The Colorful Martian Sky

February 2016

Author Marianne Dyson’s Science Snacks Newsletter

Hello, and thanks for subscribing to my monthly Science Snacks newsletter. I hope to see some of you at my upcoming appearances (listed below) and share space stories with you!  

The Colorful Martian Sky

In the January Science Snacks, I discussed the recent discovery of liquid water on Mars and that several pages of Welcome to Mars (coauthored with Buzz Aldrin) are being updated to reflect the discovery. The changes (to pages 12 and 70) weren’t ready in time to be included in the second print run.

But the second printing (on right in image) does include rotation of the robots on the cover flap, and a change to the Martian Home art on pages 80-81.


Caption: The Martian Home art depicts a scene from a future settlement where kids enjoy Buzz’s favorite coconut ice cream (note the goat and a coconut palm!) at his Ice Cream Parlor while adults dine at my Pasta Palace. The question is, should the sky above be pink or blue?

The “true” color of the Martian sky has been debated since the first spacecraft sent back images from the surface. Most NASA images show a pink or butterscotch sky. This color results from dust suspended in the atmosphere, similar to dusty or smoggy skies on Earth. But dust also scatters blue light, as seen in sunset photos taken by the rover Spirit. And under some conditions, such as when ice clouds form, the sky may appear violet (see images).

converted PNM file
converted PNM file

Caption: This sunset seen by Spirit in March 2014 appears blue near the sun and pink farther away. The sun is also about two thirds the diameter and less bright on Mars than it appears from Earth. (MER, Texas A&M, Cornell, JPL, NASA photo)

The scene depicted in the Martian Home art may be from a buried habitat with an artificial sky. (As noted on page 75, “Under 16 feet of dirt, we’ll get the same amount of radiation we get on the surface of Earth.”) Or the art might reflect the sky after terraforming has thickened the atmosphere as shown in the Green Mars art on pages 88-89.

However, to be consistent with the cover illustration showing a future Mars city under a dome (that protects from radiation via coatings or clear gel of some kind) with a lovely pink sky in the background, we decided to recolor the illustration on pages 80-81.

While researching this topic, I answered another question about the sky on Mars—do the stars twinkle there at night? The answer: no, the air is too thin. (“Why do stars twinkle, and do they twinkle on Mars?” by Whitehead, Hizinga, and Mossman, American Journal of Physics, 2012) But, if you observe from inside the Mars Home dome, would they twinkle? Let’s build one and find out!

Writing about Space

The anthology, Touching the Face of the Cosmos: On the Intersection of Space Travel and Religion that contains my story, “The Right of Interference” is out via Kindle and will be available in paperback March 1. If you order after using the link from my website, I get a credit from Amazon.

Speaking about Space

I’ll be speaking at the following events. Watch my website Contact page for updates and local (Houston) events.

Thursday, February 18, 5:30 pm. AIAA Distinguished Lecturer. Ohio Space Institute, 22800 Cedar Point Road, Cleveland, OH 44142. Free, open to the public.

Friday, February 19, speaker for “Dinner with a Slice of History.” International Women in Air & Space Museum, Burke Lakefront Airport, 1501 North Marginal Road, Cleveland, OH 44114. Open to the public. Tickets $15-17. Proceeds benefit museum.

Monday, March 7, after 4 pm. Guest speaker. University of Florida Society of Women Engineers. Gainesville, Florida. “Mission Control: Solving Problems in Realtime.”

Saturday, April 23, Ohioana Book Festival, Featured Author. Sheraton Columbus Hotel at Capitol Square, 75 E. State St., Columbus, OH 43215.

Author: Marianne

Marianne Dyson is an award-winning children's author, science fiction writer, and former NASA flight controller. To invite her to speak or order her books, visit her website,