News from Mars: Laser-Blasting and Soil Sampling

mars_lifeAs the exploration of Mars goes on, the small army of robotic rovers, satellites and orbiters continue to provide us with information, photographs and discoveries that remind us of how great a mystery the Red Planet truly is. For instance, in the past month, two major stories have been announced concerning the nature of Martian soil, its ancient history, and some of the more exciting moments in it’s exploration.

For example, Curiosity made news as its high resolution camera caught an image of sparks being generated as it zapped a Martian rock. In it’s lifetime, the rover has used its million watt Chemistry and Camera (ChemCam) laser to zap over 600 rock or soil targets as part of its mission. However, this was the first time that the rover team was able to get the arm-mounted Mars Hand Lens Imager (MAHLI) to capture the action as it occurred.

Curiosity-Laser-BeamThe ChemCam laser is used to determine the composition of Martian rocks and soils at a distance of up to 8 meters (25 feet). By hitting targets with several high-energy pulses, it is able to yield preliminary data for the scientists and engineers back at Earth to help them decide if a target warrants a closer investigation and, in rare cases, sampling and drilling activities.

ChemCam works through a process called laser-induced breakdown spectroscopy. The laser hits a target with pulses to generate sparks, whose spectra provide information about which chemical elements are in the target. Successive laser shots are fired in sequence to gradually blast away thin layers of material. Each shot exposes a slightly deeper layer for examination by the ChemCam spectrometer.

Mars_novarockAs Curiosity fired deeper into the target rock – named “Nova” – it showed an increasing concentration of aluminum as the sequential laser blasts penetrated through the uninteresting dust on the rock’s surface. Silicon and sodium were also detected. As Sylvestre Maurice, ChemCam’s Deputy Principal Investigator at the Research Institute in Astrophysics and Planetology, said in a statement:

This is so exciting! The ChemCam laser has fired more than 150,000 times on Mars, but this is the first time we see the plasma plume that is created… Each time the laser hits a target, the plasma light is caught and analyzed by ChemCam’s spectrometers. What the new images add is confirmation that the size and shape of the spark are what we anticipated under Martian conditions.

During it’s first year on Mars, Curiosity has already accomplished its primary objective of discovering a habitable zone on Mars that contains the minerals necessary to support microbial life billions of years ago when Mars was wetter and warmer. Currently, the rover is driving swiftly to the base of Mount Sharp at the center of Gale Crater, where it hopes to find more.

Mars_soilIn that same vein, according to new geological information obtained by Curiosty’s images and soil examinations, samples that were pulled out of a crater that is estimated to be some 3.7 billion years old contain more evidence that Mars was once much warmer and wetter. These findings were announced in a recent paper published in the online edition of Geology by University of Oregon geologist Gregory Retallack.

Unlike Earth, the Martian landscape is littered with loose rocks from impacts or layered by catastrophic floods. However, recent images from Curiosity from the Gale Crater reveal Earth-like soil profiles with cracked surfaces lined with sulfate, ellipsoidal hollows and concentrations of sulfate comparable with soils in Antarctica’s McMurdo Dry Valleys and Chile’s Atacama Desert.

mars-180-degrees-panorama_croppedRetallack, the paper’s lone author, studied mineral and chemical data published by researchers closely tied with the Curiosity mission. As a professor of geological sciences and co-director of paleontology research at the UO Museum of Natural and Cultural History, he internationally known as an expert on the recognition of paleosols – ancient fossilized soils contained in rocks.

As he explains in the paper:

The pictures were the first clue, but then all the data really nailed it. The key to this discovery has been the superb chemical and mineral analytical capability of the Curiosity Rover, which is an order of magnitude improvement over earlier generations of rovers. The new data show clear chemical weathering trends, and clay accumulation at the expense of the mineral olivine, as expected in soils on Earth. Phosphorus depletion within the profiles is especially tantalizing, because it attributed to microbial activity on Earth.

dryvalleysThe ancient soils do not prove that Mars once contained life, but they do add to growing evidence that an early, wetter and warmer Mars was more habitable than the planet has been in the past 3 billion years. Surface cracks in the deeply buried soils suggest typical soil clods. Vesicular hollows, or rounded holes, and sulfate concentrations, he said, are both features of desert soils on Earth.

Since Curiosity is currently on its way to Mount Sharp, future missions will be needed to fully explore these features. But as Retallack explained, the parallels with Earth are quite exciting:

None of these features is seen in younger surface soils of Mars. The exploration of Mars, like that of other planetary bodies, commonly turns up unexpected discoveries, but it is equally unexpected to discover such familiar ground.

The newly discovered soils indicate that more benign and habitable soil condition existed on Mars than previously expected. What’s more, their dating to 3.7 billion years ago places them within a transition period when the planet went from an early, benign water cycle to the acidic and arid Mars of today. This is especially important since major changes were taking place on Earth at around the same time.

Living-Mars.2Roughly 3.5 billion years ago, life on Earth is believed to have emerged and began diversifying. But some scientists have theorized that potential evidence that might indicate that life existed on Earth earlier may have been destroyed by tectonic activity, which did not occur on Mars. Basically, it may offer some credence to the theory that while flourished on Earth, it originated on Mars.

One person who supports this theory is Steven Benner of the Westheimer Institute of Science and Technology in Florida.  In the past, he has speculated that life is more likely to have originated on a soil planet like Mars than a water planet like Earth. In an email interview with Science Daily, Benner wrote that Retallack’s paper:

[S]hows not only soils that might be direct products of an early Martian life, but also the wet-dry cycles that many models require for the emergence of life.

So in addition to shedding light on the mysteries of Mars, Curiosity has also been pivotal in addressing some major questions which only increase the mystery of our own existence. Did life as we know it originate on Mars but flourish on Earth? Are there still some remnants of this microbial “Eden” being preserved deep within the soil and rocks? And could life exist there again some day?

All good questions that will no doubt keep robotic rovers, orbiters, landers, and even manned missions busy for many decades to come! In the meantime, check out the video from NASA’s Jet Propulsion Laboratory of Curiosity’s spark-generating laser blast being caught on tape:


Sources:
universetoday.com, sciencedaily.com

News From Space: We Come From Mars!

Mars_Earth_Comparison-580x356Men are from Mars, women are… also from Mars? That is the controversial theory that was proposed yesterday at the annual Goldschmidt Conference of geochemists being held in Florence, Italy. The proposal was made by Professor Steven Benner of the Westheimer Institute of Science and Technology in Florida and is the result of new evidence uncovered by his research team.

The theory that life on Earth originated on Mars has been argued before, but has remained contentious amongst the scientific community. However, Benner claims that new evidence supports the conclusion that the Red Planet really is our ancestral home by demonstrating that the elements for life here could only form on Mars, and came here via a Martian meteorite.

Asteroid-Impacts-MarsAccording to the theory, rocks violently flung up from the Red Planet’s surface during mammoth collisions with asteroids or comets then traveled millions of kilometers across interplanetary space to Earth. Once they reached Earth’s atmosphere. they melted, heated and exploded violently before the remnants crashed into the solid or liquid surface.

All that would be needed is for a few of those space born rocks to contain microbes from Mars surface. These building blocks of life would have to survive the journey through space and the impact on Earth to make this happen. But research into Exogenesis – the possibility that life was transplanted on Earth by meteorites – has already shown that this is possible.

curiosity_sol-177-1What’s more, NASA’s Curiosity Rover was expressly created to search for the the environmental conditions that would support life. Less than half a year into its mission it accomplished just that, locating proof of the existence of water and a habitable zone. Between it and the Opportunity Rover, the search to determine if life still exists – in the form of organic molecules – continues and is expected to yield results very soon.

But of course, Benner was quick to point out that there is a difference between habitability (i.e. where can life live) and origins (where might life have originated). The presence organic molecules alone is not enough when it comes to the mystery of life’s creation, and when it comes to making the great leap between having the necessarily elements and the existence of living organisms, scientists remain hung up on two paradoxes.

These are known as the tar paradox and the water paradox, respectively. The former paradox addresses how life as we know it comes down to the presence of organic molecules, which are produced by the chemistry of carbon and its compounds. However, the presence of these compounds does not ensure the creation of life, and laboratory experiments to combine and heat them has only ever produced tar.

mars_lifeAs he puts it, the origin of life involves “deserts” and oxidized forms of the elements Boron (B) and Molybdenum (Mo) – namely borate and molybdate. Essentially, these elements are the difference between the formation of tar and RNA, the very building block of life:

Certain elements seem able to control the propensity of organic materials to turn into tar, particularly boron and molybdenum, so we believe that minerals containing both were fundamental to life first starting. Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidized form of molybdenum was there too.

The second paradox relates to water, which is believed to be intrinsic for life to flourish, but can be also hazardous to its formation. According to modern research, RNA forms prebiotically, requiring mineral species like borate to capture organic elements before they devolve into tar and molybdate to arrange the material to give it ribose – organic sugars, also intrinsic to life.

Mars-snow-header-640x353This can only occur in deserts, he claims, because water is detrimental to RNA and inhibits the formation of borates and molybdates. And from a geological standpoint, there was simply too much water covering the early Earth’s surface to allow for this creation process to take place:

[W]ater is corrosive to RNA, which scientists believe was the first genetic molecule to appear. Although there was water on Mars, it covered much smaller areas than on early Earth. Various geologists will not let us have these [borates and molybdates] on early Earth, but they will let us have them on Mars. So IF you believe what the geologists are telling you about the structure of early Earth, AND you think that you need our chemistry to get RNA, AND IF you think that life began with RNA, THEN you place life’s origins on Mars,

All of this has served to throw the previously-held theory – that life came to Earth through water, minerals and organics being transported by comets – into disarray. Based on this new theory, comets are a bad candidate for organic life since they lack the hot, dry conditions for borate and molybdate formation.

Living-Mars.2If the new theory is to be believed, Mars boasted the proper conditions to create the elements for life, while Earth possessed the water to help it flourish. If such a partnership is needed for the creation of organic life, then scientists will need to reevaluate the likelihood of finding it elsewhere in the universe. Between the existence of water and hot dry environments, life would seem to require more specialized conditions than previously though.

But of course, the debate on whether Earthlings are really Martians will continue as scientific research progresses and definitive proof is discovered and accepted by the majority of the scientific community. In the meantime, Curiosity is expected to rendezvous with Mount Sharp sometime next spring or summer, where it will determine if organic molecules and elements like Boron and Molybdenum exist there.

And on Nov. 18th, NASA will launch its next mission to Mars – the MAVEN orbiter – which will begin studying the upper Martian atmosphere for the first time, determining its previous composition, and where all the water went and when was it lost. So we can expect plenty more news to come to us from our neighboring Red Planet. Wait and see!

Source: universetoday.com