Posted on Aug 17, 2018
“Arguably, the notion that life may have once existed on the Red Planet is the most compelling scientific reason to send investigators there. The ancient Martian rocks reveal a very different world in the distant past—one with a thicker and warmer atmosphere and perhaps even an Earth-like climate, seas and precipitation. This has been inferred from the widespread evidence of fluvial features on the surface first mapped by Mariner 9. Such intriguing results motivated the Viking missions of the 1970s to search for potential life with Martian soils, which yielded ambiguous results.”
However, continues Ramses Ramirez , a planetary scientist and astrobiologist with the Earth-Life Science Institute in Tokyo in today’s Scientific American Blog, NASA’s Curiosity rover recently confirmed the presence of surface organics and seasonal releases of methane. There is even evidence for a subsurface lake at Mars’s south pole. Thus, the prospect that Mars may possess life, even today, has never been better—and several rover missions dedicated to finding it are already in the pipeline. However, robots will never be as clever, flexible and creative as people are. Even should these missions unambiguously discover life, humans will still be needed on the scene to properly assess its nature and history on the Red Planet.
Moreover, because Mars likely had a more Earth-like climate in the past, Martian rocks could tell us a lot about our planet. The moon never had plate tectonics. In contrast, ancient terrains on Mars record magnetic stripes—similar to those found on our ocean floor—construed to be possible evidence for past plate tectonics, a process that has only been found on Earth and is associated with its long-term habitability. A growing body of evidence also suggests that volcanism and meteoritic impacts each could have triggered hydrothermal systems within the Martian crust. These hydrothermal systems, which include heat and fluids within rock, could have provided habitats for the origin of life on both Earth and Mars. Such Martian life could still be preserved as fossils within rocks in the same way that extinct life on Earth is.
For a while in 1996, it even appeared that we’d found it. Even as Mars Pathfinder launch preparations were under way, scientists announced they’d found evidence of fossilized Martian bacteria within a chunk of rock, known as ALH84001, that had been blasted off the surface of Mars by an asteroid impact and eventually fell to Earth as a meteorite in Antarctica. Subsequent analyses could not prove that the “fossils” inside the rock were anything more than mineral formations. Nevertheless, public and scientific interest in this meteorite was very high, contributing to the rising popularity of astrobiology, the search for and (eventual) study of life in the cosmos. Human exploration of the Red Planet, together with the search for life there, have both remained—and will continue to be—central goals of the NASA Astrobiology Roadmap.
Also notable is the fact that Mars hosts two tiny moons, Phobos and Deimos, potato-shaped bodies that may be important to understanding how planets form and even how they may become habitable. It is possible that one (or both) may be a piece of Mars that was blasted into orbit by an incoming asteroid. Another notion is that at least one of them could have been an asteroid itself, captured by Mars billions of years ago. Scientists think that asteroids that may have helped supply the Earth with water; the exploration of Phobos and Deimos could help confirm that theory. Indeed, Japan’s Martian Moons Exploration (MMX) program, slated to launch in 2024, will be the first robotic sample return mission to Phobos. Such a mission could pave the way for human exploration of these moons.
Continue reading…
Image credit: Alex Orman, The Martian
Most Viewed Space & Science Headlines (2018)
Artificial Intelligence Is Already Out There, and It’s Billions of Years Old” (WATCH Video)
The Alien Observatory –“When We see Something Unusual, That’s Out of Whack, It Can Be a Sign of Life”
‘Ghost Signals’ of Extraterrestrial Civilizations Haunt the Milky Way –Suggests the New Drake Equation (WATCH Video)
“Odds That There has Never Been Another Civilization in the Universe One in Ten Billion Trillion” –A Joe Rogan Interview
Stephen Hawking’s Great Question –“Why Isn’t the Milky Way Crawling With Mechanical or Biological Life?”
The Alien Observatory –“The Mystery of Where Extraterrestrial Life is Hiding Deepens”
“We’re Entering Uncharted Territory” –The Exoplanet Revolution May Reveal that Rise of Civilizations May Not be Unusual
“The Big Rip” –When Matter and Spacetime are Gradually Torn Apart Through Expansion of the Universe
Alien Ocean Worlds–“There May be Life There, but Could It be Technology-Based”
“Humans are the First to Arrive at the Interstellar Stage” –Physicist Answers the Fermi Paradox
NASA Scientists Seek Fossils of Ancient Mars’ Life –“Was There a Common Ancestor? Maybe We’re All Martians
