What happened to Mars? A planetary mystery

Nov 13, 2013 by Dr. Tony Phillips
NASA's MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft, inside a payload fairing, is hoisted to the top of a United Launch Alliance Atlas V rocket at the Vertical Integration Facility at Cape Canaveral Air Force Station's Space Launch Complex 41. The move and hoisting operations mark another major milestone for the launch team as everything proceeds on schedule to launch Nov. 18, when the Atlas V will lift MAVEN into space and on to Mars. The two-hour launch window extends from 1:28 to 3:28 p.m. EST. MAVEN is the first spacecraft devoted to exploring and understanding the Martian upper atmosphere. It will orbit the planet in an elliptical orbit that allows it to pass through and sample the entire upper atmosphere on every orbit. The spacecraft will investigate how the loss of Mars' atmosphere to space determined the history of water on the surface. Credit: NASA

Billions of years ago when the planets of our solar system were still young, Mars was a very different world. Liquid water flowed in long rivers that emptied into lakes and shallow seas. A thick atmosphere blanketed the planet and kept it warm. In this cozy environment, living microbes might have found a home, starting Mars down the path toward becoming a second life-filled planet next door to our own.

But that's not how things turned out.

Today, Mars is bitter cold and desiccated. The planet's thin, wispy provides scant cover for a surface marked by dry riverbeds and empty lakes. If Martian microbes still exist, they're probably eking out a meager existence somewhere beneath the dusty Martian soil.

What happened? This haunting question has long puzzled scientists. To find the answer, NASA is sending a new orbiter to Mars called MAVEN (Mars Atmosphere and Volatile Evolution).

"The goal of MAVEN is to figure out what processes were responsible for those changes in Martian climate," says Bruce Jakosky, Principal Investigator for MAVEN at the University of Colorado at Boulder.

Scheduled for launch in Nov. 2013, and due to arrive in Sept. 2014, MAVEN is bristling with instruments to study Mars' . That's where many researchers believe the answer lies.

The only way Mars could have been wet and warm 4 billion years ago, is if it also had a thick atmosphere. CO2 in the Martian atmosphere is a greenhouse gas, just as it is in our own atmosphere. A thick blanket of CO2 and other greenhouse gases would have provided the warmer temperatures and greater atmospheric pressure required to keep from freezing solid or boiling away.

Something caused Mars to lose that blanket. One possibility is the . Unlike Earth, Mars is not protected by a global magnetic field. Instead, it has "magnetic umbrellas" scattered around the planet that shelter only part of the atmosphere. Erosion of exposed areas by solar wind might have slowly stripped the atmosphere away over billions of years. Recent measurements of isotopes in the Martian atmosphere by Mars rover Curiosity support this idea: light isotopes of hydrogen and argon are depleted compared to their heavier counterparts, suggesting that they have floated away into space.

Scientists have also speculated that the planet's surface might have absorbed the CO2 and locked it up in minerals such as carbonate. However, this theory has faded in recent years as Mars rovers and orbiters have failed to find enough carbonate to account for the missing gas.

MAVEN will be the first mission to Mars specifically designed to help scientists understand the ongoing escape of CO2 and other gases into space. The probe will orbit Mars for at least one Earth-year. At the elliptical orbit's low point, MAVEN will be 125 km above the surface; its high point will take it more than 6000 km out into space. MAVEN's instruments will track ions and molecules in this broad cross-section of the Martian atmosphere, thoroughly documenting the flow of CO2 and other molecules into space for the first time.

Once Jakosky and his colleagues know how quickly Mars is losing CO2 right now, they can extrapolate backward in time to estimate the total amount lost during the last four billion years. "MAVEN will determine if loss to space was the most important player in driving Martian climate change," Jakosky says.

In the grand scheme of the Solar System, Earth orbits alongside a world that began with as much promise for life as our own … yet turned out so differently. After all these years, MAVEN could write the final chapter in a haunting planetary mystery.

Explore further: NASA to probe why Mars lost its atmosphere

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orti
1.6 / 5 (17) Nov 13, 2013
I don't understand. He says "If Martian microbes still exist ...". Do we know they ever did? Also, isn't Mars less massive? Even Earth has only a whisper thin atmosphere. And hasn't it ceased geologic activity that could refresh surface minerals and gases? Is there a need for exotic explanations for the lack of atmosphere?
julianpenrod
1 / 5 (18) Nov 13, 2013
orti demonstrates the failing of many, namely, failing to put the depth of consideration called for into a discussion. They say Mars is smaller than earth and describes the, frankly, considerable atmosphere on earth as "whisper thin". If it has a low density, that doesn't mean there isn't a lot of it.
But the fact is that Mars supposedly managed to have a considerable atmosphere for the long time it took to assemble oceans and for those oceans to do major amounts of erosion. And that happened while the planet was hot from geologic processes. So size and heat don't seem to have played so much a role. And Mars is far from the sun now, so solar heating shouldn't drive the atmosphere away. But, then, Venus has ten times earth's atmosphere even though it is smaller and closer to the sun. Traditional representations don't seem to apply.
Lurker2358
1.7 / 5 (18) Nov 13, 2013
Venus has nearly 100 times Earth's atmosphere.

That's One Hundred, lest ye think I made a typo.
baudrunner
1 / 5 (21) Nov 13, 2013
According to accounts of the ancients, accounts that far predate biblical history (never mind the glossing over of the story of creation - it didn't happen that way), the planet Nibiru, or planet X, which has a 3,600 year orbit around Sol, once made a close pass of Mars, stripping it of most of its atmosphere and water. Maven might very well find that atmospheric loss occurred over one short term event, validating that account.

I would like to point out that the Vega solar system was recently discovered to include a planet with an irregular orbit of 2,200 years, and also an asteroid belt like Sol's.

Planet X's existence has not been ruled out. So far NASA is being cautious, calling it a dead brown dwarf star. Time will prove that explanation to be wrong, I am sure.
bjt
4.1 / 5 (7) Nov 13, 2013
It may be possible that Mars gravity isn't strong enough to retain water molecules which have an atomic weight of 18. CO2 molecules have an atomic weight of 44, which Mars gravity can retain.
deatopmg
1.3 / 5 (14) Nov 13, 2013
"The only way Mars could have been wet and warm 4 billion years ago, is if it also had a thick atmosphere. CO2 in the Martian atmosphere is a greenhouse gas, just as it is in our own atmosphere. A thick blanket of CO2 and other greenhouse gases would have provided the warmer temperatures and greater atmospheric pressure required to keep liquid water from freezing solid or boiling away."

Nonsense. The atmospheric pressure of CO2 on Earth today is roughly 40 mbar. At that partial pressure it already absorbs roughly 95% of the LWIR it's absorption spectrum allows. Therefore, no matter how much higher the partial pressure of CO2 was on early Earth or Mars only about 5% more energy could have been absorbed (not including the small addition absorption due to band broadening at the MUCH higher partial pressures)

Basic physics that some atmospheric scientists chose to ignore to promote their meme..
LagomorphZero
1.2 / 5 (11) Nov 13, 2013
@deatopmg: What you said is true while the sun is up and available for the CO2 to absorb heat from, but it seems like there would need to be a large atmosphere (though not necessarily CO2) to hold the heat on the dark side of mars to maintain liquid water during the night.
goracle
1.4 / 5 (14) Nov 13, 2013
According to accounts of the ancients, accounts that far predate biblical history (never mind the glossing over of the story of creation - it didn't happen that way), the planet Nibiru, or planet X, which has a 3,600 year orbit around Sol, once made a close pass of Mars, stripping it of most of its atmosphere and water. Maven might very well find that atmospheric loss occurred over one short term event, validating that account.

I would like to point out that the Vega solar system was recently discovered to include a planet with an irregular orbit of 2,200 years, and also an asteroid belt like Sol's.

Planet X's existence has not been ruled out. So far NASA is being cautious, calling it a dead brown dwarf star. Time will prove that explanation to be wrong, I am sure.

Stop glossing over the important role that the dark elves had in it. They want their fair share of your uncritical speculation.
goracle
1.5 / 5 (13) Nov 13, 2013
"The only way Mars could have been wet and warm 4 billion years ago, is if it also had a thick atmosphere. CO2 in the Martian atmosphere is a greenhouse gas, just as it is in our own atmosphere. A thick blanket of CO2 and other greenhouse gases would have provided the warmer temperatures and greater atmospheric pressure required to keep liquid water from freezing solid or boiling away."

Nonsense. The atmospheric pressure of CO2 on Earth today is roughly 40 mbar. At that partial pressure it already absorbs roughly 95% of the LWIR it's absorption spectrum allows. Therefore, no matter how much higher the partial pressure of CO2 was on early Earth or Mars only about 5% more energy could have been absorbed (not including the small addition absorption due to band broadening at the MUCH higher partial pressures)

Basic physics that some atmospheric scientists chose to ignore to promote their meme..

Yeah, you tell those conspiring physicists how it really is, Mr. forum genius!
baudrunner
1.3 / 5 (15) Nov 13, 2013
Stop glossing over the important role that the dark elves had in it. They want their fair share of your uncritical speculation.

goracle: I'm serious. I could give you a reading list that would enlighten you, but judging from your comment, you don't appear to be much into enlightenment. Tell me more about these dark elves.
orti
1.3 / 5 (12) Nov 13, 2013
Boy, this thing really clobbers your formatting when you hit submit. How do you enter a table?
orti
1.5 / 5 (15) Nov 13, 2013
OK. Here are some numbers (relative to Earth):
(Apparently Mercury is an odd-ball -- being denuded by solar wind.)

Earth Venus Mars Moon
planet mass 1 0.815 0.107 0.0123
planet dia 1 0.95 0.533 0.272
atmosphere mass 1 102.5 0.005 nil
surface pres 1 90.7 5.9e-6 na
active geology yes note 1 no no
srfc escape vel 1 0.92 0.446 0.214
surface temp
gas N2/O2 CO2 CO2 na
gas atomic wt 1 1.7 1.7 na

Note 1: Radar measurements suggest Venus was resurfaced by volcanic activity about 500 mya.

It seems to me that either Earth or Venus is the outlier. Some articles attibute the difference to Venus being initally closer to the Sun, and time has amplified that difference.

So again, why is Mars' atmosphere considered odd?
PhotonX
5 / 5 (3) Nov 13, 2013
I would like to point out that the Vega solar system was recently discovered to include a planet with an irregular orbit of 2,200 years, and also an asteroid belt like Sol's.
And Vega also has a circumstellar dust cloud just like ours. Oh, wait...I guess we don't. My bad.
Planet X's existence has not been ruled out.
Neither has Russell's Teapot.
Jonseer
1.8 / 5 (16) Nov 13, 2013
How much atmosphere would Mars have if all the frozen CO2 locked up in the S pole melted completely.

I have never even seen this estimated, even though there are good #s regarding the total amount of CO2. Much of it remains completely frozen year round locked deep in layers of water ice and dust. There is only enough time in a martian summer to melt the surface layers of frozen CO2.

Considering the dramatic changes the minimal melt of the South Pole CO2 load causes, I have to wonder if the frozen CO2 at the South Pole is enough to warm up the planet.

I have to say one thing I do love about these researcher guesses is how at the time they say Mars was warmer and wetter, Earth geologists are arguing over why Earth wasn't frozen over due to a weak sun at the time.

Those contradictory positions between Mars and Earth scientists is a great example of not communicating. No matter how thick the Mars. Atmos was, if the Earth should have been frozen, then Mars never had a chance.
baudrunner
1.3 / 5 (14) Nov 14, 2013
@Jonseer:

I have perused an awful lot of Mars rover, Mars Express, Mars Orbiter, and so on, images, and I have to agree with the mountain of evidence that exists that water once teemed over the surface of that planet. NASA scientists are convinced of that fact. The experts no longer consider it a "possibility", but a certainty. Read and see for yourself.

As a matter of fact, there is still what appears to be a residual frozen lake on the very bottom of Hebes Chasma, a six kilometer deep gouge in the surface, north of Valles Marineris. And surrounding it are what appear to be the ruins of some kind of settlement, protected from erosion by wind. Crazy? Nope. However, I don't believe that life ever evolved on Mars beyond the Archaea stage, which will probably be found deep beneath the surface on some future Mars mission. That means that there might be oil there, too.
Torbjorn_Larsson_OM
3 / 5 (1) Nov 15, 2013
A recent theory, consistent with water flow patterns, is that the habitable ocean period was a mere 200 Ma, between 3.8 and 3.6 Ga bp. Enough to get life started, FWIW.

Creationist trolling is hilarious: "[religious ']history[']" - religious texts are myths.

The specific texts dates back ~ 400 years before the specific religion in question in the archeological record (the Dead Sea scrolls ~ 2.2 ka bp vs the first purely christianist texts ~1.8 ka bp), far from the millenniums it purports, and 100 % fails, to describe.

This incompetence of incompetents makes many deconverts from religion, see Dawkins's Convert's Corner.
philw1776
1.3 / 5 (12) Nov 16, 2013
I would really like to see some numbers where the (~40 % of today?) faint early sun, Mars' greater distance from the sun (~40% of Earth's insolation) and any putative dense atmospheric gasses heat retention capability were presented together. Early Mars, "Doing More with Less!"
VENDItardE
1 / 5 (11) Nov 17, 2013
Stop glossing over the important role that the dark elves had in it. They want their fair share of your uncritical speculation.

goracle: I'm serious. I could give you a reading list that would enlighten you, but judging from your comment, you don't appear to be much into enlightenment. Tell me more about these dark elves.


their is no goracle...just another Scott sockpuppet like : Sinister1811 | toot | Nikolaus | goracle | Colombe | VendicarH | TheSicilian | Blotto | Ballerina
NOM
5 / 5 (3) Nov 17, 2013
So we have a sockpuppet crying about someone else using sockpuppets
goracle
1.4 / 5 (9) Nov 17, 2013
Stop glossing over the important role that the dark elves had in it. They want their fair share of your uncritical speculation.

goracle: I'm serious. I could give you a reading list that would enlighten you, but judging from your comment, you don't appear to be much into enlightenment. Tell me more about these dark elves.


their is no goracle...just another Scott sockpuppet like : Sinister1811 | toot | Nikolaus | goracle | Colombe | VendicarH | TheSicilian | Blotto | Ballerina

Hint: 'their' and 'there' are two different words with different meanings. Your path to enlightenment appears to involve a highly-convoluted yoga posture that would make a proctologist envious.
rockwolf1000
2.3 / 5 (3) Nov 18, 2013
According to accounts of the ancients, accounts that far predate biblical history (never mind the glossing over of the story of creation - it didn't happen that way), the planet Nibiru, or planet X, which has a 3,600 year orbit around Sol, once made a close pass of Mars, stripping it of most of its atmosphere and water. Maven might very well find that atmospheric loss occurred over one short term event, validating that account.

I would like to point out that the Vega solar system was recently discovered to include a planet with an irregular orbit of 2,200 years, and also an asteroid belt like Sol's.

Planet X's existence has not been ruled out. So far NASA is being cautious, calling it a dead brown dwarf star. Time will prove that explanation to be wrong, I am sure.


The ancients also say the earth is resting on the back of a turtle. I read that the turtle drank all of Mars' water therefore we don't need to invoke ridiculous planet "X" ideas. No need to wait.