(Agencies)
Updated: 2007-11-12 20:33

At the beginning of the year, Mars was 221 million miles (356 million kilometers) from Earth. This week, it will be 63 million miles (102 million kilometers) away and it now shines some 10 times brighter than it did on New Year's Day.

Since January 1, Mars has progressed more than halfway around our sky and now is on an easterly course through the background stars of the Zodiac. It currently is in the center of the constellation of Gemini, the Twins.

But on Thursday, November 15, that steady eastward course is going to come to a stop.

Actually, for the past few weeks, Mars has appeared to slow in its eastward trajectory as seen from Earth. It seems to waver, as if it had become uncertain. Finally, on November 15, it will pause and come to a halt.

Then, for about the next 11 weeks, the "wandering star," as ancients called it, will reverse its course in the heavens and move backward against the star background - toward the west. Then, on January 30, 2008, it will pause again, before resuming its normal eastward direction.

All the planets exhibit this "retrograde motion" at one time or another. But for the longest time, the ancient astronomers were unable to come up with a satisfactory explanation for it. For one thing, while behaving in this strange manner, Mars will also appear to deviate somewhat from its normal course; the retrograde motion will appear to bring it a little above its regular orbital track. In other words, for those of us watching from Earth, Mars will appear to travel in a loop.