December 10, 2013 at 09:43Curiosity 2013: lake, geology, radiation
Since June, Curiosity on the road, does not stop anywhere longer than a couple of weeks, does not conduct serious research, only crawls and crawls to Mount Sharpe, slowly but surely. However, in the last section of the Yellowknifle Bay full-scale study, he took with him a supply of the extracted soil from the Cumberland well, and periodically carried out analyzes on the road. NASA held a press conference where it spoke about the latest scientific results of the mission. They talked about clay, potential organics, geological dating and radiation on the surface of Mars.
Before you begin the review, you need to understand a little about the Yellowknifle Bay stratigraphy. Let me remind you: stratigraphy is the science of layers. The surface that Earth, that Mars, resembles a layer cake. The lowest, main layer from which all subsequent ones arose is called a crystalline foundation in geology. Above, layers are deposited on the foundation that have arisen under the influence of various influences: falls of asteroids and meteorites, erosion by water, weathering, glacial erosion, layers on the Earth are added as a result of the activity of organisms, from stromatolites and limestones to the cultural layer left by man.
We are only interested in a few meters of surface layers, as Curiosity can study them. To the surprise of NASA geologists, even those few meters were as diverse as no one expected.
In the Yellowknifle Bay lowland, geologists have identified three main layers: the deepest and most interesting - clay Sheepbed;
(Please note: it is red only because of covering dust, so its color is pale gray-blue.) A
little higher is the “threshold” of dense sandstone of Gillespie Lake;
and even higher dark rocks called Glenelg:
(Specifically, this cliff was called Point Lake)
Curiosity drilled two wells at Sheepbed, John Klein and Cumberland. Clay particles were found in both, but Cumberland showed an even higher water content. Taking with him several servings of Cumberland clay, the rover set off on the road, and geologists sat down for a long study of the data.
The analysis performed by the SAM device showed the presence of water, oxygen, carbon dioxide, sulfur oxide, nitric oxide, hydrogen sulfide, hydrogen chloride in the soil. SAM only studies gases that are released from the soil when heated in a microwave or when the soil is placed in a liquid solvent. A high carbon content may indicate the presence of hydrocarbon compounds, i.e. organics, however, scientists emphasize that they can not vouch in its Martian origin - perhaps these are traces of solvent. In addition, organic compounds of non-biological origin were found in meteorites, so organic matter on Mars does not mean life, even the past.
(Please note that some indicators have been increased to fit the graphs to the same size).
Often, optimists who do not want to part with the hope of finding Martians, even the dead and microbiological ones, use the argument: "On the surface, all organic matter was destroyed by radiation, we must drill a few meters and look there."
We must think that NASA is not working stupid people, so they thought about it before sending a device with a 7-centimeter drill to Mars. The preliminary studies and modeling conditions given here this interesting graph:
Because it is clear that at a 5 cm depth for 1 billion years radiation will destroy all the complex organic compounds such as proteins.. However, more primitive compounds with atomic massless than 100 ams can last longer - up to one and a half billion years. And the number of such compounds includes some amino acids, alcohols and other simple organic compounds.
However, such subtleties were not even useful when scientists set an approximate date for the appearance of Sheepbed layers on the surface. It turned out that the Yellowknifle Bay lowland is the result of wind erosion. This site collapsed millions of years and Cumberland appeared on the present surface of “only” about 80 million years ago. For geological history, this is not such a long time, and even more so for such a calm planet as Mars.
It turns out that at first the Sheepbed layer was formed several billion years ago, then it was covered with new layers, and then, under the influence of changing conditions, the wind began to destroy the upper levels, gradually reaching deep clay:
This study allowed us to adjust future plans and set new goals for ways of the rover. Previously, scientists did not anticipate drilling operations up to approaching Mount Sharpe, but now they have pointed to a new target called KMS-9.
They decided that the youngest surface, in which it makes sense to look for organic matter, is hidden under the “thresholds”, so they saw a suitable section just 600 meters ahead:
Curiosity will complete this journey in about a couple of months.
Perhaps these changes in plans are due to the fact that NASA is worried about the state of Curiosity wheels, which turned out to be too weak against the sharp stones of Gale Crater. Now, on the tread of the front four wheels, several holes can be seen and some are quite impressive:
However, while damage is visible only on thin sheets, whose thickness is 0.8 mm, the frame is much thicker and has not even cracked anywhere. Therefore, you should not worry too much about the health of the rover - it will pass along a solid surface on a mesh cord, but it was not going to sands anyway. Moreover, NASA is constantly engaged in this, that changes plans, so do not escalate.
Let's continue on radiation. Earlier, before the Curiosity landing, scientists had very relative data obtained from satellites. MSL carries on board the RAD radiation telescope, which scrupulously fixes everything that is streaming onto it from space. As it turned out, not so little is being poured, but not so much as previously thought:
It seems that the conditions on the surface are only about twice as good as in space, but do not forget that Curiosity made space measurements when it was inside the capsule, and on Mars itself it was practically “without a hat”. Of course, a few millimeters of aluminum, from which the first houses of Martian settlers will be, will not constitute a serious obstacle to cosmic rays, but the atmosphere will slow down the particles, so the protective qualities of the home will increase. But anyway, if future landing modules are two-story, it is better to equip the bedrooms on the ground floor.
It is curious that the rover practically does not record the effect of solar radiation, i.e. even a tiny atmosphere protects the planet. But from the interstellar cosmic rays its protection is weaker, but still it is inversely proportional to its thickness. What's even funnier is that during solar flares, the intensity of cosmic rays decreases, i.e. solar radiation crowds out "enemy competitors" and shields the planet from radiation. The graph built for the first three hundred solos on the planet shows interesting patterns:
Differences in the intensity of radiation exposure occur due to fluctuations in atmospheric pressure. In the afternoon, the surface and atmosphere heats up and rushes up and to the sides, moving to less warm areas, i.e. to the night side. It turns out that the daytime atmosphere is more voluminous, but less dense and easier to let through cosmic particles. The night cold atmosphere is thinner, but denser, and, thus, better protects against radiation. It turns out that the most “protected” time on the surface of Mars is about 8 in the morning, and the most “radioactive” time is the evening after 16:00:
As can be seen from this graph, the season also plays an important role. True, all these fluctuations in radiation exposure are within 10%, so that it is better not to refuse lead underwear.
A light dust storm covered the hundredth Mars rover, and I was interested to see how the dust hanging in the atmosphere will affect radiation, and for sure: a few solos show a decrease in the intensity of space bombardment. So, future colonists should remember: you can walk in the morning and in a storm. But it’s better, even on Earth, to think about how to replenish the atmosphere of Mars.
Let us return to the results of the study of Cumberland samples.
The data obtained, even during a preliminary study, made it possible to say that the name Yellowknifle Bay was prophetic, and the rover actually turned out to be at the bottom of the bay, although it was dry. The composition of the soil corresponds to the bottom sediments of a freshwater lake:
Moreover, all conditions indicate that the lake was fully adapted for habitation.chemolithotrophic microorganisms, i.e. those that extract energy from mineral compounds, rather than sunlight or the absorption of their own kind.
Of course, most of the media immediately seized on this idea, and some directly stated that the microbes lived there for sure. Although, in fact, scientists only confirmed what they told back in the spring.
Unfortunately, another event, which is of great importance for science and the further study of the entire solar system, went almost unnoticed. Curiosity for the first time, for interplanetary missions, performed geological dating with the radioisotope potassium-argon method !
The resulting value gave the age of Lake Cumberland at 4.2 + -0.4 billion years. Preliminary dating of the crater, which was based on an analysis of the intensity of meteorite bombardment of the surface, showed a value of 3.6-4.1 billion years: The
nature of the chemical composition of the Cumberland soil indicates that these particles were brought by the flow of water from the shaft of the Gale Crater and deposited in a standing lake water.
Although the radioisotope method slightly aggravated the age of the crater, in general, the value turned out to be quite accurate. It is worth explaining that the early figure of 3.6 billion years did not come from the ceiling, but based on the assessment of the late heavy bombing projected at that time. The bombing was dated due to geological samples brought from the moon. Those. - watch your hands - Curiosity, having studied the soil from Mars, confirmed the reality of the landing on the moon. Well, in addition to this, he confirmed the fidelity of the current theory of the evolution of the solar system and modern methods of dating of planets and satellites.
During my trip to Mount Curiosity I saw many new breeds that can tell even more about the past of Mars, I look forward to some major conference, where the results of these travel observations will be published. And all this is just a warm-up. The tastiest thing is to come:
1920x1200 Vk
NASA release
Publications in ScienceMag
PS Then Mars One announced the start of fundraising for its first private mission to Mars ...
Before you begin the review, you need to understand a little about the Yellowknifle Bay stratigraphy. Let me remind you: stratigraphy is the science of layers. The surface that Earth, that Mars, resembles a layer cake. The lowest, main layer from which all subsequent ones arose is called a crystalline foundation in geology. Above, layers are deposited on the foundation that have arisen under the influence of various influences: falls of asteroids and meteorites, erosion by water, weathering, glacial erosion, layers on the Earth are added as a result of the activity of organisms, from stromatolites and limestones to the cultural layer left by man.
We are only interested in a few meters of surface layers, as Curiosity can study them. To the surprise of NASA geologists, even those few meters were as diverse as no one expected.
In the Yellowknifle Bay lowland, geologists have identified three main layers: the deepest and most interesting - clay Sheepbed;
(Please note: it is red only because of covering dust, so its color is pale gray-blue.) A
little higher is the “threshold” of dense sandstone of Gillespie Lake;
and even higher dark rocks called Glenelg:
(Specifically, this cliff was called Point Lake)
Curiosity drilled two wells at Sheepbed, John Klein and Cumberland. Clay particles were found in both, but Cumberland showed an even higher water content. Taking with him several servings of Cumberland clay, the rover set off on the road, and geologists sat down for a long study of the data.
The analysis performed by the SAM device showed the presence of water, oxygen, carbon dioxide, sulfur oxide, nitric oxide, hydrogen sulfide, hydrogen chloride in the soil. SAM only studies gases that are released from the soil when heated in a microwave or when the soil is placed in a liquid solvent. A high carbon content may indicate the presence of hydrocarbon compounds, i.e. organics, however, scientists emphasize that they can not vouch in its Martian origin - perhaps these are traces of solvent. In addition, organic compounds of non-biological origin were found in meteorites, so organic matter on Mars does not mean life, even the past.
(Please note that some indicators have been increased to fit the graphs to the same size).
Often, optimists who do not want to part with the hope of finding Martians, even the dead and microbiological ones, use the argument: "On the surface, all organic matter was destroyed by radiation, we must drill a few meters and look there."
We must think that NASA is not working stupid people, so they thought about it before sending a device with a 7-centimeter drill to Mars. The preliminary studies and modeling conditions given here this interesting graph:
Because it is clear that at a 5 cm depth for 1 billion years radiation will destroy all the complex organic compounds such as proteins.. However, more primitive compounds with atomic massless than 100 ams can last longer - up to one and a half billion years. And the number of such compounds includes some amino acids, alcohols and other simple organic compounds.
However, such subtleties were not even useful when scientists set an approximate date for the appearance of Sheepbed layers on the surface. It turned out that the Yellowknifle Bay lowland is the result of wind erosion. This site collapsed millions of years and Cumberland appeared on the present surface of “only” about 80 million years ago. For geological history, this is not such a long time, and even more so for such a calm planet as Mars.
It turns out that at first the Sheepbed layer was formed several billion years ago, then it was covered with new layers, and then, under the influence of changing conditions, the wind began to destroy the upper levels, gradually reaching deep clay:
This study allowed us to adjust future plans and set new goals for ways of the rover. Previously, scientists did not anticipate drilling operations up to approaching Mount Sharpe, but now they have pointed to a new target called KMS-9.
They decided that the youngest surface, in which it makes sense to look for organic matter, is hidden under the “thresholds”, so they saw a suitable section just 600 meters ahead:
Curiosity will complete this journey in about a couple of months.
Perhaps these changes in plans are due to the fact that NASA is worried about the state of Curiosity wheels, which turned out to be too weak against the sharp stones of Gale Crater. Now, on the tread of the front four wheels, several holes can be seen and some are quite impressive:
However, while damage is visible only on thin sheets, whose thickness is 0.8 mm, the frame is much thicker and has not even cracked anywhere. Therefore, you should not worry too much about the health of the rover - it will pass along a solid surface on a mesh cord, but it was not going to sands anyway. Moreover, NASA is constantly engaged in this, that changes plans, so do not escalate.
Let's continue on radiation. Earlier, before the Curiosity landing, scientists had very relative data obtained from satellites. MSL carries on board the RAD radiation telescope, which scrupulously fixes everything that is streaming onto it from space. As it turned out, not so little is being poured, but not so much as previously thought:
It seems that the conditions on the surface are only about twice as good as in space, but do not forget that Curiosity made space measurements when it was inside the capsule, and on Mars itself it was practically “without a hat”. Of course, a few millimeters of aluminum, from which the first houses of Martian settlers will be, will not constitute a serious obstacle to cosmic rays, but the atmosphere will slow down the particles, so the protective qualities of the home will increase. But anyway, if future landing modules are two-story, it is better to equip the bedrooms on the ground floor.
It is curious that the rover practically does not record the effect of solar radiation, i.e. even a tiny atmosphere protects the planet. But from the interstellar cosmic rays its protection is weaker, but still it is inversely proportional to its thickness. What's even funnier is that during solar flares, the intensity of cosmic rays decreases, i.e. solar radiation crowds out "enemy competitors" and shields the planet from radiation. The graph built for the first three hundred solos on the planet shows interesting patterns:
Differences in the intensity of radiation exposure occur due to fluctuations in atmospheric pressure. In the afternoon, the surface and atmosphere heats up and rushes up and to the sides, moving to less warm areas, i.e. to the night side. It turns out that the daytime atmosphere is more voluminous, but less dense and easier to let through cosmic particles. The night cold atmosphere is thinner, but denser, and, thus, better protects against radiation. It turns out that the most “protected” time on the surface of Mars is about 8 in the morning, and the most “radioactive” time is the evening after 16:00:
As can be seen from this graph, the season also plays an important role. True, all these fluctuations in radiation exposure are within 10%, so that it is better not to refuse lead underwear.
A light dust storm covered the hundredth Mars rover, and I was interested to see how the dust hanging in the atmosphere will affect radiation, and for sure: a few solos show a decrease in the intensity of space bombardment. So, future colonists should remember: you can walk in the morning and in a storm. But it’s better, even on Earth, to think about how to replenish the atmosphere of Mars.
Let us return to the results of the study of Cumberland samples.
The data obtained, even during a preliminary study, made it possible to say that the name Yellowknifle Bay was prophetic, and the rover actually turned out to be at the bottom of the bay, although it was dry. The composition of the soil corresponds to the bottom sediments of a freshwater lake:
Moreover, all conditions indicate that the lake was fully adapted for habitation.chemolithotrophic microorganisms, i.e. those that extract energy from mineral compounds, rather than sunlight or the absorption of their own kind.
Of course, most of the media immediately seized on this idea, and some directly stated that the microbes lived there for sure. Although, in fact, scientists only confirmed what they told back in the spring.
Unfortunately, another event, which is of great importance for science and the further study of the entire solar system, went almost unnoticed. Curiosity for the first time, for interplanetary missions, performed geological dating with the radioisotope potassium-argon method !
The resulting value gave the age of Lake Cumberland at 4.2 + -0.4 billion years. Preliminary dating of the crater, which was based on an analysis of the intensity of meteorite bombardment of the surface, showed a value of 3.6-4.1 billion years: The
nature of the chemical composition of the Cumberland soil indicates that these particles were brought by the flow of water from the shaft of the Gale Crater and deposited in a standing lake water.
Although the radioisotope method slightly aggravated the age of the crater, in general, the value turned out to be quite accurate. It is worth explaining that the early figure of 3.6 billion years did not come from the ceiling, but based on the assessment of the late heavy bombing projected at that time. The bombing was dated due to geological samples brought from the moon. Those. - watch your hands - Curiosity, having studied the soil from Mars, confirmed the reality of the landing on the moon. Well, in addition to this, he confirmed the fidelity of the current theory of the evolution of the solar system and modern methods of dating of planets and satellites.
During my trip to Mount Curiosity I saw many new breeds that can tell even more about the past of Mars, I look forward to some major conference, where the results of these travel observations will be published. And all this is just a warm-up. The tastiest thing is to come:
1920x1200 Vk
NASA release
Publications in ScienceMag
PS Then Mars One announced the start of fundraising for its first private mission to Mars ...
