Why Go to Mars? Water, Life, and Exploration

Planet Mars Still Rules the Night Sky

January 29, 2019
Mars InSight Landing
NASA/JPL-CALTECH

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Mars is still brilliant at dinnertime—just as the latest InSight probe has begun sending us revelations from its surface. At this time of year, Mars is one of the sky’s brightest objects between 6:00 and 8:00 PM. Simply look left of where the sun sets for that brilliant orange “star.” You can’t miss it. We keep sending landers there, and interest in Martian colonies remains high—but why?

True, Mars’ super-close visit happened four months ago, in late July, and, also true, our own planet keeps racing away from it at 66,000 miles an hour. After a six-month journey in deep space, NASA’s InSight spacecraft touched down on the planet’s surface just a few minutes before 3:00 pm ET on November 26th. The news was relayed by briefcase-sized satellites—Mars Cube One-A and Mars Cube One-B—which made the trip, too. The “CubeSats” stationed themselves above the planet, taking this photo of the surface—still dust-filled after the landing.

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Image: First photo from InSight. Credit: NASA/JPL-CALTECH

The Good News

On paper, Mars sounds like it may be a friendly place similar to our own planet:

  • Its day is just a half hour longer than ours.
  • Its axis is tilted compared with its orbit, just as Earth is tilted on its axis.
  • It has polar ice caps. That means Mars goes through seasons, just like Earth.
  • And its surface sometimes nudges a bit above the freezing point—which is bearable compared to other planets. (Venus is a balmy 900° Fahrenheit, for example!)
  • There’s even water ice here and there. Mars’ surface has riverbeds, floodplains, and features that could have only been made with water.

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Image: Artist’s rendition of Mars with water. NASA

…and The Bad News

But the downsides of Mars are really discouraging:

  • The Martian surface air pressure matches our own way up at 100,000 feet. Meaning, the Red Planet’s surface air is 30 times thinner than the air atop Mount Everest. 
  • And even that thin, barely-there gas is merely carbon dioxide. No oxygen. You can’t breathe there.
  • It means that no one’s ever going to stroll outdoors there. Martian colonies will be entirely indoor experiences, except for walking in a pressurized space suit.

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Photo: Mars’ surface. Credit: NASA

Why Go to Mars?

So why bother?

  1. The main reason often cited for colonizing Mars is to have some backup real estate if Earth gets too crowded or if we mess it up too badly. That could be a valid reason someday. But right now, Earth boasts vast tracts of inhospitable places like the Antarctic and the Atacama desert where precisely nobody is lining up to live. An Atacama settlement would be incomparably more life-friendly and inexpensive than living on Mars. At least you can breath everywhere in the Vicuna zip code. So perhaps we’re not really running out of terrestrial real estate.

  2. Okay, but what about the fact that it’s our nature to explore—and there are no other suitable planets? Mercury and Venus are far too hot and all the others have no surfaces to land on. They’re gas giants. After Earth, Mars is the planet with the most hospitable climate in the solar system. So, when it comes to planets, it’s Mars or nowhere, and ‘nowhere’ doesn’t have much of a ring to it.  

  3. Then, there’s the search for life. Can we better understand the story of water? The Mars exploration rovers are helping us conduct chemical experiments on the rocks’ composition which can help us read the history of Mars. Did it once hold life—primitive, bacteria-like life? If so, did life on Mars predate Earth’s life and is there a connection? Could there be bacteria in the subsurface alive today? What are the minimal conditions needed for life? What does the history of climate change on Mars tell us about Earth?

  4. What about the expense? Ah, here’s where we get to the nub. As the Apollo Moon landings were ending in 1972, everyone including NASA predicted manned Martian visits by the 90s. Then in the 90s, experts pushed our first human Mars footsteps to the 2010s. Now it’s the 20-teens and NASA is saying the 2030s. Going there is always 15 years in the future. That’s because it’s so expensive—and dangerous.

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Photo: Artists’ rendering of InSight with open solar panels. NASA.

So, just like our ancestors for countless millennia, we’re left gazing distantly at that bright orange beacon in the south at nightfall, so easy to identify. Like them, we speculate and wonder.  

And while we’re on the topic, mark December 14 on your calendar. That’s when Mars will hover just above the half Moon—a very cool conjunction.

Learn more about “Planet Mars, Earth’s Neighbor.”

About This Blog

Welcome to “This Week’s Amazing Sky,” the Almanac’s hub for everything stargazing and astronomy. Bob Berman, longtime and famous astronomer for The Old Farmer’s Almanac, will help bring alive the wonders of our universe. From the beautiful stars and planets to magical auroras and eclipses, he covers everything under the Sun (and Moon)! Bob, the world’s mostly widely read astronomer, also has a new weekly podcast, Astounding Universe

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