Courtesy of EarthSky
A Clear Voice for Science
The waxing gibbous moon and planet Mars can be seen in the eastern sky at nightfall tonight.
These two worlds climb highest in the sky in mid to late evening and set in the west tomorrow before the onset of dawn. You can see the moon and Mars close together on our sky’s dome for most of the night tonight.
The moon and Mars aren’t really close together in space. They only appear to be close, because they reside along the same line of sight. The moon, our closest neighbor in space, lies about 360,000 kilometers – or 224,000 miles – distant tonight. Meanwhile, Mars moves through space at more than 300 times the moon’s distance.
Earth passed between the sun and Mars about a month ago, as we do about every two years. Therefore, Earth and Mars are still relatively close together. That is why Mars still shines as brightly as the sky’s brightest stars. However, that will change in the months ahead as our planet Earth in its smaller, faster orbit around the sun leaves Mars trailing behind. Three months from now, Mars will be twice as far from Earth as it is tonight. By the end of the year, Mars will have retreated to the far side of the sun, at more than three times tonight’s distance.
As our planet continues to pull away from Mars, this reddish world will continue to dim in our sky throughout the year 2010. So, enjoy Mars tonight while it is still in its moment of glory. It will be less noticeable as the months pass.
Written by Bruce McClure
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