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I'm a bit confused - werent the NASA landers looking at the Martian dirt for microscopic traces of evidence of water in the past? or perhaps digging for some si

I'm a bit confused - werent the NASA landers looking at the Martian dirt for microscopic traces of evidence of water in the past? or perhaps digging for some sign of water? and the NSA probe just flys by and says hey look out the window, there's a entire lake of frozen water, sitting on the surface, that noone has ever observed before.

Retra 8y ago
I believe the landers were looking for historical traces of liquid water. Mars has a significant amount of frozen water around the poles, as has been known for a while, and this is just one example of some of it.
rory096 8y ago
We've long known (since Mariner 9 spectroscopy in 1972) that Mars' polar ice caps consist of a combination of water and dry ices and grow & shrink each season through direct deposition of water vapor from the atmosphere (sublimating back into water vapor in the spring, with no liquid phase). Mars Phoenix (which landed in the upper northern hemisphere and dug for soil samples) was intended to figure out whether the ground environment near the ice cap was conducive to life. It found that the soil does contain water ice distributed throughout it, but also contains hostile perchlorates. More recently, satellite imagery has found evidence of liquid water, both in seasonal flows on mid-latitude slopes (as a briny mixture with low freezing temp), and in underground lakes beneath the south polar ice cap. tl;dr: This Korolev crater pic is a fun pretty-picture post offering an opportunity to educate readers with a seasonal twist. No new science here.
borkt 8y ago
Theyve been looking for water (liquid H2O). We have known about the caps well back, at least the 70s.
jessriedel 8y ago
This image is digitally generated from topographical maps collected by satellite. There are no probes on Mars that are located in a place where they could actually take a picture like this. EDIT: My first sentence was wrong. As finnh points out, it's actually based on a real satellite photo that was then stretched to give the illusion of a perspective from low altitude.
- phkahler 8y ago
  And yet the article says: this feature, known as Korolev crater, is found on Mars, and is shown here in beautiful detail as seen by Mars Express. It is in fact a synthetic image constructed from a couple data sources. Not a real image taken from a camera. It may as well be one of those "artists conception of...." images used whenever a new planet is discovered.
  - finnh 8y ago
    I think that's just for the perspective, though? We'd have to be flying much, much lower to get the perspective shown in the image. The straight-overhead view is less CGI-y (still composed, but of multiple overhead strips): https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of_Korolev_crater https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_o... I'd like to know more about the input images...
    - jessriedel 8y ago
      Thanks for this info.
InclinedPlane 8y ago
To summarize: We've known for very long that the Mars polar caps contained water ice (since Mariner 9 and the Viking orbiters in the 1970s). We've known that the ice sublimates and deposits on the surface during local winter at high latitudes (Viking landers, 1970s). We've known that Mars had substantial amounts of liquid water on its surface at least for transitory periods (Mariner 9 & Viking orbiters, 1970s). Since the early 2000s we've known that Mars contains substantial amounts of water ice in the form of sub-surface permafrost. Specifically that much of the surface of the planet, if not all of it, is underlain with permafrost that is as much as half water ice in some areas, at a minimum depth below the surface of only around a meter. This permafrost layer exists even in middle latitudes and might exist even at equatorial latitudes at a greater depth. During the same time frame the Spirit and Opportunity rovers provided evidence that Mars experienced extended periods (of at least many millions of years) where substantial quantities of liquid water existed on the planet, leading to the formation of various geological features and minerals which could only be produced under those conditions. More recently (within the last 10 years) the Mars Reconnaissance Orbiter has provided evidence of the presence of sub-surface glaciers on Mars. These glaciers are vast volumes of water ice under thin layers of loose surface soil (a few meters to just one meter), and they exist all over Mars at latitudes as low as 30 deg. To put that in perspective, that's about the same latitude as New Orleans and San Diego. Even more recently (this year) data from the Mars Express orbiter pointed to the existence of a lake of liquid water 1.5 km beneath the Southern polar cap, likely made up of very briny water. All of this points to several interesting conclusions. Firstly, in regards to future colonization of the planet by humans there appears to be abundant and easily accessible reserves of water ice throughout much of the planet. This means that there are a great many (instead of very few) prime locations on Mars for placing settlements. With water ice and the CO2 atmosphere you can make: water (of course), oxygen, hydrogen, and methane which makes it possible to manufacture key resources for interplanetary transit (LOX/methane as a rocket propellant), human habitation (water and oxygen), farming (water, CO2, oxygen, sunlight), energy storage and fuel for vehicles (oxygen and hydrogen or methane), and even the beginnings of industry (plastics from methane, iron and steel from carbon monoxide et al, glass, aluminum, etc.) Being able to site settlements at mid latitudes means being able to choose areas that have decent sunlight most of the year, making it possible to grow crops using natural sunlight and to use solar power as at least one component of power generation. Secondly, in regards to the history of Mars the evidence of the presence of liquid water over geologically significant time periods combined with the evidence of pockets of sub-surface liquid water existing even into the present day means that Mars may have harbored environments suitable for the formation and existence of life, and some of that life may actually still exist through to the present day.
zokier 8y ago
For reference this is Viking photo (so 1975) of the pole: https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00161 https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00161 See that circular crater filled with ice in the top part of the picture. That's the same crater. So it is not exactly unknown feature on Mars. Also this is more close to the "true" picture, without the fake 3d perspective applied: http://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of_Korolev_crater http://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of... Final detail that Mars Express is still satellite, buzzing around at 300+ km altitude. The pretty pictures we see are composites of pictures like these: https://i.imgur.com/leNaYkM.jpg https://i.imgur.com/leNaYkM.jpg (which is also not completely raw)

Retra 8y ago

I believe the landers were looking for historical traces of liquid water. Mars has a significant amount of frozen water around the poles, as has been known for a while, and this is just one example of some of it.

rory096 8y ago

We've long known (since Mariner 9 spectroscopy in 1972) that Mars' polar ice caps consist of a combination of water and dry ices and grow & shrink each season through direct deposition of water vapor from the atmosphere (sublimating back into water vapor in the spring, with no liquid phase). Mars Phoenix (which landed in the upper northern hemisphere and dug for soil samples) was intended to figure out whether the ground environment near the ice cap was conducive to life. It found that the soil does contain water ice distributed throughout it, but also contains hostile perchlorates. More recently, satellite imagery has found evidence of liquid water, both in seasonal flows on mid-latitude slopes (as a briny mixture with low freezing temp), and in underground lakes beneath the south polar ice cap. tl;dr: This Korolev crater pic is a fun pretty-picture post offering an opportunity to educate readers with a seasonal twist. No new science here.

borkt 8y ago

Theyve been looking for water (liquid H2O). We have known about the caps well back, at least the 70s.

jessriedel 8y ago

This image is digitally generated from topographical maps collected by satellite. There are no probes on Mars that are located in a place where they could actually take a picture like this. EDIT: My first sentence was wrong. As finnh points out, it's actually based on a real satellite photo that was then stretched to give the illusion of a perspective from low altitude.

phkahler 8y ago
And yet the article says: this feature, known as Korolev crater, is found on Mars, and is shown here in beautiful detail as seen by Mars Express. It is in fact a synthetic image constructed from a couple data sources. Not a real image taken from a camera. It may as well be one of those "artists conception of...." images used whenever a new planet is discovered.
- finnh 8y ago
  I think that's just for the perspective, though? We'd have to be flying much, much lower to get the perspective shown in the image. The straight-overhead view is less CGI-y (still composed, but of multiple overhead strips): https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of_Korolev_crater https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_o... I'd like to know more about the input images...
  - jessriedel 8y ago
    Thanks for this info.

InclinedPlane 8y ago

To summarize: We've known for very long that the Mars polar caps contained water ice (since Mariner 9 and the Viking orbiters in the 1970s). We've known that the ice sublimates and deposits on the surface during local winter at high latitudes (Viking landers, 1970s). We've known that Mars had substantial amounts of liquid water on its surface at least for transitory periods (Mariner 9 & Viking orbiters, 1970s). Since the early 2000s we've known that Mars contains substantial amounts of water ice in the form of sub-surface permafrost. Specifically that much of the surface of the planet, if not all of it, is underlain with permafrost that is as much as half water ice in some areas, at a minimum depth below the surface of only around a meter. This permafrost layer exists even in middle latitudes and might exist even at equatorial latitudes at a greater depth. During the same time frame the Spirit and Opportunity rovers provided evidence that Mars experienced extended periods (of at least many millions of years) where substantial quantities of liquid water existed on the planet, leading to the formation of various geological features and minerals which could only be produced under those conditions. More recently (within the last 10 years) the Mars Reconnaissance Orbiter has provided evidence of the presence of sub-surface glaciers on Mars. These glaciers are vast volumes of water ice under thin layers of loose surface soil (a few meters to just one meter), and they exist all over Mars at latitudes as low as 30 deg. To put that in perspective, that's about the same latitude as New Orleans and San Diego. Even more recently (this year) data from the Mars Express orbiter pointed to the existence of a lake of liquid water 1.5 km beneath the Southern polar cap, likely made up of very briny water. All of this points to several interesting conclusions. Firstly, in regards to future colonization of the planet by humans there appears to be abundant and easily accessible reserves of water ice throughout much of the planet. This means that there are a great many (instead of very few) prime locations on Mars for placing settlements. With water ice and the CO2 atmosphere you can make: water (of course), oxygen, hydrogen, and methane which makes it possible to manufacture key resources for interplanetary transit (LOX/methane as a rocket propellant), human habitation (water and oxygen), farming (water, CO2, oxygen, sunlight), energy storage and fuel for vehicles (oxygen and hydrogen or methane), and even the beginnings of industry (plastics from methane, iron and steel from carbon monoxide et al, glass, aluminum, etc.) Being able to site settlements at mid latitudes means being able to choose areas that have decent sunlight most of the year, making it possible to grow crops using natural sunlight and to use solar power as at least one component of power generation. Secondly, in regards to the history of Mars the evidence of the presence of liquid water over geologically significant time periods combined with the evidence of pockets of sub-surface liquid water existing even into the present day means that Mars may have harbored environments suitable for the formation and existence of life, and some of that life may actually still exist through to the present day.

zokier 8y ago

For reference this is Viking photo (so 1975) of the pole: https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00161 https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00161 See that circular crater filled with ice in the top part of the picture. That's the same crater. So it is not exactly unknown feature on Mars. Also this is more close to the "true" picture, without the fake 3d perspective applied: http://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of_Korolev_crater http://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of... Final detail that Mars Express is still satellite, buzzing around at 300+ km altitude. The pretty pictures we see are composites of pictures like these: https://i.imgur.com/leNaYkM.jpg https://i.imgur.com/leNaYkM.jpg (which is also not completely raw)