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Welcome to the Deep Dive.
Today we are focusing on the red planet, on Mars, a world that for centuries has served as this kind of mythic arena.
It really has.
It's been a canvas where we've projected just about everything.
Exactly.
Our wildest hopes, our engineering fantasies, and our deepest fears about life beyond Earth.
And it's a place where that hope has often made it.
Well, difficult to maintain the patience and tolerance for ambiguity that science really demands.
There's this great old story about a newspaper publisher who telegrammed an astronomer desperate for a headline.
He asked for 500 words right away on whether there's life on Mars.
And what did he get back?
The astronomer who understood you can't just, you can't rush these things.
He just replied, nobody knows, nobody knows, nobody knows 250 times.
That is the perfect way to put it.
And it's really the conflict we're tracing today.
We've always wanted that quick definitive answer.
So our mission now is to follow this tension from those 19th century fantasies and frankly glarius mistakes to the hard -won realities from our robotic space missions.
Especially the Viking landers in the 70s.
We're moving from a time where you could argue the intelligence was on this side of the telescope to the age of hard evidence and seeing what that evidence actually tells us.
OK, let's unpack that.
Let's start with why Mars?
Why did it capture the imagination so much more than, say, Venus?
Everybody talked about Martians.
It really just comes down to visibility and similarity.
Of all the planets, Mars looks the most Earth -like, at least at first glance.
You can see the surface.
You can see the surface through its thin atmosphere.
It has polar ice caps that you can watch grow and shrink with the seasons.
And clouds, right.
Drifting white clouds.
Drifting clouds, huge dust storms sometimes, and maybe the biggest thing.
A day that's almost exactly 24 hours long.
The similarities are so compelling.
It's just an easy jump to think, well, if it looks like home, someone must be home.
Exactly.
And nothing crystallized that feeling.
Both the hope and the fear.
Like H .G.
Wills' The War of the Worlds back in 1897.
Oh, those opening lines are still just incredible.
The idea that we were being watched keenly and closely by intelligence is greater than man's.
It taps right into that fear that maybe we aren't the top dogs.
That these vast, cool, unsympathetic minds were looking at Earth with envious eyes.
And for a long, long time, the focus of that hope and terror was just that one bright red point of light in the sky.
Which brings us to the man who really embodied the hope side of things, Puss of a Lowell.
The wealthy Bostonian.
Right.
He was completely electrified by this announcement in 1877 from the Italian astronomer Giovanni Schiaparelli.
Schiaparelli reported seeing Canali.
Canali, exactly.
And this is the moment where one tiny linguistic mistake just launches a thousand theories.
The critical tipping point.
It is.
Because Canali in Italian just means channels or grooves, natural things.
But in English?
In English it was immediately translated as canals.
And canals imply, well, they implied builders.
Intelligent construction.
And Lowell was completely swept up in that idea.
He was.
He dedicated his life to it.
He built his own observatory in Flagstaff, Arizona, specifically to observe Mars.
And what he thought he saw was just incredible.
His notebooks are filled with them.
Hundreds, thousands of these straight lines crisscrossing the planet.
He built this entire elaborate vision around them.
A global network of irrigation ditches.
Exactly.
Built by an older civilization, a wiser race, fighting this desperate battle to move water from the melting polar caps down to the thirsty inhabitants near the equator.
And you have to remember the context of the time.
This was the great age of engineering on Earth.
Oh, absolutely.
The Suez Canal, the Panama Canal.
With the massive irrigation projects in the American Southwest, it made perfect sense to them.
If we can do this, surely an older, wiser race could do it on a planetary scale.
But not everyone was buying it.
And the most serious challenge came from a very unlikely source.
Alfred Russel Wallace.
The co -discoverer of evolution, yes.
And he was in his 80s at this point.
He wasn't using a telescope.
So what did he use?
A pencil and paper.
He just did the physics.
And his analysis was devastating for Lowell's theory.
Oh, so.
He showed that Lowell got the temperature completely wrong.
Lowell thought Mars was, you know, as pleasant as the south of England.
And it wasn't?
Not even close.
Wallace proved that because it's farther from the sun and has such a thin atmosphere, Mars was almost everywhere below the freezing point of water.
It was a world of permafrost.
So, if it's that cold and the air is that thin, moving liquid water is impossible.
Impossible.
Wallace said that trying to move water in open canals across the planet would be the work of madmen rather than of intelligent beings.
Why madmen?
Because every single drop would either evaporate into the thin air or just soak into the ground within 100 miles.
It couldn't work.
Still, the myth just refused to die.
I mean, you had Edgar Rice Burroughs in his Barsoom novels.
John Carter fighting four meter tall green men on the banks of those canals.
The power of that myth was just immense.
Until the space age.
That was the ultimate reality check.
Definitely.
When Mariner 9 mapped the entire planet with resolution that just blew away any telescope on Earth.
Not one canal, not one lock, not one tributary.
Nothing.
So what were they seeing?
Lowell and the others?
What was actually happening?
Well, the consensus today is that it was a kind of malfunction.
A malfunction of the telescope.
Of the human hand, eye, and brain combination.
Especially when you're straining to see something at the very limit of visibility through a shimmering atmosphere.
What astronomers call bad seeing.
Your brain just, it wants to connect faint, blurry dots into straight lines.
It's an optical illusion.
Lowell was sincere.
He truly believed he was seeing them.
As the old joke goes, the only real question was which side of the telescope the intelligence was on.
Precisely.
Okay, so that brings us to the next massive challenge.
We've gone from the telescope to actually trying to land a working lab on the surface, and that was incredibly hard.
It was.
The Soviet Union's early missions really showed how hard.
They were incredibly persistent, but just plagued by failures.
Like a Mars 3 lander.
Mars 3 actually landed successfully in 1971, which was an amazing achievement.
But it landed right in the middle of a massive global dust storm.
And then it just went silent.
It did.
The theory is that the near surface WANs, maybe moving at 500 kilometers an hour, caught the parachute and just dragged the lander, smashing it to pieces.
So in the US plan, the Viking missions for 1976, safety had to be the absolute top priority.
Oh, completely.
The constraints on where they could land were severe.
What were they?
Well, four main things.
One, the site had to be low lying.
The atmosphere so thin, you need every bit of it to slow down with the parachute.
Okay, makes sense.
Two, you needed low winds.
Three, the ground couldn't be too rough or too soft like quicksand, which they had to check with radar from Earth.
And four, not too close to the poles where ice could make things unstable.
That sounds like a list designed to eliminate 99 % of the planet.
It pretty much did.
It was a very, very conservative approach.
They found places that worked.
But the result was that the landing sites, Christ and Utopia Planitia, were, to be blunt, dull.
They were safe, but boring.
Exactly.
Ancient, featureless floodplains.
We landed in what were essentially the empty parking lots of Mars, far away from the cool stuff like the giant volcanoes or the river valleys.
But the landings themselves were a huge triumph.
I mean, after a journey of nearly a billion kilometers.
A huge success.
The very first picture they took was of the lander's own foot pad.
Just to make sure it wasn't sinking.
Right.
And with great relief, they saw it sitting high and dry.
And then came that first panoramic view of the Martian horizon.
It looked familiar.
It was stark and red and lovely.
It looked a lot like parts of Colorado or Arizona.
It was a real place, but it was empty.
Utterly lifeless to the naked eye.
No air cars, no short swords, no footprints.
Not even a lizard or a patch of moss.
And that failure to see any big life forms forced this huge shift in strategy.
If life was there, it had to be microscopic.
Which makes sense.
On Earth, for three billion years, microbes were it.
Big stuff is a pretty recent development.
Exactly.
So to look for life on Mars, he had to start thinking small.
And that leads to the Mars jurors' experiments here on Earth, simulating the Martian environment.
Yeah.
They recreated the conditions.
Low oxygen, freezing temperatures, that fierce UV light from the sun.
And what happened to Earth microbes?
A lot of them died, but a surprising number survived.
They survived by hiding under tiny pebbles or grains of sand to escape the UV light.
So the thinking was, if our microbes could manage, any native Martian microbes should do even better.
So the Viking landers carried these tiny automated biology labs, three different experiments, all looking for signs of metabolism.
Right.
They were looking for signs that something in the soil was eating, breathing, or photosynthesizing.
Let's break those down.
What was the first one?
The first was the gas exchange experiment.
They basically just added some moisture to the soil and looked to see if any gases, like oxygen or methane, were produced or consumed.
Okay.
And the second?
That was the labeled release experiment.
And this one was maybe the most exciting.
It fed the soil a nutrient soup, sort of chicken broth for microbes.
It was tagged with radioactive carbon.
So if anything ate the soup?
It would exhale radioactive gas as waste.
And the third was the pyrolytic release, which mimicked photosynthesis.
It gave the soil radioactive carbon from the air and a little simulated sunlight to see if anything built organic matter.
And the results were tantalizing.
Incredibly tantalizing.
Two of the three experiments came back with positive results.
The labeled release, especially, showed this big burst of gas right away, just like you'd expect from hungry microbes.
So two positive results.
That sounds like a home run.
What was the catch?
The catch was a huge contradiction.
You have to ask the question.
If there's life, where are the dead bodies?
You mean the organic material left behind?
Precisely.
The Viking Organic Chemistry experiment, a completely separate instrument, found virtually no organic matter in the soil at all.
Less than on the moon, which we know is sterile.
So you have signs of living things, but no signs of dead things.
That doesn't add up.
It doesn't.
So if it wasn't biology, what was causing those positive results?
And this is where the clay comes in.
This is the clay twist.
It turns out that certain types of clays, like montmorillonite, which we now know exist on Mars,
can mimic those results perfectly in the complete absence of life.
So it was just weird chemistry.
Super exotic, aggressive, inorganic chemistry.
The clays act as catalysts.
They can absorb and release gases and trigger chemical reactions that look a lot like respiration or photosynthesis, but it's not life.
So that doesn't completely rule out life on Mars?
No, not at all.
But it removes the compelling evidence from the Viking experiments.
Life could still be deeper down, somewhere else.
But the clay itself is still a fascinating discovery for the origin of life, even here.
Oh, absolutely.
These clays are amazing catalysts.
They can grab simple molecules like amino acids and link them together into more complex chains.
They may have been the forge of life on the early Earth, so Mars might be showing us how we got started.
And we can't talk about this search without mentioning Wolf Vishniak, a microbiologist who really championed the search for microbes.
He was a wonderful, dedicated scientist.
His own experiment, the Wolf Trap, was actually cut from the Viking mission to save money.
But he didn't give up.
He went to the most Mars -like place on Earth, the dry valleys of Antarctica, to prove that life could exist in those extreme conditions.
He was convinced it could.
And tragically, he died there.
He did.
He had a fatal fall while he was out collecting samples.
His last notebook entry just recorded the soil temperature, minus 10 degrees Celsius,
a typical summer day on Mars.
But his work, it paid off.
It did.
His colleagues retrieved his samples, and using his techniques, they found them teeming with microbes.
A whole variety, including a new species of yeast, all hiding inside the rocks, protected.
He was right.
It's an incredible legacy.
It just reinforces that idea that if life is on Mars, it's probably hiding where a Viking couldn't look.
Exactly.
Below the surface, shielded from the radiation.
So Viking gave us this incredible wealth of information, far beyond just the life question, geology, weather.
But what's the next step?
We can't keep landing in the parking lot.
The future has to be about mobility.
We need rovers.
A smart rover that can look around, see a fascinating old riverbed or a volcano in the distance, and then just go there.
And drill down.
And drill deeper than Viking ever could.
Imagine the public being able to follow along day by day, seeing new Martian vistas on their screens.
It'd be amazing.
So eventually, after the robots, after we bring samples back, after humans finally walk on Mars, we'll face the ultimate question.
What do we do with the planet?
And that gets into the really profound ethical questions of terraforming.
Making Mars into a second Earth.
Right.
And the ethical rule has to be simple.
If there is any life there, even just microbes, Mars belongs to the Martians.
Full stop.
We preserve it.
But if it's truly lifeless, then the project could begin.
You could thicken the atmosphere, warm the planet by heating the polar caps.
Maybe with genetically engineered dark plants to absorb more sunlight.
It's a project that would take centuries.
And if it worked, if you released the ancient atmosphere and water,
you'd have to move that water from the poles down to the equator where people would live.
You would.
You would need a planetary scale water management system.
You would.
You would build canals.
We would build canals.
Lowell's vision, which was born from this trick of the light and self -deception,
might actually become a kind of premonition.
He was right about the canals, just wrong about who would build them.
Exactly.
The Martians who build them won't be some ancient dying race.
The Martians will be us.
A truly stunning full circle moment for this entire story.
Thank you for exploring the red sands of Mars with us today.