We have always been interested in the Moon. 2,000 years ago, people already knew it moves around the Earth and where it would be in the sky at different times of the year.
When scientists could use telescopes to study the Moon more closely, their ideas began to change. They could see the Moon was made of rocks. And they believed the Moon had once been a planet. It was caught in Earth's gravity millions of years ago.
In 1969, Moon rocks were finally brought to the Earth by astronauts. To their surprise, scientists found that the Moon and the Earth are made of the same things except for water.
After years of study, some scientists think that the Moon was once part of the Earth. They believe maybe 4 million years ago, something hit the Earth. These rocks slowly joined together and after many years became the Moon.
In the future, even though our ideas about the Moon may change again, we will still be interested in it.
| A. They thought Moon rocks would be different from those on Earth. B. This sent billions of rocks into space around our planet. C. Then the rocks were studied by scientists. D. But everything about it was learnt by watching it carefully at that time. E. So more scientific research was done for the information. |
