WHY DOES THE MOON LOOK BIGGER SOMETIMES? (TWO THEORIES EXPLAINED)

The supermoon rises over Çamlıca Mosque, in Istanbul, May 26, 2021. (AA Photo)

Wed 01 March 2023:

The Moon appears significantly larger near the horizon than it does high in the sky, as you may have noticed. Why does the Moon sometimes appear larger? Could light refraction be the origin of this physical phenomenon?

No, it is not a physical phenomenon that makes this natural Earth’s satellite appear different. Sometimes people say that it may be caused by the refraction of light in the atmosphere.

But while this physical mechanism of redirecting light waves as they pass from one medium to another exists, atmospheric refraction is not strong enough to cause an increase in the size of such magnitude. The real answer may surprise you – keep reading below.

Wenatchee, WA, United States.

Does Moon really look bigger sometimes?

Yes, the Moon can appear to look bigger sometimes, and it is a well-known phenomenon. Usually, people notice the change when the Moon is near the horizon, not when it is high in the sky.

But while it appears that way, it is actually not changing in size. The true Moon’s size remains the same, regardless of its position in the sky.

So why do we see it differently from time to time?

Why does the Moon look bigger sometimes?

In fact, it is a psychological phenomenon.

If you took a photo of the Moon at various heights above the horizon, you would see that it is the same size. You can also cup your hand into a fist and look through it. The Moon will appear smaller.

Interestingly, scientists do not know a definitive answer to why our brain is tricked into seeing different sizes of the same celestial object.

Two theories explained

There are two different leading theories explaining this illusion.

One theory says that this phenomenon is likely linked to the mechanism that produces everyday size-distance perception. Usually, when rigid objects move in depth, the angular size of the light image stimulating our eyes grows or shrinks. Our brain is adapted to automatically translate this change in light stimulus into the change in size perception of the object.

Why does the Moon look bigger sometimes?

In fact, it is a psychological phenomenon.

If you took a photo of the Moon at various heights above the horizon, you would see that it is the same size. You can also cup your hand into a fist and look through it. The Moon will appear smaller.

Interestingly, scientists do not know a definitive answer to why our brain is tricked into seeing different sizes of the same celestial object.

Two theories explained

There are two different leading theories explaining this illusion.

However, this mechanism must operate in an unusual situation when the Moon is near the horizon. The closeness of the horizon makes the Moon appear relatively close to us. It seems that the position in depth is changing, but the light stimulus remains constant. The size-distance perception mechanism thus changes Moon’s perceived size and makes it appear very large.

Another theory says that when the Moon is near the horizon, it is often compared to foreground objects such as trees, buildings, and other objects, making it appear larger. Additionally, the brain also processes the Moon as a more distant object when it is high in the sky, which also contributes to the illusion.

Final word

Why does the Moon look bigger sometimes? The answer is simple: your psychology – and your brain – causes this illusion. The real size of the Earth’s natural satellite remains the same, but we perceive it differently when the Moon is close to the horizon.

Written by Giedrius Pakalka and Alius Noreika

Article Originally published in Technology.org Click here

___________________________________________________________________________________________________________________________________

FOLLOW INDEPENDENT PRESS:

TWITTER (CLICK HERE)
https://twitter.com/IpIndependent