Page:The Music of the Spheres.djvu/274



MARS AND SATURN

Diameter—4230 miles

orbit of the little planet Mars, 141,000,000 miles from the sun, encompasses the orbits of Earth, Venus and Mercury, and forms the boundary line between the four inner planets and the planetoids or minor planets. Beyond the planetoids are the four great planets, Jupiter, Saturn, Uranus and Neptune.

The orbit of Mars is very eccentric, more eccentric, in fact, than any other planet in the solar system with the exception of Mercury. At its nearest approach to the earth's orbit it is only 35,000.000 miles away, while at its furthermost point it is distant 62,000.000 miles. The two planets, however, when at different points in their orbits, may be over 200,000,000 miles apart. This eccentricity in the orbit of our neighbor Mars causes it to differ in brightness as we see it shining as a star, for, although it is always large and beautiful, at its nearest approach to the earth it shines with more than tenfold the brilliancy of a first magnitude star. At such a time its fiery light attracts the attention of everyone. Such extreme increase in light can only occur in the months of August and September and then only about every fifteen years. This was a much heralded astronomical event of the year 1924, when the two planets were closer together than any other time during more than a hundred years. However, Mars was low in the sky and not in such a good position for observation as it will