'Luna-tic' answers questions about the moon

The moon is our closest neighbor in space. For thousands of years, our ancestors have gazed up at its silvery glow and tried to make sense of its rhythm and aura. Memorialized in literature, song and dance since the dawn of time, the moon tugs at our romantic nature and inspires our soul.

Here, I answer the most common lunar questions I receive at the Cincinnati Observatory.

Why can I sometimes see the whole moon even when only a crescent is illuminated?

This effect is caused by earthshine – the light of the sun shines on the Earth and reflects upon the moon. Earthshine brightens the moon enough to see it against the darkness of the sky. Now moonshine, that’s something else entirely.

What is a blue moon?

A blue moon refers to the second full moon in a calendar month. The term, as we now know it, only dates back to a 1946 Sky and Telescope magazine article. A blue moon doesn’t actually make the moon appear blue in color. But during the next blue moon on Jan. 31, 2018, it will look strange. That morning, we will have a partial lunar eclipse. Look for the shadow of the Earth blocking out part of the moonlight just before sunrise that day.

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Why does the moon look bigger when it is near the horizon?

This effect is called the moon Illusion and it has been debated for centuries. Although the moon appears larger when it is near the horizon, it really isn’t. You can measure the size of the moon by holding a hole-punched index card at arm’s length. The moon is about the same size as the hole both on the horizon and high in the sky. It just looks larger.

Is there a difference between the far side and dark side of the moon?

Yes. Since the same face of the moon is always pointing to us, we never get to see the other side or far side. Only 24 Apollo astronauts have actually seen the far side for themselves. But the far side is not always dark, nor is the dark side always far. The “dark side of the moon” is merely the part of the moon not currently illuminated by the sun. It is always changing based on the moon phases.

How long does it take to travel to the moon?

When the astronauts went to the moon in the 1960s and 1970s, it took them three days to get there (and three days to get back). A rocket called the Saturn V launched them into space. The Saturn V stood 363 feet tall (equal or greater in height to many city skyscrapers), and still remains the largest launch vehicle ever used.

Why doesn’t the moon have a better name?

It is just called "the moon." The name is a holdover from the old English word "Mona" and a time when astronomers didn’t know other moons existed. However, the moon goes by other names in our cultures. To the ancient Greeks, it was "Selene," in Latin and Spanish, it is "Luna," and in Swahili, it is "Mwezi."

So many moon myths and such little time – moon phases, eclipses, tides, craters and even green cheese. The more you observe and study this ball of rock 240,000 miles from Earth, the more you’ll turn into a moon-lover, or as we astronomers say, a “Luna-tic.”

Dean Regas is the Outreach Astronomer for the Cincinnati Observatory and author of the book, Facts From Space! He can be reached at dean@Cincinnatiobservatory.org

IF YOU GO: International Observe the Moon Night

What: Look up and check out the moon. Join local astronomers for close-up views of the lunar landscape through telescopes

Where: Cincinnati Observatory, 3489 Observatory Place, Mount Lookout

When: Saturday, Oct. 28, from 7-9 p.m.

Admission: $10/adult, kids are free thanks to Cincinnati March for Science

Information: No reservation required. Visit: www.cincinnatiobservatory.org for more