Mars Rovers Must Rove Responsibly

~ J.S. Pailly ~ 16 Comments

We’ve sent several robotic space probes to Mars already, and several more will be heading to the Red Planet in the next few years. Mars is already the second most heavily explored planet in the Solar System, after Earth.

But our robots are forbidden by international law from entering regions where Martian water appears to be flowing, or regions where Martian life could hypothetically exist. Why? Because there’s a chance that microorganisms from Earth hitched a ride aboard our space probes, survived the journey to Mars, and might start to grow and reproduce if they’re exposed to Martian water.

Yesterday, we talked about a paper in the journal Astrobiology which argued that the risk of contamination is minimal, and we should let our Mars rovers do their jobs. Go explore, and if there’s Martian life, go find it! Today we’re looking at a response to that paper, also published in Astrobiology, in fact in the same issue of Astrobiology. A response which raises several concerns, such as:

  • In the last few decades, we’re learned that Earthly microorganisms can be far more resilient than we ever imagined. Some of them very well might survive—and thrive—on Mars.
  • We’ve also learned that Mars is far less hostile to life than we previously assumed. Quite a few microbes from Earth might find Mars a rather comfortable place to live.

Taken together, these two points suggest that we have not overestimated the risk of contaminating Mars. In fact, we may have drastically underestimated the risks, and we need to be more careful, not less careful, about where we let our Mars rovers go. Otherwise:

  • We might destroy the very Martian life forms that we’re so desperately hoping to find.
  • We might make Mars’s water undrinkable for future human settlers.
  • We might end up misidentifying a stowaway microbe from Earth as a new form of life native to Mars, and the authors of this response paper argue that even our best gene sequencing technology might not be able to clear up the potential confusion.

Even if our Mars rovers keep their distance from Mars’s potentially-habitable or potentially-inhabited areas, there’s still a lot of valuable science they can do, especially when they’re investigating areas that used to be lakes or rivers, areas that could have supported lots and lots of alien life in the past, even if they’re bone dry and very thoroughly lifeless in the present.

So let’s take things slow. Let’s stick to the original plan (and current international agreements) and continue to explore Mars in a responsible and methodical manner.

Or maybe not. Gosh, I don’t know. After reading these two papers back to back, I really don’t know what to think.

Let a Mars Rover Rove

~ J.S. Pailly ~ 8 Comments

In the near future, human beings will probably set foot on the planet Mars. Human beings will likely do a lot of other things on Mars too: coughing, sneezing, peeing, pooping… it won’t be long until Mars is thoroughly contaminated with our germs.

We may have contaminated Mars already, at least a teeny bit, with our robotic space probes. You see, these probes may not have been as thoroughly cleaned and sterilized as they were supposed to be before they left Earth. Consequently, our Mars rovers, like the Curiosity rover, are forbidden from entering or even approaching sites where liquid water may be present.

This is to ensure that we don’t endanger any native Martian life that could hypothetically be living in those watery areas. It’s also to ensure that we don’t misidentify Earth germs as native Martian microbes at some point in the future.

But according to this paper published in the journal Astrobiology, we really should lighten up and let our Mars rovers do their jobs. We’ve spent billions on these robots, and we’re not using them to their best. While there is some risk of contamination, it’s only a small risk, or so the authors of the paper claim.

First off, the Martian environment is extremely cold, there’s lots of radiation, and an abundance of harsh, oxidizing chemicals in the soil. In short, Mars can do a better job sterilizing out space probes than we can. The very few Earth germs that might have made it to Mars thus far wouldn’t be able to spread far.

As for misidentifying an Earth germ as a Martian microorganism, the authors of the paper claim this wouldn’t be a problem. At this point, we have a pretty good idea which Earthly bacteria could have hitched a ride to Mars, because we know which bacteria were later found in the clean rooms where our space probes were built. Those bacteria can be easily identified with gene sequencing.

So let’s send the Mars rovers in. Let them do their jobs. Let them study Mars’s recurring slope lineae and other watery features, or any other areas where life could possibly exist. Let’s do this now, while the risk of contamination is still relatively low, because the humans are coming, and they’re bringing a whole lot more germs with them!

Or maybe not! As I’ve said before, these kinds of scientific papers should be understood not as final declarations of fact but as part of an ongoing conversation among scientists. In tomorrow’s post, we’ll talk about the other side of the argument.

Sciency Words: Polygon Terrain

~ J.S. Pailly ~ Leave a comment

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

POLYGON TERRAIN

This phenomenon goes by several different names: polygon terrain, polygon patterned terrain, polygonal patterned ground formations… you get the idea. For the purposes of this blog, I’m making polygon terrain the official way to say it, because that matches up with other terrain-related terms we’ve seen, like chaos terrain or cantaloupe terrain.

Polygon terrain is a distinctive pattern of either cracks or ridges that draw polygonal shapes across the landscape. On Earth, these polygons tend to appear in arctic climates. They’re caused by the repeated freezing and thawing of underground glaciers.

When the ice thaws, the ground above it can sink down a little. Then when it refreezes, the ground is forced back up. Overtime, the surface starts to break and crack, producing a landscape that looks like this:

Images courtesy of Wikipedia.

Polygon terrain seems to be uncannily common in Mars’s northern hemisphere, in regions such as Utopia Planitia. This suggests two things:

  • There are large glaciers buried beneath the layers of surface dust and surface rock.
  • Those glaciers periodically thaw and refreeze.

Thawing Martian glaciers might or might not produce liquid water. Instead, the ice may sublimate, skipping its liquid phase and turning directly into water vapor. But still, during warmer seasons, it’s possible we might find a trickle of liquid beneath these polygon terrain regions—perhaps even enough to sustain a few extremophile microorganisms.

In the future, human explorers on Mars may take a keen interest in Mars’s polygon terrain. This kind of surface geometrization may not have anything to do with advanced alien civilizations, but it’s still worth a look if you’re searching for simpler forms of alien life. Or at least, it’s a good place to check if your colony is in desperate need of liquid water.

P.S.: For a slightly more detailed (without being unintelligibly technical) discussion of polygon terrain, please check out this post from Planetary Geomorphology Image of the Month.

Fish in Space!

~ J.S. Pailly ~ 4 Comments

So the cartoon… I mean, the highly technical diagram in yesterday’s post implied that being in space wouldn’t be much of a thrill for fish. I mean, they swim up, they swim down… they swim in whatever direction they want, right?

But then I found a video showing a side-by-side comparison of the fish tank aboard the International Space Station and an identical fish tank down here on Earth, and it looks like I was very, very wrong. Fish do change their swimming behavior in microgravity. It’s really pretty, actually, watching them spin and twirl about.

Dining on Mars, Part 4: Tilapia

~ J.S. Pailly ~ 14 Comments

The first colonists on Mars will have to be, out of necessity, vegans. Growing plants on Mars will be challenging enough; raising livestock would be utterly impractical. If we must include animal protein in a Martian diet, the only realistic option would be bugs like crickets or mealworms.

However, as a Mars colony grows, a few “luxury foods” might be added to the menu, including heartier sources of protein like seafood. That may not make a lot of sense at first. Mars is a barren, desert planet. How could we bring fish to a place like that?

But research has already done about how fish fare in space. The Japanese Aeropace Exploration Agency (JAXA) built a fish tank aboard the International Space Station.

Building large, underground aquariums on Mars wouldn’t be too difficult, compared to all the other aboveground and belowground structures a Mars colony would need. And if your colony settled in a region like Utopia Planitia, you should have more than enough water to fill your fish tanks (as we’ll see in Friday’s post).

In Robert Zubrin’s book The Case for Mars, he casually mentions that tilapia would be a good choice for Martian fish farming, because they’re herbivores and they could eat a lot of the plant matter that we can’t digest. I’ve found some research that seems to back Zubrin’s suggestion up; however, there’s some concern about whether or not Martian tilapia would be as nutritious as the Earthling kind. A lot will depend on the sorts of plant matter available for us to feed our Mars-born fish.

Personally, I love seafood. Also, I’m a big fan of aquariums, so living on Mars is starting to sound even more appealing to me. And there is still one more food source that I want to tell you about that might (might!) be a viable option for a self-sustaining Mars colony. Stay tuned!

P.S.: And if you want to try the Mars colony diet out yourself, check out Kate Rauner’s blog to get some recipes!

Molecular Monday: Venus’s (Formerly) Unknown Absorber

~ J.S. Pailly ~ 2 Comments

Today’s post is part of a bi-weekly series here on Planet Pailly called Molecular Mondays, where we take a closer look at the atoms and molecules that make up our physical universe.

Okay, I know I said March would be Mars Month here on Planet Pailly, but for today’s episode of Molecular Mondays, we really must talk about the latest news from Venus. Our best lead for finding life on Venus has just dried up.

The idea of life on Venus has always been a long shot, but for the last few decades planetary scientists have been puzzled by a mysterious something in the Venusian atmosphere. A something that absorbs large quantities of light in the ultraviolet and near-ultraviolet part of the spectrum. This unknown UV absorbing substance has come to be known as the “unknown absorber.”

In his book Venus Revealed, planetary scientist David Grinspoon hypothesizes that the unknown absorber could perhaps maybe possibly be a “photosynthetic pigment” similar to chlorophyll. If so, that would mean there are little, photosynthetic microorganisms swarming about in Venus’s atmosphere, gobbling up UV radiation and converting it into usable energy. This hypothesis is extremely unlikely—Grinspoon makes that abundantly clear—but we could never rule the idea out entirely.

Except, unfortunately, we can now rule this idea out entirely. The unknown absorber has been identified. It’s not a photosynthetic molecule. It’s not even a particularly complicated molecule. It’s just a simple sulfur/oxygen compound called disulfur dioxide.

The story goes like this: sulfur monoxide (SO), which is fairly common in Venus’s atmosphere, combines with itself to form disulfur dioxide (S2O2). Specifically, it creates two different versions (or isomers) of disulfur dioxide called cis-OSSO (which has its oxygen atoms oriented in the same direction, as pictured above) and trans-OSSO (which has its oxygen atoms oriented in opposite directions). Then when cis- and trans-OSSO absorb ultraviolet light, they break back down into sulfur monoxide, and the cycle begins anew.

So our best hope for finding life on Venus appears to be gone. Oh well. It was a long shot anyway. I still have high hopes for finding life (probably fossilized life) on Mars.

Sciency Words: Canali

~ J.S. Pailly ~ 2 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

CANALI

In last week’s episode of Sciency Words, we looked at one of the maps of Mars drawn by Italian astronomer Giovanni Schiaparelli, and we talked about how Schiaparelli invented many of the place names we still use for Martian geography today. But Schiaparelli’s work also led to one of the most embarrassing mistakes in the entire history of astronomy, and it all happened because of a word: canali.

Looking through his telescope, Schiaparelli saw (or thought he saw) little lines crisscrossing the Martian surface, and he labeled these lines “canali,” which is Italian for channel, but the word was mistranslated into English as “canals.”

It seems Schiaparelli believed these “channels on Mars” were a natural phenomenon, but that’s not the impression English-speaking astronomers got when they started reading about “canals on Mars.” And some astronomers, most notably American astronomer Percival Lowell, were so excited by the idea of Martian canals that they turned their own telescopes on Mars and saw (or thought they saw) exactly what they wanted to see.

This would be the same kind of technological geometrization that Carl Sagan would later write about in reference to Earth, but on a much larger scale. Except it’s not true. Mars is not covered in canals. Even before NASA started sending space probes to Mars, researchers found that the whole thing was probably a trick of the eye. To quote from a paper from 1903:

Our conclusion from the entire experiment is that the canals of Mars may in some cases be, as Mr. Green suggested, the boundaries of tones or shadings, but that in the majority of cases they are simply the integration by the eye of minute details too small to be separately and distinctly defined.

However, in more recent times our space probes have discovered other oddly geometric patterns on Mars, the kinds of patterns that may reveal a very different kind of Martian secret. But I’ll save that for next week!

Martian Snowflakes

~ J.S. Pailly ~ 10 Comments

Thus far in my on-again/off-again mission to Mars, I’ve learned that while ancient Mars may have been a wet and watery place, that does not necessarily mean it was anything like Earth. The evidence I’ve seen from Mars’s Tharsis region and the surrounding area suggests that Mars has had a rather violent history with water. But I’ve heard that other regions—most notably the Utopia Planitia region—may have a different story to tell about Mars’s watery past… and its watery present.

I’ve only just started learning about Utopia Planitia, and right away I was in for a surprise. On September 13, 1977, the Viking-2 Lander took a photograph of what appeared to be a light dusting of snow on the ground. Then on May 18, 1979, approximately one Martian year later, it happened again. This is the 1979 photo:

We can’t be 100% sure what happened, specifically. Did it really snow at the Viking-2 landing site, or does it just look like snow? Could it instead be a layer of frost, like how back on Earth morning dew turns to frost during the winter? Is this snow/frost made of frozen H2O, frozen CO2, or a mixture of both?

Personally I’d like to believe that it snowed, and that it was genuine H2O snow. I love snow. I love how quiet and pretty and restful snow is, and somehow the idea of snow drifting even more slowly to the ground (because of Mars’s reduced gravity) appeals to me. I wish I’d started studying something other than the Tharsis Bulge and Valles Marineris canyon earlier, because clearly I’ve been missing out!

P.S.: I think there should be something like the Lunar X-Prize for whoever builds the first snowman on Mars.

Sciency Words: Utopia Planitia

~ J.S. Pailly ~ 2 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

UTOPIA PLANITIA

As a lifelong Star Trek fanatic, I’ve known the name Utopia Planitia for almost as far back as I can remember. It is (or rather, will be) the site of a prominent human colony on Mars, and by the 24th Century it will be the location of one of Starfleet’s most important shipyards. The U.S.S. Enterprise-D, the U.S.S. Defiant, and the U.S.S. Voyager will all be built there. But where did the name Utopia Planitia come from?

In the 1870’s and 1880’s, Italian astronomer Giovanni Schiaparelli drew what were, at the time, the most accurate and detailed maps of Mars ever produced. But Schiaparelli had a problem. He had trouble matching the pre-established names from older Mars maps to his new map. The old maps were, to put it bluntly, wrong. The new map looked so different that Schiaparelli had to throw out all the old geographic names (goodbye, Kepler-land and Cassini-land!) and make up new ones.

For inspiration, Schiaparelli turned to the Bible, Greek and Roman mythology, and other classical sources. That included several names for “paradise,” like Eden, Arcadia, and Utopia. Clicking the image below will take you to a NASA history page, where you can take a closer look at one of Schiaparelli’s maps (I believe it’s his original map from 1877, but I’m not 100% sure). Bear in mind that this map was drawn based on what Schiaparelli saw through his telescope, and it was intended for use by other telescope observers of his time, so north and south are flipped around.

At about 260° longitude and 50° north latitude, you’ll find a small, triangular shape marked Utopia.

In Greek, the literal meaning of Utopia is “no place,” but the word has come to mean paradise or fantasy-land… a place so idealistically perfect that “no place” like it could exist in reality. And so Utopia Planitia means “the plains of paradise” or “the plains of fantasy.” Thematically speaking, I can’t think of a better place for all those wonderful ships from Star Trek—and the idealistic vision of the future those ships are supposed to represent—to be constructed.