Once I was a school pupil, I labored on the Charlevoix Astronomical Observatory in Qubec.
It was a fairly first rate summer season job, as I bought to look at celestial our bodies till the lifeless of night time, discuss to astronomy buffs about house exploration and watch kids be amazed by Saturn’s rings.
Over the handfuls of astronomy nights I’ve hosted, one query has constantly come up:
Does life exist anyplace 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 considering, was an enormous project for me as a CEGEP pupil on the time.
I merely supplied a easy most definitely, earlier than including a shocking and if that is the case, the reply lies right here, on Earth, in locations referred to 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 house missions per yr, manned or unmanned, is just not real looking, 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 ambiance of Venus.
What if these locations have been, actually, habitats the place life has developed?
Lakes below ice
For instance, think about Europa, one of many moons of Jupiter, which, together with Mars, is likely one of the high 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, nearly 400 lakes exist in comparable situations, that’s to say that they lie under a everlasting ice blanket, protected against the whole lot that occurs on the floor. These are often known as 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 ambiance or publicity to photo voltaic radiation, making it a completely darkish place that’s poor in vitamins and topic to huge stress not very hospitable.
Nevertheless, the water on the floor of the lake is concentrated in oxygen, the important thing chemical component for dwelling metabolism.
A love for excessive situations
In 2008, analyses of the ice masking Lake Vostok revealed the presence of micro-organisms! This basically implies that life can certainly adapt to hostile environments that will in any other case be deadly for many organisms. These super-organisms, or extremophile, are capable of tolerate these excessive situations.
In consequence, the waters of Lake Vostok, remoted from the Earth’s floor for hundreds of thousands of years, may nicely comprise life too a super planetary analogue.
Learning Lake Vostok, and its potential extremophile life types, is nearly like being on Jupiter’s moon Europa. And it is nearly like learning its ocean. Had been Lake Vostok capable of develop life, why not the ocean on Europa as nicely?
Subglacial lakes reminiscent of Vostok are only one instance of the handfuls of planetary analogue websites which have been recognized. For instance, with the intention to research sure Martian craters, the Earth’s deserts are the proper 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 research of which tells us in regards to the improvement of life in scorching environments the place water is proscribed.
Making ready for house missions on Earth
In addition to offering a greater understanding of life and its emergence, investigating planetary analogues has one other benefit: getting ready and simulating house missions.
Simply suppose if we’re creating a brand new know-how to pattern a rock on Mars, it could be smart to strive 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 impression craters, volcanoes, deserts, all around the Earth, for months on finish. All so they might follow their methods with quite a lot of tailored instruments, all slowed down by their house fits.
All of it begins on Earth
Area exploration and the understanding of our photo voltaic system start on Earth. At first look, this concept could appear counter-intuitive, but it surely really makes loads of sense when you think about the distant, nearly inaccessible and excessive environments our planet accommodates.
Astrochemistry and astrobiology have emerged on this identical method, as multidisciplinary fields that equip us for our analysis into the evolution of Earth and life.
Now, if I have been requested the query Does life exist anyplace 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. In consequence, scientists have to be cautious of their method and keep away from leaping to hasty conclusions.
Life in Lake Vostok will not be synonymous with life on Europa, removed from it. However let’s simply say that it is a superb first step that may information us significantly in our future missions.
(The Dialog: By Daniel Fillion, Universit du Qubec Rimouski)
