If you looked up in the sky from almost anywhere in the eastern United States the past few nights, you might have noticed the moon looks a little bit different. Since the weekend, the moon has had an orange hue to it. The moon is often orange in color as it rises and sets above the horizon each day, but this time, it’s orange from the time it rises until the time it sets.
At moonrise and moonset, there are two factors in play that turn the moon orange and make it look bigger. First, the moon doesn’t change the size, it’s just an optical illusion in our minds.
According to Scientific American, “When the moon is near the horizon, the ground and horizon make the moon appear relatively close. Because the moon is changing its apparent position in depth while the light stimulus remains constant, the brain’s size-distance mechanism changes its perceived size and makes the moon appear very large.”
It looks orange because you are looking at it through more of earth’s atmosphere on an angle. When you look straight up at the moon, you’re looking directly at it into space. When it’s rising, you are looking at it, but through more of earth’s atmosphere because of the angle.
“Earth’s atmosphere is like a sphere of gases that surround the planet. … Orange and red light, which have longer wavelengths, tend to pass through the atmosphere, while shorter wavelengths of light, such as blue, get scattered. That’s why the Moon — and the Sun! — look orange or red when they’re rising or setting,” according to Wonderopolis.
So why has the moon been orange every night recently, even when it’s high in the sky? Believe it or not, even here on the east coast, you can blame the wildfires out west.
The particulates in the air from the fires in Oregon, California, Alaska and Canada, but mostly from Oregon’s “Bootleg” fire. The fire is so large, it has created its own weather pattern, according to the National Weather Service. It has blanketed much of the U.S. northeast and mid-Atlantic with a thick later of smoke in the atmosphere that has made the past two sunny days overcast and hazy with extremely reduced visibility.
At night, that smoke gives the moon an orange tint as you peer through the layers of atmosphere, now full of particles that originated 3,000 miles away in Oregon.
“Smoke from the Western U.S. and Canada is causing periods of reduced visibility across the northern half of the country, including Western and North Central NY. Smoke will continue over the region through Wednesday morning, before a cold front helps push the smoke east,” the National Weather Service said.