Muni Barash, age 12, of Pittsburgh, Penna., for the question:

Do the planets travel side by side?

No, the planets do not travel side by side around the sun. Little Mercury makes three trips around the sun while the earth is making one trip. Venus makes a complete trip around its orbit in 225 days. And the earth makes almost two yearly trips while Mars is making one. Jupiter's yearly trip around its orbit takes 12 earth years and SaturnIs year is equal to 29 earth years.

There is little, but not much, difference in the speed at which the planets travel their orbits. The vast difference is in the size of the orbit's, the distance each planet must travel to complete its yearly journey. The orbit of Mercury is 72 million miles wide, the orbit of Venus' about 134 million miles wide. Earthts orbit is about 186 million miles wide and the orbit of Saturn is over 17,000 million miles wide. No wonder the earth can make 29 trips around its orbit while Saturn is malting only one.