Although it makes up 70 per cent of our planet’s surface, scientists still don’t all agree on where Earth’s water actually comes from.
Now, researchers claim to have found the origins of water in the earliest moments of the universe.
Scientists from the University of Portsmouth have detailed that water originated in the remnants of supernova explosions approximately 100 to 200 million years subsequent to the Big Bang.
These findings suggest that the ingredients for life on Earth were in place billions of years earlier than previously thought.
Through the use of computer simulations, the scientists have demonstrated that water likely emerged during the extinction of the earliest stars in the universe as they collapsed into supernovae.
As the oxygen produced by these blasts cooled and mixed with the surrounding hydrogen, water was able to form in the clumps of material left behind.
These dense, dusty cores are also the most likely origins of the material that would go on to form the first planets.
In the research publication authored by Dr. Daniel Whalen and colleagues, they express, ‘Our simulations not only highlight the presence of a fundamental element for life in the cosmos within 100–200 Myr post-Big Bang but also suggest that water played a significant role in the composition of the initial galaxies.’

While 70 per cent of Earth’s surface is covered with water (pictured), the origins of this key ingredient for life have long baffled scientists. Now, scientists say they have identified the first source of water in the universe and it is billions of years earlier than expectedÂ
Water, which has the chemical formula H2O, is made up of two ingredients: hydrogen and oxygen.
Hydrogen was formed along with the other light elements such as helium and lithium in the first few minutes after the Big Bang as the sea of super-heated particles cooled and clumped into atoms.
However, oxygen’s atoms are so large that they can’t be formed in this way.
Instead, oxygen and the other heavier elements had to be forged by the nuclear reactions created by stars.
About 100 million years after the Big Bang, about 13.7 billion years ago, clouds of primordial hydrogen and helium came together under the force of gravity.
As they grew denser, the pressure at the core eventually became so great that it kickstarted nuclear fusion reactions which transformed the gas clouds into stars and brought the first light to the cosmos.
Eventually, these stars burned through their supplies of hydrogen fuel and collapsed in on themselves, triggering enormous supernovae.
Briefly reaching temperatures around 1,000,000,000°C (1,800,000,000°F), those explosions fused the raw material from hydrogen and helium atoms into larger molecules including oxygen.

Scientists say that water would have been formed in the aftermath of stellar explosions called supernovae that were hot enough to create oxygen. These are the same types of blasts which produce nebulae like the Crab Nebula (pictured)

The scientists used computer simulations to model two supernova explosions, one from a star 13 times the mass of the sun (left) and one from a star 200 times the mass of the sun (right). These images show the heat produced by those blasts with the yellow and red regions showing greater heatÂ

The explosions scattered hydrogen and oxygen in a halo surrounding the blast. Over the next 90 million years, those elements came together to produce water. The larger supernova (red) produces more water at a greater speed than the smaller explosion (blue)Â
In their paper, published in Nature Astronomy, the researchers modelled what would happen in the aftermath of two supernova explosions – one from a star 13 times the mass of the Sun and the second for a star 200 times the mass of the Sun.
This simulation showed that the first and second supernovae produced 0.051 solar masses of oxygen and 55 solar masses of oxygen respectively.
After the explosion, a cloud of hydrogen and oxygen is shot out into an enormous halo surrounding the remnants of the star where they start to combine into water.
At first, the low density of the halo means water levels stay fairly low but, as the halo starts to clump together under gravity, the water levels start to increase dramatically.
After 30 to 90 million years the smaller supernova produced the equivalent of one hundred-millionth to one millionth of a solar mass of water.
The second, large explosion meanwhile produced 0.001 solar masses of water after just 3 million years.
If that water could survive the violent galaxy formation process, then it could have been one of the key components of the first galaxies.
What makes this finding particularly interesting is that this could explain how water arrived on habitable planets such as Earth.

The resulting cloud cores of the smaller (left) and larger (right) supernovae produced water which could have made its way into the first galaxies. If this is correct, it means water could have been present on planets for billions of years longer than previously thoughtÂ

The clouds of debris left behind by primordial supernovae are a likely origin for small stars like our sun and the protoplanetary disks from which planets are formedÂ
The dense ‘molecular cloud cores’ in which water formed most abundantly are a likely origin of protoplanetary disks, swirling clouds of dust that go on to form planets, and low-mass stars such as our sun.
In some of those disks, water levels could be almost as high as they are anywhere else in the universe today.
The researchers write: ‘These disks would have been heavily enriched by primordial water, to mass fractions that were 10–30 times greater than those in diffuse clouds in the Milky Way in the CC supernova core and to only a factor of a few lower than those in the Solar System today.’
The large amount of water and high chance of a low-mass star forming raises the possibility that planets with liquid water could form in the aftermath of those first supernova explosions.
This implies that a key condition for life might have been met billions of years earlier than scientists had previously thought.