Night Sky on Mars

Marianne Dyson, September 2016

My Night Sky Observing at the Worldcon in Kansas City was rained out. I hope some of you had clear skies and observed Saturn, Mars, and Antares aligned in Scorpio (which is now a triangle), and used my Animated Moon Map to find the Apollo sites.

This month the autumnal equinox falls on September 22, and that got me wondering about what season it is on Mars, and what I might take people to see if I did a Night Sky program there. My brain liked this exercise, so I thought I’d share this “snack” with you.

An equinox is when the sun’s path crosses a planet’s equatorial plane. On the equinox, day and night are equal lengths. Like Earth, Mars is “tipped” on its axis, so it too has equinoxes. But because the north pole of Mars points to a different part of the sky, and the inclination is 25 (versus Earth’s 23.5) degrees, the constellations we associate with spring and fall equinoxes are different on Mars.

Polaris is our north star because it is “above” the spin axis of Earth. All the other stars (and their constellations) appear to rotate around it in a big circle every 24 hours.

The Martian north pole points to a spot without any bright star about 28 degrees from Polaris in the direction of Capricorn (RA 20.5 hours). This pole is about halfway between Alderamin in Cepheus and Deneb in Cygnus a.k.a. the Northern Cross. (Reference: Byrd, Deborah, “Does Mars have a North Star,” EarthSky, 6-16-16) Since Cepheus and Cygnus are on opposite sides of the pole, and rotate around it every Martian sol (24 hours 39 minutes), they can be used to tell time and month on Mars like the Big Dipper and Cassiopeia on Earth.

Mars does not have a pole star. But Deneb and Sadr in constellation Cygnus, can be used as “pointer” stars to locate the pole in the direction of Alderamin in Cepheus. The constellations Cepheus and Cygnus rotate around the pole and can be used like a clock to tell time.
Mars does not have a pole star. But Deneb and Sadr in constellation Cygnus, can be used as “pointer” stars to locate the pole in the direction of Alderamin in Cepheus. The constellations Cepheus and Cygnus rotate around the pole and can be used like a clock to tell time. (Image by Tomruen via Wikimedia Commons with labels modified by Marianne Dyson)

Equinoxes occur twice a year as the sun passes north (spring), then south (fall), of the equator. On Mars they are the first sol of Months 1 and 7 of a 12-month year where a month is the time it takes Mars to pass through 30 degrees of its orbit. Because the orbit is elliptical, instead of each month being 56 sols (668 sols /year divided by 12), the northern fall and winter months average 50 days and the spring and summer months last about 62 days.

The months of fall (gray) and winter (red) are shorter than the months of spring (green) and summer (orange) because Mars moves faster at perihelion than aphelion. (Image from Kuuke’s Strerrenbeelden.)
The months of fall (gray) and winter (red) are shorter than the months of spring (green) and summer (orange) because Mars moves faster at perihelion than aphelion. (Image from Kuuke’s Strerrenbeelden.)

The Martian fall equinox was July 4, 2016. Fall lasts until the winter solstice which is November 28 on Mars and December 21 on Earth. So this October, it will be fall on both Earth and Mars. We will be admiring Cassiopeia (the “W”) and Cepheus to the north, Cygnus overhead, and Perseus (the square) to the south.

For the Martians, the sun is moving toward Leo and then into Virgo at their winter solstice. Cassiopeia and Cygnus are high up for them, too. But because their pole is shifted toward Capricorn, they also have a good view of the Sagittarius teapot and should also see some of Earth’s southern hemisphere constellations, Indus and Piscus Austrinus.  

Like us, Martians will see Venus as an evening star in October, while Earth and the Moon will be visible in the morning. And the Milky Way should be spectacular without any light pollution or buildings to spoil the view. It will also look different because the atmosphere of Mars is too thin to make stars twinkle. 

If we had the Worldcon on Mars, we’d never have to cancel because of rain. I’ll volunteer to do Night Sky Observing, and then lead a discussion about why we should build a Martian Stonehenge to help us view the vernal equinox in Mars Year 42 (Earth date 5-22-32). I hope you’ll join me!

Writing about Space

I’m teaching short story writing in an after-school enrichment program at St. Thomas the Apostle school in Nassau Bay (across from JSC) that may be expanded to include members of the community if there is interest. If your student in 4th grade and up likes creating stories, and would like a published mentor to help them develop their skills, please call the St. Thomas and ask for the Director of Enrichment.

I offer technical and content editing for adult writers, as well as workshops for groups of five or more on writing memoirs and publishing them. See my Resources for Writers page for more information.

Speaking about Space

Watch my website Contact page for updates & Twitter for photos.

Monday, September 12, Houston Science Fiction/Fantasy Writers MeetUp.

Saturday, September 17, 6-9:30 pm. 35th Anniversary of STS-1 & 2 at Space Center Houston. (Tickets no longer available.)

Monday, November 14, 2016, 4-5:30 pm Central Time. I’ll be a guest on The Space Show with Dr. David Livingston. Listen live & see list of upcoming shows

Terraforming Mars

Marianne Dyson,  August 2016

The 47th World Science Fiction Convention (where they give the Hugo Awards) is in Kansas City, Missouri August 17-21. I’m moderating a panel called “The Real Martians” on Friday at 4 pm. One of the topics we will address is terraforming Mars. Could we? Should we?

The term terraforming, which means to transform a world to support human life, was coined by science fiction writer Jack Williamson in 1942. According to BestScienceFictionBooks.com, the concept dates back to H.G. Wells’ 1898 book, The War of the Worlds, where the invading Martians planned to reverse-terraform (?marsaform) Earth.

August-RedGreenBlueMarscover

Caption: Red (1992), Green (1993), Blue Mars (1996) trilogy by Kim Stanley Robinson is considered one of the best and most complete treatment of terraforming in fiction.

While the idea of terraforming Mars has been around a long time, only in recent decades have we obtained the knowledge and ability to actually try it. The answer to the “Could we?” question is a qualified “Yes.”

I say qualified because Mars will always be different from Earth in ways that aren’t feasible to change. Mars is smaller, farther from the sun, and lacks a magnetic field (which helps, but is not essential to protect Earth from radiation). So terraforming Mars really means changing the temperature and atmosphere to make living there easier.

The key to warming Mars is to thaw the carbon dioxide (dry ice) at the south pole. Unlike water ice, dry ice changes directly from a solid to a gas when heated.

Carbon dioxide absorbs heat from the sun that would otherwise be radiated back into space, like the glass of a greenhouse traps the warm air inside. The “greenhouse effect” of increased carbon dioxide will thus spur the thawing of more dry ice and water ice that is now frozen in the dirt. A thicker atmosphere would block radiation harmful to life and allow water to circulate. Some plants and animals could then survive on the surface in about 100 years, though there wouldn’t be enough oxygen for humans to breathe for a thousand years or more.

To thaw the south pole, more sunlight could be directed there via giant reflectors in orbit. Covering the white ice with black dust would increase absorption. If we need more gas to jumpstart greenhouse warming, we might divert some comets containing ammonia to Mars.

August-MeltMars-web

Caption: To thaw the southern ice cap on Mars, we can blacken the ice and reflect sun from orbit. See for yourself: freeze two bottles of water. Wrap one with black paper and the other with white and sit both in the sun. Pour out and measure the water from each after 20 minutes—which one melted more? Use “mirrors” of aluminum foil (wrapped picture frames) to speed up melting. (Photo by Marianne Dyson)

The question of “Should we?” terraform Mars is addressed in a paper, “Planetary Ecosynthesis on Mars,” by NASA planetary scientist Chris McKay. He points out that even if we are successful, the same geologic processes that robbed Mars of its early atmosphere will do so again in 10 to 100 million years. So why bother?

McKay argues that warming Mars “could be of great utilitarian value for humans in terms of the knowledge derived ranging from basic biology to global ecology.” He also notes that any life on Mars today is at risk of extinction if we do NOT thicken the atmosphere.

I therefore answer the “Should we?” warm Mars with a “Yes.” Once we are on Mars, the expense to terraform will be minimal in comparison. And the knowledge gained by “controlling” another biosphere may be the ultimate space spinoff by showing us how to keep Earth habitable and also how to adapt to live elsewhere when the sun brightens and toasts the Earth in about 500 million years.

What do you think? Come and share your thoughts with “The Real Martians” at Worldcon!

Writing about Space

Bring your copy of Welcome to Mars or any of my other books to the Science Fiction and Fantasy Writers of America (SFWA) table in the Exhibit Hall at Worldcon on Friday, August 19 from 1-2 pm to get them signed or just to chat with me about space topics. I’m not allowed to sell books at the SFWA table, so order them ahead of time from Amazon or via my website.

Speaking about Space

Watch my website Contact page for updates & Twitter for photos.

August 17-21, MidAmeriCon II, the 74th Science Fiction Worldcon, Kansas City, MO. Friday: signing at the SFWA table in the Exhibit Hall, 1-2 pm. “The Real Martians” panel at is in room 2201 at 4 pm. At 9 pm, join me in room 2502B where we will gather to then go outside (weather permitting) for night sky observing (with my 70mm binoculars). Saturday I’ll be at the SFWA business meeting 10 to noon and volunteering in the SFWA suite 2-4 pm. Sunday I’m on the “Next Year at 100k” panel about commercial space at 11-am. My MidAmeriCon schedule.