“The origins of life remains one of the great unsolved mysteries of science.”
- Paul Davies
In a mere billion years following its formation, Earth evolved from a desolate and barren rock
into a vibrant world teeming with microorganisms.
But how did life emerge on our ancient planet?
Scientists speculate it all started with lightning.
Electrically charged beams of light ignited crucial chemical reactions in Earth's early
atmosphere, which consisted of a primordial soup of ammonia, methane, water vapor, and
carbon dioxide.
This theory has been proven experimentally where researchers replicated the conditions
by passing electrical sparks through a similar gas mixture.
After a few days, the mixture yielded several simple carbon molecules.
Since carbon easily bonds with other atoms, it facilitated the formation of long chains,
branched structures, and even rings, gradually giving rise to larger and more complex molecules
such as DNA and RNA.
Carbon, the essential element for life on Earth, forms the basis of all living creatures.
So far, we have identified over 300 million potentially habitable worlds.
The groundbreaking James Webb Space Telescope recently detected carbon dioxide in the atmosphere
of exoplanet WASP-39b, raising hopes for proof of extraterrestrial life.
The quest to discover a planet where life has emerged continues.
But what if our perception of life is limited by our "carbon chauvinism," and the potential
for life elsewhere in the universe is radically different, even at the molecular level?
What will we find out there if we shift our vision and broaden our approach?
Let’s find out!
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Scientists hypothesize that if alien life exists, it would likely be based on carbon
as its fundamental building block.
Since the universe comprises the same chemical elements, it's possible the recipe for creating
different life forms is universal.
Carbon is the basis of every biological molecule we know of.
Its unique capability to form stable bonds with four other atoms allows for the creation
of long molecular chains and intricate structures.
It is the basis for proteins and DNA, vital components that drive the functioning of life.
However, the existence of carbon-based life on other planets doesn't imply a mere replication
of Earth's life forms.
Even slight variations in environmental conditions can give rise to profoundly distinct life
forms.
Consider Earth’s gravity compared to an alien world.
If the gravity of an exoplanet was too strong, our blood would be pulled down into our legs,
our bones may break, and we could even be pinned helplessly to the ground and unable
to move.
Inhabitants of such a world would likely have stout and robust bodies as this would provide
stability and resistance to the overwhelming gravitational pull.
Thick and sturdy skeletons, possibly reinforced with natural armor-like coverings, could aid
in supporting their weight.
These adaptations would help counteract the constant downward force and prevent structural
damage to their bodies.
In a high-gravity environment, organisms would likely choose to live on the planet's surface
or maybe even underground.
Surface or underground-dwelling life forms might develop special features like unique
limbs or gripping mechanisms to firmly hold onto the ground, ensuring stability.
Such creatures would likely be slow-moving and deliberate to counteract the increased
resistance and strain.
Crawling or rolling might be common ways of getting around as they offer greater stability
and lower the risk of injury.
Another possibility is that such forms could have evolved multiple limbs or appendages
to distribute their weight and improve mobility, allowing them to traverse the terrain more
efficiently.
But moving would require a lot of energy, and it could be quite difficult.
On the other hand, in a low-gravity environment, small and fast creatures would experience
the exact opposite.
They could accelerate, jump, and fly further and faster compared to creatures on Earth.
Monstrous crickets, hawk-sized butterflies, or birds larger than airplanes could potentially
inhabit this strange alien world.
If we consider a planet with an elongated orbit, seasonal fluctuations would be incredibly
severe there.
During unfavorable seasons, its inhabitants would likely enter a state of hibernation
or deep anabiosis similar to Earth's hibernating animals.
In the distant reaches of a planet, situated far from its host star, where the ambient
light conditions are considerably dim, the eyes of all creatures would naturally tend
to be larger in size.
This adaptation would enable them to capture and utilize as much available light as possible
to perceive their surroundings effectively.
Conversely, in the presence of intense starlight, the evolutionary pressures would likely favor
the development of smaller eyes accompanied by dense eyelids.
This reduction in eye size and the protective covering would serve to shield against the
excessive brightness, allowing for optimal vision in such luminous environments.
The concept of life existing on planets without a protective magnetosphere and exposed to
deadly radiation may be difficult to imagine.
However, scientists suggest that organisms could adapt to these conditions and sustain
themselves from cosmic radiation energy.
Astrobiologist Dimitra Atri proposes that intense surface radiation could become a food
source for small life forms which would seek protection underground, and emerge to gather
nutrients.
On a highly molten planet, liquid water would be unlikely.
Carbon, which requires interaction with water to form organic molecules, may not be suitable
for the formation of life in such an environment.
Instead, scientists believe that silicon, an element similar to carbon, could play a
significant role in the formation of alien life.
Silicon shares carbon's ability to form multiple bonds and generate diverse molecular structures.
Nonetheless, its reactivity at typical Earth surface temperatures is limited compared to
carbon, meaning it’s less suitable for intricate organic chemistry.
As scientists discover more exoplanets, some of them incredibly hot, the idea of silicon-based
life forms gains attention.
One such planet, GJ 1252 b, located just 65 light-years away, orbits close to its star,
resulting in scorching temperatures.
In this extreme environment, it is possible to speculate about the existence of unusual
life forms like living rocks or crystalline organisms.
Silicon-based life forms, if they exist, might find chemical compounds like liquid ammonia
or methane more suitable for their survival than water.
However, high temperatures pose a challenge as these life forms would evaporate.
An intriguing solution could be sulfuric acid, dangerous to our skin, eyes, lungs, and teeth.
In 2022, researchers from the Massachusetts Institute of Technology discovered that sulfuric
acid facilitates the formation of various organic compounds based on silicon.
Sulfuric acid remains in liquid form even at temperatures exceeding 300°C [572°F].
Venus' clouds contain abundant aerosol droplets of sulfuric acid, which makes the planet a
potentially comfortable habitat for silicon-based microbes.
Considering these unique characteristics, silicon can compete with carbon as a fundamental
building block for life on a cosmic scale.
But what could happen if we try to mix these elements and make them work as a whole?
Many scientists consider silicon and carbon to be a very promising combination.
Even here on Earth, we have examples that prove this.
Diatoms, a type of algae, have a silicon-based shell, while single-celled organisms called
radiolarians have a skeleton made of silicon.
And now scientists have discovered a new method to encourage living organisms to chemically
bond carbon and silicon together.
They achieved this using a technique called 'directed evolution', where microbes were
guided to produce never-before-seen molecules.
By focusing on enzymes, which are proteins that facilitate chemical reactions, researchers
mimicked nature's own process of evolving new enzymes.
Through mutations, they obtained a mutant enzyme capable of generating over 20 different
organo-silicon compounds, 19 of which were entirely novel to science.
The experiment has demonstrated that the mutant enzyme could generate organo-silicon compounds
in a controlled environment, such as a test tube.
But not just that, scientists have also genetically engineered E. coli bacteria to produce a mutant
enzyme within their cells, leading to the creation of organo-silicon compounds by the
bacteria themselves.
If researchers can successfully establish connections between silicon and carbon this
easily, nature might’ve done the same someplace else in the universe.
Or, perhaps, Mother Nature may have chosen another chemical element capable of producing
life.
Boron has significant interest among researchers due to its intriguing capabilities.
Surpassing all elements except carbon, boron possesses the most diverse chemical composition.
Among its most promising compounds are boranes, which can incorporate up to 12 boron molecules.
The intricate structures of boranes have the potential to foster the emergence of life
or... stimulate dramatic reactions.
Known to exhibit a high reactivity, diborane gas, for instance, can spontaneously ignite
upon contact with air or water.
So, for life forms composed of boron to flourish, an environment devoid of atmospheric oxygen,
seas, and oceans would be crucial.
On top of that, only an extremely cold planet would create a suitable environment for such
organisms.
And if its inhabitants are warm-blooded, they would probably need thick skin or fur.
Unlike boron, which is relatively scarce in space, metals can be found much more often.
Astronomers are aware of several worlds rich in iron.
Mercury, for instance, contains a significant amount of metals.
The exoplanet GJ 367 b in the constellation Vela appears to be composed almost entirely
of iron.
The exoplanet WASP-121 b in the constellation Puppis is believed to have clouds of metallic
vapor, and instead of raining water, it experiences precipitation of liquid rubies and sapphires.
So just for a moment, let's consider the possibility of metallic life on such planets.
A researcher from the University of Glasgow has synthesized living cells from a rare metal
called Tungsten, or Wolfram.
Under normal conditions, the chemical element is a solid, heavy, shiny metal with a silver-gray
color.
The results showed that these cells can selectively allow certain chemical substances to pass
through while blocking others, which closely resembles the functions performed by the walls
of organic cells.
Determining the hypothetical form of metallic life is indeed a challenge.
Scientists speculate such living creatures would possess remarkable resilience, rendering
them virtually bullet-proof.
In the vast reaches of space, life can come in unimaginable forms, consisting of the most
unexpected elements, such as toxins.
Although seemingly bizarre, researchers are contemplating the possibility of life forms
that predominantly rely on arsenic biochemistry.
The backbone of this idea lies in the fact that arsenic can occasionally substitute phosphorus
in molecules, the very building blocks found in every cell of our bodies.
These elements bear a remarkable chemical resemblance.
There’s even a hypothesis suggesting that early life on Earth might have employed arsenic
biochemistry as an alternative to phosphorus in the structure of its DNA.
Even today, certain marine algae on our planet continue to incorporate arsenic into complex
organic molecules.
Recently, a groundbreaking discovery was made within NASA's astrobiology program, where
scientists identified the first microorganism known to exist on Earth that can reproduce
using arsenic.
This peculiar bacterium, named GFAJ-1, was found thriving in California's Mono Lake.
GFAJ-1 substitutes arsenic for phosphorus in its DNA and other essential cellular components.
While researchers still need further investigation for definitive conclusions, the finding suggests
that nature can potentially incorporate arsenic into the biochemistry of organisms on other
planets.
Perhaps, it is just too early for a civilization like us to understand the ways of nature.
Fossil microorganisms indicate that life appeared early on Earth, but how and where it began
remains uncertain.
Living organisms are complex, with intricate systems of genes and molecules.
And this is a problem as even the most basic bacterial cell contains hundreds of genes
and thousands of diverse molecules.
Some scientists believe that before genes or cell walls, the first requirement for life
was a metabolic engine.
It is central to life, and many researchers believe it was at the core of the first living
cells.
Once initiated, these engines could produce the chemicals required for life and eventually
lead to the self-assembly of cells.
However, metabolism is still a very complicated mechanism, which makes scientists wonder which
came first: the chemical engine responsible for constructing cells, or the cellular mechanisms
needed to create the engine.
In a fascinating experiment, scientists combined 12 chemicals in water that are part of the
process called glycolysis.
They heated these mixtures to resemble conditions near an undersea volcano at a temperature
of 70°C [160°F] for five hours.
To further simulate the primordial ocean, the researchers added substances like iron
and sodium, which were believed to be present during that time.
Iron, in particular, had a positive effect on the reactions.
After several years of experimentation, scientists achieved a set of 28 working reactions, including
a complete metabolic cycle.
Life is unimaginably diverse, and even the intricate process of metabolism is just one
of the many possible mechanisms that can drive the emergence of life.
Could it be that metabolism is merely one mechanism among many guiding the emergence
of life forms?
Perhaps, hidden within the vast cosmic expanse, lie numerous parallel pathways, each with
its own set of intricate reactions, orchestrating the grand symphony of life in ways we have
yet to understand.
There’s a possibility that life itself could consist of diverse combinations of elements,
evolving from cosmic dust in plasma.
Recent studies have confirmed that inorganic dust comprised of iron, silicon, magnesium,
and carbon, exhibits astonishing lifelike behavior within plasma.
Under certain conditions, these particles can combine to create complex compounds that
allow for interactions similar to those found in organic matter.
Previously, scientists believed that solid particles in cosmic plasma merely created
thread-like formations.
However, through advanced computer modeling, scientists have discovered something interesting:
these thread-like structures have the ability to arrange themselves into spiral or helical
shapes through self-organization.
Even more surprisingly, researchers have discovered that these formations can engage in interactions
and undergo transformations similar to those observed in DNA and proteins.
These mysterious helices and spirals formed by solid particles can divide or replicate,
creating two copies of the original structure.
Through interactions with each other, they change and evolve.
During this process, the plasma keeps the most well-adapted copies while getting rid
of the less stable ones.
Somewhere out in the universe there could be a living helix in a cosmic plasma cloud,
slowly evolving into a much more complex organism.
Or maybe there are nano-microbes that have settled on a neutron star.
These creatures, according to astrophysicist Frank Drake, would be made up of tightly packed
nuclei instead of regular atoms, forming "nuclear molecules."
Their lives would be incredibly short due to fast nuclear reactions.
If they existed, they would only live for a few minutes, and would only be visible under
a microscope.
But then let us consider the opposite.
What if there are enormous beings in the cosmos observing us like we observe microbes under
a huge microscope?
How big could these creatures be?
The size of elephants?
Or even larger, like an entire ocean, a planet, a galaxy, or even a cluster of galaxies?
Maybe they encompass the entire Universe!
Life might not necessarily rely on atoms and molecules but could be intricately interwoven
with the very fabric of the cosmos.
According to this idea, life is omnipresent, existing in a seamless manner all around us.
This thought challenges conventional assumptions and invites us to contemplate the profound
nature of life in the broader context of the universe.
Which idea resonates most with you?
Share your thoughts in the comments below.
If you found this video interesting, make sure to stay tuned for more captivating cosmic
findings.
Thanks for watching!