Why does the moon looks different each night?
If you’re a Moon lover, you have noticed that the Moon never looks exactly the same for two nights in a row. The Sun is the only object in our solar system which emits light. The Moon is not changing its shapes but the way Sunlight illuminates it.
The shifting in Sunlight creates the lunar phases which are also called lunar cycles. Sometimes, the Moon appears fully bright during a full Moon. It becomes invisible during the new Moon.
In this article you’ll explore why the Moon looks different each night. If you’re a Moon lover, this article is for you.
8 Moon Phases
The Moon completes its one orbit around the earth in about 27.3 days. But, earth is also moving, the Moon takes 29.5 days to complete lunar cycles and contains 8 lunar phases. As the Moon revolves, the Sun illuminates different portions of it. The Moon changes from invisible to fully bright and then back to invisible again.
Here are the 8 phases of the Moon explained:
New Moon: During this phase the Moon becomes totally invisible. This occurs because the Moon and Sun are positioned on the same side of the earth. The Moon is in between the earth and Sun and we can see only the dark side of the Moon.
Waxing Crescent: As the Moon starts to revolve around the earth, the right edge of the Moon becomes visible as a curved crescent shape.
First Quarter: The Sunlight illuminates half the surface of the Moon during this phase. The Moon rises at noon and sets at midnight during the first quarter.
Waxing Gibbous: The sun illuminates the surface of the Moon and more than the half surface of the Moon becomes visible to us.
Full Moon: The sun illuminates the full side of the Moon during this phase. We can see the full and bright Moon. The Moon rises as the Sun sets and is visible all night. The Moon is on the opposite side of the Sun.
Waning Gibbous: The illuminated portion of the Moon starts to reduce after the full Moon. During this phase more than the half Moon is visible.
Third Quarter: During this phase, you can see the half Moon from earth.
Waning Crescent: The small silver of the Moon is visible during this phase.
The half side of the Moon is visible to us only while the other remains in the dark. We see changes in illuminated half of the Moon shapes as it revolves in its orbit.
Lunar Libration
Lunar liberation is also the reason for the changing shapes of the Moon each night. The Moon rotates synchronously during its lunar cycle. These vibrations are lunar liberation. The libration changes the outline of the Moon by shifting the craters and Maria near the limb.
The Moon wobbles longitudinally, because it moves faster near the earth and slower when it moves away. Libration in latitude is because of the Moon axis.
We see 59% of the Moon instead of 50% because of the libration.
Atmosphere & Optics
The air near the horizon is thicker which scatters the blue light. Due to this the Moon appears yellow, orange or red.
More air leads to more light loss which softens the details of the Moon.
The Moon looks larger near the horizon. The Moon is not actually growing but it is because of psychological size-distance illusion.
Moonrise & Moonset
The Moon rises and sets at different times during the whole month. The Moon completes its orbit in about 27 days, 7 hours and 43 minutes. The Moon moves away at 12 to 13 degrees each day.
That’s why the moon takes 50 minutes more to rise each day. The earth has to move more each day and then the moon becomes visible to us.
Conclusion: Why Does the Moon Looks Different?
The Moon looks different each night because of sunlight. The sunlight illuminates different portions of the Moon as it revolves in its orbit. This leads to changes in the Moon shapes during 8 lunar phases.
The Moon appears yellow or orange where air is thicker. Similarly, it appears bigger near the horizon due to illusion.