Once I was a school scholar, I labored on the Charlevoix Astronomical Observatory in Qubec.
It was a fairly respectable summer season job, as I received to watch celestial our bodies till the lifeless of evening, speak to astronomy buffs about area exploration and watch youngsters be amazed by Saturn’s rings.
Over the handfuls of astronomy nights I’ve hosted, one query has constantly come up:
Does life exist wherever else?
Answering this elementary query, articulated by the primary philosophers, which has transcended time and eras and nonetheless stays on the coronary heart of our rational pondering, was an enormous task for me as a CEGEP scholar on the time.
I merely supplied a easy probably, earlier than including a shocking and if that is the case, the reply lies right here, on Earth, in locations known as planetary analogues.’
Planetary analogues are areas on Earth that replicate a number of excessive situations discovered on one other celestial physique. For instance, temperature, stress and photo voltaic radiation.
Each for technical and monetary causes, finishing up a number of area missions per yr, manned or unmanned, is just not lifelike, particularly as these missions take a number of years to finish.
But the Earth, our magnificent blue planet the place life thrives, has some excessive, harmful and merciless locations. These locations can reproduce sure situations discovered within the arid deserts of Mars or the suffocating environment of Venus.
What if these locations had been, in truth, habitats the place life has developed?
Lakes below ice
For instance, take into account Europa, one of many moons of Jupiter, which, together with Mars, is without doubt one of the prime contenders in our quest for extraterrestrial life. Its floor is roofed in a dense layer of ice about ten kilometres thick, beneath which lies an ocean. An ocean of liquid water!
It seems that in Antarctica, virtually 400 lakes exist in related situations, that’s to say that they lie under a everlasting ice blanket, protected against every part that occurs on the floor. These are often called subglacial lakes.
Such is the case of Lake Vostok, the biggest and deepest lake in Antarctica. It was within the Sixties that scientists first suspected the presence of a lake beneath a four-kilometre thick layer of ice.
This icy barrier deprives the lake of gaseous exchanges with the environment or publicity to photo voltaic radiation, making it a completely darkish place that’s poor in vitamins and topic to monumental stress not very hospitable.
Nevertheless, the water on the floor of the lake is concentrated in oxygen, the important thing chemical component for residing metabolism.
A love for excessive situations
In 2008, analyses of the ice protecting Lake Vostok revealed the presence of micro-organisms! This primarily signifies that life can certainly adapt to hostile environments that might in any other case be deadly for many organisms. These super-organisms, or extremophile, are capable of tolerate these excessive situations.
Because of this, the waters of Lake Vostok, remoted from the Earth’s floor for tens of millions of years, might properly comprise life too a really perfect planetary analogue.
Learning Lake Vostok, and its attainable extremophile life varieties, is sort of like being on Jupiter’s moon Europa. And it is virtually like finding out its ocean. Had been Lake Vostok capable of develop life, why not the ocean on Europa as properly?
Subglacial lakes akin to Vostok are only one instance of the handfuls of planetary analogue websites which have been recognized. For instance, with a purpose to examine sure Martian craters, the Earth’s deserts are the right playgrounds. Scientists are exploring the Mojave (United States), Atacama (Chile) and Namib (Africa) deserts, that are dry and arid. Their soil additionally accommodates extremophiles, the examine of which tells us in regards to the improvement of life in scorching environments the place water is proscribed.
Making ready for area missions on Earth
In addition to offering a greater understanding of life and its emergence, investigating planetary analogues has one other benefit: making ready and simulating area missions.
Simply suppose if we’re creating a brand new expertise to pattern a rock on Mars, it could be smart to attempt it out first, would not it? And never simply inside NASA studios, the place the parameters are managed. We should step out and go to distant, uncomfortable areas.
That is what the Apollo astronauts of the 50s and 60s did (those that aimed for the moon). They went to meteorite affect craters, volcanoes, deserts, everywhere in the Earth, for months on finish. All so they may follow their strategies with quite a lot of tailored instruments, all slowed down by their area fits.
All of it begins on Earth
House exploration and the understanding of our photo voltaic system start on Earth. At first look, this concept could seem counter-intuitive, but it surely really makes plenty of sense when you think about the distant, virtually inaccessible and excessive environments our planet accommodates.
Astrochemistry and astrobiology have emerged on this similar manner, as multidisciplinary fields that equip us for our analysis into the evolution of Earth and life.
Now, if I had been requested the query Does life exist wherever else? I, nonetheless naive, however beginning my PhD within the chemistry of maximum polar environments, would reply:
Ask me once more in 5 years!
Joking apart, analogues have their limitations in that the situations can by no means be recreated of their entirety. Because of this, scientists should be cautious of their method and keep away from leaping to hasty conclusions.
Life in Lake Vostok isn’t synonymous with life on Europa, removed from it. However let’s simply say that it is a wonderful first step that may information us significantly in our future missions.
(The Dialog: By Daniel Fillion, Universit du Qubec Rimouski)
