Origin of Life: From Chemical Soup to Living Systems

To understand the origin of life, we must begin long before Earth itself existed—with the birth of the universe. The story starts nearly 13.8 billion years ago with the Big Bang, a cosmic event that marked the beginning of time and space. In its aftermath, the universe was a seething mass of energy and fundamental particles. As it expanded and cooled, these particles combined to form hydrogen and helium—the simplest elements and the primary building blocks for stars.

Over hundreds of millions of years, gravity gathered these gases into massive clouds that collapsed under their own weight to form stars. Within these stellar furnaces, nuclear fusion gave rise to heavier elements like carbon, nitrogen, oxygen, and iron—the essential ingredients for life. When massive stars exhausted their fuel, they exploded as supernovae, scattering these life-enabling elements across the cosmos. These cosmic events seeded the interstellar medium with the raw materials from which new stars and planetary systems would emerge.

Around 4.6 billion years ago, in a relatively quiet corner of the Milky Way, one such cloud of gas and dust began to collapse. From this swirling disk, our Sun was born at its center, while the remaining material coalesced into planets, moons, asteroids, and comets. Among these was Earth—a rocky planet positioned at just the right distance from the Sun to allow liquid water, a crucial component for life as we know it.