Mars, as observed by NASA’s Viking 1 orbiter in the 1970s.
The search for life on Mars should not only focus on the distant past, some researchers say.
Four billion years ago, Mars ‘ surface was apparently quite habitable, with rivers, lakes and even a deep ocean. Indeed, some astrobiologists view ancient Mars as a better cradle for life than the Earth, and they suspect that the life on our planet may have come here long ago on board of Mars rocks blasted into space by a powerful impact.
Things changed when Mars lost its global magnetic field. Charged particles streaming from the sun were then free to strip away once thick atmosphere, and the strip they did. This process was changed in march in the cold, dry world we know today, with approximately 3.7 billion years ago, observations of NASA’s MAVEN orbiter suggest. (The earth still has the global magnetic field, to explain how our planet remains so livable.)
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But this state of affairs does not necessarily mean that Mars is a dead planet today.
“If Mars had life 4 billion years ago, Mars still has life. Nothing has happened on Mars would have wiped out life,” said Michael Finney, co-founder of The Genome nership, a non-profit organization that runs the Progress in Genome Biology and Technology conference.
“So, if there is life on Mars, it can be moved, it can are hiding a little bit, but it is probably still there,” Finney said last month during a panel discussion on the Breakthrough, Discussing conference at the University of California, Berkeley.
One of the most promising hiding places, the Mars underground. Although the Red Planet’s surface has no liquid water these days — with the exception possibly of temporary flows on warm slopes, and again — there is likely that much of the wet stuff in buried layers. For example, observations by Europe’s Mars Express orbiter suggest that a large lake is located on the lurk under the Red Planet’s south pole.
The earth of the various inhabitants of advertising their presence in dramatic and obvious ways; an advanced alien civilization would probably figure out pretty quickly, just by scanning our atmosphere, that our planet is inhabited.
We don’t see such clear evidence in the Martian air, but scientists have spotted some intriguing hints recently. For example, NASA’s Curiosity rover has rolled by two plumes of methane in the 96-meter-wide (154 kilometers) Gale Crater, the six wheeled robot has been exploring since 2012 touchdown. The rover mission also determined that a baseline methane concentrations in the Storm the air will go through cycles in the season.
More than 90% of the Earth, the atmospheric methane is produced by bacteria and other organisms, so it is possible the gas is a signature of the modern Martian life.
But the jury is definitely still out on that. Abiotic processes can generate methane, and the reaction of hot water with certain types of rock is an example. And even if the Mars methane is biogenic, the creatures that could be long dead. Scientists think the Red Planet methane plumes leaked from the ground, and there’s no telling how long the gas was trapped down there for it to make its way to the surface.
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Looking for DNA
NASA’s 2020 Mars rover, which is scheduled for launch next summer, will hunt for signs of long-dead Red Planet life. So will the European-Russian ExoMars rover, a mission that will lift off at about the same time.
But some researchers are pushing to expand the hunt to existing Martian life. One of them is a molecular biologist Gary Ruvkun, who is based at the Massachusetts General Hospital and Harvard Medical School.
Ruvkun is one of three main researchers on the Search for Extra-Terrestrial Genomes (SETG) project, which is the development of an instrument for detecting past or present DNA – or RNA-based life on Mars and other alien worlds.
He was on the Breakthrough Discuss panel with Finney and several other researchers, and he also gave a lecture at the conference of the construction of the case for the application of the SETG instrument on future Mars rovers and other robotic explorers.
A part of this case centers on panspermia, the idea that life spread throughout the solar system, and perhaps the galaxy, by natural or artificial means. If life did indeed come to Earth from somewhere else, there is a good chance that once flourished on Mars, the thinking goes. The Red Planet could be from the source, or it may be “sown” as the Earth was.
Ruvkun views panspermia as very likely; during his Breakthrough Discuss, talk, he described himself as “a religious fanatic” about the idea. Ruvkun cited as evidence in the beginning of the rise of the ATP-synthase, the enzyme that makes the energy-storage molecule adenosine triphosphate.
ATP synthase goes all the way back to the base of the tree of life on Earth, which means this intricate and complex molecule up and running by about 4 billion years ago, Ruvkun said.
“It is not only that life is also a bit up to kind of work,” he said. “It is as if I they are super strong evolved very quickly. That is the reason why panspermia is so attractive.”
If panspermia is indeed a thing, then the life forms we find on Mars or elsewhere in our solar system, will likely be related to us, Ruvkun and others have motivated. That is, such organisms will use DNA or RNA as their genetic molecule. So, we have to go hunting for this stuff.
“It seems to be really idiot to not look for DNA on Mars,” Ruvkun said during his speech. “It is an experiment that is worth the effort, we would say.”
Related: Ancient Mars Could Have Supported Life (Photos)
Not only Mars
Mars is not the only place in our solar system where alien life may thrive today. Indeed, most astrobiologists would the Red Planet down the list a bit behind the Jupiter-moon Europa and the Saturn satellites, Enceladus and Titan.
Europa and Enceladus harbor deep oceans of salt water beneath their icy shells. Titan is thought to have buried water of the ocean, and it is also a sport lakes and seas of liquid hydrocarbons on the surface. (NASA is developing an ocean-characterize Europa flyby mission which will start in the early to mid-2020. The agency also wants to send a life-hunting lander to the surface of the moon in the near future. And a Titan mission is one of two finalists for a NASA “New Frontiers” to launch in 2025, along with a comet sample-return project. We need to learn that a NASA picks for the end of the year.)
Even hellish Venus, a climate-change cautionary tale for the Earth, might still harbor some habitable redoubts, say scientists.
Such as Mars, Venus once plentiful surface water, but a runaway greenhouse effect baked the stuff away and left the planet with a surface temperature high enough to melt lead. However, the conditions seem to be fairly clement is about 30 miles (50 km) above the Venusian surface.
Penny Boston, director of the NASA Astrobiology Institute at the agency’s Ames Research Center in California, said she thinks the opportunities of the modern Venus life are low because of the “need” of the planet.
Regardless, the possible existence of cloud-dwelling life on Venus “in any case, should be questioned,” Boston said during the same Breakthrough Discuss panel discussion.
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Original article on Space.com.