Sunday, July 29, 2018

Mars at opposition, July 29, 2018

Mars is currently at opposition. That means - well, for simplicity's sake, imagine that the Earth is the center of the solar system, and the Sun and planets go around it. At opposition the Sun and the thing in opposition - in this case, Mars - are directly opposite each other in Earth's sky. From a practical point of view, this means we are as close (or nearly as close, orbital mechanics can be complicated) to Mars as we will be during our current orbit around the Sun. This isn't a record-close opposition, so Mars isn't as big or as bright as it has been at other times, and certainly isn't the size of the Full Moon, despite what internet hoaxes passed along by pranksters and well-meaning dupes will tell you. Actually, the just-past-Full Moon dims the light of Mars a bit, as it lights up haze in the atmosphere and makes the sky brighter than it would be otherwise. Still, it's worth going out to view, now and for the next few nights. Mars will be the bright red thing in the south, not quite halfway up the sky. It will fade rapidly as we leave it behind in our own trip around the sun. So catch it while you can!

Mars showing true color. Bigger than actual size due to brightness.

Mars, actual size at 42x magnification. (Dim in upper center. You may need to click to see the full-sized version to actually see it.) Compare to these images of the Moon and Jupiter at the same magnification.

Same image, brightness and contrast enhanced.

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