A new theory for making liquid water once possible on Mars
In order to explain the many gullies on Mars, scientists at Brown University have now proposed a new model that says liquid water could exist periodically on the surface of Mars, caused by the cyclical changes in the planet’s rotational tilt, ranging from 11 to 60 degrees.
From editor’s summary of the paper:
Some steep slopes on Mars have gullies with morphologies suggesting that they were formed by a fluid. However, the planet’s current climate is not conducive to the melting of water ice at those locations, and mechanisms involving carbon dioxide ice do not explain the distribution of the gullies. [This paper] simulated how the climate of Mars differed when its axis tilted by different amounts over the past few million years. At a tilt of 35 degrees, the ice caps partially melted, raising the atmospheric pressure, and there were higher summer temperatures. Under these conditions, the atmospheric pressure at the gullies would be above the triple point of water, so it could melt to form a liquid.
The paper estimates these conditions last existed on Mars about 630,000 years ago, though the process repeated itself many times over the past several million years, each time causing some water ice to melt and flow down to form gullies. As the planet’s inclination then changed, conditions changed as well, producing colder temperatures at these latitudes so the water froze once again.
Though this is only a model with many uncertainties, it suggests a more reasonable explanation for the past existence of liquid surface water on Mars, temporary, periodic, and rare, than most other models. Combined with the possibility that ice glaciers themselves could have contributed to the formation of many of Mars’ riverlike channels, it seems that scientists are beginning to form a rough concept explaining how Mars evolved to what it is today.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
In order to explain the many gullies on Mars, scientists at Brown University have now proposed a new model that says liquid water could exist periodically on the surface of Mars, caused by the cyclical changes in the planet’s rotational tilt, ranging from 11 to 60 degrees.
From editor’s summary of the paper:
Some steep slopes on Mars have gullies with morphologies suggesting that they were formed by a fluid. However, the planet’s current climate is not conducive to the melting of water ice at those locations, and mechanisms involving carbon dioxide ice do not explain the distribution of the gullies. [This paper] simulated how the climate of Mars differed when its axis tilted by different amounts over the past few million years. At a tilt of 35 degrees, the ice caps partially melted, raising the atmospheric pressure, and there were higher summer temperatures. Under these conditions, the atmospheric pressure at the gullies would be above the triple point of water, so it could melt to form a liquid.
The paper estimates these conditions last existed on Mars about 630,000 years ago, though the process repeated itself many times over the past several million years, each time causing some water ice to melt and flow down to form gullies. As the planet’s inclination then changed, conditions changed as well, producing colder temperatures at these latitudes so the water froze once again.
Though this is only a model with many uncertainties, it suggests a more reasonable explanation for the past existence of liquid surface water on Mars, temporary, periodic, and rare, than most other models. Combined with the possibility that ice glaciers themselves could have contributed to the formation of many of Mars’ riverlike channels, it seems that scientists are beginning to form a rough concept explaining how Mars evolved to what it is today.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
It could also explain the layering.
Like the rings of a tree each layer could indicate the length of time each wet cycle lasted.
I’ve been thinking about it, it may explain some things but Mars it’s just too far from the sun to have much warmth for defrosting large amounts of liquid to cut gullies or river channels which require sustained continuous heating for large fluid flows. The lack of dry lake beds or ocean Shoreline is also a concern. Not enough wind to create waves, or froze too quickly to create a shoreline?
And yet the evidence of the rivers and delta deposits are everywhere!
No, I do not have a better explanation.
Unless Mars was a moon of a larger planet that broke apart and became the astroid belt… And it’s original orbit upon gravitational release was very elongated bringing it closer to the sun making the conditions right for rapid ice melting?
A close call with the earth could’ve changed it’s elongated orbit to make it more circular… Even though it’s not very circular now.
Max: The simplest solution for creating the canyons and channels on Mars to me appears to be evident in the many images coming from orbit. We now know that ice glaciers are common on Mars, much more than seen on Earth, and that ice can flow somewhat like a river given the right conditions.
Glaciers on Mars will be similar, but not identical to Earth glaciers, because of the weaker gravity and alien climate. Nonetheless, it is a simple explanation that requires no complex models or theories or special conditions. The new theory that I highlight in the post has the advantage of accepting the presence of glacial ice, and using it to produce very temporary liquid water. That, combined with flowing glaciers, might be all we need to explain everything we see on Mars.
Once we put aside our Earth-based assumptions.
It could be as simple as liquid water was far more abundant millions of years ago and all we are seeing now is the effects of the ever decreasing amount of water.
In a million years all there might be is massive amounts of never ending dust storms.
Without a strong magnetic field Mars atmosphere is literally being blown away by the solar winds. And with it goes the water.
pzatchok: The problem has not been a lack of water, the problem is that, based on all we know of Mars’ climate, atmosphere, and history, no model can come up with a circumstance where liquid water can exist and flow on the surface. The atmosphere is too thin and cold. Water in this situation will always sublimate directly from a solid to gas.
The orbital data tells us strongly that there has always been a lot of ice on Mars, with there being much more in the past.