Oceans covered much of Mars in the ancient past, and seasonal dark streaks observed on the Red Planet's surface today may be caused by salty flowing water.įurther, NASA's Curiosity rover has found carbon-containing organic molecules and "fixed" nitrogen, basic ingredients necessary for Earth-like life, on the Martian surface.įarther afield, observations by NASA's Kepler space telescope suggest that nearly every star in the sky hosts planets - and many of these worlds may be habitable. The key is to build a body of evidence that cannot be explained away by anything other than biology, says Vago.For example, oceans of liquid water slosh beneath the icy shells of the Jupiter moons Europa and Ganymede, as well as that of the Saturn satellite Enceladus. If we happen upon past life relics, we need to be able to tick a good number of independent biosignatures and to do it repeatedly with various samples, says Vago. Depending on how they were entombed, they may be preserved, he says. The microbes would have died long ago the cell membranes would have ruptured and their chemical guts spread into the geological record, says Vago. When organisms are metabolically active, they can repair any radiation induced damage so we would have access to a high concentration of biomolecules, he says. Present life would give itself away via the sheer quantity and good state of preservation of the biomolecules, says Vago. When it comes semantics at a hypothetical post-detection press conference, he says that rather than ‘this was/is life,’ official statements are more likely to read: ‘Currently, the only explanation for our results is life we could not think of any other way to produce our findings.’ Will MOMA be able to differentiate between past and present life? We need both sides for a consistent interpretation, he says. The optimists will declare to have seen evidence for life while the pessimists will carefully search for non-biological explanations, says Goesmann. While the identification of molecules will most likely contain little ambiguity, the significance for “life detection” is tricky, he says. What is MOMA’s biggest scientific challenge?Ĭonverting results into significance, Fred Goesmann, MOMA’s Principal Investigator, and a planetary scientist at Germany’s Max Planck Institute in Gottingen, told me via email. The probability that we may find something that is suggestive of life is something like 50%, he says. The probability that we will find organic molecules, I think is like 100%, says Vago. This will enable the team to avoid sample contamination by perchlorates, colorless and odorless salts, that can be an unwanted byproduct of the kind of heat needed to conduct such sample analysis. Instead of thermal heat, MOMA will use a laser to separate the largest organic compounds from the minerals to which they were originally bound. Then these gas phase chemical samples will undergo onboard analysis to determine if they look promising for biology in both their makeup and their distribution. To do so, MOMA will either use heat or ultraviolet laser pulses to convert chemical species in the samples into a gas phase. Mass spectrometers measure the chemical makeup and mass of given substances in gaseous states. MOMA must first vaporize the compounds it collects so they can be detected by the instrument’s mass spectrometer. Dig a foot and a half below the surface and the temperature is minus 60 degrees Fahrenheit it's a wonderful freezer, he says. Once Mars lost its surface water, it turned very cold, says Vago. The ensuing cold temperatures beneath the surface would also have aided in their preservation. Once Mars lost its water and dried out, these microbial colonies would have turned into microfossils preserved by this sedimentary ash. Because Mars is thought to have been very volcanically active at the time, ash from its volcanoes would have fallen on its ocean’s surface. Some four billion years ago, it’s likely there were microbial colonies living in some sort of hydrothermal system beneath the surface of Oxia Planum.
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