“Imagination is more important than knowledge.” — Albert Einstein.

Many theories abound concerning the origin of Earth’s oceans, which cover more than 70% of Earth’s surface. An array of scientific theories exists, including outgassing, comet and asteroid bombardment, volcanic activity and other possibilities during the first approximately two billion years of Earth’s ~4.6 billion-year history.

Three useful studies by National Air and Space Association (NASA) Ames scientists and the University of Colorado describe Earth’s early atmosphere as being rich in (escaping) hydrogen and helium, and a planet devoid of free oxygen and water, with continuous volcanic activity spewing ash, extraterrestrial bombardments of carbonaceous meteorites and an array of noxious gases.

A new hypothesis

In 2010, an important experiment (In-Situ Resource Utilization field demonstration) was conducted in Hawaii by a group of US, Japanese and Canadian entities, primarily by Lockheed Martin Corporation at a Japan/US Science, Technology & Space Applications Program (JUSTSAP) symposium, which the author chaired. The experiment was designed to demonstrate that water could be obtained from volcanic ash to simulate regolith rich in silicates (silicon oxides) found throughout the Moon, as a potential source of rocket fuel (“Dust to Thrust”) and for other human applications.

The experiment conducted on Mauna Kea, not far from the Visitors Center at 3,000 meters, demonstrated that volcanic ash rich in silicates (especially silicon dioxide [SiO2]) fed into a ~three-meter elongated glass chamber (on a small conveyor belt) then intensely heated by solar energy at atmospheric pressure, produced water at an outlet tap at the far end of the chamber — after hydrogen had been injected into the chamber.

Hydrogen reduction of SiO2 involves reacting SiO2 with hydrogen gas, typically at high temperatures to produce silicon (Si) or silicon monoxide (SiO) and water (a key process for green silicon production and semiconductor passivation, involving complex kinetics controlled by temperature, pressure and gas conditions), often via the typical reaction: SiO2+2H2⇌Si+2H2O — although there is also a parallel reaction which forms silicon oxide (SiO) plus water.

A significant volume of water was recovered relative to the mass and volume of the volcanic dust, with perhaps >65% SiO2. Water was formed by hydrogen atoms combining with oxygen atoms from the silicates, using intense solar heat. At the time, this was a fascinating experiment, but it begged the question: Where would the hydrogen come from? One possibility could be as a component of the rocket fuel used to reach the Moon & Mars.  

Circa 2018, following more science-based evidence that the Earth’s early atmosphere for the first ~2 billion years was a reducing atmosphere rich in escaping hydrogen and other reducing gases, an intriguing, serendipitous hypothesis emerged. Namely: Could most of the water in Earth’s oceans have come from “in gassing” of dry volcanic ash loaded with SiO2, interacting with hydrogen, in the presence of intense solar radiation* and other high-energy sources?

*Initial Hadean Era (4.5–4 Billion Years Ago) 

• Molten & Scorching: The first few million years were dominated by intense heat from planetary accretion and giant impacts (like the one forming the Moon), keeping Earth molten with surface temperatures potentially exceeding 2,000°C.
• Cooling & Solidification: After the magma ocean solidified, the surface cooled enough for rock to form, but intense volcanic activity and greenhouse gases kept it very warm.

Water vapor and condensed liquid water could probably have been produced in sufficient quantities, depending on ambient temperatures, when combined with other events (e.g., carbonaceous chondrite meteorites [~20% water], comet bombardment, Earth’s nascent weather cycles, etc.), to form the early oceans on Earth — and possibly other planets and their moons in the solar system (e.g., Europa, Enceladus, Pluto, etc.), and elsewhere in the cosmos, followed by condensation.

Contrary to some previous speculation that insufficient free hydrogen existed in Earth’s early atmosphere, due to the escape of low-density gases, including hydrogen, it now appears that considerably more hydrogen was available and for longer periods.

Possible next steps

The next step is to determine if this “silicates-to-water” hypothesis holds scientific water! 

• Could sufficient water/water vapor have been generated over a period of many hundreds of millions of years from volcanic dust on Earth (in conjunction with bombardment from comets, asteroids, and other chemical & atmospheric processes) to form the early oceans on Earth? The author postulates affirmatively*
• Was the bombardment of the early Earth by chondritic carbonaceous meteorites and comets sufficient to explain the formation of the oceans? The author believes not, based on the probable lack of sufficient impact volumes.

*The key question being: Is this hypothesis both necessary and sufficient to explain the probable origin of Earth’s oceans? The author believes so — largely based on the aforementioned experiment of “silicates to water” he witnessed in Hawaii in 2010, plus scientific data indicating longer periods of hydrogen in Earth’s early reducing atmosphere, than previously postulated.

[The author is a past chairman of JUSTSAP and a current Corporation board member of the Woods Hole Oceanographic Institution.]

[JUSTSAP formed the organization called PISCES (Pacific International Space Center for Exploration Systems) in 2006/7 while the author was chairman. This organization was instrumental in the “Dust to Thrust” experiments.]

[Kaitlyn Diana edited this piece.]

The views expressed in this article are the author’s own and do not necessarily reflect Fair Observer’s editorial policy.