Richard Larkin, age 8, of Coventry, R.I., for his question:

WHICH PLANET WAS DISCOVERED FIRST?

The cave men lived long ages ago, but no doubt they loved to gaze at the starry sky just as we do. Sometimes they saw golden Venus or the red planet Mars. Sometimes they saw giant Jupiter and Saturn, though they never saw Saturn's rings. For thousands of years, they thought that the planets were strange wandering stars. But they knew four of them and gave them names. These planets can be seen without a telescope  and all four were discovered before the dawn of history.

Little Mercury is very close to the sun, but sometimes it also may be seen. About 400 years ago, wise men figured out that the planets orbit around the sun. Then they knew that the earth must be added to the list of planets. The last three planets cannot be seen without a telescope, so they had to wait for one to be invented. Then Uranus was discovered and later Neptune. Little Pluto is far from the sun. It was not discovered until 1930.