By Jim Haklar
The night sky is always changing. The Moon goes through its cycle of waxing and waning. Patterns of stars called constellations come and go with the seasons. Planets move through the night sky as well. Sometimes, a planet or the Moon will appear to come close to another planet or star. The point at which they appear to be at their closest is called a conjunction. In reality, the two objects that are in conjunction are usually far apart. Even though conjunctions are optical illusions, they are still pretty to look at.
In October the planet Mars passed close to the star called Regulus. Often referred to as the heart of the Lion, Regulus is one of the brightest starts in the sky and is the brightest star in the constellation of Leo. While it may have looked like Mars and Regulus were close, they were in fact very far apart. Regulus is so far away that its light takes over 70 years to reach the Earth (and light travels at 186,000 miles a second).
Anybody that likes to look up at the night sky should try to see a conjunction. They are fairly common, and yearly publications such as the Old Farmer’s Almanac provide the dates that conjunctions happen. And don’t worry if you miss a conjunction on a certain date. Heavenly bodies such as planets move relatively slowly, so there will still be a nice view for several days befo
re and after the actual conjunction.
About the Author: Jim is an environmental engineer at the EPA’s Edison, New Jersey Environmental Center. In his 28 years with the agency he has worked in a variety of programs including Superfund, Water Management, Public Affairs, and Toxic Substances. He has been an amateur astronomer since he was a teenager, and can often be found after work in the back of the Edison facility with his telescope.