Did water exist before earth? Scientists uncover a cosmic mystery

Water covers about 70% of our planet, yet its origins have remained one of the greatest scientific mysteries. Where did Earth’s water come from? Was it delivered by asteroids, formed deep within our planet, or did it exist long before Earth itself? A study now suggests that water could have formed in the earliest moments of the universe, long before our solar system was even a thought.

A Cosmic Birth of Water

Researchers at the University of Portsmouth have unveiled a remarkable discovery: water may have first appeared in the debris of supernova explosions between 100 to 200 million years after the Big Bang. This revelation challenges previous assumptions and suggests that the essential ingredient for life was present billions of years earlier than previously believed.

Using cutting-edge computer simulations, scientists demonstrate that the violent deaths of the universe’s first stars played a crucial role in water formation. When these massive stars reached the end of their lives, they collapsed into supernovae, spewing vast amounts of oxygen into space. As this oxygen cooled and combined with the omnipresent hydrogen in the aftermath of the explosion, water molecules began to emerge in the dense, dusty remnants.

The Building Blocks of Life in a Chaotic Universe

Water is a simple yet essential molecule, composed of hydrogen and oxygen. Hydrogen, one of the earliest elements in the universe, formed minutes after the Big Bang. Oxygen, however, required more time. It had to be forged through nuclear fusion inside the first generation of massive stars. As these stars exploded in spectacular supernovae, they scattered oxygen across the cosmos, making water formation possible in the cold, swirling clouds of debris.

The researchers simulated two supernova events—one from a star 13 times the mass of our Sun and another from a colossal star 200 times the mass of the Sun. The results were striking. The larger explosion produced significantly more water, with up to 0.001 solar masses of water forming within just three million years. Over the next 90 million years, water levels continued to rise, potentially seeding the first galaxies with life’s most essential ingredient.

Could This Explain Earth’s Water?

If water was already abundant in the universe long before our solar system formed, it raises an intriguing possibility: the water on Earth today could be remnants of these ancient cosmic explosions. The dense molecular clouds where early water formed also gave birth to the first planets and low-mass stars, similar to our Sun. If some of this water survived the turbulent formation of galaxies, it could have been incorporated into planets like Earth billions of years later.

The study’s authors suggest that protoplanetary disks—the swirling clouds of gas and dust that form planets—could have been heavily enriched with primordial water. Some of these disks contained water levels comparable to those found in today’s Milky Way. If these findings hold, it means that Earth, and possibly other habitable planets, inherited their water from the very first chapters of the universe’s history.

What Does This Mean for Life Beyond Earth?

The implications of this discovery extend far beyond our own planet. If water was abundant in the early universe, it could mean that the conditions for life existed much earlier than previously thought. This raises the possibility that habitable planets could have formed billions of years before Earth, increasing the chances of extraterrestrial life somewhere in the cosmos.

Astronomers have already identified exoplanets within the “Goldilocks zone”—regions around stars where liquid water could exist. The Trappist-1 system, just 39 light-years away, has seven Earth-like planets, three of which could have liquid water. If water is indeed a universal ingredient from the dawn of time, then life may not be as rare as we once assumed.

A Universe Teeming with Possibilities

This study challenges us to rethink everything we know about the origins of water and life itself. If water formed in the aftermath of the universe’s first explosions, then the seeds of life may have been scattered across the cosmos for billions of years. Could this mean that life elsewhere in the universe is not just possible, but likely?

As we continue to explore the cosmos, from analysing distant exoplanets to probing the atmospheres of faraway worlds, we may one day find the answer. But for now, one thing is certain: the story of water is far older, and far more cosmic, than we ever imagined.