An Explanation of Why People Can See the Moon during the Day

VIVA – The moon is usually only visible at night. It turns out that some people can see the moon during the day. It is because of the Earth's atmosphere and the Moon's orbital cycle. If our planet had no atmosphere, the Moon would be visible from Earth all the time from night to day.

Meanwhile, the phase of the Moon means when it moves between Earth and the Sun where the illuminated side is facing away from us and the dark side of the moon is facing the Earth so that it is invisible to sky observers on Earth.

According to the Live Science website, Tuesday, November 1, 2022, gas particles in the atmosphere, especially nitrogen and oxygen, scatter light that has short wavelengths, such as blue and purple light.

This scattering involves absorbing and re-emitting light in different directions and gives the earth a blue sky.

A Professor of Astronomy and Astrophysics at Villanova University in Pennsylvania, Edward Guinan, stated that to be visible during the day, the moon must overcome the scattered light from the Sun.

For two or three days around the new Moon, the Moon is not visible to observers on Earth because its position in the sky is obscured by the Sun's light that is scattered beyond the Moon.

But as usual, the moon's relative proximity to Earth averages 238,900 miles where the reflected light appears brighter to us than objects that emit or reflect light more distant, such as stars or other planets.

According to Edward Guinan, the stars visible from Earth are one million billion times brighter than the light of the Sun and millions of times fainter than the moon.

The scattered light from the Sun is so bright in the sky that it often exceeds the light of the stars during the day.

Astronomers use surface brightness as a way to measure the brightness of objects in the sky, such as galaxies or nebulae, by measuring the amount of light they emit across areas of the night sky, as observed from Earth.

Because the Moon is closer to Earth than the stars, its surface brightness is greater than the brightness of the sky's surface. It means that we can easily see it shining in the daytime.