What water reveals about human knowledge – and its limits
written by
Around 4.500.000.000 years ago, 10.000.000 after the Moon-forming event, a day on Earth was about 6 hours long, and the Moon was way closer – 24.000 to 32.000 km away from Earth (today it is 383.000Km). The Sun was a fast-spinning baby star, taking 9 to 10 days per spin (today, it is 24 (equator) and 35 (poles) days).
The Moon-forming event increased Earth’s and Moon’s temperatures while making them intensely spin and rotate around each other. With such loaded energies, the initial tidal interactions between Earth and Moon were more violent, resulting in energies being dissipated at a faster pace, with both objects considerably slowing their rotation and spin within their first millions of years. At this point, the Sun was way more radioactive despite having lower temperatures (nuclear fusion was just starting).
A stream of charged particles, the solar wind, was reaching the terrestrial planets, making radioactivity at least 5 times higher than today. The solar wind and the intense tidal interactions between Earth and the Moon created a layer of charged particles early on, a combined magnetosphere around both objects. In turn, the magnetosphere enables a layer of gas to be trapped between the planet’s surface and space – the atmosphere.
Still around 4.500.000.000 years ago (due to gravity, rotation, and tidal interactions), the densest materials (metals like iron and nickel) were sinking to form Earth’s metallic core at the same time that the less dense materials (silica-like) were accumulating in a layer around the core called the mantle.
Near the mantle surface, the pressure and temperatures caused the mantle minerals to split their chemical compositions, releasing gases and water molecules (roughly 7% of the mantle minerals have 2% of their composition made out of water molecules – which (due to the mantle proportions) is enough to fabricate several oceans like the ones we have at Earth’s surface today). The water molecules from the mantle outgassing could get trapped at the planet’s surface because of the atmosphere, making planet Earth (probably already) with water on its surface.
This is a brief description of HOW and WHEN water appeared on Earth’s surface, according to scientific knowledge based exclusively on empirical evidence.
Believe it or not, scientists are only recently (perhaps) beginning to understand WHAT water actually is.
As commonly known, water behaves differently than any other liquid at Earth’s surface. It gets less dense (expands) at freezing temperatures, which is why ice floats on liquid water. It has a high boiling point compared to other liquids. And it has a high surface tension, creating a membrane-like outer layer that makes it more resistant and cohesive in its liquid form (which explains why insects can walk on water and why water droplets assume a spherical shape). These are just a few of the several “anomalous” features that water, as it is known at the Earth’s surface, presents.
Over the past three decades, advancements in computational modeling have significantly improved the accuracy of molecular simulations. This progress has allowed for detailed studies of the behavior and structure of water molecules, particularly in conditions that cannot be found on the Earth’s surface.
These studies provide evidence that water has two distinct states, that those two states are interconvertible, and that ice has at least 21 different forms – and the list continues to grow.
Under different pressures and temperatures, water solidifies into distinct crystalline structures, each with its own molecular arrangement and density. The familiar ice from a freezer is Ice Ih, a hexagonal structure found on Earth’s surface. But in the upper atmosphere, Ice Ic—a cubic form—can exist. Under high pressure, dozens of other phases emerge, from Ice II to Ice XXI, each with different properties.
Under extreme pressures and temperatures, oxygen atoms remain fixed while hydrogen protons flow like a liquid, resulting in superionic ice, which is believed to exist in large amounts deep inside Uranus and Neptune, whose movement of protons generates the unusual magnetic fields observed around these planets.
In addition to these forms, water can also freeze into a glassy, non-crystalline state called amorphous ice. There are at least three types (low-density, high-density, and very high-density amorphous ice), with the amorphous form believed to be the most common ice in the universe.
From all these data, one thing is safe to say – the water molecule H₂O is remarkably adaptable and can assume many different designs, always reacting to temperature and pressure (together or in isolation) to determine its state and, consequently, its molecular structure.
Curiously, like many other things in “science”, researchers often take for granted that what humans experience at Earth’s surface is “normal” or “standard”, only to become disappointed with the results of their experiments.
What happens at Earth’s surface is not universal or common. The acknowledgment that the ice found on Earth’s surface (ice I) is extremely rare in the universe is, somehow, painful because it leads to an inconvenient truth – that humans do not know a lot about everything.
Actually, humans know very little about very little. Things are still not given, controlled, or known. Interestingly, since the dawn of written records, humans have consistently believed they were at the peak of their knowledge, mastering their own time—only to become a laughable footnote to generations to come. In many ways, we are still similar to the ones who lived many years ago.
Perhaps, for the first time in history, humans should acknowledge how little is actually known—about water, about everything—and from that starting point, build what could be a truly new age for human knowledge. At the very least, with such a humble starting point, perhaps striving to “know about everything” can get more interesting.