In response to last month’s supermoon mania, Lake brings you the lowdown on lunar lore
The Moon became a star on Nov. 14 when it achieved “Supermoon” status. “Supermoon” means the Moon and Earth are at their closest point in the Moon’s orbit at the same time that the Moon phase is full. The last time it was as close was Jan. 26, 1948; the next time will be Nov. 25, 2034. All that combined to make the November Supermoon a big deal.
But the Moon is always a big deal in our night sky.
It’s the closest celestial body to Earth, the brightest object in the night sky and changes appearances constantly. As a result, the Moon holds an unparalleled fascination for people today, just as it has since the first humans looked toward the heavens.
People lucky enough to spend time on Lake Martin are doubly blessed with lunar observations since the relatively dark areas around our lake make the Moon look that much brighter than when it is viewed from a lit-up city, and the Moon’s reflection in the still night lake surface makes any lunar viewing twice as much fun.
So for our Nature of the Lake feature this month, we decided to take an in-depth look at the Moon.
First off, the Moon is a moon. The capital ‘M’ Moon is the name of the celestial body that orbits Earth. Our Moon is also a lower case ‘moon,’ which is the word used to describe any large body orbiting a planet. There are a total of 173 moons in our solar system orbiting the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
The Moon is Earth’s only natural satellite. It is about a fourth the size of Earth, with a diameter of 2,159 miles. To put that in perspective, the United States is about 2,680 miles wide.
The surface area of the Moon is about 14.6 million square miles, less than the surface area of Asia, which covers about 17.2 million square miles. Scientists think the moon is 4.6 billion years old.
Earth’s moon is only the fifth largest moon in our solar system – Ganymede, which orbits Jupiter, is the largest moon in our system at 3,273 miles wide. Next in size is Titan, which orbits Saturn, and then Callisto and Io, which orbit Jupiter. Europa, which also orbits Jupiter, comes in sixth place after our moon.
The Moon’s orbit around Earth is an elliptical, not circular, which means that, at times, it is closer to Earth than other times. It takes 27.3 days for the Moon to orbit the Earth, roughly – but not equal to – a month on our modern calendar.
The moon is made of rock and does not emit light. When we see the moon in the sky, we are seeing the Sun’s light hitting one side of the Moon.
The same side of the Moon always faces the Earth. With apologies to Pink Floyd, there is no such thing as “The Dark Side of the Moon” since both sides receive the same amount of sunlight as the Moon rotates; however, since the Moon rotates on its axis at exactly the same rate that the Moon rotates around the Earth, we only see one face of the Moon. The other (not dark) side of the Moon has been seen in sunlight by only a few humans – those who saw it from a spacecraft.
Neil Armstrong, a member of the Apollo 11 crew, was the first person to ever set foot on the Moon, in 1969. When he stepped from the lunar module onto the Moon’s surface, the people on Earth heard his famous words, “That’s one small step for man, one giant leap for mankind,” transmitted by radio; however, Armstrong said the world heard wrong, explaining that what he really said was, “That’s one small step for a man, one giant leap for mankind,” which makes more sense. No matter how you hear it, it was a big step.
Only 12 people have ever walked on the Moon, and all were American males who experienced weight loss only dreamed about by the folks on the South Beach Diet. The Moon’s gravity is about 17 percent of gravity on Earth. That means a person who weighs 100 pounds on Earth would weigh only 17 pounds on the Moon. As a result, a person who could jump 10 feet on Earth could jump almost 60 feet on the Moon, a feat only dreamed about by high jumpers the world over.
Back on Earth, we see the Moon gradually change shapes each month. The phases of the Moon are really our point of view of the sunlight side of the Moon as it orbits the Earth.
To understand lunar phases, it helps to understand four lunar terms. “Crescent” means less than half the Moon is lit by the sun so that it appears like a thumbnail. “Gibbous” means more than half the moon is lit by the sun, so it appears as a lopsided ball. “Waxing” means growing, and “waning” means shrinking.
A lunar eclipse is when the Moon, Earth and Sun are lined up in that order so that the Earth’s shadow travels across the Moon.
A solar eclipse is when the three bodies are lined up so that the Moon passes in front of the sun and its shadow travels across the Earth.
Have you ever noticed that the Moon appears much larger when it first rises above the horizon than when it is high in the sky? That’s an optical illusion called the “Ponzo Illusion” caused by our minds comparing the Moon to trees and other objects it passes by on the horizon. The photo of the Moon behind the Smith Mountain Fire Tower on the cover of this issue looks huge in comparison to the tower; however, if you hold your thumb beside the Moon as it comes over the horizon, and then again when it is high in the sky, you will see it is the same size compared to your thumb in both instances.
And about that supermoon – if you missed it last month, you’re in luck.
There’s another slightly smaller supermoon coming on Dec. 14, the last of three that occur in 2016.
The next big buzz-worthy celestial event viewable from Alabama will be coming this summer on Aug. 21, when there will be a total solar eclipse visible from the United States.
On that day, the Moon will pass in front of the sun, completely blocking the sun and making its corona visible from many parts of the U.S., including nearby in Tennessee and North Carolina. The event will appear as a partial lunar eclipse from most of North America, including the Lake Martin area. The last total solar eclipse visible from the United States was in 1979, the next time will be in 2024.
It’s a biggie, an event rarer than a Blue Moon, which, by the way is when two full moons fall in the same calendar month.
In fact, there will be four Blue Moons before the next total solar eclipse in 2024, and half of them will occur in 2018 – on Jan. 2 and 31 and March 2 and 31 – making 2018 a double Blue Moon year, a super-rare event that won’t happen again until 2037.
Which, if you remember, is three years after the next supermoon in 2034.
If you would like to know more about the Moon, check out NASA’s 4-1/2 minute video, Narrated Tour of the Moon, on YouTube. Another website full of good lunar information is Space.com.