Snow on Mars?
Click to see full image.
At today’s presentations at the 50th Lunar and Planetary Science Conference in Texas, scientists showed images and data [pdf] suggesting that many of the Martian gullies found on cliff faces are formed when the dust layer protecting underlying snow gets blown away and the exposed snow/ice then melts.
The image on the right was taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) in 2009, and has been cropped to post here. The white streaks are what they suggest is exposed ice/snow.
From their paper [pdf]
We interpret these observations to indicate that the light-toned materials are exposures of subsurface, water-ice mantle materials that are very similar to … [materials] being exhumed due to slumping caused by sublimation or seasonal frost processes. … The bright white/yellow appearance of these materials in [MRO] near-infrared imagery is consistent with the presence of dust (relatively clean water ice typically appears relatively blue) that partially covers, or is mixed in with ice deposited as snow, within the pasted-on materials.
A dust content of 1,000 parts per million by mass (p.p.m.m.) is sufficient for melting to occur for a wide range of snow properties and atmospheric pressures, and can occur under current conditions in the mid-latitudes. Modeling suggests that a 5-cm dust lag layer is enough to ‘protect’ the underlying snow from the Sun, and that for melting to occur, rapid exposure of the preserved snowpack is necessary.
Their presentation also included images of this same location, taken across three Martian years and showing the white streaks appearing and then disappearing.
The formation process of these gullies remains one of the primary geological mysteries that Mars presents to us. Is water involved? Ice? Brine? Does this material come from below, leaking out? Or is it placed on the surface as frost?
All of these have been suggested as an explanation. All have problems that make them poor answers.
What these scientists are suggesting is that, rather than water or brine leaking out from below ground or frost being laid down on the surface, the gullies form when subsurface ice/snow is exposed to the Sun and melts. They note that “Subsurface ice can be permanently stable at latitudes poleward of 25° due to slope effects, especially on pole-facing slopes.”
In other words, in latitudes higher than 25 degrees latitude, there could be a lot of snow and ice just below the surface on these slopes, covered by dust so that it doesn’t melt. With time small areas get exposed, melt away, and the subsequent disturbance causes small slides that produce the gullies. This conclusion seems reasonable, considering the number of other studies that suggest the presence of a ice table on Mars, below the surface. Moreover, this cliff is part of a major canyon draining into the eastern side of Hellas Basin, the basement of Mars, where there is ample other evidence of the presence of historic water and modern ice.
As always, I think like a colonist on Mars. These cliffs now appear to me as prime real estate, places to look for easily accessible water on Mars. That they are near Hellas Basin increases their value, as the low elevation of this basin means it will have a thicker atmosphere which will ease colonization. If we can find some caves in this region, we might then have all the ingredients for building that first Martian colony.
The support of my readers through the years has given me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Four years ago, just before the 2020 election I wrote that Joe Biden's mental health was suspect. Only in this year has the propaganda mainstream media decided to recognize that basic fact.
Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Even today NASA and Congress refuse to recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
Please consider supporting my work here at Behind the Black.
You can support me either by giving a one-time contribution or a regular subscription. There are five ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation:
5. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above. And if you buy the books through the ebookit links, I get a larger cut and I get it sooner.
Click to see full image.
At today’s presentations at the 50th Lunar and Planetary Science Conference in Texas, scientists showed images and data [pdf] suggesting that many of the Martian gullies found on cliff faces are formed when the dust layer protecting underlying snow gets blown away and the exposed snow/ice then melts.
The image on the right was taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) in 2009, and has been cropped to post here. The white streaks are what they suggest is exposed ice/snow.
From their paper [pdf]
We interpret these observations to indicate that the light-toned materials are exposures of subsurface, water-ice mantle materials that are very similar to … [materials] being exhumed due to slumping caused by sublimation or seasonal frost processes. … The bright white/yellow appearance of these materials in [MRO] near-infrared imagery is consistent with the presence of dust (relatively clean water ice typically appears relatively blue) that partially covers, or is mixed in with ice deposited as snow, within the pasted-on materials.
A dust content of 1,000 parts per million by mass (p.p.m.m.) is sufficient for melting to occur for a wide range of snow properties and atmospheric pressures, and can occur under current conditions in the mid-latitudes. Modeling suggests that a 5-cm dust lag layer is enough to ‘protect’ the underlying snow from the Sun, and that for melting to occur, rapid exposure of the preserved snowpack is necessary.
Their presentation also included images of this same location, taken across three Martian years and showing the white streaks appearing and then disappearing.
The formation process of these gullies remains one of the primary geological mysteries that Mars presents to us. Is water involved? Ice? Brine? Does this material come from below, leaking out? Or is it placed on the surface as frost?
All of these have been suggested as an explanation. All have problems that make them poor answers.
What these scientists are suggesting is that, rather than water or brine leaking out from below ground or frost being laid down on the surface, the gullies form when subsurface ice/snow is exposed to the Sun and melts. They note that “Subsurface ice can be permanently stable at latitudes poleward of 25° due to slope effects, especially on pole-facing slopes.”
In other words, in latitudes higher than 25 degrees latitude, there could be a lot of snow and ice just below the surface on these slopes, covered by dust so that it doesn’t melt. With time small areas get exposed, melt away, and the subsequent disturbance causes small slides that produce the gullies. This conclusion seems reasonable, considering the number of other studies that suggest the presence of a ice table on Mars, below the surface. Moreover, this cliff is part of a major canyon draining into the eastern side of Hellas Basin, the basement of Mars, where there is ample other evidence of the presence of historic water and modern ice.
As always, I think like a colonist on Mars. These cliffs now appear to me as prime real estate, places to look for easily accessible water on Mars. That they are near Hellas Basin increases their value, as the low elevation of this basin means it will have a thicker atmosphere which will ease colonization. If we can find some caves in this region, we might then have all the ingredients for building that first Martian colony.
The support of my readers through the years has given me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Four years ago, just before the 2020 election I wrote that Joe Biden's mental health was suspect. Only in this year has the propaganda mainstream media decided to recognize that basic fact.
Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Even today NASA and Congress refuse to recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
Please consider supporting my work here at Behind the Black.
You can support me either by giving a one-time contribution or a regular subscription. There are five ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation:
5. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above. And if you buy the books through the ebookit links, I get a larger cut and I get it sooner.
Readers: the rules for commenting!
No registration is required. I welcome all opinions, even those that strongly criticize my commentary.
However, name-calling and obscenities will not be tolerated. First time offenders who are new to the site will be warned. Second time offenders or first time offenders who have been here awhile will be suspended for a week. After that, I will ban you. Period.
Note also that first time commenters as well as any comment with more than one link will be placed in moderation for my approval. Be patient, I will get to it.