People who move to Southwest Florida from up north often say that they miss the changing of the seasons because weather here is always the same.
Meteorologically speaking, however, Southwest Florida has two distinct seasons: The dry season, which runs from Nov. 1 through May 31, and the rainy season, June 1 through Oct. 31.
Obviously, the defining characteristic of the rainy season is rain, and rain means clouds, and clouds mean bad news for astronomers because we don’t want to haul our telescopes outside or open our home observatories to look at overcast skies.
But not every night during the rainy season is cloudy and overcast skies can have breaks. If you want to continue observing during our least astronomy-friendly five months, keep a pair of binoculars handy and seek out these upcoming celestial targets:
• The Hercules Cluster (M13). This is one of the most spectacular of the 160 known globular clusters. Located in the constellation Hercules, it’s 25,000 light years from Earth and made up of 100,000 closely packed stars. In addition to being great binocular targets, globular clusters are fascinating objects. In a sky full of stars, they are the movie stars, and they’re very old – 12 to 13 billion years old, compared to Earth’s 4.5 billion years. You can imagine one globular cluster saying to another, “We can remember when Earth was a whippersnapper.”
• The Great Pegasus Cluster (M15). Another globular cluster, M15, is 33,600 light years from Earth and contains more than 100,000 stars. M15 is in the constellation Pegasus and rises after midnight during early July. Starting July 10, it rises just after sunrise and is visible all night through October.
Even if you don’t own a pair of binoculars, July has some interesting naked-eye night sky events:
• Conjunction of Venus and Mars. Beginning just after sunset at the end of June, Mars started to slowly catch up to Venus low in the western sky until the planets will be a mere 0.5 degrees apart on July 13. As a bonus, a waxing crescent moon will be just to the east of Venus and Mars.
Finally, for folks who like air-conditioned comfort with their astronomy, The Bishop will present a new show called “15: Mission of Discovery,” celebrating the 50th anniversary of the Apollo 15 mission July 21 through Aug. 15 in The Planetarium.
When people think of the Apollo program, they tend to remember Apollo 11 (the first moon landing) and Apollo 13 (the “successful failure”), but Apollo 15 was an extremely important mission as well. For one thing, mission commander David Scott and lunar module pilot Jim Irwin became the first humans to drive a vehicle on another world – the 460-pound Lunar Roving Vehicle (LRV) could cruise at 8 mph, allowing the astronauts to cover more of the lunar surface than on any previous mission.
In three extravehicular activities (EVAs), Scott and Irwin traveled 17.5 miles, compared to Apollo 14’s previous record of 2.1 miles. Scott and Irwin also set a record for most time on the lunar surface during EVAs: 18 hours and 37 minutes.
In a lighthearted experiment, Scott also proved Galileo’s theory that, when dropped in a vacuum, two objects will fall at the same rate regardless of mass. During the mission’s third EVA, Scott dropped a hammer and a falcon feather from the same height, and the objects reached the lunar surface at the same time.
But the most important scientific part of the mission was geological. As in all previous lunar missions, the Apollo 15 astronauts were supposed to bring moon rocks back to Earth. But for this mission, Earth-bound geologists wanted Scott and Irwin to look for something specific: Anorthosite, pieces of the moon’s primordial crust that could help scientists determine how the moon formed. So, the astronauts spent many long days with geologists in locations across the United States learning the basics of geology.
Of course, Scott and Irwin were Air Force test pilots, total alpha gearheads, who were being told to tromp around with geologists in such places as California’s San Gabriel Mountains, Colorado’s San Juan Mountains, Hawaii’s volcanic areas, and Ely, Minnesota, where they inspected the famous Pillow Rock, a massive specimen of ellipsoidal lava flow that formed beneath Earth’s primeval seas 2.7 billion years ago.
You might think that these hot-shot flyboys would be bored by something as mundane as geology, but they took to it like true scientists, and on Aug. 1, 1971, when they discovered a 269-gram (9.48 ounces) chunk of anorthosite – the first anorthosite ever found on the moon – they sounded like two kids finding a 5-inch megalodon shark tooth at a local beach:
Irwin: “Oh, man! I …”
Scott: “Look at that!”
Irwin: “Look at the glint!”
Scott: “Ahhhh.”
Irwin: “You can almost see twinning in there!”
Scott: “Guess what we just found! Guess what we just found!”
Irwin: “I think we found what we came for!”
Scott: “Crystalline rock, huh? Yes, sir. You better believe it!”
Officially designated Sample 15415, this anorthosite quickly became known as the Genesis Rock, and scientists concluded that it was formed 30 miles beneath the moon’s surface 4 billion years ago, when the moon was still an ocean of molten lava that had just started to cool. For reference, our solar system is 4.5 billion years old.
So, NASA threw Scott and Irwin a curveball when the space agency put the test pilots through rigorous geological training, but the pilots mastered their new discipline and made one of the most significant discoveries in the history of lunar exploration.
Southwest Florida’s rainy season is more of a spitball for area astronomers, but there’s no reason we can’t make the best of the season and seek out celestial targets of opportunity. (And don’t forget: you can always see the stars in The Bishop’s spectacular Planetarium!)
Howard Hochhalter is manager of The Planetarium at The Bishop Museum of Science and Nature. Each month, he hosts Stelliferous, a live discussion at the Museum of what’s happening in our night skies and in the world of astronomy. Visit The Bishop online at BishopScience.org to register for the program or learn about other events and activities at the Museum.
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