File:Why the Sun and Moon (3D) appear to be the same size in the Sky (01Nov2021).jpg

English: The Sun is much, much bigger than the Moon. The fact that the Sun is much, much farther away from the Earth than the Moon is from Earth makes the Sun appear so small. i.e., about the same apparent size as the Moon. In the same way, distant objects appear smaller than they do close up.

The Sun’s diameter is about 864,000 miles, whereas the Moon’s diameter is about 2,160 miles, meaning the Sun’s diameter is about 864,000/2,160 = ~400 times the diameter of the moon.

The diagram explains how the illusion works.

The distance from the Earth to the Moon is about 240,000 miles, and the distance from Earth to the Sun is about 93,000,000 miles. This means that, on average, the sun is about 390 times farther away from the Earth as it is from the Moon. Which is about a 1:1 ratio. The diameter of the Moon is about 2,160 miles. The Sun, with a diameter of about 864,000 miles, is about 400 times the diameter of the Moon.

On average, the Moon appears to be about 97% of the sun due to variations in the distance of the Moon from earth and the angle of its orbit. Sometimes the Moon will appear to be somewhat smaller than the Sun, which we see during an annular eclipse. And sometimes the Moon will appear to be as large as the sun, which we see during a total eclipse.

A solar eclipse can occur only when the Moon is close enough to the ecliptic plane during a new moon. Total eclipses are rare because the timing of the new moon within the eclipse season needs to be more exact for an alignment between the observer (on Earth) and the centers of the Sun and Moon.

On average, the Sun appears to be about 0.015 degrees larger than the Moon.