How Mars lost its water to space

How the sun pumps out water from Mars into space

Russian and German physicists have offered an explanation for the new data obtained by Martian satellites, capturing the “escape” of hydrogen atoms from the upper Martian atmosphere into outer space. The developed model fits well with the observations and explains a number of puzzling phenomena related to the atmosphere of Mars. The research was published in the journal Geographical Research Letters.

The atmosphere of Mars is cold and rarefied, like the Earth atmosphere at high altitudes. Under such conditions, there is no liquid water, but rather clouds consisting of tiny ice crystals. On Earth, such clouds — called “feathery” — are formed at 6 kilometers above the surface. As the ice crystals are rather heavy, the bulk of the water is contained in the lower atmospheric layer, approximately 60 kilometers thick. However, the data obtained from the U.S. satellite MAVEN (short for “Mars Atmosphere and Volatile EvolutioN”) and the Hubble Space Telescope evidences a periodic stream of hydrogen atoms escaping the planet. Their only source may be water dissociating into oxygen and hydrogen in the upper atmospheric layers (70-80 kilometers from the ground) as a result of exposure to ultraviolet radiation.

The researchers have ventured a guess as to how water is “launched” to this seemingly unreachable altitude.

According to observations, the number of hydrogen atoms flying away into outer space increases during the time of summer solstice in the Southern Hemisphere and during dust storms. Moreover, fluctuations of water concentration in the upper and lower atmosphere occur simultaneously. This led the physicists to put forward a hypothesis that some sort of a “pump” must be driving the water up. The team used numerical modeling to explain the nature of this process.

The basis for the study was provided by the Martian General Circulation Model (MGCM) developed at the Max Planck Institute in Germany. The model provides a detailed description of the water transfer from the ground and into the thermosphere (the atmosphere layer where temperature declines with height), and takes into account the impact of dust storms. Previously, MIPT researchers and their German and Japanese co-authors presented a model describing the distribution of water vapor and ice in the Martian atmosphere over the course of a year. The model came to be a part of a broader description of the processes taking place on Mars. Unlike that earlier research, the new model takes water photodissociation into account.

Heliographic longitude (Ls) is an angle between the imaginary straight lines connecting the sun and Mars during the spring equinox (Ls = 0°) and at any given moment. The values of Ls between 0° and 90° correspond to springtime in the Northern Hemisphere, between 90-180° to summer, between 180-270° to fall, and between 270-360° to winter. The Martian orbit is much more elongated compared to the almost circular orbit of the Earth, and summer in the Northern Hemisphere corresponds to the planet’s position in aphelion (the orbit point that is farthest away from the sun), while in the Southern Hemisphere, the summer corresponds to perihelion (the point in the orbit that is the closest to the sun). Thus, the ‘northern’ summer is much colder than the ‘southern’ one. CREDIT
Space Science Council of RAS

Carried away by the wind

As the processes occurring in the atmosphere of Mars are clearly seasonal, it is often necessary to identify the time frame in which a certain event occurs. On Earth, we would have simply named a date — for example, March 20, the spring equinox day. But even though a calendar of its own has been developed for Mars (the Darian calendar), consisting of 24 months, each 27-28 days long, it is not very convenient. It is not that easy to figure out from the phrase “day 20 of the Pisces month” which season in which hemisphere is meant. In practice, it is much easier to pin a point in the orbit where the planet is. For this purpose, heliographic longitude is used (figure 1).

Modeling has demonstrated that water concentration in the atmosphere changes significantly over the year, reaching its maximum at the heliographic longitudes of 200° to 300°. In this time, the planet passes perihelion, the point in the orbit where Mars is closest to the sun (figure 2).

“Water vapor flows are at their maximum at Ls = 260°, which corresponds to the southern summer, when average planet temperature is also at its maximum. During the period from Ls = 220° to 300°, the ice on the surface of Mars at southern latitudes intensely sublimates, and at altitudes below 40 kilometers, the resulting water exists as water vapor, while higher up, it forms ice clouds,” explains Dmitry Shaposhnikov, the lead author of the paper and a researcher at the MIPT Laboratory of Applied Infrared Spectroscopy.

Seasonal winds blowing along meridians carry heat and moisture from the “summer” hemisphere over to the “winter” hemisphere. The distribution of flows at altitudes above 120 kilometers evidences that there are also other winds existing in the lower and the adjacent middle latitudes, but their contribution to the overall layout is not that significant.

The bulk of the water is concentrated in the lower atmosphere, below 30 kilometers, but calculations have shown that water can “seep” into upper atmosphere layers, caught up in a small upward flow of water vapor between 20° and 70° southern latitude that only exists during perihelion — a bottleneck of sorts (figure 2c). If the water manages to pass it, seasonal winds carry it toward the North Pole. Along the way, some of the H2O breaks down, affected by UV rays, into hydrogen and oxygen, while most of it, together with the cooling air, descends back into lower atmospheric layers, condensing around the North Pole area. That way, the Martian northern polar cap is formed (the southern one is much smaller).

Dusty and foggy

Dust storms, sometimes engulfing the entire planet, naturally have an impact on the circulation of water, but in a way that is far from obvious. First, dust-laden air heats up more, which prevents water condensation. Second, dust particles promote ice crystal formation (the dust provides a nucleus for ice formation), leading to more clouds. Third, the storms affect the circulation of air streams along meridians.

In order to study the impact of strong dust storms, the parameters were taken of the global dust storm that occurred during perihelion in Martian year 28 (calculated from April 11, 1955), that is in the years 2006-2007 on Earth. Modeling has shown that the temperature increased by over 20 degrees Celsius at the South Pole, and by over 45 C at the North Pole. Winds blowing from pole to pole have also become stronger.

Dmitry Shaposhnikov explains: “More atmospheric heating in the north is due to the fact that the airflow arriving from the south cools off, intensely descending onto the planet’s surface and transferring to the surface the energy that becomes thermal energy [see figure 3]. Our calculations have shown that a higher temperature during a dust storm causes an increase in water vapor concentration and a higher intensity of airflow circulation.”

Higher water content causes the hydrosphere thickness to increase from 60 to 70 kilometers. Ice clouds become denser and relocate to higher altitudes. A higher content of dust particles in the air promotes the formation of a large number of tiny ice crystals, which take longer than usual to settle down. Due to this, ice clouds are located higher in a storm, locking in more moisture. Therefore, a higher content of dust in the air helps water pass through the bottleneck and get into higher atmospheric layers.

Is it the sun that rules the tides?

The moon is responsible for the tides on Earth. On Mars, the satellites Phobos and Deimos are too small to have any significant impact. The sun has the strongest influence on the planet, its gravitation also affecting water vapors. As a result, during the day, there is an “ebb tide” observed — the formation of an upward water vapor flow — while in the evening, there is a “high tide”, when a downward flow is formed (figure 4).

“The sun is operating as a pump, which ‘activates’ in the daytime and helps water reach heights of over 60 kilometers above the ground. During a dust storm, the concentration of moisture in the air and airflow speed are higher, and therefore, the ‘pump’ is able to lift water higher up,” Dmitry Shaposhnikov explained.

All theory, dear friend, is gray …

In order to verify model validity, the authors have compared the obtained results with the data collected by Mars Reconnaissance Orbiter, MRO, in the 28th Martian year. Both modeling and experimentation have shown increased water content in the atmosphere during the perihelion (figure 5). Unfortunately, the measurements conducted by MRO in the very dust storm and at heights exceeding 80 kilometers proved unsuccessful. However, at the highest altitude accessible for measurement using this apparatus (about 70 to 80 km), the measured and calculated values of water vapor content have turned out to be almost the same: approximately 70 to 80 cubic centimeters per cubic meter.

The results of night measurements directly before a global dust storm (Ls between 200-250°) also fit well with the modeling, demonstrating increased water content in a downward water vapor flow. However, according to the MRO data, water content maxes out at the height of 40 to 50 kilometers, while the model provides for lower water content as the height decreases. This could perhaps result from the fact that the distribution of dust particles by size preset in the model is different from the actual distribution. The model also predicts a sharp drop in water content in the atmosphere after Ls = 330°, which is not supported by experimental data.

However, the experimental and calculated season-dependent distributions of water content are quite similar (see figure 5). Both demonstrate the existence of a bottleneck in the Martian water circulation, which may only be passed by water at a certain time during perihelion. Water is also more likely to successfully pass the bottleneck if perihelion coincides with a dust storm.

“The new model aligns well with the observations and allows to explain a number of phenomena in the Martian atmosphere (the presence of water vapors at altitudes above 80 kilometers, the seasonal fluctuations, the impact of dust storms and solar tides) and may be used to test new hypotheses,” Alexander Rodin commented. He is one of the authors of the study and the head of the MIPT Laboratory of Applied Infrared Spectroscopy.

Rodin added: “We are very much looking forward to receiving the data provided by the Russian ACS spectrometer unit within the ExoMars global project, whose capabilities are much broader than those of the MRO instruments whose data we relied on. Moreover, the research demonstrates just how significant the processes localized in the polar areas of a planet may be for its global climate. By the way, this applies to the Earth, too.”


All model data are available online at The research was partially supported by the Russian Science Foundation (RSF) and German Science Foundation (DFG). MOSCOW INSTITUTE OF PHYSICS AND TECHNOLOGY

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June 18, 2019 11:26 pm

The recent articles on this site by Philip Mulholland describe the nature of the ‘pump’ quite comprehensively and I have previously described how that solar induced pumping action involves convective overturning which results in a mass induced greenhouse effect without any need for greenhouse gases.

Reply to  Stephen Wilde
June 19, 2019 1:59 am

The so-called greenhouse effect warms the surface of the Earth. Convective overturning cools the surface of the Earth — the opposite of the greenhouse effect.

Reply to  Dave Burton
June 19, 2019 5:56 am

You should read Philip’s articles.
Kinetic energy taken up by rising air returns to the surface in falling air and cannot be lost to space in between because in the process it is transformed to and from potential energy which is not heat and so does not radiate away.
Convection introduces a delay in the loss of energy to space and so must warm the surface.

Reply to  Stephen Wilde
June 19, 2019 6:33 am


Ever heard of condensation, latent heat and radiation?

Reply to  tty
June 19, 2019 8:28 am

None of those processes serve to reduce the potential energy created when gases expand during uplift.
Otherwise there would not be the observed recovery of KE from PE during the subsequent descent.

Reply to  Stephen Wilde
June 19, 2019 7:04 am

Kinetic energy is only one part of what happens when air rises and falls. And you are correct, the kinetic energy can’t be lost to space. However when water vaporizes, rises high in the atmosphere, then condenses, that energy is easily lost to space.

Reply to  MarkW
June 19, 2019 8:31 am

The condensate cannot radiate potential energy to space.
It can only radiate at the temperature of the height at which it finds itself so the PE is preserved until descent begins.

Reply to  MarkW
June 19, 2019 9:08 am

Unfortunately not all the energy is converted from purely kinetic to potential. Entropy always takes its cut. …And, the thermal losses are capable of radiating to space.

Reply to  Rocketscientist
June 19, 2019 10:03 am

Only the portion that does become PE is required to cause the mass induced greenhouse effect.

Reply to  MarkW
June 19, 2019 12:06 pm

I need to see a mechanism. Thats how I can communicate in sciencey language

Reply to  Mick
June 19, 2019 12:45 pm

Of course. I’ve set it out previously here and elsewhere:

“i) Start with a rocky planet surrounded by a non-radiative atmosphere such as 100% Nitrogen with no convection.
Assume that there is no rotation to confuse matters, ignore equator to pole energy transfers and provide illumination to one side from a nearby sun.
On the illuminated side the sun heats the surface beneath the gaseous atmosphere and, since surface heating is uneven, gas density differentials arise in the horizontal plane so that warmer, less dense, Nitrogen starts to rise above colder, denser, Nitrogen that flows in beneath and convective overturning of the atmosphere has begun.
After a while, the entire illuminated side consists of less dense warm rising Nitrogen and the entire dark side consists of descending, denser and colder Nitrogen.
The Nitrogen on the illuminated side, being non-radiative, heats only by conduction from surface to air and cannot assist cooling of the surface by radiating to space.
There will be a lapse rate slope whereby the air becomes cooler with height due to expansion (via the Gas Laws) as it rises along the line of decreasing density with height. That density gradient is created by the pull of gravity on the individual molecules of the Nitrogen atmosphere.
At the top of the rising column the colder denser Nitrogen is pushed aside by the warmer more buoyant and less dense Nitrogen coming up from below and it then flows, at a high level, across to the dark side of the planet where descent occurs back towards the surface.
During the descent there is warming by compression as the Nitrogen moves back down to the surface and then the Nitrogen flows along the surface back to the base of the rising column on the illuminated side whereupon the cycle repeats.
Thus we have a very simplified climate system without radiative gases consisting of one large low pressure cell on the illuminated side and one large high pressure cell on the dark side.
ii) The thermal consequences of convective overturning.
On the illuminated side, conduction is absorbing energy from the surface the temperature of which as observed from space initially appears to drop below the figure predicted by the S-B equation. Instead of being radiated straight out to space a portion of the kinetic energy at the surface is being diverted into conduction and convection. Assume sufficient insolation to give a surface temperature of 255K without an atmosphere and 33K absorbed from the surface into the atmosphere by conduction. The surface temperature appears to drops to 222K. Those figures are illustrative only since there is dispute about the actual numbers for the scale of the so called greenhouse effect.
On the dark side the descending Nitrogen warms as it falls to the surface and when it reaches the surface the cold surface will rapidly pull some of that initially conducted energy (obtained from the illuminated side) out of the descending Nitrogen so that the surface and the Nitrogen in contact with it will become warmer than it otherwise would have been, namely by 33K.
One can see how effectively a cold, solid surface will draw heat from the atmospheric gases by noting the development of radiation fog above cold surfaces on Earth. The cold surface quickly reduces the ground level atmospheric temperature to a point below the dew point.
That less cold Nitrogen then flows via advection across the surface back to the illuminated side which is then being supplied with Nitrogen at the surface which is 33K warmer than it otherwise would have been.
That describes the first convective overturning cycle only.
The key point at that stage is that, as soon as the first cycle completes, the second convective cycle does not need to take any further energy from incoming solar radiation because the necessary energy is being advected in by winds from the unlit side. The full effect of continuing insolation can then be experienced once more so the surface goes back up to 255k from 222k.
ADDITIONALLY the air moving horizontally from the dark side to the illuminated side is 33K warmer than it otherwise would have been so the average temperature for the whole sphere actually rises to 288K
Since that 33K flowing across from the dark side goes straight up again via conduction to fuel the next convective overturning cycle and therefore does not radiate out to space, the view from space would show a radiating temperature for the planet of 255K just as it would have done if there were no atmosphere at all.
In that scenario both sides of the planet’s surface are 33K warmer than they otherwise would have been, the view from space satisfies the S-B equation and radiation in from space equals radiation out to space. Radiative capability within the atmosphere not required.”

and it has been mathematically modelled for several planets by Philip Mulholland so here it is for Venus:

So, convection is all one needs. If there were no convection the atmosphere would behave like a solid, would become isothermal via conduction alone and there would be no greenhouse effect because from surface to top of atmosphere the temperature would be as per the S-B prediction.
As soon as convection starts the time taken for the KE to PE and PE to KE conversions delays the exit of energy to space and the surface temperature rises.

If that can happen in a non GHG atmosphere it follows that GHGs cannot be the cause of the observed surface temperature rise.

Reply to  MarkW
June 19, 2019 1:35 pm

“The condensate cannot radiate potential energy to space. It can only radiate at the temperature of the height at which it finds itself”

Indeed. Which is exactly what we see in the IR spectrum from TOA. Where does that radiation come from in your skydragon world?

Reply to  MarkW
June 19, 2019 1:54 pm

MarkW, “when water vaporizes, rises high in the atmosphere, then condenses, that energy is easily lost to space.”

Right. The water cycle is a classic phase-change refrigeration cycle, just like the Freon refrigeration cycle in your refrigerator: Water evaporates at the surface, absorbing latent “Heat Of Evaporation” (evaporative heat loss). Because the molecular weight of water vapor molecules is just 18 (compared to 28 for nitrogen), water vapor is a lifting gas, and moist air is lighter than dry air (contrary to intuition). So the moist air rises to the mid-troposphere, where the water condenses into clouds, releasing the latent heat which it had absorbed at the surface.

That process is the most important way in which heat is removed from surface of the Earth.

Stephen wrote, “In that scenario both sides of the planet’s surface are 33K warmer than they otherwise would have been, the view from space satisfies the S-B equation and radiation in from space equals radiation out to space.”

Nope, you double-counted some heat.

Both sides of your hypothetical planet are losing heat to space, by radiation, all the time. If air movement carries heat from the warm side to the cold side, the warm side gets colder and the cold side gets warmer, but both sides continue to lose heat via radiation: the warm side more slowly, but the cold side more quickly, because of the heat you moved from warm side to cold side.

You assume that if movement of air from the warm side to the cold side cools the warm side by 33K, all that heat will do double-duty: it will warm the cold side, and then it will still be warm enough to warm the hot side by 33K when it returns there.

But since the cold side is continually losing energy by radiation to outer space, that is not the case. Only a portion of the energy will still be available to help keep the hot side warmer. The air that returns to the warm side will be cooler than the air that departed it.

So, air movement causes the cold side to be warmer, but it also causes the warm side to be cooler.

There is no “mass induced greenhouse effect.”

If you were to calculate the average surface temperatures over your hypothetical N2-atmosphere planet, and then remove the atmosphere, wait a while, and then repeat the calculation, you’d find that without an atmosphere the hot side is hotter, and the cold side is colder, but the average temperature is lower.

But that’s not because of any mass-induced greenhouse effect. It is because radiative emissions are proportional to the 4th power of the absolute temperature, which would curb the heating on the hot side. So, without an atmosphere, the cold side temperature would drop by more than the hot side temperature would rise.

Reply to  Dave Burton
June 19, 2019 2:40 pm

Not correct.
Read my narrative again and study Philip Mulholland’s mathematical model.
Recycling of energy which delays emission to space always results in more energy within the system and a raised surface temperature.
No double counting by me but rather you are counting just one half of a reversible process because you fail to include the warming effect on the lit side of returning air that is warmer than it otherwise would have been.

Reply to  MarkW
June 19, 2019 3:30 pm

Stephen wrote, “No double counting by me but rather you are counting just one half of a reversible process because you fail to include the warming effect on the lit side of returning air that is warmer than it otherwise would have been.”

Stephen, you’ve forgotten what the “otherwise” case is. There’s no “returning air” in the “otherwise case.” The “otherwise case” is without air moving heat between the hot and cold side of your hypothetical planet.

Air which departs from the hot side is warmer than air which flows to the hot side from the cold side.

That cools the hot side (and warms the cold side).

My advice: Stay away from the PSI disinformation site and their skydragon disinformation book, unless you like being confused. Here are some good information sources, which don’t lie to you, unlike PSI:

Reply to  Dave Burton
June 23, 2019 8:54 am

“That cools the hot side (and warms the cold side).”

Correct, so the air flowing back to the hot side is warmer than it otherwise would be and since insolation on the hot side continues at full strength that warmer air from the cold side must have its energy content added to the thermal effect of continuing insolation on the hot side.

Reply to  MarkW
June 20, 2019 10:24 am

Stephen, the model you illustrate is a great work of fiction using principles that are exaggerated.
Noon world has 117 days of one sunrise to sunrise on Venus. Earth’s arctic has nearly 180 days of darkness, nearly that much of sunlight. 365 days from sunrise to sunrise. Earth has almost 80% nitrogen. This is where your model will be substantiated or defeated.
I have lived above the Arctic Circle and I can tell you that the circulation forces of rising air and wind of circulating colder air, does not exist. Outside a Low pressure storm system, there’s virtually never any wind at all. (Believe me, arctic villages, far away from the grid, would love to have a dependable source of electricity other than fossil fuel’s)
Re-formulate your model to reflect actual existing conditions. That’s the only way that anyone will believe it. Empirical evidence will trump any theory every time.

Reply to  Max
June 20, 2019 10:43 am

Philip has run the model for other planets and it works for them all just by varying the partitioning of energy transfer at the surface between radiation to space and conduction/ convection to or from the atmosphere so I guess it has been substantiated.
As regards winds circulating I suggest you study Hadley cells.

June 18, 2019 11:28 pm

So back when the Martians were industrializing, blithely spewing that deadly carbon dioxide into the atmosphere, little did they know that this barren desolation would result from their MGW (Martianogenic Globsl Warming). We have been warned!

Rod Evans
Reply to  Richard
June 19, 2019 12:48 am

Did you forget the sarcasm icon? Please tell us that is a joke comment.

Reply to  Rod Evans
June 19, 2019 7:05 am

I’m 97% certain that the comment was meant as a joke.

Ed MacAulay
Reply to  Richard
June 19, 2019 9:13 am

So does this water pump operate in earth’s atmosphere? If so how long do we have untill the hydrogen is all pumped off into space. Should we be constructing giant underground caverns to store the water untill it is needed? At least the government does its part since many areas already have a water tax.

michael hart
June 18, 2019 11:39 pm

“Unlike that earlier research, the new model takes water photodissociation into account.”

Who’d have thunk it? Planetary modellers ignore an obviously present process.
But I bet, like the ones who build models of the earth, they would have claimed they were right if challenged about it beforehand.

Moderately Cross of East Anglia
June 19, 2019 12:53 am

Hang on, ultraviolet light disassociates hydrogen from water in Mars’ upper atmosphere … I feel a new type of deep space exploration propulsion drive coming on here…

Dudley Horscroft
June 19, 2019 1:40 am

OK, so at very high altitudes water (as ice crystals) is dissociated into hydrogen and oxygen. This is at least believable. It is also the same process as is reported for Venus losing all its water.

But, to lose the hydrogen, each hydrogen molecule must attain escape velocity. Easier to attain such a speed for Mars than Venus (lower gravity) but Mars is far colder and it would be more difficult for each hydrogen molecule to get the necessary energy.

Even so, if the hydrogen goes, that leaves the oxygen. So Mars should have an oxygen atmosphere – oxygen molecules much heavier than hydrogen molecules and needing far more energy to reach escape velocity!. The lack of oxygen can be explained on Venus as the planet is hotter than Mars. But the oxygen also appears to have gone on Mars!

Problem: Earth is a little bit heavier than Venus, so gravity is a little bit more, but it is colder. Earth is much heavier than Mars but is a lot warmer. So how come both Mars and Venus lost their water, but Earth has kept it? One is almost led to think that Earth pinched Venus’s water during a near collision, and then pinched Mars’s water and atmosphere also during a near collision. Far fetched, but it seems to make as much sense as the possibility that Mar’s water just disassociated, flew off the planet, and is happily orbiting the sun in the same orbit as Mars. Or where else could it have gone?

Crispin in Waterloo but really in Johor
Reply to  Dudley Horscroft
June 19, 2019 6:59 am

Hydrogen can diffuse into space without reaching any velocity at all. Floats up, as it is light.

Once high enough it wafts away on the solar wind. The same thing happens on Earth – we just have a lot more water and get more each time a comet strikes.

If Mars was much heavier and had a decent magnetic field and if Venus was a lot cooler they would both have retained a lot of water.

We are just lucky.

Maybe one day we will be able to geoengineer some comets into Mars and get the atmosphere back. We have lots of time to think about how to do it.

Reply to  Dudley Horscroft
June 19, 2019 7:07 am

Venus is a lot closer to the sun compared to Mars. As a result there is a lot more energy available to accelerate those hydrogen atoms.

Michael J. Dunn
Reply to  Dudley Horscroft
June 27, 2019 12:20 pm

Just a thought: The water may still be on Venus in the form of sulfuric acid. It is formed by the hydration of sulfur trioxide (SO3 + H2O => H2SO4, a standard industrial process).

June 19, 2019 1:43 am

Professor Brian Cox Explained it ALL.
On the BBC program Planets.
It is all down to global warming.
The lack of a ionisation layer.
If we peoples of earth do not take care we could end up the same way.
Said he, as perambulated about Mars type locations on the planet Earth.
Presuming He got to those locations using mechanical means.
Plus a camera crew and gophers.

June 19, 2019 1:47 am

So magnetic field of planet has almost no impact on protection of atmosphere from solar wind. All water lost on Mars is caused by physical, mechanical phenomenon transporting water higher than safe from solar wind.
Earth is losing atmosphere too, but because of magnetic field, it is only concentrated to areas around poles.
And problem of Mars is not losing of water, there is still plenty to fill oceans, but it is losing of CO2.
Venus, Earth, Mars started with similar amounts of CO2 in atmosphere. Around 100bar. Venus due gravity protected its CO2 and is still in same state.
Earth protected CO2 with gravity but biosphere sequestrated carbon from atmosphere into carbonates, removed from atmosphere, balanced increased sun output with cooling from less massive atmosphere.
Mars has not enough gravity and is directly losing CO2, what caused declining of Mars temperature. And prevented creation of biosphere.
Mars with 2 bars of CO2 atmosphere would be habitable for plants.

Reply to  Peter
June 19, 2019 6:55 am

Earth never had nearly as much CO2 in the atmosphere as Venus has. There is empirical data (splashmarks from raindrops) that show that even in the Archaean the Earth’s atmosphere can’t have been more than a few times denser than now.

And 2 bars of CO2 is not enough to make Mars inhabitable. CO2 has too narrow absorption bands. H2O is needed too.

Reply to  tty
June 20, 2019 12:51 am
There is pretty good chance that Venus and Earth started with same amount of carbon in atmosphere.
Currently most of carbon is stored in carbonates by biological processes. From where it got there?

2 bars would be enough to make some parts of Mars habitable for plants.
2 bars would allow water stay in liquid state on surface all the time. Currently maximum temperature reached in equatorial regions on Mars is up to 21C. With higher atmospheric pressure this region would be bigger, temperature would be higher, creating enough of liquid water to create massive hydrologic cycle.
And here you have your absorption bands.
You don’t need much water in atmosphere to saturate water absorption bands.
From there it is positive feedback to stable CO2+water atmosphere.

Reply to  Peter
June 20, 2019 9:52 am

Peter said;
“Mars has not enough gravity and is directly losing CO2, what caused declining of Mars temperature. And prevented creation of biosphere.
Mars with 2 bars of CO2 atmosphere would be habitable for plants.”

True, Mars lacks the gravity to hold any more atmosphere than it currently has. It’s in balance now with the solar wind which blows away the lighter elements, more than it deposits. Mars ice caps have enough CO2 to double the thickness of the Martian atmosphere should they melt.
(There is lots of oxygen on Mars, it reacted with the iron in the soil making Mars red)

As for 2 bars of pressure, twice Earth normal pressure of 1 bar at sea level, is not possible. Mars current average atmospheric pressure is 7 millibars. Or .007 bars of pressure. About the same, if you are freeze drying food, where solid water turns directly into a gas like dry ice. Currently the only place on Mars is the Helenas basin impact crater which is deep enough due to atmospheric compression to have liquid water. Water ice would melt at 34°F but would boil away before it reaches 40°F
To give you an idea how thin Martian atmosphere is, mount Olympus volcano is 7 miles high. The top is outside Martian atmosphere in outer space.

June 19, 2019 1:51 am

Re: “…the thermosphere (the atmosphere layer where temperature declines with height)…”

It sure is obvious when science news gets filtered through “science journalists” or “science communicators.”

I believe this is the source link:

Reply to  Dave Burton
June 19, 2019 6:41 am


Typical thermal profile of the Martian atmosphere:

ALWAYS GET THE ORIGINAL PAPER, the filtered version is not only invariably wrong, it can even be the opposite of what the paper actually says.

Tip: even if the paper is paywalled the abstract is almost always available.

old construction worker
June 19, 2019 2:00 am

Mars: CO2= about 95% Water vapor= about .03%: interesting. It seems to me looking for water vapor ice crystals among dry ice crystals is looking for a needtle in the hay stack. I guess they can do it.

June 19, 2019 2:45 am

Re.Terra forming Mars, so it needs CO2, can we pollute it ?

Also I would consider that water rich meteorites must land on Mars, so
is it still rich in water , but hidden under its surface. ?


Reply to  Michael
June 19, 2019 9:26 am

Mars has plenty of CO2. What it lacks is hydrogen and nitrogen.
Mars atmosphere:
•Carbon dioxide: 95.32 percent.
•Nitrogen: 2.7 percent.
•Argon: 1.6 percent.
•Oxygen: 0.13 percent.
•Carbon monoxide: 0.08 percent.
•Also, minor amounts of: water, nitrogen oxide, neon, hydrogen-deuterium-oxygen, krypton and xenon

Reply to  Rocketscientist
June 20, 2019 12:54 am

On the contrary.
Mars CO2 content is high only as percent of atmosphere, but absolute carbon content on Mars is low.
And it has a lot of hydrogen maybe all of primordial in buried ice.

Zig Zag Wanderer
June 19, 2019 3:02 am

The error they are making is to validate models with observations. What they need to do, according to Climate Scientology, is to adjust observations until they match the models.

They’re was also no mention of CO2, the most important substance in the climate is any planet in the galaxy, and probably the universe.

Rank amateurs at best.

June 19, 2019 3:44 am

Mars and Venus have no electromagnetic field generated from within , hence no magnetic re-connection on the night side and the solar wind blows their surface away into space like a tail of a comet. Hydrogen is the most abundant element in the universe , you only need 1 proton and 1 electron to form hydrogen and the sun emits plenty. On Earth the protons are guided to the poles along magnetic pause lines were they interact with neutrons emitted from Earths interior to form other elements like oxygen.

Reply to  jmorpuss
June 19, 2019 4:35 am

As I said above. Magnetic field has no direct impact on blowing atmosphere away.
It is only changing direction of particles and turning them to polar area and then down. It is not changing their speed or energy.
Collision with atmosphere occurs anyway. It is only located in polar area, but proportionally more intensive, thus wonderful auroras.

Reply to  Peter
June 19, 2019 6:06 am

Peter without magnetic re-connection on the night side there’s no atmospheric pressure buildup.

When a planet behaves like a comet: The tail of Venus and the weak solar wind.
by European Space Agency
“—Measurements obtained with ESA’s Venus Express spacecraft have shed new light on the interaction between the solar wind and the second planet from the Sun. During a rare period of very low density solar outflow, the ionosphere of Venus was observed to become elongated downstream, rather like a long-tailed comet.

Scientists have long known about the existence of the solar wind, a continuous outflow of electrons and protons which flows at high speed across interplanetary space. However, this stream of charged particles is highly variable, both in speed and density.

Under normal conditions, the solar wind has a density of 5 – 10 particles per cubic cm at Earth’s orbit, but occasionally the solar wind almost disappears, as happened in May 1999. Although such unusual episodes have been studied near Earth, which is surrounded by a strong magnetic field, there have been very few opportunities to study what happens near planets with negligible magnetic fields, such as Venus. ”

Reply to  jmorpuss
June 19, 2019 6:27 am
Earth is constantly leaking stream of particles from polar regions.
Magnetic field around poles also works as trap for solar wind particles, bringing them down to atmosphere. Auroras are stream of captured particles circulating magnetic poles interacting with atmosphere, causing loss of particles by collisions.

Reply to  jmorpuss
June 19, 2019 7:10 am

The Earth emits neutrons?????
Please provide documentation of this astounding fact.
Regardless, without fusion, those neutrons could never form anything other than hydrogen atoms.

Reply to  MarkW
June 20, 2019 2:31 pm

Nuclear fission chain reactions occur in nature. In 1972, scientists at the French Atomic Energy Establishment at Pierrelatte discovered the nearly intact remains of a natural nuclear fission reactor in a 0.5-m-thick seam of uranium ore located at Oklo, in the Republic of Gabon (7). “Subsequently, other reactor zones were discovered in the region and appear to have functioned as self-sustained nuclear fission reactors about 1,800 million years ago (8).

At the time that the Oklo reactor was active, the proportion of 235U in natural uranium was sufficiently great for nuclear fission chain reactions to occur in a thick mass of natural uranium ore. In addition to functioning as a thermal neutron reactor moderated by ground water, the Oklo reactor also functioned as a fast-neutron breeder reactor, producing additional fissile material in the form of plutonium and other transuranic elements (9).”

Michael J. Dunn
Reply to  jmorpuss
June 27, 2019 12:36 pm

Very interesting about Oklo—but entirely irrelevant to your earlier point about solar protons interacting with terrestrial neutrons to form heavy elements by fusion. For one thing, no proton-neutron fusion has ever been observed (and it would only form deuterium). You have no starting point.

Reply to  jmorpuss
June 19, 2019 1:38 pm

Fortunately the Earth’s interior isn’t emitting neutrons, or we wouldn’t be here.

Reply to  tty
June 21, 2019 8:52 am

Perhaps that should read “the sun is not emitting neutrons or we wouldn’t be here”.
The solar output should be a “factor of three” more neutrons minimum then it is emitting.
The earth admits neutron particularly granite which is radioactive. It’s not a great amount. 1/2 of all neutrons that penetrate the earth pass right through, that’s why neutron detectors are deep underground in salt mines not near granite sources of radioactive contamination.
Neutron detectors can locate nuclear reactors from all over the world and instantly detect any atomic weapons that are tested. When they were first installed, there was nearly a nuclear crisis set off by a false alarm. It turned out they detected neutron radiation from a supernova of a distant galaxy. Not possible if the Sun is a nuclear reactor. The detectors would be useless in the solar noise.

Reply to  Max
June 21, 2019 2:49 pm

Max a very learned explanation ,Thanks

Michael J. Dunn
Reply to  Max
June 27, 2019 12:38 pm

Max, you are confusing neutrons with neutrinos.

Kevin kilty
June 19, 2019 5:42 am

The title implies that Mars has lost its water. Yet if its polar caps were melted they would cover the planet to a depth of something like 20m. There is frozen water just under its surface, and its mantle probably contains much more that has never seen the surface.

Reply to  Kevin kilty
June 19, 2019 6:29 am

Yes, what is a chance for mars rover to scoop dirt and find water ice? And yet it happened.
Also radars are showing water everywhere under surface.
Gullies are cerated by water seeping from cliffs.
We see only tip of iceberg here, literally.

Svend Ferdinandsen
June 20, 2019 11:32 am

What is the explanation of the very dense atmosphere on Venus?

Reply to  Svend Ferdinandsen
June 21, 2019 12:55 am

Hi Svend, it is because of gravity. Venus has enough gravity to keep heavier elements as CO2, O2, N2 in its atmosphere and reduce loss.
Same with Earth, but on Earth carbon was stripped from atmosphere by biological processes to carbonates, coal etc. We have still almost all primordial carbon on Earth. If we turn all carbonates and coal back to CO2 we will end up like Venus. But biosphere will not allow it to happen.
Mars has low gravity not able to hold carbon. It was stripped by solar wind and it is simply not there anymore.
All planets are losing their atmosphere, only difference is in rate.

Svend Ferdinandsen
June 20, 2019 11:33 am

Can they also explain the very dense atmosphere on Venus?

Reply to  Svend Ferdinandsen
June 20, 2019 2:19 pm

Svend Ferdinandsen
Venus dense atmosphere is only on the side facing the sun , were the planets surface is heated and puts up some sort of resistance to push back. Venus has no way of internally generating a electromagnetic field like Earth to create magnetic re-connection on the dark side ,so Venus losses it’s dense atmosphere to space . Venus looks more like a comet with it’s tail.

“Venus Can Have ‘Comet-Like’ Atmosphere. … The side of Venus’ ionosphere that faces away from the sun can billow outward like the tail of a comet, while the side facing the star remains tightly compacted, researchers said. ”

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