It was the night of February 27th, 2013. Rob and I were driving down a stretch of dark highway when it happened. As we crested a hill something strange appeared at the horizon: an orange, glowing, ovoid object slowly rising from the earth like a distant bubble of blooming magma – fiery and ominous. After the initial surprise of the unsettling sight I quickly realized that it was just the moon. But my goodness, it was so surreal-looking; so much larger than usual, with a rich orange hue, and strangely squashed.
By the time we got home, the moon was higher in the sky. While I couldn’t capture the full effect of what we had experienced while we were driving, I was able to catch its distorted shape and color, just not as pronounced as it was when the moon was low on the horizon.
It’s not hard to imagine how superstitions surrounding such events come about. We perceive something strange and have to come up with a reason or purpose for its occurrence. It’s the way our minds work and sometimes we just can’t help it.
A search through Google about “red/orange moon superstitions” gives you numerous examples of past superstitions such as:
- when the moon is orange it means that the moon is angry
- it signifies something horrible is about to happen to you
- a death in the family is about to occur
- war is imminent
- it is a sign of good luck
How popular these beliefs were in the past or how many of these beliefs are still held by some people is hard to tell. I’m hoping that we can all agree such superstition is ridiculous, yet there are countless modern, educated people who experience strange or unexplained phenomena and choose to classify it as proof of the supernatural rather than what it truly is: something which they simply don’t understand or may have misperceived.
So, what caused this wondrous lunar event?
First off, the cause of the orange color: when viewing the moon on the horizon, the Earth’s atmosphere causes the light of the moon to be dispersed differently. Since the atmosphere is thicker when looking at the sky on the horizon, the blue light is dispersed in the atmosphere and the red/orange light is what ends up coming through. This frequently happens to the sun at sunrise and sunset, but it’s harder to catch and to notice the effect on the moon.
The moon’s distorted shape was also because of the atmosphere. It acts as a lens, bending and distorting the light – an effect called “atmospheric refraction”. Atmospheric refraction also causes the wavy distortion when looking through the air above hot surfaces and it is what makes the stars twinkle.
As for the moon looking bigger, this actually isn’t caused by atmospheric refraction. As a matter of fact, the moon is slightly smaller when it is at the horizon because it’s farther away (as illustrated in the picture below). So what’s the deal? Two words: moon illusion. When the moon is close to the horizon our mind tells us that it is bigger than it actually is because there are smaller, distant terrestrial references to compare it to, as opposed to the moon’s typical celestial backdrop.
I created two optical illusion images to illustrate how our brains trick us. The first one is the Ponzo illusion. The idea behind this illusion is that our brains judge objects’ sizes according to their background. The moon on the horizon is set against distant landscape, making it seem larger by comparison.
I put together the slideshow below to demonstrate how these lines are identical, but they look different in size due to the “Ponzo Illusion”.
The second illusion I did is the Ebbinghaus. It’s generally the same idea as the Ponzo, but it uses two circles of the same size; one circle is surrounded by larger circles and the other circle of the exact same size is surrounded by smaller circles. The one surrounded by the smaller circles looks as if it is slightly larger than the circle that is identical to it but surrounded by bigger circles. Our brains see the circles, compare them to their surroundings, and make a judgment on size.
What is interesting about these sorts of optical illusions is that even after you find out that it’s an illusion and you know how it works, you still can’t stop yourself from seeing the illusion. There’s nothing wrong with admitting that our brains simply can’t help but be fooled in certain situations. We must humbly concede these faults and rely on the scientific method to explain the unexplainable rather than relying on our own faulty wiring.