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Artistic conception of Europa satellite and its sub-surface ocean and water volcanoes. Credit JPL/NASA

Search for life beyond our planet from the atacama desert to mars and ocean worlds

In our planet water is synonym of life. Life started in the oceans and nowadays every ocean, sea, river and lake are full of living creatures. Despite the life buoyancy in our planet still the question is there life beyond the earth is still open and ocean worlds might be home of new life forms.

  
Dr. Juan Carlos Beamin

Report: Dr. Juan Carlos Beamin

30, September 2019

Since ancient times the question are we alone? had puzzled and inspired humankind. In our days the technology has developed so fast that within a century we switched from horse-driven vehicles to planes and space rockets. Is in this era that the question are we alone? had started to appear more often in science journals and in scientific discussion, since we now can actually explore not only our planet, but the Moon, Mars and beyond.

As humans living on Earth, we seek life forms that are similar to the ones we find on our planet. Search for life over Mars soil had been done in the past decades, and the Cassini-Huygens missions explored Saturn and its main satellite Titan both with negative results so far.

Dr. Yasuhito Sekine, from the Tokio Institute of Technology, study the possibility of finding life or developing life in conditions different than we have in our world, he is particularly interested in the origin and evolution of planetary and satellite atmospheres, including Earth, Mars and Titan,  chemical evolution of atmospheres and geochemistry and geological analysis of ancient sedimentary rocks to understand what caused the rise in atmospheric oxygen in Earth atmosphere. 

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Dr. Yasuhito Sekine during his visit to Universidad Autónoma de Chile before the sample collection campaign in the Atacama desert. 

Why did you travel from Japan to Chile?

"Atacama desert is the perfect analog site to mars environment", Dr. Sekine comments, "I’m doing research related to planetary science, to investigate the paleoenvironment on Mars. We will do field work on Atacama desert to get samples in different sites to understand the past environment on mars."

This trip was organized by Dr. Armando Azúa, a researcher at Centro de astrobiología and associate researcher at Universidad Autónoma de Chile, he investigate how living organisms can survive under extreme conditions in the Atacama desert and several times a year comes to gather soil samples at different locations. 

The main reason Atacama desert is well suited for these studies, is because it has remained the same for a long period of time, it became the desertification process around 14 million years ago, reaching an increased aridity period 6 million years ago and kept as is until today according to a study. So if there are no signs of life in a territory like Atacama desert, the chances of detecting life are much worst since its aridity history goes back to nearly 3.000 million years.

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Picture of the driest place measured on the Atacama desert. credit. Armando Azúa-Bustos

Field work, near Yungay village, in the north of Chile, is related to hyper arid regions and search for extremophiles, mainly bacterias that survive under these extreme. furthermore a study published after the last time it rained in the hyper-arid regions of Atacama desert, between 78% and 85% of the bacterias previously studied were decimated, and only four different types of bacteria were able to survive the rains.

After a few minutes discussing about some of the details about the trip, Dr. Sekine refers to the importance of develop new lines of work, "Is important to do this work (collaborative work), not only with people from different countries, but from different disciplines, (they) always provide ideas for the new research and also doing research in different countries is important to widen the view, because many countries have their own cultures or their own research lines, so knowing new research is exciting."

 

From one of the driest places on earth to ocean worlds.

Each planet and their satellites are different, some like Mercury barely have an atmosphere, and Venus has such a thick atmosphere that the greenhouse effect considerably heats the surface of the planet.

One particularly interesting type of planets or worlds are the ocean worlds, characterized by being completely covered by water (Earth is 75% covered in water so is not an ocean world) or the surface is covered with ice and below this ice crust an ocean lies before the rocky interior. In our solar system there are at least two of these ocean worlds, Europa and enceladus, satellites of Jupiter and Saturn respectively. Both of them are covered by a thick layer of ice.

What are the perspective of developing life in Europa and Enceladus in their subsurface oceans without receiving direct sunlight? 

"Formation of organic materials requires chemical energy" comment Dr. Sekine, and then add "Some researchers believe the chemical reaction networks produce proto-metabolic reaction to create life, I think, the chemical cycle or energy cycle within ocean world could support or maintain organic chemical networks, which could make or harbor life in ocean world."

The researcher also mention "If we can find life within ocean worlds such as Enceladus or Europa, we can notice that the sunlight is not always necessary to make life, this is a really important insight into understanding origin of life in mars. So one of the reasons why I’m focusing my research in ocean worlds to search for life is also very important the origin of life in other places.

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Image from Cassini mission showing the water plume from the Saturn satellite Enceladus. The plume is made of water ice expelled through a
cryo-volcano. Images like this ensure that there is liquid water in the interior of Enceladus. Credit NASA/JPL/Space institute.

Since light is not the main energy source for the chemical reactions, what would be the key ingredients to form life? would they be the same we know on earth?

"I don’t know exactly the answer, I’m considering (as the main elements) carbon, nitrogen, oxygen, phosphorus and sulfur those are the key elements to make the building materials based on our life, so I think, carbon, nitrogen, oxygen phosphorus all of them are available in ocean worlds."

Today we hear very often about habitable planets, or breakthrough discoveries regarding the possibilities of life, what would be the ideal biomarker to look for life beyond our planet? 

"Definitively for finding of life out there, we need sample returns, we can  calculate the biomarkers, and test the molecules that can be form by biotic reaction, so if we can find those biomarkers,  that could be a sign that could be life, but we need sample returns." Finish the last phrase firmly, then after a pause he continue, " sample return are very expensive, so before the sample return we need some identify biomarkers, traces of molecules and study habitability, but the definitely claim or proof of life beyond our earth requires a sample return." 

 

In deep...
Europa the future challenge in the search for extratterestrial life


 

Europa is the third largest moon of Jupiter, the ice covered surface daily changes due to exposure to sunlight, sublimated water ice during day condenses during night forming risks and therefore planning a mission to Europa needs to take into account these terrain changes. The only way to build a successful lander that reaches Europa is to develop a complete autonomous navigation system, a system that can process and redefine trajectories on the flight as Neil Armstrong did in 1969 when he landed on the Moon.

Dr. Juan Carlos Beamin
Reportage: Dr. Juan Carlos Beamin

30, September 2019

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