Wednesday 14 February 2024

Upside down moon - again




I saw another upside down moon on Monday night. The first time I saw one was on 24 January, 2018 and the other one, one year later on 11 February, 2019

I am always awed when I see one and immediately go to the terrace to have a closer look. From the comments I have received on the 2019 post, many people feel the same. 

Here's the scientific explanation:

An upside down moon is a result of the moon's orbit around the earth, and the earth's orbit around the sun. And exactly when you see the moon in the shape of a U (lit on the bottom) rather than a backward C depends on what latitude you are at.

We see the moon in the night sky because it is reflecting light from the sun. So the lit part of the moon always points towards the sun. As the earth travels around the sun, the tilt of the earth on its axis sometimes points the northern hemisphere towards the sun and sometimes points the southern hemisphere towards the sun. But this also changes the apparent path of the moon across the night sky when you are on earth looking out at it. Sometimes it travels at an angle towards the horizon and sometimes it travels straight down toward the horizon. When the crescent moon travels straight down the horizon, you will get the U shaped moon. This can happen once or twice a year, depending on the latitude of your location.





I saw it again last night and took this photograph at 9:10 pm. The lit part is slightly bigger and you could see very clearly the roundness of the shape - it's not so discernible in the photograph but it's there if you look closely enough.


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