Week of April 21-27, 2024
We've got another full moon this week.
Seems like we just had one last month, doesn't it? And the month before that. Well, this is not a coincidence. The moon orbits the Earth with a period of about one month and, therefore, sunlight shining on it from different angles throughout the month produces the shapes we know as phases.
In fact, this lunar cycle gives rise to the calendar division we know as a month (or "moonth" if you prefer) and was developed into a lunar calendar by ancient sky watchers. Even today, the lunar calendar is in use to mark holy days by Muslim and Jewish communities around the world, and the Chinese still use it for festive occasions.
When the moon lies opposite the sun in our sky, its visible face is illuminated fully by sunlight, and we call it a "full" moon. And since the moon rotates on its axis with nearly the same period as the moon's orbit, we always see the same dark gray features on the lunar surface that form massive plains of solidified magma called "mare" (MAH-ray). This is helpful when trying to understand the seemingly confusing behavior of our cosmic neighbor.
Occasionally, I receive notes from observant sky watchers asking why the full moon appears upside down when it's setting in the west at sunrise. It's not that complicated, and you can see this for yourself this week.
On the evening of Tuesday, April 23, go outdoors around sunset, and if the sky is clear, keep watch toward the east-southeastern horizon. It won't be long before you spot the full moon rising. Yes, it looks larger than normal (it's a powerful optical illusion created in your brain) and yes, it appears redder than normal (this is caused by dust particles in the atmosphere scattering out shorter wavelength light).
But forget all that for the moment. Look at its features — the gray markings from which one can imagine the face of the "man in the moon." They seem to trace out a large "C" on the lunar disk, with the open part of the "C" appearing on the right side.
A few hours later, after the Earth has turned a quarter of the way around, go out and look at the moon again and notice the pattern traced by the lunar mare. It still forms the letter "C," but the open end now appears more toward the lower right side!
By sunrise, the full moon will be setting in the western sky, and you may (or may not) be surprised to see the open area of the letter "C" now appearing at the bottom of the moon.
So what's going on here? Nothing unusual, really. Hang a photo of the moon on your wall and stand in front of it. If you tilt your head to the left, then straight up and down and then to the right, you'll see how the orientation of the moon appears to change in response.
This is quite similar to what happens as our Earth rotates. Check it out. It's simply the moon changing its orientation as we view it differently throughout the night.
Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at creators.com.
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