Short article: K2-18b and the Mystery of Life’s Origins

K2-18b and the Mystery of Life’s Origins

Hearing about K2-18b reignited my long-standing thoughts about the origin of life. I couldn't stop myself from expressing this excitement at such a meaningful moment.

How lucky we are, and how fortunate our planet is, to be placed so perfectly at just the right distance from the Sun. Because of this precise positioning, Earth has been able to maintain an environment suitable for life. Our planet held onto its atmosphere, nurtured its oceans, and provided the conditions necessary for life to emerge.

At the same time, Mars was not so lucky. It was severely affected by the powerful solar tides and the gravitational influence of Jupiter. Mars, once potentially capable of accommodating life, lost its atmosphere and became the barren desert we see today. Meanwhile, Earth survived and continued to evolve, creating a safe environment where life could grow and flourish.

The origin of life on Earth happened gradually. Complex molecules began to form amino acids, carbohydrates, lipids — and ultimately nucleic acids. Among them, DNA and RNA emerged as the primary molecule, the ultimate thread that connects all living beings on Earth. "We" meaning every life form, from humans to the smallest microbe, all united by DNA.

It raises an interesting question: if life grew across every corner of Earth using DNA as the communicating molecule, why was it only DNA and not another molecule? Universal answer is sustainability of this molecule, but this is not enough. Despite the evolution of countless different species and races, the basic structure of nucleosides in DNA has remained constant across all forms of life. This universal code links us in ways we are only beginning to fully appreciate.

Recently, about 124 light-years away, we discovered K2-18b a planet that appears to have conditions similar to Earth's, but huge as 2.5 times bigger. Water vapor has been detected in its atmosphere, and it contains elements known to us here on Earth.

But this discovery also leads us to wonder: while we have the capacity to detect familiar elements, what if K2-18b holds elements or molecules that we have never encountered before? How would we identify something completely unknown, beyond the reach of our current understanding?

If life exists there, K2-18b might offer us a chance to rewind and explore the origins of life once again but this time from a new perspective. Will we find that life on K2-18b is based on the same DNA and familiar molecules? Or will we encounter a completely different hereditary molecule, something entirely new that challenges our current definitions of life itself?

The possibility of discovering new forms of life fills us with wonder. We always keep our fingers crossed, hoping that we are not alone in this vast universe. Perhaps someday, our children will have new cosmic neighbors, new friends just next door in the universe waiting to be discovered.

Dr Nikunj Bhatt