Tag Archives: extraterrestrial life

NASA Rover Finds Conditions Once Suited for Ancient Life on Mars

An analysis of a rock sample collected by NASA’s Curiosity rover shows ancient Mars could have supported living microbes.  Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon — some of the key chemical ingredients for life — in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet last month.

“A fundamental question for this mission is whether Mars could have supported a habitable environment,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at the agency’s headquarters in Washington. “From what we know now, the answer is yes.”

Clues to this habitable environment come from data returned by the rover’s Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments. The data indicate the Yellowknife Bay area the rover is exploring was the end of an ancient river system or an intermittently wet lake bed that could have provided chemical energy and other favorable conditions for microbes. The rock is made up of a fine grain mudstone containing clay minerals, sulfate minerals and other chemicals. This ancient wet environment, unlike some others on Mars, was not harshly oxidizing, acidic, or extremely salty.

The patch of bedrock where Curiosity drilled for its first sample lies in an ancient network of stream channels descending from the rim of Gale Crater. The bedrock also is fine-grained mudstone and shows evidence of multiple periods of wet conditions, including nodules and veins.

Curiosity’s drill collected the sample at a site just a few hundred yards away from where the rover earlier found an ancient streambed in September 2012.

“Clay minerals make up at least 20 percent of the composition of this sample,” said David Blake, principal investigator for the CheMin instrument at NASA’s Ames Research Center in Moffett Field, Calif.

These clay minerals are a product of the reaction of relatively fresh water with igneous minerals, such as olivine, also present in the sediment. The reaction could have taken place within the sedimentary deposit, during transport of the sediment, or in the source region of the sediment. The presence of calcium sulfate along with the clay suggests the soil is neutral or mildly alkaline.

Scientists were surprised to find a mixture of oxidized, less-oxidized, and even non-oxidized chemicals providing an energy gradient of the sort many microbes on Earth exploit to live. This partial oxidation was first hinted at when the drill cuttings were revealed to be gray rather than red.

“The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms,” said Paul Mahaffy, principal investigator of the SAM suite of instruments at NASA’s Goddard Space Flight Center in Greenbelt, Md.

An additional drilled sample will be used to help confirm these results for several of the trace gases analyzed by the SAM instrument.

“We have characterized a very ancient, but strangely new ‘gray Mars’ where conditions once were favorable for life,” said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology in Pasadena, Calif. “Curiosity is on a mission of discovery and exploration, and as a team we feel there are many more exciting discoveries ahead of us in the months and years to come.”

Scientists plan to work with Curiosity in the Yellowknife Bay area for many more weeks before beginning a long drive to Gale Crater’s central mound, Mount Sharp. Investigating the stack of layers exposed on Mount Sharp, where clay minerals and sulfate minerals have been identified from orbit, may add information about the duration and diversity of habitable conditions.

NASA’s Mars Science Laboratory Project has been using Curiosity to investigate whether an area within Mars’ Gale Crater ever has offered an environment favorable for microbial life. Curiosity, carrying 10 science instruments, landed seven months ago to begin its two-year prime mission. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., manages the project for NASA’s Science Mission Directorate in Washington.

Are we ready to meet ET?

Once only science fiction, astronomers are now finding hundreds of planetary systems beyond our own. Given recent discoveries through space exploration, it is entirely feasible that we may soon discover the existence of extra-terrestrial life (ET) forms on other planets.

The idea of extra-terrestrial life forms fascinates some and terrifies others. And even though our search for ET never quite panned out, we never stopped looking.

However, could this all be about to change following the discovery of hundreds of exoplanets (planets outside our Solar System), and thousands of candidate exoplanetary systems, some of which might be habitable for life.

 

Speaking about these momentous discoveries at the Cambridge Science Festival on March 16, NASA’s Dr Jennifer Wiseman will reveal how these exoplanets may provide evidence of biological activity, and discuss the profound invigoration of scientific and related religious and philosophical thought this might inspire if we find that life could thrive beyond Earth.

In a recent interview, Dr Wiseman said: “It’s a very exciting time for astronomy; we are finding a plethora of planets around other stars, including some that may be similar to Earth in size and temperature. The question that humans have had for centuries – whether or not there are planets similar to our own around other stars – seems more and more to be best answered as, ‘Yes!’”

It is expected that there is at least one planet, on average, orbiting around each star in our Milky Way galaxy, resulting in hundreds of billions of exoplanets, some fraction of which are the size of Earth at similar distances from their parent stars as Earth is to the Sun. These staggering numbers means there is a real possibility that we are on the verge of discovering our twin. If so, could this also mean the discovery of alien life forms similar to humans? And, what could this mean for humanity’s self-image if we were to discover that we are not unique or alone in the universe?

As Senior Project Scientist for NASA’s Hubble Space Telescope and Director of the Dialogue on Science, Ethics and Religion for the American Association for the Advancement of Science, Dr Wiseman is uniquely placed to provide both insights into the latest developments in the search for inhabitable exoplanets, as well as reflections on philosophical and religious implications of finding life on another planet.

From identifying seismic wave activity and colour patterns on these other worlds, to the use of enormous telescopes that could potentially hunt for evidence of alien life by their atmospheres, astronomers are continuing to find new ways to look for that tantalising hint of life.

In January this year, astronomers announced the discovery of an Earth-like exoplanet candidate orbiting a star similar to our Sun in the ‘habitable zone’ – the area around a star within which it is theoretically possible for water to exist on a planet’s surface (and therefore also the possibility of supporting life). And in February, Harvard researchers identified three planets as ‘objects of interest’ – meaning they could also be potentially habitable.

Harvard astronomer and lead author Courtney Dressing, who presented the findings at the Harvard-Smithsonian Center for Astrophysics, said: “We thought we would have to search vast distances to find an Earth-like planet. Now we realise another Earth is probably in our own backyard, waiting to be spotted.”

In addition, the World Economic Forum Global Risks report for 2013 states that, “Given the pace of space exploration, it is increasingly conceivable that we may discover the existence of alien life or other planets that could support human life. … In 10 years’ time, we may have evidence not only that Earth is not unique, but also that life exists elsewhere in the universe.”

The report continued, “The discovery of even simple life would fuel speculation about the existence of other intelligent beings and challenge many assumptions that underpin human philosophy and religion.”

Professor Meric Srokosz, Associate Director of The Faraday Institute for Science and Religion, Cambridge (the organisers of the event) said: “This is a unique opportunity to hear a genuine expert in her field, and to learn and think about one of the questions that continues to fascinate: is there life out there in the universe?”