Nov 17, 2024 06:00 AM
(This post was last modified: Nov 17, 2024 06:01 AM by C C.)
https://www.space.com/space-exploration/...-thinks-so
INTRO: In 1975, NASA's Viking 1 spacecraft entered orbit around Mars, carrying a mission to unlock the secrets of the Red Planet. Soon, it released twin landers that drifted toward the Martian surface and eventually made history as the first American spacecraft to touch down on the world.
For over six years, Viking 1 continued to orbit Mars' Chryse Planitia region while its landers collected soil samples using robotic arms and onboard laboratories, marking a groundbreaking chapter in humanity's exploration of the Martian environment.
At the time, however, little was known about environmental conditions of the Red Planet, and the Viking life detection experiments were modeled after culturing techniques commonly used to identify microbes on Earth. These methods involved adding water and nutrients to those aforementioned soil samples, then monitoring for any signs that suggest microbes might be living in the samples. Such signals were associated with responses to the additives — essentially an influx of components needed to complete normal life cycles as we know them — and included things like growth, reproduction and the consumption of food for energy.
One day, both Viking landers reported a potential positive detection of microbial activity in their soil samples, and the findings naturally sparked decades of intense debate. Had we finally found proof of life elsewhere in the universe? However, most scientists now believe the results were negative or — at best — inconclusive. They think it's more likely that the positive readings have an alternative explanation.
But that's most scientists.
According to Dirk Schulze-Makuch, an astrobiologist at the Technische Universität Berlin in Germany, there may be another facet to this mystery that hasn't yet been considered: Viking may indeed have discovered life on Mars, but the water-based nature of its life-detection experiments might have unintentionally killed it.
In a recent commentary published in the journal Nature Astronomy, titled "We may be looking for Martian life in the wrong place," he argues that because Mars is even drier than one of the most arid places on Earth, the Atacama Desert, where microbes obtain water through salts that draw moisture from the atmosphere, any analogous Martian life would be highly sensitive to the addition of liquid water. Even one drop too much could threaten their existence.
Breaking space news, the latest updates on rocket launches, skywatching events and more!
Yet, the Viking experiments were conducted under the assumption that Martian life would require liquid water, like most life forms on Earth. Thus, Schulze-Makuch believes, the results of the experiments might be best explained not as the absence of organic life, but as the human-driven destruction of arid microbial organisms exposed to too much water.
If the assumptions about organisms thriving in Mars' hyperarid conditions are accurate, Schulze-Makuch argues that NASA should rethink its longstanding "follow the water" strategy for finding life beyond Earth. Instead, he suggests adopting a "follow the salts" approach.
Space.com sat down with Schulze-Makuch to discuss this intriguing take on the Viking experiments, how the community has reacted to it, and what it might mean for life-seeking experiments going forward.
The interview has been edited for length and clarity... (MORE - details, the interview)
INTRO: In 1975, NASA's Viking 1 spacecraft entered orbit around Mars, carrying a mission to unlock the secrets of the Red Planet. Soon, it released twin landers that drifted toward the Martian surface and eventually made history as the first American spacecraft to touch down on the world.
For over six years, Viking 1 continued to orbit Mars' Chryse Planitia region while its landers collected soil samples using robotic arms and onboard laboratories, marking a groundbreaking chapter in humanity's exploration of the Martian environment.
At the time, however, little was known about environmental conditions of the Red Planet, and the Viking life detection experiments were modeled after culturing techniques commonly used to identify microbes on Earth. These methods involved adding water and nutrients to those aforementioned soil samples, then monitoring for any signs that suggest microbes might be living in the samples. Such signals were associated with responses to the additives — essentially an influx of components needed to complete normal life cycles as we know them — and included things like growth, reproduction and the consumption of food for energy.
One day, both Viking landers reported a potential positive detection of microbial activity in their soil samples, and the findings naturally sparked decades of intense debate. Had we finally found proof of life elsewhere in the universe? However, most scientists now believe the results were negative or — at best — inconclusive. They think it's more likely that the positive readings have an alternative explanation.
But that's most scientists.
According to Dirk Schulze-Makuch, an astrobiologist at the Technische Universität Berlin in Germany, there may be another facet to this mystery that hasn't yet been considered: Viking may indeed have discovered life on Mars, but the water-based nature of its life-detection experiments might have unintentionally killed it.
In a recent commentary published in the journal Nature Astronomy, titled "We may be looking for Martian life in the wrong place," he argues that because Mars is even drier than one of the most arid places on Earth, the Atacama Desert, where microbes obtain water through salts that draw moisture from the atmosphere, any analogous Martian life would be highly sensitive to the addition of liquid water. Even one drop too much could threaten their existence.
Breaking space news, the latest updates on rocket launches, skywatching events and more!
Yet, the Viking experiments were conducted under the assumption that Martian life would require liquid water, like most life forms on Earth. Thus, Schulze-Makuch believes, the results of the experiments might be best explained not as the absence of organic life, but as the human-driven destruction of arid microbial organisms exposed to too much water.
If the assumptions about organisms thriving in Mars' hyperarid conditions are accurate, Schulze-Makuch argues that NASA should rethink its longstanding "follow the water" strategy for finding life beyond Earth. Instead, he suggests adopting a "follow the salts" approach.
Space.com sat down with Schulze-Makuch to discuss this intriguing take on the Viking experiments, how the community has reacted to it, and what it might mean for life-seeking experiments going forward.
The interview has been edited for length and clarity... (MORE - details, the interview)