Many people in New York City might have felt like Martians this week when smoke from more than 400 Canadian wildfires descended on the Northeast, creating other-worldly sky colors from orange to fire red.
The wildfire smoke has created poor air quality conditions for more than 100 million people and even hazardous ratings – the most extreme rating on the Air Quality Index – for major cities, including New York City, Philadelphia and Washington.
Why does the sky turn orange or red from wildfire smoke?
Mars is nicknamed the Red Planet because of its color. Mars gets its rusty color from the large amounts of iron on its surface.
On Earth, the sky changes colors because of how light is absorbed and reflected by different molecules.
This week, because of the ongoing wildfires burning in Canada and weather patterns sending smoke down into the U.S., the sky has been orange and red in some places. Smoke molecules do better scattering wavelengths of red light. As the smoke particle concentration builds, the redder the hue in the sky. The result of the very dense smoke on Wednesday created out-of-this-world skies in New York and New Jersey.
Below is a view of the Raritan River in New Jersey on Wednesday.
Below is a view of Mars from NASA's Perseverance Rover taken in February.
Smoke creates the same red-orange color-changing effect on the moon and the sun. A blood-red moon rose over Philadelphia on Monday when the smoky conditions began to descend into the Northern U.S. and only allowed red wavelengths from moonlight to pass through.
On Wednesday afternoon, when the smoke concentration was highest, New York City was rust-colored or red.
Sunset on Mars or smoke in Washington?
The smog has created a blueish hue over some areas, including in the Washington Metro area, looking a little like the sunrises and sunsets on Mars.
According to NASA, the sky above Mars appear blue around sunrise and sunset because the light passes through large amounts of dust in the atmosphere scattering blue light. During the day, the sky is more orange because the atmosphere absorbs blue light.
Above is a sunset as seen by NASA's Spirit rover on Mars and below the Lincoln Memorial on the National Mall shrouded in smoke on Wednesday, creating a pink-blue tint in the air.