ISxtraterrestrial life, that family science fiction trope, that the kitsch fantasy, that CGI nightmare, has become a matter of serious discussion, a "risk factor", a "scenario".
How did ET move from science fiction to a serious scientific effort modeled by macroeconomists, funded by fiscal conservatives and discussed by theologians?
Because, following a series of remarkable discoveries over the past two decades, the idea of an alien life is not as far-fetched as it seemed.
The discovery now seems inevitable and probably imminent.
It's just chemistry
While life is a special kind of complex chemistry, the elements involved are nothing special: carbon, hydrogen, oxygen and so on are among the most abundant elements in the universe. Complex organic chemistry is surprisingly common.
Amino acids, just like those that make up every protein in our body, have been found in the tails of comets. There are other organic compounds in the Martian soil.
And at 6,500 light years away, a giant cloud of space alcohol floats among the stars.
Even the habitable planets seem to be common. The first planet outside our solar system was discovered in 1995. Since then, astronomers have cataloged thousands.
Based on this catalog, astronomers at the University of California, Berkeley, worked out up to 40 billion land-size exoplanets in the so-called "habitable zone" around their star, where temperatures are mild enough to allow the Liquid water to exist on the surface.
C is even a potentially Earth-like world that orbits our nearest neighbor, Proxima Centauri. Just four light years away, that system could be close enough to allow us to use current technology. With the Breakthrough Starshot project launched by Stephen Hawking in 2016, plans for this are already underway.
Life is robust
It seems inevitable that another life is out there, especially considering that life appeared on Earth shortly after the formation of the planet.
The oldest fossils ever found here are 3.5 billion years old, while clues in our DNA suggest that life could have started as early as 4 billion years ago, just as the giant asteroids stopped crashing to the surface.
Our planet was inhabited as soon as it was habitable, and even the definition of "habitable" proved to be a rather flexible concept.
Life survives in all kinds of environments that seem boring to us:
Honestly, some of these conditions seem to be duplicated elsewhere in the solar system.
Fragments of promise
Mars was once hot and humid, and was probably a breeding ground for life before Earth.
Today, Mars still has underground liquid water. A gas strongly associated with life on Earth, methane, has already been found in the Martian atmosphere, and at levels that mysteriously rise and fall with the seasons. (However, the result of the methane is in question, with an orbiter on Mars that recently confirms the detection of methane and another that does not detect anything).
The Martian insects could appear as soon as in 2021, when the ExoMars rover Rosalind Franklin will go hunting for them with a two-meter drill.
In addition to the Earth and Mars, at least two other places in our solar system could be inhabited. The moon of Jupiter Europe and the moon of Saturn The enceladus are both icy worlds, but the gravity of their colossal planets is enough to boil their bowels, dissolving water to create vast subglacial seas.
In 2017, specialists in the crystal clear waters of the University of Tasmania concluded that some Antarctic microbes could survive on these worlds. Both Europe and Enceladus have submarine hydrothermal air intakes, just like those on Earth where life may have originated.
When a NASA probe tasted the geyser material in Enceladus space last June, it found large organic molecules. Perhaps it was something that lived in the spray; the probe did not have the right tools to detect it.
Russian billionaire Yuri Milner has been so excited by this prospect, he wants to help finance a return mission.
A second genesis?
A discovery, if it came, could upset the world of biology.
All life on Earth is related, ultimately descends from the first living cell to emerge about 4 billion years ago.
Bacteria, fungi, cacti and cockroaches are all our cousins and we all share the same basic molecular mechanism: the DNA that produces RNA and the RNA that produces proteins.
A second example of life, however, could represent a "second genesis", partly unrelated to us. Perhaps he would use a different coding system in his DNA. Or it may not have DNA but another method for transmitting genetic information.
By studying a second example of life, we could begin to understand which parts of the mechanism of life are universal and which are only the particular incidents of our primordial soup.
Perhaps amino acids are always used as essential elements, maybe not.
We might even be able to work out some universal biology laws, the same way we have for physics – not to mention new points of view on the question of the origin of life itself.
… the rapid appearance of life on Earth was not a fluke. "
A second independent "tree of life" would mean that the rapid appearance of life on Earth was not a fluke; life must abound in the universe.
It would greatly increase the possibility that, somewhere among those billions of habitable planets in our galaxy, there might be something we could talk about.
Maybe life is contagious
If, on the other hand, the microbes discovered were actually connected to us, it would be a bomb of a different kind: it would mean that life is contagious.
When a large meteorite hits a planet, the impact can splash the pulverized rock into space, and this rock can then fall on other planets like meteorites.
Life on Earth has probably already been taken to other planets, perhaps even to the moons of Saturn and Jupiter. Microbes could survive the journey.
In 1969, the Apollo 12 astronauts recovered an old probe that had sat on the moon for three years in extreme cold and vacuum conditions – they were vital bacteria still inside
Since Mars was probably habitable before Earth, it is possible that life originated there before I hitchhiked up a space rock up to here. Maybe we're all Martians.
Even if we never find another life in our solar system, we could still detect it on any of the thousands of known exoplanets.
It is already possible to watch starlight filtered through an exoplanet and say something about the composition of its atmosphere; The abundance of oxygen could be a telltale sign of life.
A verifiable hypothesis
The James Webb Space Telescope, designed for the 2021 launch, will be able to take these measurements for some of the Earth-like worlds already discovered.
Only a few years later space telescopes will arrive that will directly photograph these planets.
Using a trick like the sun visor in your car, planetary telescopes will be paired with giant umbrellas called stellar stars that will fly in tandem 50,000 kilometers away at the right point to block the blinding star light , allowing the faint grain of a planet to be captured.
The color and variability of that point of light could tell us the length of the planet's day, if it has seasons, if it has clouds, if it has oceans, maybe even the color of its plants.
The ancient question "Are we alone?" It has gone from being a philosophical remedy to a verifiable hypothesis. We should be prepared for an answer.
This article is an excerpt from an essay, "The search for ET", in The New Disruptors, 64th edition of Griffith Review.
This article was originally published in The Conversation by Cathal D. O & # 39; Connell. Read the original article here.
. (tagToTranslate) Extraterrestrial life (t) Aliens (t) Mars (t) Planets (t) Science fiction (t) Explanation (t) Standard (t) Science