Explain the larger moon phenomenon near the horizon

Optical illusion makes the Moon become huge when close to the horizon is the most famous illusion in the world, but no expert can give correct answers.

The ancient Greek philosopher Aristotle argued that the Earth's atmosphere magnified the Moon when near the horizon. This hypothesis is proven wrong. The scattering effects of air can cause the Moon to be red or orange but do not change the celestial size, according to Vox.

The moon at the horizon seems to be much bigger.(Photo: NASA).

Using a tool called anecdotal machine , astronomers can determine that the full moon is 0.52 degrees wide (compared to 360 degrees for the entire sky) and remains constant throughout the night. In fact, according to accurate measurements, the Moon is about 2% larger than the Moon at the horizon at the top of the horizon, due to the distance observed to the horizon further.

The Moon phenomenon is larger because of the human brain. "People are looking for a simple answer , " said Donald Simanek, a physicist who specializes in Moon illusion. "But this answer lies in the functions of the human brain that we only know very little."

Mechanical measurements show that the Moon is at the top of the head larger than the Moon at the horizon.(Photo: Bob King).

Recently, some neuroscientists began using MRI magnetic resonance imaging to understand the cause. While the final conclusion cannot be made yet, their research helps explain part of the brain's process of interpreting visual information.

A 2006 MRI study results in similar hallucinations in the laboratory. The left sphere feels bigger and farther away than the right sphere, despite the true size of both. This phenomenon is similar to the illusion of a bigger moon at the horizon.

Researchers come up with a hypothesis to explain this mistake of the brain. When the car gradually goes far ahead, the eye's view with the car will get smaller. Due to the fact that the car is not shrunk, the brain adjusts the observation size so that our eyes still see the car of the same size when moving away.

The left sphere looks bigger and is farther away from the right sphere, similar to the Moon at the horizon.(Photo: Murray).

At a much larger distance than for the Moon, we cannot feel the exact depth. If the sense of the horizon is farther away from the top of the head, this mechanism will also trick the brain, making us see the Moon bigger than its true size.

"If estimating the distance to the Moon is larger, the brain will perform calculations and decide that the objects must be larger to fill the same space," Ralph Weidner, a German neurologist studied Save Lunar illusion by MRI experiment, said.

Most people, when asked, answered that the Moon looked both big and close, not far away. Researchers updated new explanations based on neuroscience to solve this problem. Accordingly, our brain has two basic systems for processing visual information: one decides what you will look at (the ventral stream) and one determines the location of the observed object (dorsal stream) . Each system corresponds to a different region of the brain.

Illusion Ebbinghaus, the left circle seems smaller than the right.(Photo: Phrood ~ commonswiki).

The new hypothesis suggests that these two systems work in order to create the illusion of the Moon. The Ventral stream performs the process according to the old interpretation, which co-adjusts for the Moon to become larger when it is found far away. The Dorsal stream will then redefine the position of the Moon in the direction of deducing that the Moon is larger than normal, meaning it must be close, Weidner said.

Weidner and colleagues tested this hypothesis by placing humans in an MRI machine and using 3D glasses to show them the illusion of the Moon, along with another illusion that works in a similar way.

Participants will see a circle approaching or far away but the angle of view is always adjusted to keep the value constant. All volunteers shared that they found the circle bigger when it moved away, like the Moon.

Researchers identify the brain's ventral stream region for both hallucinations. Although it has not provided solid evidence, experiments show a size effect - the true distance is related to the illusion of the Moon at a larger horizon.