Written By Shagun Thakur, Cosmofluencer (Batch 1)

We live in a Universe full of mysteries and enigmas, which always causes curious minds and researchers to ‘scratch their heads’ in search of the most powerful impetus. We don’t know if we’re in a shadow universe or a holographic universe, but we’re still trying to figure out our ultimate reality.

Although our constant struggle and research have resulted in many new discoveries and breakthroughs, we still have many unanswered questions. How did life ever begin? How did the very first organism survive? Why is only Earth habitable in our solar system? Is it possible that aliens exist? All these questions gave rise to a new branch of science known as Astrobiology. 

The term Astrobiology is composed of two words: Astro (space or star) and Biology (the science of life), which together form the meaning, science, and studies of life in space. This branch of space science has the potential to explain and answer the important question – how? Let’s investigate further to find out.

All of space and matter was contained in a volume less than one trillionth the size of the period at the end of this sentence about 13.6 billion years ago, where it all began with a bang, the BIG BANG! Everything we see, feel, and hear today was once a dot that is still expanding at the speed of light. The creation of the universe was a process by chance that was (and still is) the origin of LIFE and us.

When it comes to our own planet, scientists believe that the origin of life, even under very favorable conditions, is only 1%. So, we can say that we are the result of that 1% chanced-upon process.

But how could this have happened?

Of course, the origin of the planet Earth (the floating rock in the emptiness of deep space we live on today) is supposed to be 4.5 billion years old, when it was nothing more than a huge piece of sizzling hot rock (Image 1) with no atmosphere, completely covered with gases like Methane, Carbon Dioxide, and Ammonia that was constantly flogged with bursts of UV rays from the Sun, asteroids, and meteoroids.

As a result of the bond breaking of water (H2O – from volcano steam) into hydrogen (H2) and oxygen (O2), lighter hydrogen escaped into space. At higher atmospheric spheres, oxygen later combined with ammonia (NH3) to form water, carbon dioxide, and ozone, forming the OZONE LAYER, which preserved the required atmosphere and temperature for the origin and still preserves the survival of life. As the temperature dropped, water vapors fell as RAIN, filling the asteroid-impacted depressions with water and transforming them into seas and oceans. After 500 million years of earth formation, life appears from nowhere, implying that the first living cell was formed nearly 4 billion years ago. But how exactly, is still an open question.

Many astrobiologists believe in the spores or panspermia theory, which proposes that life on Earth arrived from outer space in the form of spores.

Modern space researchers have demonstrated that bacteria can survive the rigors of space travel and the airless, waterless environment of the moon. This discovery removes one of the theory’s obstacles, but it sheds no light on the origin of life. It is clear, however, that whether it was extraterrestrial or intraterrestrial, it all began with a basic unit of life known as the cell. The idea of making a cell has been proposed in the theory of abiogenesis by Redi, Spallanzani, and Pasteur, who stated, “Life always comes from pre-existing life.” Because of the reducing environment, this gave rise to the notion that the origin of life from non-living materials was possible on primitive earth.

This concept was later developed by a Russian biochemist Alexander Oparin in 1923 and an English biologist JBS Haldane in 1928, and was summarized in a book in 1938 as abiogenesis first, but biogenesis ever since. They proposed that the first life arose from a collection of chemicals through a progressive series of chemical reactions in which atoms combined into inorganic molecules, inorganic molecules into simple organic compounds (monomers), simple organic monomers into complex organic compounds (polymers), polymers into aggregates which finally got organized into living matter, meaning the first-ever prokaryotic cell (the brief idea of theory).

To test this theory of abiogenesis, a US Nobel Prize winner chemist named SL Miller, born in 1893, set up an apparatus (Image 2) consisting of a gas flask, a condenser, and a liquid flask interconnected with tubes and fitted with energy sources, creating the same conditions as primitive earth. He then used chromatographic and calorimetric methods to determine the chemical composition of the product of the chemical reactions in the mixture. He discovered many simple organic compounds, including amino acids like glycine, Alanine, and aspartic acid, as well as adenine and simple sugars like ribose. Which are nothing more than the components of a cell and its nucleus. This explains how cell genesis was possible on primitive Earth’s reducing conditions but not on modern Earth’s conditions. As a result, this theory of abiogenesis remains the most widely accepted explanation for the origin of life on Earth. The truth is that there are many unanswered questions about LIFE and our existence, as life is not limited to Earth and could exist anywhere.

Imagination and curious minds are great things, right? We still ain’t aware of many facts, many logics even out of our daily lives, though there’s always something left out of everything we know today! But where did this exploration start? In the imagination of a curious mind. What do you think of the theories and explanations above? Can you think of some more possibilities? Do spark up the comments section with your thoughts and views.