As an International Dark Sky Community, Fountain Hills is blessed with darker skies than the Phoenix metro area. The Fountain Hills Library has an award-winning telescope lending program and Ted Blank, NASA Solar System Ambassador, leads the robust Fountain Hills Astronomy Club.
This week, you can see a special treat in the early night sky without a telescope. Look toward the west shortly after sunset and you will see the planet Mercury. It is the most difficult of the five brightest naked-eye planets to see, but you can clearly see it this week. Because it the closest to the Sun, it never wanders very far from the Sun in our sky, leaving us with brief opportunities for viewing it.
Mercury is the smallest of our eight planets, only slightly larger than our Moon. Although Mercury’s year is only 88 days long, one day on the hot planet lasts for 59 Earth days.
The surface of Mercury resembles our Moon with numerous impact craters. On its sunny side, it can ready a scorching 800 degrees Fahrenheit (although Venus is hotter). But on its dark side, temperatures can drop to 300 degrees below zero because there is almost no atmosphere to hold in the heat.
The Mariner 10 spacecraft flew by the planet in 1974 and 1975 and photographed less than half of its surface. Over 30 years passed before we explored it again. NASA’S MESSENGER flew by in 2008 and 2009. In 2011, it began its orbit of Mercury, mapping and taking pictures of the surface rocks and measuring heights of mountains and depths of craters and valleys.
The earliest known recorded observations of Mercury were made by an Assyrian astronomer in the 14th century BCE and referred to it as “the jumping planet”. It was the Romans who named the planet after the swift-footed Roman messenger god, Mercury.