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NASA’s Curiosity rover has identified more life forms on Mars as scientists try to learn whether the Red Planet once had life.
Five of the seven different types of organisms, which were confirmed in the six-wheeled rover’s study of a rock formation near the equator, had never been identified before on Mars, the researchers said.
Experiments have also revealed that there is another combination of organisms with a structure similar to the precursor of DNA, the molecule that carries genetic information to organisms on Earth.
Organic compounds, molecules made up primarily of carbon atoms combined with other elements, form the structural basis of all life on Earth. The number identified on Mars is now large. However, scientists note that all these compounds may have been created through unnatural processes.
Like the other planets in the solar system, Mars formed about 4.5 billion years ago. At the beginning of its history, it was warmer and wetter than the cold and dry place it is today. Researchers estimate that the rock taken by the rover – sediment laid down by flowing water – dated to at least 3.5 billion years ago.
“Right now we can’t say that Mars once had life, but our findings support the evidence that Mars was a habitable planet at the time when life appeared on Earth,” said astronomer and planetary scientist Amy Williams of the University of Florida, a member of the Curiosity science team and lead author of a study published Tuesday in the journal Nature Communications.
NASA scientists believe that there may be an ocean of water deep on the surface of Mars. The discovery advances the search for life beyond our planet and suggests that Mars may have conditions that could support microbial life, past or present. Matthew Cimone, chief interpreter at the HR MacMillan Space Center in Vancouver, tells us more about these findings.
Identifying definitive evidence of past life now would require returning rock samples to Earth for testing.
“To be clear, we haven’t found evidence of life with this research, but we’re continuing to refine the block-by-block molecules that existed on Mars,” Williams said.
Curiosity settled in the Gale crater, which was formed by an ancient impact on the Martian surface, in 2012. It carried out research that is now being described in 2020 in a crater called Glen Torridon, where there is an abundance of clay minerals that indicate that water once existed. If there was ever microbial life on Mars, a lot of water would be a habitable place.
Clay minerals can hold organic molecules better than other minerals, making them a good target for finding such compounds, Williams said.
The test was performed by the rover’s Sample Analysis at Mars (SAM) instrument. The rover drilled into the ground at a site named Mary Anning, in honor of the 19th century English paleontologist. The powdered rock sample was then placed in a small cup containing a chemical that breaks down the complex organic matter into small pieces that can be detected by the SAM instrument.
“The Curiosity rover is designed to search for a habitable environment, places where life would want to live if it ever appeared on Mars. This research contributes to that story, that the places on Mars were habitable in the past and had the ingredients for life as we know it,” said Williams.
Canadian research scientist Kelly Haston tells As It Happens host Nil Köksal what it was like to spend more than 12 months with three crewmates in a 157-square-meter space designed by NASA to simulate the eventual Mars mission.
Scientists last year announced that a rock sample found by another NASA rover, Perseverance, in a different area of the crater contains features that may have been produced when the rock was formed by a chemical reaction involving bacteria.
NASA rovers have been at the forefront of understanding the Martian habitat, including finding life.
“Although we will never know whether this organic matter arose from geologic processes, meteorite falls, or life, our work suggests that if complex organisms from life were preserved on Mars, we should be able to detect them with current and future instruments,” said Williams.
