Clockwork Planets

by Tammy Plotner on August 13, 2010

Bottoms up! Mercury, Moon, Saturn, Venus, Mars...

While the Perseid meteor shower has been putting on quite a show, there’s an awesome “no telescope needed” eye-catching apparition that only requires a clear western skyline. If you haven’t been watching the planets – Mercury, Saturn, Venus and Mars – line up like clockwork, then don’t despair. You have a few more days yet!

While the uniformed all-too-often see “signs of bad portent” in a planetary alignment, the rest of us know this is a perfectly normal function of our solar system called a conjunction. This is a simple positional alignment as seen (usually from Earth’s viewpoint) from any given vantage point. The world isn’t going to end, the oceans aren’t going to rise… and Mars is darn-sure not going to be the size of the Moon. All alignments of at least two celestial bodies are merely coincidental and we even have a grand name for what’s happening – an appulse.

When planets are involved, their near appearance usually happens in the same right ascension. They really aren’t any closer to each other than what their orbital path dictates – it just appears that way. In the same respect, there is also conjunction in ecliptical longitude. But, if the planet nearer the Earth should happen to pass in front of another planet during a conjunction it’s called a syzygy!

One thing is for sure… You don’t have to be a syzy-genius to simply enjoy the show and the predictable movements of our solar system. Just find an open western skyline and watch as twilight deepens. Tonight the Moon will be directly south of Venus and over the next couple of days the planetary alignment will gradually separate as brilliant Venus seems to hold its position, while Mars, Saturn and Mercury drift north. Enjoy the show! Because just like the yearly Mars/Moon Myth?

It happens like clockwork…

Many, many thanks to the incredible Shevill Mathers for providing us with this breathtaking photo. (Do you know just how hard it is to get a shot like that without over or under exposing? I dare you to try it…) Every fox has a silver lining!


Tammy is a professional astronomy author, President Emeritus of Warren Rupp Observatory and retired Astronomical League Executive Secretary. She’s received a vast number of astronomy achievement and observing awards, including the Great Lakes Astronomy Achievement Award, RG Wright Service Award and the first woman astronomer to achieve Comet Hunter's Gold Status.

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