Hello, young learners!
It’s me, Kiki, back again with another chapter in my Knowledge Corner. I was thrilled with your active response to our previous post – ‘Why do we see stars at night?’. On that note, we have added another interesting segment about the night sky. It’s about the ‘different phases of the moon’. You might have wondered that if the moon is a spherical heavenly body, then why does its shape change every other day? On some days, we see a crescent moon, and other days a half moon shows up in the night sky. Besides, there are new moon days when the moon is not visible at all and full moon days when we see the bright full moon lighting up the night sky.
These different shapes of the moon seen in the night sky are called the ‘phases of the moon’. There are eight phases of the moon that happen within a span of 30 days – that’s one complete cycle. If you keep track of the moon for 30 days, it will seem like the invisible moon grows to its full size and shrinks back to being invisible again! Fascinating, isn’t it?
In this section, we are going to learn about the different phases of the moon and why we see them.
Let’s keep a track of when the moon is invisible and is called the new moon day. Let’s call it – Day One.
From the next day on, we can see the moon slowly reappearing in the sky. For the first few days, the moon resembles a small crescent – this phase is called the waxing crescent phase.
Then, we see the moon slowly grow bigger into a semi-circle shape. This phase is called the first quarter.
The next phase of the moon is called the waxing gibbous phase. It looks like three-fourths of a circle.
On the 15th day after the new moon, we see the full bright, round moon in the night sky. And that’s called the full moon.
After the full moon phase, the moon begins to disappear in stages. The process will be the opposite of what happens in the first 15 days. This phase also takes place in a period of 15 days and is called the waning phase!
In the waning gibbous phase, the moon goes back to what size it was in the waxing gibbous phase. The next phase is the last quarter, where the moon reduces to the size of the half moon.
As the moon disappears before the end of the month, it takes the shape of a crescent and is rightly called the waning crescent.
At the end of 30 days, the moon disappears again, becoming the new moon.
The different phases of the moon occur because the moon doesn’t have its own light. That’s right! So how does it shine so bright, you might ask! Just like the Earth, the moon is illuminated by the sun! Based on its position, one half of the circular moon is always illuminated by the sun.
However, as the moon orbits around the Earth, we see the moon every night in different shapes and sizes, based on its position. It does one round around the Earth in a little less than 30 days – 29.5 to be exact!
So, what’s the link between the position of the moon and the Earth? Depending on where the position of the moon is, we are able to see the lit portions of the moon from Earth. That’s how we are able to see different shapes. When the moon is nearest to the Earth, the dark side of the moon is seen from its surface. It’s invisible. This happens on New Moon Day!
In the days before and after a new moon, we see a sliver of the moon that takes the shape of the crescent. During this time, the moon travels from the nearest point to the Earth to its furthest. During the first few days and the last few days of its journey, we see the waxing and waning crescents.
Depending on the journey of the moon, its shape changes from crescent to half moon, three fourth of a moon and full moon as it reveals the portion to Earth illuminated by the sun.
Isn’t it fascinating to understand the science behind the shapes of the moon? Can you tell us what phase we are in currently? Share your answers with us in the comments.
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