NASA released this rover photo of a “blue” sunset on Mars:

A striking scene.  But why is the sunset “blue,” instead of red or orange?

Dust in the Martian atmosphere has fine particles that permit blue light to penetrate the atmosphere more efficiently than longer-wavelength colors. That causes the blue colors in the mixed light coming from the sun to stay closer to sun’s part of the sky, compared to the wider scattering of yellow and red colors. The effect is most pronounced near sunset, when light from the sun passes through a longer path in the atmosphere than it does at mid-day.

In other words, the sky isn’t actually blue–debris in the atmosphere distort how we see the sun’s light.

This phenomenon doesn’t just occur on Mars . . . or with sunlight.  It also happens in our minds.  Our pendent beliefs and biases–like the dust in the Martian atmosphere–alter the way we perceive the world around us.

Often these filters are the useful product of experience, helping us navigate more efficiently through life’s unending grind.  But sometimes the particles affecting our perception are psychological constructs which cloud, rather than enhance, our vision.

This happens to me when I’m feeling depressed.  My mind puts a negative tint on the world around me. And not just on the bad things happening, but on ordinary, everyday incidents.  I synthesize chance events into a grand plot the universe is waging against me.

In my more even-tempered moments, when I’m not sad, I recognize how this distortion further brings me down. But by then it’s too late to help me through a darker stretch.

So next time I’m feeling melancholy, I’ll try think of the martian sunset.  It will remind me that things aren’t always as blue as they appear.  My mental martian dust alters how I see them.