Why does the full moon sometimes appear huge in the sky?

The Moon Illusion: Why the Full Moon Looks So Huge Sometimes

A popular theory concerns how the human brain perceives the size of objects depending on whether they are closer or farther away. US space agency NASA It has been added to their websiteThe brain does not seem to realize that the distance of the moon does not change much whether it is low on the horizon or high in the sky. A full moon low in the sky appears larger than a moon high in the sky, in part because the human brain compares it to other familiar objects in its immediate vicinity.

Silas Laycock, an astronomer at the University of Massachusetts Lowell, explains on the conversation platform, “The illusion is that the Moon is so far away that it appears the same size no matter where you are on Earth.” They are the objects to which we compare the Moon and which appear larger or smaller depending on the distance between them. “When the moon appears next to a distant house or a mountain far away, the moon appears huge,” Laycock adds. NASA assures: “It’s all in the head. The apparent size of the moon is a real illusion, not a physical effect.

Moon Illusion: When the full moon is low, you can’t believe your eyes

In the case of the Moon Illusion, you literally cannot believe your eyes. But very simple tricks reveal the illusion and make the moon shrink to its actual size:

• If you cover the full moon with your finger when it’s low on the horizon and later when it’s high in the sky, you can see that it works both times – the moon is always the same size.
• Using a roll of paper as a “scope” to observe the full moon obscures the environment that confuses the brain. The moon “shrinks” back to its normal size.
• If you photograph the low moon and the moon in the sky with the same camera settings, you can see that the moon is the same size in both images. You can’t photograph the illusion of the moon because it happens completely in your head – you can only recreate it with the help of zoom effects.

The moon illusion has nothing to do with the super moon

One thing is certain: while the so-called supermoon is a little closer to Earth than usual and therefore may appear larger, this has nothing to do with the moon illusion, which always occurs when the moon is low in the sky.

NASA also maintains that the exact nature of the moon illusion has not yet been fully elucidated. Because there is one particular question that remains unanswered by current theory: Why do astronauts in Earth orbit also see the illusion of the Moon, even though there are no objects to which their brains can compare the Moon? “So there’s likely to be more behind that,” says NASA. But don’t worry too much about the lack of a definitive explanation, because the full moon, made huge by the illusion of the Moon, is just a very impressive sight.

Machine assistance was used in this editorial article. The article was carefully screened by editor Tanya Banner before it was published.