Keep a Weather Eye on the Moon

As the full moon rises on Wednesday, you will get a unique view of its size. That’s because the moon will look unusually large as it rises in the evening. It’s simply an illusion (a trick that happens when the moon is near the horizon) that is more prominent during a full moon, but it’s a neat sight to behold. Even space station astronauts will witness the same effect.

According to an article on Yahoo News, “The illusion will be particularly noticeable at this ‘solstice moon,’ coming just two days before summer starts in the Northern Hemisphere. The reason, according to NASA, lies in lunar mechanics: The sun and full moon are like kids on a see-saw; when one is high, the other is low. This week’s high solstice sun gives us a low, horizon-hugging moon and a strong, long-lasting version of the illusion.

Here’s how it works: Your mind believes things on the horizon are farther away than things overhead, because you are used to seeing clouds just a few miles above, but the clouds on the horizon can indeed be hundreds of miles away. So if we think something (such as the moon) is farther away, and it’s not, then it seems larger.

If you remain doubtful, test the idea yourself. Go out at moonrise with a small object, perhaps a pencil eraser. Hold it at arm’s length as the moon rises and compare the sizes of the moon and the eraser, then repeat the experiment an hour or two later when the moon is high in the sky.”

Moonrise times vary by location. On Wednesday, it will come up at these local times at these locations: Dallas, 9:03 p.m.; New York City, 8:58 p.m.; Seattle, 9:51 p.m.