What is Life and Will Curiosity Find it on Mars? (Issue #14)

by: Nicole Willett

The definition of what life is has eluded scientists for many generations…

This is partially due to the many extreme organisms that have been found that push the traditional boundaries outward in every direction.  What is a virus? It can reproduce, but it is considered not to be life because it must have a host to reproduce.  Does size matter?  Can something be too small to be alive?  There are bacteria that are smaller than viruses.  Can something be too big to be alive?  Recently, I have heard scientists debating whether the entire universe is a living organism.  In order to come up with a definition we must describe what elements are needed for life as we know it to exist.  We must also decide whether or not water is necessary and in what state.  Can organisms live in soil with a high or low pH content?  Are there energy gradients available for an organism to utilize the chemicals available for metabolism?  What temperatures can life survive at?

blog 14 jonlieffmd comAll of these questions must be addressed before scientists come up with a true definition for life.  A simple definition of life from dictionary.com states, “the condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation toenvironment through changes originating internally.”  This definition may work for laymen but when it comes to the plethora of extreme organisms we are finding now and with the search for organisms on Mars, we need a much more specific definition.  As with all things in science, we have had a hard time getting everyone to agree on a true definition. 

Some things to consider are the six required elements necessary for all life on Earth thus far.  Biologists like to call it CHNOPS.   

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That acronym stands for is Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur.  Interestingly, the Curiosity Rover’s SAM and CheMin instruments found CHNOPS in their latest sample of the rock called “John Klein” that was drilled recently.  These results can all be found on NASA and JPL websites.  Another interesting find is methane in the forms of chloromethane and dichloromethane.  These are widely reported as “simple organics” in the press.   These molecules were also found at the “Rocknest” site in an earlier soil sample taken by Curiosity.  The discovery of organic molecules is the pièce de résistance that we have all been awaiting.   Organics in general refer to something that was at one time alive or is alive now.  We know from studying life forms on Earth that methane is a common organic molecule that is a waste product of bacteria and macro organisms.   However, about 10% of methane on Earth is a result of geological activity.  The rovers and orbiters have not detected any macro organisms, but scientists are diligently looking for evidence of an environment conducive to microorganisms. 

blog 14 nasa jpl 4betterAgain the scientists caution that these results may be contaminants from Earth.  But, this seems to be a pattern.   Mars scientists are repeatedly confirming and reconfirming the presence of water on Mars.  Also, they are stating and restating the potential habitability of Mars.  Dr. John Grotzinger, project scientist for the Curiosity mission, went so far as to state, “”We have found a habitable environment.  The water that was here was so benign and supportive of life that if a human had been on the planet back then, they could drink it.”  Wow, that is quite a statement.  Not only are NASA scientists stating that Mars was habitable they are stating that humans could have consumed the water that sat and flowed on the surface of the Red Planet.  Think about the potential ramifications of that information. 

As the scientists, go over and over the information from Mars, they continue to make amazing discoveries.  Another significant find is the electrochemical gradient of the different molecules found inside of the John Klein rock.  An electrochemical gradient is another important piece of the “life on Mars” puzzle because life forms use these gradients to move ions across membranes in order to perform many metabolic and other biological functions.   Some of the molecules found in the rocks have different electric charges; some are more oxidized than others.  This was cleverly illustrated at last week’s press conference.  Dr. Grotzinger held up a battery to demonstrate the way rock eating microbes utilize the energy gradients formed by molecules, such as sulfates and sulfides, to their advantage in their metabolic processes.  This finding has extraordinary implications if everything that has been reported remains true. 

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So, what is life and will Curiosity find it on Mars?  Well, we know that there is no single definition that everyone agrees on.  Keep in mind that the requirements for life as we know it are: water, a source of energy, and evidence of organics.  The types of methane found are known as simple organics. However, we also know that there are definite signatures for life as we know it.  NASA is finding more and more evidence with every scoop of soil analyzed by Curiosity’s onboard lab.  If the day comes when there is a confirmation of life on Mars, it will change humanity forever.  I am looking forward to that day.
[Images: NASA JPL, jonlieffmd.com, psrd.hawaii.edu]

Rock Eaters, Will Curiosity Find Them? (Issue #13)

by: Nicole Willett

Last week NASA’s Curiosity rover made history by drilling into the first rock on another planet.  The rock, named John Klein, had a hole drilled that was 0.63 inches in diameter and 2.5 inches deep.  Surprisingly, the soil beneath the iron red surface was bright grey.  The soil sample has been sent to the suite of instruments in the belly of the rover, including SAM and CheMin.  These mini laboratories will analyze the soil content to find out its composition.  Everyone is anxiously awaiting the results of these tests.  Unfortunately, Curiosity went into “safe mode” several days ago due to a corrupt file on its main computer.  (As this blog was being posted, NASA announced that the computer had returned to “active status”.)  This will inevitably delay the results.  However that does not stop people from speculating about what the science lab onboard the rover might discover.

curiosity drillScientists are hoping to find more evidence of past water on Mars.  What would be even more amazing is if Curiosity found evidence of an extreme organism or extremophile.  Because Curiosity drilled into a rock, they may find evidence of an extreme organism known as a lithotroph, aka a “rock-eater”.  Astrobiologists have been studying these extremophiles for many years and have discovered many amazing things about them.  An extremophile is a general term for any organism that lives beyond what is commonly thought of as “normal” conditions.
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Astrobiologists have looked at rocks from the most inhospitable places on Earth.  They have found organisms living beneath rocks, between rocks and inside of rocks.  There are several types of rock-eaters, and they have been given unusual names like autolithotrophs, hypoendoliths and cryptoendoliths.  They are known collectively as lithotrophs.  These organisms are truly rock-eaters.  They actually digest the rock they live on or inside of. Lithotrophs have developed a unique way to metabolize the minerals in the rocks.  These organisms have learned to survive in very extreme environments.  If a lithotroph was found on the Red Planet, it would be a polyextremophile that is highly resistant to ultra-violet (UV) radiation, able to tolerate dry and desiccating conditions and tolerant to extremely cold temperatures.  A polyextremophile is an organism that lives beyond the realm of what the general public sees as normal with several extreme adaptations for survival.  Some live exposed to so much UV radiation that it kills almost every other organism in the vicinity.  These are known as radio resistant organisms.   

water bear eggOther organisms referred to as xerophiles live in places that receive little to no rainfall for years or even decades. There are also organisms that live in extremely cold conditions.  These are known as psychrophiles, or cryophiles. They can survive temperatures as low as -15o C.  On Earth, cryophiles live in salty or briny sea water.  The salt and minerals in the water lower the freezing point.  This is another interesting twist to the conditions scientists are seeking on or below the Martian surface.  We know the mineral content of the soil in the many areas we have visited on Mars.  They are similar in composition to the places on Earth that harbor many types of extremophiles.

It has been said by astrobiologists that if the Viking Lander would have landed in the Atacama Desert on Earth, it very likely would not have detected life. This is due to the types of organisms that have adapted to live there.  They would not have been recognized by the sophisticated equipment on Viking.  The Atacama Desert is frequently used as a Mars-Earth analog for astrobiology experiments.

atacama_desert_boliviaThe more we seek, the more we find.  The more we find, the more questions we have.  Curiosity is an interesting double entendre.  Our rover is named Curiosity, and human curiosity is what drives us to explore in space and on Mars.  As Professor Brian Cox once said, “I don’t need answers to everything; I want to have answers to find.”                                                                       
[Images: discovery.com, nasa.gov, sciencephoto.com, humanandnatural.com]
 

Curiosity’s Search Begins (Issue #4)

by: Nicole Willett

The Mars Science Laboratory (MSL) Curiosity Rover was launched on November 26, 2011 from Cape Canaveral Florida.  The MSL had generated quite a fan base over the years and months leading up to her launch and landing.  On August 5, 2012 the entire world was watching with heightened anticipation.  As the updates were streaming through live from the Jet Propulsion Laboratory, at The Mars Society Convention hall in Pasadena, the excitement and anxiety was building.  Each update from the team at JPL received a round of applause.  When word was given of a successful landing there were high fives, laughter, tears and even a few hugs.   The successful landing of Curiosity was the culmination of many years of hard work, scientific and engineering prowess, and American ingenuity. 

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Curiosity landed on target in Gale Crater.  Her successful landing proved that NASA can land a heavy rover (1,980 lbs, 899 kg) on the surface of Mars, using a technique that had not been used before.  The engineers designed a parachute combined with a sky-crane landing system.  This complex system seemed “just crazy enough to work” according to MSL’s lead engineer Adam Steltzner.   The successful landing also proved that we could land in a more precise landing circle, which is, the target area given by the scientists for the predicted landing site.   The landing site was named Bradbury Landing in honor of the late science fiction author Ray Bradbury. Almost immediately after landing Curiosity started sending images of the surface of Mars to NASA. 

Curiosity has many tasks on Mars.  Some of which are to:  assess the habitability of Mars, find the inventory and/or source of organic carbon, look for evidence of biological processes, investigate geological processes, planetary processes, cycling of water, and surface radiation.    She will start by examining the rocks and soils.  The history of a planet can be determined from studying the geology.  The suite of instruments carried on the rover will try to determine if the chemical building blocks of life are present or if they were present in the past.  Some of the scientific instruments she carries are:  several types of cameras, spectrometers, radiation detectors, environmental monitoring systems, and atmospheric instruments.  These instruments will make assessments that not only will help us to better understand the Red Planet, but it will also help prepare for human exploration.

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The instrumentation on the one ton rover is the most complex suite of scientific instruments to be sent to Mars. Several types of cameras are on board, each of which have a different purpose. For example the MastCam gives true color images and uses multiple spectra.  The ChemCam is a suite of instruments that uses a laser to identify types of rocks and determine the composition of soils.  There is an Alpha Particle X-ray Spectrometer (APXS) to determine what elements are in each sample tested.   The Sample Analysis at Mars (SAM) will analyze solid and gas samples looking for organic molecules.  SAM is a suite of instruments that takes up over half of the scientific payload which has been described as having an entire Chemistry lab reduced to fit on the rover.  This mini-lab is a group of three instruments searching for compounds of carbon, hydrogen, oxygen, and nitrogen and their potential association with life.

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This mission is currently underway.  Last week Curiosity discovered some unusual material on the surface of Mars and right beneath the soil nearby. The first anomalous object was determined to be debris from the rover.  When the rover scooped up soil there were other bright objects found.  On October 17, 2012 a scoop of Martian regolith was put into the CheMin, the Chemistry and Mineralogy instrument.  This will determine what the soil is composed of, and hopefully what the mysterious bright objects are.

There will be many new discoveries made by the Curiosity Rover over the next two years or more. We are all waiting patiently for anything she has to show us.  It is a very exciting and inspiring time for Earthlings.  We are witnessing events that are due to our willingness to work hard as a team to accomplish a common goal.  This is a measure of our character as human beings.  We mustcontinue our exploration… OnToMars~

In addition to this week’s blog:    A Special Presentation by Bob Bruner

Life on Mars in a Box

The environmental requirements for life are:

1. Source of molecules from which to build its own cellular structures and for reproduction

2. Source of energy to maintain biological order and to fuel the many chemical reactions that occur in life

3. Liquid medium, most likely liquid water, for transporting the molecules of life

The key to this puzzle is whether all these ingredients for life came together in the right proportions at the right time.

The image of the “Life on Mars in a Box” contains illustrations of research results that show these requirements are met on the planet Mars:

1. Image (center) of the volcanoes on Mars demonstrates that an energy source is available; other sources would be cosmic rays, UV rays, etc. coming from space

2. Dark mineral, Goethite (upper left), and light mineral, Gypsum (lower left), show hydrothermal groundwater circulation during the early history of Mars (Ehlmann et al, Nature, 2011)

3. Piece of the Murchison meteorite (lower right) contains non-biological carbon in the form of amino acids, and shows the availability of life-building molecules throughout the solar system (Kvenvolden et al, Nature, 1970)

4. Piece of the Shergottite meteorite (upper right) from Mars, which contains non-biological carbon created by volcanic action during the early history of Mars, shows a second source of life-building molecules (Steele et al, Science, 2012)

References:

Beyond UFOs, by Jeffrey Bennet, 2008, Princeton University Press

Conversation with Pamela Conrad, NASA Astrobiologist and Assistant Principal Investigator of the SAM instrument on the Mars Science Laboratory which landed on Mars in August, 2012

Exhibit prepared by Robert Bruner

Denver Museum of Nature and Science volunteer

bobbruner40@hotmail.com

Images [NASA, JPL]

The Search for Life on Mars from Viking to Curiosity (Issue #3)

by: Nicole Willett

For centuries there has been speculation about life on Mars, from microbes to little green men.  Scientists have spent an enormous amount of time and resources searching for clues to previous or current life on the Red Planet.  The latest mission to search for the clues to life on Mars is NASA’s Mars Science Laboratory (MSL) Curiosity.

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With much fanfare, on August 5, 2012, the MSL Curiosity landed successfully in Gale Crater on Mars.  The landing site was named Bradbury Landing site in honor of the late science fiction author Ray Bradbury.  There have been many predecessors to the Curiosity Rover on Mars, including orbiters, rovers, and landers.  Over the past few years NASA has been using the “follow the water” strategy in an effort to find evidence of past or current life on Mars.  We know that everywhere we have water on Earth we have life.

The Viking 1 & 2 landed on Mars in 1976.  The main purpose of the scientific experiments was to search for life.  The first soil test for Viking yielded positive results for life, however the tests that followed all yielded negative results.   These results are controversial and are still being studied and debated to this day.  Another important finding from the Viking missions was that water vapor was released from the soil samples that were heated in the gas chromatograph mass spectrometer.

The Pathfinder Sojourner Rover landed on July 4, 1997.  The Sojourner Rover was the first rover deployed on another planet.  The X-ray spectrometer examined the soil and determined that Mars clearly had a warmer and wetter past.  The Sojourner Rover confirmed previous volcanic activity by discovering basaltic rock.  Scientists state that volcanic ash increases soil fertility.  The rover also found many elements including magnetite.  The discovery of magnetite is important because it is found on Earth in bacteria, brains of bees, termites, fish, mollusk teeth, some birds, and humans.  Scientists must use Earth as an analog for any discoveries made on Mars.

The European Space Agency launched the spacecraft, Mars Express, which arrived at the Red Planet in December 2003.  This orbiter is tasked with high resolution imaging of the entire surface as well as mapping the mineral and atmospheric composition.  The information gained from Mars Express helps space agencies determine landing sites for future rovers and landers.

The Mars Exploration Rovers (MER) Spirit and Opportunity landed on Mars three weeks apart in early 2004.  These two wonderful rovers were scheduled to work only 90 days, which they far exceeded.  Spirit landed January 4, 2004 and sent its last communication to Earth March 22, 2010.  The Opportunity Rover landed on January 25, 2004 and continues to roam the Martian surface.  The twin rovers were sent to assess habitability and evidence of past water. Both have discovered evidence of past water on Mars.  One discovery was hematite, a mineral that forms in the presence of standing water over a long period of time.  The principal investigator for the MER’s, Steven Squyres, has stated that not only did Mars have water, but it had at one time large quantities of water on its surface. 

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The Phoenix Lander arrived on the surface of the Red Planet in the north polar region on May 25, 2008.  Phoenix was searching for environments suitable for microbial life.   Phoenix discovered water ice and when scientists watched as it sublimated in front of the lander’s cameras.  Phoenix’s wet chemistry lab tested the ingredients of the soil and found perchlorate (ClO4).  This chemical could be used by future colonists for everything from rocket fuel and a source of oxygen. 

The Mars Society Convention hall, in Pasadena, was filled as we watched Curiosity land flawlessly in Gale Crater on August 5, 2012.  The rover landed to a worldwide audience anxiously watching.  This landing site was picked for many reasons, such as, the alluvial fan (ancient river delta), the depth of the crater, and the height of the peak (Mount Sharp).  Curiosity is equipped with 17 cameras, an entire science laboratory, and is tasked with assessing the habitability of Mars.   

Previous missions have found elements in the atmosphere and in the soil as well as previous liquid water which are all clues to previous life on Mars.  One piece of evidence still missing from the puzzle is organic carbon.  Curiosity’s Sample Analysis at Mars (SAM) is a suite of instruments that will analyze the contents of the Martian soil.  SAM will look for carbon containing compounds and other elements associated with life, such as, hydrogen, nitrogen, and oxygen.  Scientists are hoping to find organic carbon with a biological origin.  If found this will have to be studied and tested many times to prove what the origin actually is.  There will likely be debates about whatever Curiosity finds until there is unequivocal inarguable evidence. 

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On October 8, 2012 the Curiosity Rover, scratched the surface of Mars, scooping up its first soil in order to clean the inside of the rovers sample handling mechanism.  The sample will be shaken vigorously and then emptied onto the ground.  This procedure will be repeated several times.  The cleaning is to ensure that any contaminants left over from Earth will be discarded before any true testing takes place.  Once the instruments are cleaned and the soil tests take place, they will determine whether or not the area was once a favorable environment for microbial life.  Curiosity is equipped with more scientific instruments than any spacecraft deployed on Mars.  Her planned two year mission is sure to make many wonderful discoveries. 

Stay tuned for further updates.  ~OnToMars~
 
Images  [NASA.gov, Planetary.org, Time.com]