Exploring Mars, Looking for Life: and Still Learning

Mars is and will be in the news this month.

The UAE Hope spacecraft settled into orbit around Mars Tuesday, February 9.

Then, a day later, China’s Tianwen-1 arrived.

The UAE, United Arab Emirates, is now the fifth outfit with a successful Mars orbiter. And, if all goes well, NASA’s Mars 2020 mission will land in Jezero crater Thursday, February 18.1

The UAE’s successful orbiter is historically significant. And China’s Tianwen-1 may collect useful data. But I’ll be focusing on the NASA mission. And Mars.


None of this season’s arrivals will find signs of ancient and exotic Martian cities.

Not the colorful variety imagined by pulp science fiction artists, at any rate.

Anything that big, that blatantly artificial and dust-free would have been spotted by orbiters and/or rovers long since.

Something artificial, but not quite so dust-free? That’s something I’ll talk about later in this series.

NASA press releases have been focusing on the Perseverance rover’s astrobiology tech and the Ingenuity helicopter it’s carrying.

Both are important. But Perseverance also carries a weather station and a geology lab that includes ground penetrating radar and an X-ray fluorescence spectrometer.2

Lowell’s Canals, Mariner 4’s Craters

Lowell's Martian 'canals.' (before 1914)
(From Percival Lowell, via Wikimedia Commons, used w/o permission.)
(Lowell’s Martian “canals;” from “Distant Worlds,” Yakov Perelman (1914))

“…On the earth the sea-bottoms still hold seas, on Mars they only nourish vegetation….
“…once fertile fields become deserts….
“…That it [a canal network] joins the surface from pole to pole and girdles it at the equator betrays a single purpose there at work. … Nations must have sunk their local patriotisms in a wider breadth of view and the planet be a unit to the general good….”
(“Mars as the abode of life,” Percival Lowell (1908))

I gather that few, if any, other scientists took Percival Lowell’s Martian canals and the doomed civilization he said was building them seriously. (February 23, 2018)

But they gave generations of science fiction writers a nifty setting.

And I’m drifting off-topic.

The point I’m groping for is that life on Mars seemed possible when I was growing up.

Then, in 1965, Mariner 4 sent back pictures of big craters, small craters — and not much except craters.

Cratered landscapes and a very thin atmosphere made Mars seem more like Earth’s moon than a maybe-habitable planet.3

But Mariner 4 was a flyby mission. What we saw was a strip of Mars that happened to be ‘under’ the spacecraft as it zipped by the planet.

It was as if Martians had gotten pictures and data from part of the Pacific Ocean and decided that Earth was all wet. Covered by water. You know what I mean.

Orbital Reconnaissance

Nirgal Vallis, Mars, from Mariner 9.
(From NASA/JPL-Caltech, used w/o permission.)
(Mariner 9’s view of Nirgal Vallis, Mars.)

Then we sent spacecraft that stayed in Martian orbit, letting us get more than snapshot of our neighbor. We saw more craters. But we also found what looked a great deal like riverbeds, deltas and other water-sculpted features.

Maybe Mars wasn’t so lifeless after all. Or hadn’t been.

The last I checked, there’s still lively debate about how much Martian water is near the surface and whether observed flows are water, dust or something else.

And whether Vastitas Borealis, the biggest Martian lowland area, was an ocean four billion years back.

There’s chemical and visual evidence that says a Martian ocean existed.4 But if that’s so, scientists have other puzzles. Like where did the water go?

That’s why it’s still the “Mars ocean hypotheses,” not the “Mars Ocean.” I figure that if there was a Martian ocean, we’ll find and analyze enough data to show that it was real.

Then the IAU will decide whether it’s called the Paleo-Ocean, Oceanus Borealis or something entirely different.

Like Ketchum, after Ketchum Lake here in Minnesota. Which is between Lengby and Bijou, two other places you probably never heard of.

Back to the Perseverance rover’s landing site.

MARS 2020 and Jezero Crater

Jezero Crater's delta, image from ESA Mars Express Orbiter. (September 21, 2020)
(From ESA/DLR/FU-Berlin, via NASA, used w/o permission.)
(Jezero Crater delta, Mars.)

Jezero Crater’s fan delta looks like the Mississippi River Delta. Not exactly, of course. But land near New Orleans would look a bit like that, if North America and the Gulf of Mexico was a desert. But hadn’t been while the Mississippi river and its silt flowed.

It’s a near-certainty that Jezero Crater was a lake, upwards of 3,500,000,000 years ago. Scans from orbit show that the river in what we call Neretva Vallis carried clay from upstream, dropping it in the Jezero Crater delta.

Neretva Vallis? That’s the Jezero Crater’s inflowing river’s channel. Neretva is a river in the Pliva-Jezero-Plivsko area.

The crater is named after the town of Jezero, Bosnia and Herzegovina. The Bosnia and Herzegovina town is on Plivsko Lake and the Pliva River. Which most likely explains why we call another Jezero Crater riverbed Pliva Vallis.

Or, since the Neretva is the a major stream in that region, they’re in the Neretva area.

More to the (scientific) point: if there was life on Mars, that river delta would have been a good place for microcritters. Back when Mars was wetter and presumably warmer than it is now.

The life, if any, would most likely be long gone. But it might have left detectable traces.

And that’s why the Perseverance rover carries a bio lab.5

Ingenuity, Briefly

NASA Mars Helicopter Ingenuity.Perseverance also carries a helicopter.

Ingenuity won’t be doing much science. It’s mostly there to make the first powered flight on another planet.

The Mars helicopter has limited autonomy. And that’s something I’ll save for another day.6

If all goes well, we may find the first evidence of extraterrestrial life this year.

Assuming that we didn’t find it a couple dozen years back.

Extraterrestrial Fossils?

ALH84001, Martian meteorite.
(From NASA, via Wikimedia Commons, used w/o permission.)
(Martian meteorite ALH84001, found in Antarctica’s Allan Hills. (December 27, 1984))

ALH84001 is a rock collected back in December of 1984.

Analysis confirmed that it’s a meteorite. More analysis pegged it as a shergottite-nakhlite-chassignite, or SNC, meteorite.

Don’t bother trying to memorize those names. There won’t be a test. The point is that this particular rock formed on Mars. And was blasted off that planet during an impact.

Either that — or pretty much everything we’ve learned about rocks, planets, physics and chemistry over the last few centuries is wrong. Which strikes me as unlikely.

Assorted Martian/Antarctic rocks got divvied up among assorted scientists. Including some working with NASA.

Then, on August 6, 1996, they said they’d found fossilized microcritters. In ALH84001.7

As I see it, we discovered extraterrestrial life in 1996. Or we didn’t.

Mini-Microbial Martians? Impossible!

'Hypothetical biogenic features' in ALH84001.
(From NASA, via Wikimedia Commons, used w/o permission.)
(Structures in ALH84001, seen through electron microscopy. (1996))

Those blobby linear things look like terrestrial bacteria. Chemical traces associated with them are also associated with terrestrial microcritters.

Problem is, the ALH84001 things are far too small to be bacteria. Terrestrial bacteria simply aren’t that small.

And some current biological theory says single-cell organisms can’t be that small.

I can follow that line of reasoning.

The ALH84001 structures look like bacteria.

But they’re much smaller than terrestrial bacteria. And what we know about cellular biology suggests that single-celled organisms can’t live if they’re under a certain size.8

So the ALH84001 fossils can’t be fossilized organisms.


Or Maybe Not

ALH84001: close-up photo.
(From Johnson Space Center/NASA, used w/o permission.)
(Close-up photo of ALH84001, rounded carbonate inclusions. (1995))

On the other hand, ALH84001 is around four billion years old. And from Mars.

And fossilized thingummies in it look like bacteria. Only they’re too small.

And some scientists have showed how non-biological process can leave similar traces.

So maybe the ALH84001 are just weird little shapes that aren’t fossilized Martians.

Or maybe Terrestrial bacteria aren’t just like Martian microcritters.

Again, ALH84001 is about four billion years old. If those shapes are organisms, they lived on Mars during Earth’s early Eoarchean era.

Our bacteria are end products of everything that’s happened during the last 4,000,000,000 years. What’s happened on a planet that’s been mostly covered with water and/or ice. With surface gravity three times that of Mars.

Arguments that the ALH84001 features can’t be fossilized critters strike me as being like someone studying photos of a hummingbird. And proving that it can’t be alive, since it’s so very much smaller than an elephant.

I’ll admit to having a bias.

Ball lightning entering through a chimney, from Hartwig's 'The Aerial World.' (1886)I’ve seen ball lightning’s status change from superstition to serious science.

And I remember when thunderstorm sprites were obviously — according to highly-confident experts — hallucinations reported by unstable soldiers and pilots.

Then a scientist with the University of Minnesota recorded sprites with a videocam.

To their credit, the scientific community did not close ranks, asserting that videocams can and do hallucinate.

And now we are learning more about transient phenomena and Earth’s weather

I figure one of the problems with ball lightning was that we still don’t know how it works. Sprites are almost another matter. I suspect NIH syndrome — not invented here — may be involved.9 And that’s another topic.

Equivocal Evidence: So Far

ALH84001: scanning electron microscope image showing tunnels and curved microtunnels. (NASA (2014))I’m willing to imagine that maybe hypothetical Martian critters could have been more, well, Martian than today’s terrestrial bacteria.

Then again, maybe scientists who think nanobacteria can’t exist because they’re not like today’s terrestrial bacteria are right.

But I strongly suspect that we haven’t learned everything there is to know about life, the universe and everything.

Maybe the ALH84001 “hypothetical biogenic features” are fossilized Martian microorganisms. Or maybe they’re not.

Right now, there’s evidence supporting both views. And no evidence disproving either.

Bottom line? We don’t know. Not yet.

But we’ve learned a great deal.

And are learning that we have a very great deal left to learn:

1 Arrivals, Mars; February 2021:

2 Percy the rover:

3 Viewing Mars:

4 Reconsidering Mars:

5 Names, Mostly:

6 Testing new technology:

7 AL84001, meteorite from Mars:

8 Tiny life, maybe:

9 Bacteria and ball lightning, science and an attitude:

About Brian H. Gill

I was born in 1951. I'm a husband, father and grandfather. One of the kids graduated from college in December, 2008, and is helping her husband run businesses and raise my granddaughter; another is a cartoonist and artist; #3 daughter is a writer; my son is developing a digital game with #3 and #1 daughters. I'm also a writer and artist.
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2 Responses to Exploring Mars, Looking for Life: and Still Learning

  1. I guess this is all fascinating as well as frightening. Let us say we meet with intelligent life “out there”. What next?

    • That’s a good question.

      Maybe we’ll discover that we’re the smartest folks around. Maybe we’ll learn that some folks are much smarter than we are. Either way, as Walt Kelley’s Porky Pine said, “…Either way, it’s a mighty sobering thought.”

      And it’s something I’ll be talking about, later. (I think Porky Pine made a good point.)

Thanks for taking time to comment!