Mars at Opposition

Tonight Mars is at opposition, a once-every-25-month event in which Earth passes between the Sun and Mars, and we observe Mars at its closest approach. The patterns of alignments of the Earth with different planets is a very cyclical event, every year or two depending upon the proximity of Earth to that planet.

The relative distance from Earth to Mars at each opposition is also something that is quite cyclical. You might recall in 2003 claims that the "Mars is going to be as big as the full Moon" during that year's very favorable opposition. In fact, the disk of Mars was never that big, but hype aside, Mars appeared quite large compared to any other time in recent history. In 2012, opposition brings us Mars as a bright orange star in the east shortly after sunset, traveling across our night sky from horizon to horizon. Although it is at the closest until 2014, it is just a small dot of color through most home-based telescopes. You will need considerable power to see the polar ice caps and other surface features (such as in the photograph). My friends in the San Francisco Amateur Astronomers (SFAA) club live for such moments, and if you can visit a local observatory or visit a star party this time of year, I am sure Mars will be one of the highlights.

The next time Mars nears the size of its famous 2003 opposition is in 2018. Until then, enjoy Mars however big or small it looks. It's a fascinating planet.

Photo by Mark Killion.