Daniel Pope

Have you noticed bright reddish-orange Mars appearing above our northeastern horizon about mid-evening? It is by far the brightest point of light in that part of the sky. It really is getting brighter each night because we are catching up with Mars and getting closer.

It is not your imagination. It will continue to get brighter each night until the end of the month and then it will start to slowly fade. At present we are about 66,430,000 miles from Mars. We are moving at about 67,000 mph while Mars is moving at about 53,700 mph. By the end of the month we will have reached our closest point for this two-year cycle and be about 61,750,000 miles away. At that time we will be passing Mars from our inside orbit. Mars is fascinating because, of all the planets, it is most Earth like. It has a solid surface, polar caps, deserts, dust storms, dark areas like continents, a 24.6 hour day, a North/South axis tilted at about 25 degrees, and a diameter about half that of Earth’s. Missing are the oceans.

Giovanni Schiaparelli (1835-1910), a professional astronomer, observed Mars for several years. With a new telescope he created a new and detailed map of Mars. In his description he used the word canali which can be translated as channels or canals. We tend to think of channels as occurring naturally while we think of canals as constructed and on Earth that would be by humans.

Apparently the translation that made it to Percival Lowell (1855-1916) was canals. In 1894 Lowell built a telescope in Flagstaff, Ariz. that was much larger than Schiaparelli’s in order to study these canals. Lowell believed that he could see canals constructed by a Martian civilization to preserve the water that was left on Mars.

Over the years he thought he could see additional canals being constructed. Lowell wrote a book in 1895 about his observations and theories about Mars. He studied Mars for about 20 years publishing reports on what he had observed and he gained a great deal of notoriety. The science fiction writer, H.G. Wells, read Lowell’s book and reports and in 1898 wrote “The War of the Worlds.” Perhaps you have heard about the radio adaptation by Orson Welles which was broadcast as a Halloween special on Oct. 30, 1938, that caused quite a scare around the country. It is said that some people really thought that the Martians had landed and invaded Earth.

Since the beginning of time humans have wanted to be able to predict future events. Similarly, the ancients wanted to be able to predict the position of a planet for any time in the future. They observed that each planet traveled varying distances in fixed amounts of time. From this they knew that the planets were not moving at constant speeds. They also observed that the planets appeared bigger and brighter at times, meaning closer to Earth, while smaller and dimmer at other times, meaning farther away. The ancients had also observed and recorded the apparent retrograde or backward motion of the planets. With Mars we are witnessing the planet appearing bigger, brighter, and displaying an apparent retrograde motion.

The fact that the planets do not move at constant speeds and do not remain at constant distances and display an apparent retrograde motion made it difficult to predict future positions. Creating a model was made even more difficult by the fact that the ancients were assuming that 1) the Earth was at the center of the universe, 2) the Earth was stationary, and 3) the planets moved in perfect circles and therefore at constant speeds and distances from a center.

Ptolemy (85-165) using his own observations and data from earlier times is credited with being the first person to create a greatly improved and detailed mathematical model that accurately predicted the movements of the planets. It consisted of multiple circles of various sizes with offset centers in motion about an Earth that did not move. While the model did demonstrate the apparent retrograde motion of the planets it was cumbersome and complicated. Ptolemy’s was the accepted model for nearly 1,500 years. There are those who think that Ptolemy might not have believed that the planets actually moved as depicted in his model; rather he was simply concerned with accurately predicting the position of a planet in the future.

Others, even prior to Ptolemy’s time, had suggested that all the planets orbited the Sun but none of them produced an actual mathematical model that could be used to accurately predict the future position of a planet. That was the main reason Ptolemy’s model was the prevailing model until the mid 1600’s.

Next week we will write about Johannes Kepler (1571-1630) and his model of our Solar System that replaced Ptolemy’s that had stood for 1,500 years. What a feat!

Clear skies.