to the very beginning. The nine planets and their moons are members of the sun’s family. Most experts agree that this entire solar system was created at the same time, almost 5 billion years ago.

Nobody can prove all the details. But scientists have gathered enough evidence to make an educated guess—which is called a theory. They tell us that the evidence suggests that all the planets were formed together. This would mean that giant Jupiter is no older than little Mercury. All are the same age as the sun.

Some of the faraway stars are much older than the sun and its family. They were there more than 5 billion years ago, when our part of the heavens was dark and empty. At that time, our region was occupied by nothing more than an enormous dusty cloud. Then, perhaps about 5 billion years ago, the mysterious forces of creation began to shape that shapeless cloud. It shrank and became a huge saucer. The saucer began to spin and never stopped spinning.

After 100 million years or so, most of the dusty gases had concentrated in the center. This was the dark, unborn sun. Nine or 10 bands of dust formed bull’s eye rings circling around the center. These were the unborn planets.

Gradually the dusty debris clogged together and most of the material in our circle merged to form a round ball. This baby world was 2,000 times wider than the modern earth and 500 times heavier. The same thing happened to mold the other rings into round planets. Gradually the materials packed closer together. The big baby planets shrank—and so did the big baby sun.

The young sun and its planets were spinning around. Each planet was in orbit at its own speed and at its proper distance from the sun.. All this part of the story happened in total darkness under the black starry sky. Then at last the sun started up its mighty nuclear furnace. At last its warmth and dazzling daylight were shed upon the whirling planets. Most likely this theory explains how the Solar System really began. If this is so, then all the planets were formed together.  

Nobody is certain how the earth got its golden moon. But most experts think that it was formed from the same dusty ring. Maybe the earth and its moon grew side by side. Maybe at first they were far apart and later the earth came close enough to capture the moon.