Last night (May 5th), the sky was lit up by the "Supermoon". Many people would already be familiar with this concept as it has been in the news for over a week now. I personally wanted to click pictures of the supermoon and write a post about it. But due to bad weather, I was unable to capture any photos. Luckily, the sky was clear the night before and I had clicked a few pictures. So I have the pictures of an "almost" supermoon.
Before we go to the pictures, let me briefly describe what a supermoon is. The moon goes around the earth in an elliptical orbit. Therefore the distance between Moon and Earth varies such that, every month, the moon comes to its closest distance to Earth (Perigee) and also goes to its farthest distance from from Earth (apogee). Sometimes the lunar perigee coincides with the full moon day and this full moon is called the Supermoon (whose technical term is Perigee-syzygy).
The supermoon is bigger and brighter than an average full moon. It is about 20-30% brighter and about 12-14% bigger. There are many pictures on the web which compare the size of the supermoon with full moon at apogee (do check this link). In this post, I thought I would do the same. As mentioned earlier, I was able to click pictures of the moon a day before perigee-syzygy. Luckily, I found a picture in my photo archives which was also clicked a day before full moon on 12th August 2011 (the moon was not at apogee but it was almost there). Since the moon in both the pictures are approximately in the same phase, comparing their sizes would not be wrong. Here is the comparison...
These photos were clicked with the same camera and with the same magnification. As it would be clear, the photo on the left is an almost supermoon (May 4th 2012) while the one on the right is an average almost full moon (August 12th 2011). Neil deGrasse Tyson tweeted two days ago saying, "Moon Lunacy strikes again: The impending Supermoon is to an average full Moon what a 16" Pizza is to a 15" Pizza. So chillax." I used a desktop ruler to find that the ratio of sizes of the moon in the two images to be what a 14" pizza is to a 13" one. I guess this estimate is close enough.
Since I am talking about full moons and their apparent size, I wanted to briefly describe another phenomenon that most of us are familiar with, that is, the moon looks bigger near the horizon while it smaller when it is up in the sky. This is just an illusion. In reality, the moon near the horizon is as big as the moon up in the sky. You can perform a simple experiment to test this. Hold an object, lets say a pencil, at arms length and look at the moon at the horizon. Measure the apparent size of the moon with respect to the pencil. Now using the same technique, measure the size of the moon when it is up in the sky. You will find that the size is almost the same! (For more on the Moon Illusion, do read Phil Plait's article on this topic).
Though I was not able to captures photos of the supermoon, here is a link to pictures from around the world.
Before I sign off this post, for those who are interested in comparing the sizes of the moon on their own, I have included the original pictures below. Have fun!
These photos were clicked with the same camera and with the same magnification. As it would be clear, the photo on the left is an almost supermoon (May 4th 2012) while the one on the right is an average almost full moon (August 12th 2011). Neil deGrasse Tyson tweeted two days ago saying, "Moon Lunacy strikes again: The impending Supermoon is to an average full Moon what a 16" Pizza is to a 15" Pizza. So chillax." I used a desktop ruler to find that the ratio of sizes of the moon in the two images to be what a 14" pizza is to a 13" one. I guess this estimate is close enough.
Since I am talking about full moons and their apparent size, I wanted to briefly describe another phenomenon that most of us are familiar with, that is, the moon looks bigger near the horizon while it smaller when it is up in the sky. This is just an illusion. In reality, the moon near the horizon is as big as the moon up in the sky. You can perform a simple experiment to test this. Hold an object, lets say a pencil, at arms length and look at the moon at the horizon. Measure the apparent size of the moon with respect to the pencil. Now using the same technique, measure the size of the moon when it is up in the sky. You will find that the size is almost the same! (For more on the Moon Illusion, do read Phil Plait's article on this topic).
Though I was not able to captures photos of the supermoon, here is a link to pictures from around the world.
Before I sign off this post, for those who are interested in comparing the sizes of the moon on their own, I have included the original pictures below. Have fun!
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| Moon on August 12th 2011 |
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| Moon on May 4th 2012 |
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