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.

Liquid Water on Mars

January 2016

Author Marianne Dyson’s Science Snacks Newsletter

Hello, and a special welcome to the new subscribers who signed up at Kennedy Space Center. Each month I pick one short science news or fact to share. I hope to see many of you again at future space or writing events where we can discuss our space stories!


Buzz & I signed Welcome to Mars at Kennedy Space Center on December 19, 2015 with help from Christina (Santa hat), & ShareSpace team of Linn, Rob, & Bob.

Liquid Water on Mars

On September 28, 2015, Georgia Tech grad student Lujendra Ojha published her evidence of liquid water on the surface of Mars. That same week, the first print run of Welcome to Mars was nearly sold out. Our editor at NatGeo suggested we reflect the water discovery in the second print run. So I asked myself, what impact does finding liquid water have to our plans to settle Mars?

It wasn’t news that there is water on Mars. Astronomers have observed the polar ice caps wax and wane with the seasons for more than a century. The Viking landers photographed frost forming on the surface. The Mars Phoenix Lander released video of ice sublimating (vaporizing) from the soil underneath its thrusters. The Curiosity rover found sufficient ice in the dirt that 3 cubic feet (0.08 m3) when heated, would produce enough water (6 pints or 2.8 L) for a person for a day.

Additionally, there is ample evidence from orbiting spacecraft that Mars once had oceans. Many have speculated that some of this water remains in underground aquifers.

But no one expected to find liquid water ON THE SURFACE of Mars!

The atmospheric pressure is so low, and the temperature so cold, that exposed water ice should instantly sublimate like we saw with the Phoenix lander.

But Ojha’s analyses of Martian surface features called Recurring Slope lineae (RSL) show water does flow on the surface. The salts in the water act like antifreeze and allow it to be liquid at temperatures below freezing.


Caption: Recurring Slope Lineae (RSL), on Horowitz Crater in southern hemisphere of Mars (32 degrees south latitude, 141 east longitude), appear as dark streaks about the length of a football field. Image credit: NASA/JPL-Caltech/Univ. of Arizona

Finding water on the surface indicates that water is even more abundant than predicted. This is good news and may expand possible sites for future settlement. Or not. The presence of liquid water also increases the chances of finding alien microbes on Mars. If microbes are confirmed, is that a reason to slow or halt human settlements so as not to contaminate them or be contaminated by them?

The answer to this question depends on the nature of the Martian “bugs” and what they need from their environment to survive. Once we know that, we can determine if our use of, or changes to “their” water or minerals or energy source would be of benefit or harm to them or to us. But just knowing that something can live on Mars as it exists today would be very encouraging to our own long-term survival potential there. After all, our bodies have more microbes than human cells!

Yet I fear that because of our history, going back to the Martian canal controversy (1905), the Viking life science results (1977), and the Martian meteorite (1999), scientists will be reluctant to propose the experiments needed to confirm life on Mars. Who will risk having their career ruined by critics rejecting all data indicating life as illusionary patterns, chemical reactions, equipment artifacts, or contamination? Even if we send humans to Mars to observe microbes in action, someone will claim it is a hoax designed to boost NASA’s budget (which we should do anyway)! Hopefully, young scientists like Ojha will continue their important investigations so we can better prepare for life (native or transplanted) on the Red Planet.

The second printing of Welcome to Mars has been updated with changes to pages 12 and 70 reflecting the discovery of liquid water on Mars. What it means to the future settlers of Mars is up to them to decide!

Writing about Space

If your kids like Welcome to Mars, they might also like The Callahan Kids: Tales of Life on Mars. This is a collection of nine original stories about the first kids (ages 11 to 14) on Mars. All the stories had their science facts checked by engineers. Read the first story (by yours truly) FREE via the link on my website. EBook is $4.99 and print books are $9.00 if you use the 10 percent off code in the right-hand column.

Speaking about Space

Thursday, February 18, evening. Distinguished Lecture, Ohio Space Institute, 22800 Cedar Point Road, Cleveland, OH 44142. Details TBA.

Friday, February 19, Dinner at 6:30. Featured speaker for “Dinner with a Slice of History,” International Women in Air & Space Museum, Burke Lakefront Airport, 1501 North Marginal Road, Cleveland, OH 44114. Tickets $17. Book sales benefit the museum.

First week of March: I’ll be in Indialantic, Florida (near Melbourne) for a family reunion and would love to visit schools, libraries, astronomy clubs, women’s groups, churches, or book clubs to talk about space. Send email with contact info, and I’ll follow up.