Revealed: How Mars Lost Its Atmosphere

The Red Planet lost its protective blanket of air billions of years ago. Now astronomers are certain why

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Walter Myers / Stocktrek Images

Illustration of the Argyre impact basin in the southern highlands of Mars

One of the biggest challenges about flying to Mars is remembering why you went there in the first place. The Curiosity rover has been on the Red Planet for almost a year now, and the landing itself — an outrageous feat achieved by a stationary hovercraft that lowered the 1-ton Mars car to the surface by cables — was a global television event. But once the wheels touched the soil and all of the high fives had been exchanged, most people outside of the space community turned away.

Curiosity, however, went to Mars to work, and if its sister rovers Spirit and Opportunity — both of which arrived in 2004 and one of which is still chugging — are any indication, it should be at it for a long time. In the past year, Curiosity has already made some intriguing discoveries about the mineralogy of Mars and the planet’s watery past, and this week it delivered again. In a pair of papers published in the journal Science, investigators announced new findings from the spacecraft about one of Mars’ most long-standing mysteries: how it lost its atmosphere, and why.

(MORE: What It’s Like to Go to Mars)

Mars’ modern atmosphere is only 1% the density of Earth‘s, but the planet’s watery phase is believed to have lasted for the first billion of its 4.5 billion years, which means its air must have been around that long too. But things were never likely to stay that way. Mars has only half Earth’s diameter, 11% its mass and 38% its gravity, making it easy for upper layers of the original atmosphere to have boiled away into the vacuum of space and been blasted out by meteor hits. And that cycle would build on itself: the thinner the air became, the easier it would be for space rocks to hit the ground, unleashing still more explosive energy and, in effect, blowing still more holes in the sky.

But that’s only one mechanism. Planets can lose their air not just from the top up but also from the bottom down, as elements of the atmosphere bond with — and retreat into — the soil. Martian meteorites that landed on Earth have often been found to include gas bubbles from the Martian sky, evidence that this commingling was going on.

Curiosity scientists sought to settle the matter with the help of the rover’s Sample Analysis at Mars (SAM) instruments, a collection of sensors that sniff the air for its chemical makeup — particularly its mix of isotopes. Elements don’t come in just one form, but in different sizes and weights — such as carbon 12 and carbon 13 — determined by the number of neutrons in the nucleus. That weight issue is critical in atmospheric studies, because just as heavier metals sink downward and lighter ones rise as a molten planet is forming, so do gases stratify themselves in the atmosphere by weight.

(MORE: 78,000 People Apply for One-Way Trip to Mars)

Earlier measurements of Mars’ current atmosphere had always shown a high concentration of the heavy isotopes of carbon and oxygen — convenient elements to measure because Mars’ atmosphere is overwhelmingly made of carbon dioxide. Those findings differ from the isotopic makeup of the sun and the early solar system as a whole, in which lighter isotopes were more evenly represented. Mars, like Earth and all of the other planets, would have started out with that same relatively even mix. The fact that the heavy isotopes dominate the remaining Martian air means its lighter, high-altitude gases bled away first — supporting the top-down theory.

“As atmosphere was lost, the signature of the process was embedded in the isotopic ratio,” said NASA‘s Paul Mahaffy, principal investigator for the SAM team, in a statement. That was the theory anyway, but it took a suite of instruments like SAM to sample the air with enough sensitivity to prove the heavy-isotope imbalance. As the Science paper revealed, Curiosity indeed sealed that deal.

(MORE: An All-Wet Meteorite Arrives From Mars)

The findings are considered particularly reliable because Curiosity used two different instruments to do its work: the tunable laser spectrometer, which analyzes how Martian air pumped into a chamber reflects two different frequencies of infrared laser; and the mass spectrometer, which, as its name suggests, measures the entire spectrum of elements present in an air sample according to their mass. “Getting the same results with two very different techniques increased our confidence that there’s no known systematic error,” said NASA’s Chris Weber, lead author of one of the new papers.

Mars’ lost air is never coming back, but the little bit it does have still makes the planet a chemically active place — and plays a major role in the combination of parachutes and braking-rockets spacecraft from Earth rely on to reach the surface safely. But change is a constant everywhere in the universe, and even today, the Red Planet’s atmospheric loss is thought to be continuing. How fast that’s happening will not be known until the arrival of NASA’s next Mars probe, the Mars Atmosphere and Volatile Evolution (MAVEN) mission, which is set for launch in November. The already harsh Mars, MAVEN may find, is fast becoming harsher still — one more reason to appreciate the improbably verdant Earth.

PHOTOS: A Look at the Mars Desert Research Station in Utah

26 comments
SharadKumarSoni
SharadKumarSoni

My Theory about Why Mars lost its Atmosphere?

As far as I am seeing, our Sun getting older but when our Sun was younger mars was at green zone.

So, that is sure living Atmosphere was at Mars planet but as Green Zone sifted to Earth Mars lost its living Atmosphere.

Seed

A seed itself everything to give big tree in future, but if it not get any atmosphere [Green Zone ] to become a big tree, its all possible internal energy and property is waste.

Planet

A planet core is able to produce magnetic field only when it comes under green zone because of sun.

So, seed internal property equal to planet’s core. Both would active under proper atmosphere/condition.

Youtube:

https://www.youtube.com/watch?v=cticO9ztNn4

Blog:

http://mytheorywhymarslostitsatmosphere.blogspot.in

haskinshouse
haskinshouse

When a spacecraft goes to Mars it creates an invisible tunnel.  Earth's higher gravity sucks the Martian atmosphere to Earth.

Darr247
Darr247

Unless Mars has a molten iron/nickel core (and I'm pretty-sure it doesn't) whose spin differential creates a dynamo effect to generate a magnetic field (which is what protects Earth's atmosphere), our sun's solar wind will make creating new air on the red planet pointless, since it will just get blown away again.

sweetdigs
sweetdigs

Fast becoming?  Seriously?  lol. 

Adam_Smith
Adam_Smith

While there may be explorations and mining expeditions I don't think there will ever be actual human colonies elsewhere in the solar system; i.e., settlements with sustainable or nearly sustainable economies of their own. The resources are too limited and the environmental hazards are too great. In the far distant future perhaps earth-like worlds orbiting other stars may support human colonies but in our own star system it may actually be more practical to colonize space itself with large self-contained orbiting cities designed with some degree of self sufficiency in mind.

Ocsicnarf
Ocsicnarf

I find the article badly explained.

chippy1
chippy1

Give my regards to the invisible man in the sky,

jhoughton1
jhoughton1

So, we shoot a lot of blue-green algae onto the surface of Mars and after a few years, they'll have turned the CO2 into carbon and oxygen.  Let's think big, folks!

KingPhisting
KingPhisting

Who are the scientists trying to fool?
It's quite obvious the Reapers are responsible.

BabuG.Ranganathan
BabuG.Ranganathan

HAVING THE RAW MATERIALS AND RIGHT CONDITIONS TO SUSTAIN LIFE doesn't mean that life can originate by chance or from non-living matter.

Proteins can't come into existence unless there's life first! Miller, in his famous experiment in 1953, showed that individual amino acids (the building blocks of life) could come into existence by chance. But, it's not enough just to have amino acids. The various amino acids that make-up life must link together in a precise sequence, just like the letters in a sentence, to form functioning protein molecules. If they're not in the right sequence the protein molecules won't work. It has never been shown that various amino acids can bind together into a sequence by chance to form protein molecules. Even the simplest cell is made up of many millions of various protein molecules.

Also, what many don't realize is that Miller had a laboratory apparatus that shielded and protected the individual amino acids the moment they were formed, otherwise the amino acids would have quickly disintegrated and been destroyed in the mix of random energy and forces involved in Miller's experiment.

There is no innate chemical tendency for the various amino acids to bond with one another in a sequence. Any one amino acid can just as easily bond with any other. The only reason at all for why the various amino acids bond with one another in a precise sequence in the cells of our bodies is because they're directed to do so by an already existing sequence of molecules found in our genetic code.

A partially-evolved cell (an oxymoron) can't wait millions of years for chance to make it complete and then become living!

Please read my popular Internet articles listed below:

ANY LIFE ON MARS CAME FROM EARTH, SCIENCE AND THE ORIGIN OF LIFE, NATURAL LIMITS OF EVOLUTION, HOW FORENSIC SCIENCE REFUTES ATHEISM, WAR AMONG EVOLUTIONISTS (2nd Edition), NO HALF-EVOLVED DINOSAURS, DOES GOD PARTICLE EXPLAIN UNIVERSE'S ORIGIN?

Visit my newest Internet site: THE SCIENCE SUPPORTING CREATION

Sincerely,
Babu G. Ranganathan*
(B.A. theology/biology)

Author of popular Internet article, TRADITIONAL DOCTRINE OF HELL EVOLVED FROM GREEK ROOTS

* I have had the privilege of being recognized in the 24th edition of Marquis "Who's Who In The East" for my writings on religion and science, and I have given successful lectures (with question and answer time afterwards) defending creation from science before evolutionist science faculty and students at various colleges and universities.

TroyOwen
TroyOwen

@Adam_Smith If we don't, we can refer to ourselves as "The future extinct race."

We have to or this world or something that crashes into this world WILL end up killing us.

sweetdigs
sweetdigs

@Adam_Smith You may be right regarding space, but that has a lot of of its own challenges (mostly being that there's nowhere to go if something major goes wrong, whereas you can have multiple "colonies" on a planet).  Also, it may be much easier to construct large vessels and do processing/manufacturing on another planet - for example, Mars, where the gravity is significantly lower but still exists.

bleedingseraph
bleedingseraph

It actually depends on reclaimation abilities and efficiency of energy. The more dangerous aspect, imho, is the psychological factor involved in the colony start up process. Once the physical and energy issues have been solved and proven sustainable, the psychological factors of being so completely isolated would be devastating on the mental state of those involved in the first legs.

Gronke
Gronke

Of extremophiles tested thus far, most expired within an hour of being exposed to the level of UV radiation present on Mars. Only several strains survived 24 hours, so it is likely that at least the first few inches of Martian soil is completely sterile. We may eventually be able to bioengineer a hardy organism that is resistant to UV that can produce oxygen in an arid environment, but what's the point if Mars has neither sufficient gravity nor the magnetic field necessary to retain an atmosphere?

AlexMann
AlexMann

@BabuG.Ranganathan You're sliding towards public ridicule faster than you realize. Far from being a controversy, evolution already has vital practical applications in animal breeding, genome tracking, cancer treatment, and engineering of biomolecular machines.

The fact that you may have had some success and recognition in the public sphere only proves more that we must be louder than ever against quacks who've realized they can't fool scientists and have gone straight to the public instead. Because that's all you really want and need, an army of believers to help you fight your wars, not evidence and responsible information that can actually be of some use to mankind and development.

Congrats on using scientific terms and topics in your argumentation. You've just proven that you're so hopelessly illegitimate in your ideas that you'll try to mimic science in order to gain more credibility in the same way chinese knockoffs mimic famous brands.

Get the heck off the Internet. The printing press should've been your end in the 16th century.

FrankFMoore
FrankFMoore

@BabuG.Ranganathan 

Babu the Troll!  Nearly every Science article like this one, he uses as a platform to promote himself and is BS pseudo-science.  But I've no doubt his articles are "popular" with those who are scientifically illiterate.

Regards,
Frank F. Moore
BS - Invertebrate Zoology
MS - Analytical Chemistry
35 year career in the Natural Sciences

mharri
mharri

@BabuG.Ranganathan

 "doesn't mean that life can originate by chance or from non-living matter."

That right there? That shows you don't understand the science.

"There is no innate chemical tendency for the various amino acids to bond with one another in a sequence. Any one amino acid can just as easily bond with any other."

And that shows you don't understand the math.

One mistaken belief every Creationist seems to suffer about evolution: it's just chance. The irony here is that Creationists often refer to modern evolutionary theory as Darwinism (or neo-Darwinism), and Darwin's contribution was natural selection, which is specifically a nonrandom mechanism in evolution. Another mistaken belief is that there is only ever one possible way a protein can come into existence, leading to some very laughable probabilities. Simply put: having many pathways leads to greater chance. More to the point, according to the paper "Evolution of complexity in RNA-like replicator systems":

"The results showed that a population of replicators, originally consisting of one genotype, evolves to form a complex ecosystem of up to four species."

Maybe synthetic life hasn't been created from scratch, but the principles are sound.

jhoughton1
jhoughton1

@Gronke Okay, but even if you have to keep replenishing, like a scuba tank, it would still be interesting to have a breathable atmosphere on another planet just to see what happens.  Use it as a base for further exploration.  Whatever.  We have to keep pushing outwards -- it's our destiny, and maybe the destiny of those on other planets, too. 

jhoughton1
jhoughton1

@bleedingseraph I'm sure you're right.  I was echoing a notion put forward by James Lovelock in "The Greening of Mars."  He seemed (when the book was written, some time ago) to feel it was a possibility, the blue-green algae thing.  But maybe not.  

bleedingseraph
bleedingseraph

You missed the point, J. There is nothing keeping the atmosphere there. It will pretty much all leak away. So, we'd be hemoraging energy by constantly planting more alge or other plants that can withstand the evirons for no reason. Plus, where is all that biological material come from? It all costs energy and manpower. It'd be a tremendous strain on both resources for limited gain. Without proper shielding from the atmosphere, the radiation on the planet would kill anyone walking around--so creating breathable air in the hope to walk around the martian surface without protective gear is fultile.