Curiosity 2013: lake, geology, radiation Bashny.Net

Since June Curiosity on the road does not stop anywhere longer than a couple of weeks, it does not conduct serious research, only creeps and crawls to Mount Sharp, slowly but surely. However, in the last section of the full study Yellowknifle Bay, he picked up a stock of extracted soil from the hole Cumberland, and periodically review already on the road. NASA held a press conference where he spoke about the latest scientific results of the mission. Told about the clay, organic potential, the geological dating and radiation on the Martian surface.





Before starting the review, it is necessary to understand a little stratigraphy Yellowknifle Bay. Let me remind you: stratigraphy - the science of layers. The surface of that Earth, Mars, resembles a layer cake. The lowest base layer, from which emerged subsequent in geology called crystalline basement. Above, on the foundation laid layers that have arisen under the influence of different impacts of asteroids and meteorites fall, erosion water, weathering, glacial erosion, the world has added layers formed by the activities of organisms, from stromatolites and limestone to the cultural layer left by man.

We are interested in only a few meters of the surface layers, because they can learn Curiosity. To the surprise of geologists NASA, even those few meters were so diverse, no one expected.



In the lowland Yellowknifle Bay geologists have identified three main layers: the most profound and interesting - clay Sheepbed;



(Note: it is red only because of the coating of dust, so its color is pale blue-gray.)

slightly above - the "threshold" of dense sandstone Gillespie Lake;



and above dark rock called Glenelg:



(This particular rock called Point Lake)

In Sheepbed Curiosity drilled two wells John Klein and Cumberland. Both found clay particles, but still Cumberland showed higher water content. Taking with him a few servings of clay Cumberland, the rover went on the road, and geologists have sat down for a long study of the data obtained.

Analysis of the SAM unit shown presence in soil water, oxygen, carbon dioxide, sulfur oxide, nitrogen oxide, hydrogen sulfide, hydrogen chloride. SAM studies only gases that are released from the soil when heated in a microwave or soil indoors in a liquid solvent. The high content of carbon may indicate the presence of hydrocarbon compounds, ie, organic, but scientists point out that they can not guarantee its Martian origin - perhaps it traces of solvent. In addition, organic compounds nonbiological origin found in meteorites, so organics on Mars does not mean life, even past.


(Please note that some figures were increased to adjust schedules for one size).

Most optimists who did not want to give up hope of finding Martians, if the dead and microbiological, use the argument: "On the surface, all organic destroyed radiation, it is necessary to drill a few meters and find it».

It seems that NASA's work not stupid people, so they have thought about it before you send to Mars unit with a 7-centimeter drill. The preliminary studies and simulation environment gave Here's an interesting schedule:



From this it is clear that the 5-cm depth of 1 billion. Years of radiation destroy all complex organic compounds such as proteins. However, the more primitive the compound with атомной weight of less than 100 amu can last longer - up to one and a half billion years. A number of these compounds include certain amino acids, alcohols and other simple organic compounds.

However, such details did not come in handy, when scientists found the approximate date of the appearance of the layers on the surface of Sheepbed. It turned out that nisin Yellowknifle Bay - the result of wind erosion. This site was destroyed millions of years is Cumberland appeared on the surface of the current "only" about 80 mln. Years ago. For the geological history is not such a long time, and only for such a calm planet Mars - even more so.

It turns out that the first layer Sheepbed formed several billion years ago, then closed it with new layers, and then, under the influence of changed conditions, the wind began the destruction of the upper levels are gradually getting to the deep clay:


This study has allowed to adjust future plans, and set new goals on the path of the rover. Previously, scientists did not anticipate drilling until closer to Mount Sharp, now they pointed to a new target called KMS-9.



They decided that the youngest surface in which it makes sense to look for organics is hidden under the "threshold", so spotted a suitable site just 600 meters ahead:



This way Curiosity will do in about two months.

The data may change plans due to the fact that at NASA concerned about the wheels of Curiosity, which proved to be too weak against the sharp rocks of the crater Gale. Now the tread of the front four wheels can see some holes and some quite impressive:



However, damage is visible only in thin sheets whose thickness is 0 to 8 mm, the frame is much thicker and yet nowhere even cracked. Therefore, the health of the rover is not worth much to experience - on a hard surface, and he will pass on the net cord and into the desert and so he was not going to. Moreover, NASA is constantly engaged in that and what her plans, so do not escalate.

Continue about radiation. Earlier, before the landing of Curiosity, the scientists were very relative data obtained from satellites. MSL also carries a telescope radiation RAD, which meticulously records all that it pours out of space. As it turned out strewed not so little, but not so much as previously thought:



It seems that the conditions on the surface of only about two times better than in the space, but do not forget that space measurements Curiosity produced when he was inside the capsule, and on the Mars it is almost "no cap". Of course, a few millimeters of aluminum, from which will be the first home of the Martian settlers do not constitute a serious obstacle to cosmic rays, but the particles already hamper the atmosphere, so the protective qualities of the home increase. But still, if the future landers will be two-story, better equipped bedrooms on the first floor.

It is interesting that the rover does not record the effects of solar radiation, as It protects the planet even tonyusenkaya atmosphere. Instead of interstellar cosmic rays from her defense of the weak, yet it is very much dependent on the thickness. Schedule was built in the first three hundred Sols on the planet reveals interesting patterns:



Differences of intensity of radiation exposure occur due to fluctuations in atmospheric pressure. Day of the surface and the atmosphere heats up and rushes up and to the side, moving to a less warm areas, ie on the night side. It turns out that the day the atmosphere is more volume, but less dense and easier passes cosmic particles. Night cold atmosphere is thinner but denser, and thus better protection from radiation. It turns out that most "zazischennoe" time on the Martian surface - about 8 in the morning, and the most "radioactive" - ​​evening after 16:00:



As can be seen from this graph, of great importance and playing time of the year. True, all these fluctuations of radiation exposure within 10%, so that by the lead underwear is better not to give up.

What's even funnier - during solar flares the cosmic ray intensity decreases, ie, solar radiation replaces the "enemy of competitors" and covers the planet from interstellar high-energy radiation.

On the hundredth hydrochloric rover dust storm covered the light, and I was interested to see how the radiation will affect the hanging dust in the atmosphere, and for sure for a few Sols a decrease in the intensity of cosmic bombardment. So that future colonists should remember: you can walk in the morning and in the storm. But it is better, even in the world to think about how to fill the atmosphere of Mars.

Let us return to the study of samples Cumberland.
The data, even during the preliminary studies have to say that the title was prophetic Yellowknifle Bay, and the rover actually was on the bottom of the bay, though parched. The composition of the ground corresponds to the freshwater lake bottom sediments:



Moreover, all of the conditions indicate that the lake was completely adapted to living хемолитотрофных mikrorganizmov, ie such that the energy recovered from mineral compounds, but not the absorption of sunlight or the like themselves.

Of course, this idea immediately seized upon by most of the media, and some state explicitly that microbes live there precisely. Although, in fact, scientists have only confirmed what was told in the spring.

Unfortunately, another event which is of great importance to science and further study of the solar system, has passed virtually unnoticed. Curiosity for the first time for interplanetary missions, produced radioisotope dating of geological калий-аргоновым by !
The resulting value given the age of the Lake Cumberland 4, 2 + 0, 4 billion. Years. Pre-dating of the crater, which is made on the basis of analysis of the intensity of the bombardment surface, shows the value of 3, 6-4, 1 billion years:



The nature of the chemical composition of the soil Cumberland indicates that these particles were brought to the flow of water from the crater Gale and lay stagnant lake water.

Although the method is a little udrevnili radioisotope age of the crater, the whole value was pretty accurate. It is necessary to clarify that earlier figure of 3, 6 billion. Years took not from the ceiling, and on the basis of the proposed assessment while Поздней heavy bombardment . The bombing also was dated due to geological samples brought from the Moon. Ie - Watch your hands - Curiosity, examining the soil from Mars confirmed the reality of landing on the moon. Well, and in addition, he reiterated the commitment of the current theory of the evolution of the solar system and modern methods of dating of planets and satellites.

During his trip to the mountain Curiosity saw many new species, which will be able to tell more about the past of Mars, I look forward to any major conference where will publish the results of these observations travel. And because everything is just warming up. The most delicious - ahead:



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Source: habrahabr.ru/post/205440/