Plate tectonics could be just a period in the Earth’s development. The plates will stop moving eventually, according to scientists.
Not only that, Science News reports that researchers can now put a figure on roughly when the crust will stop moving.
“Earth’s plate tectonics could be a passing phase. After simulating rock and heat flow throughout a planet’s lifetime, researchers have proposed that plate tectonics is just one stage of a planet’s life cycle.”
Research published this month in Physics of the Earth and Planetary Interiors puts the figure at 5 billion years.
“In around 5 billion years, plate tectonics will grind to a halt as the planet chills.”
Scientists ran a simulation of the Earth’s life cycle and observed how the “plate tectonics” period arises before dwindling away.
A team of researchers including Craig O’Neill, a planetary scientist at Macquarie University in Sydney, observed that at the beginning of the simulation, the Earth’s interior was “too hot and runny” to push giant chunks of crust around. It was only after the interior cooled — about 400 million “years” into the simulated life cycle — that plate tectonics as we know it arose. The Earth’s crust began shifting and sinking.
Researchers noted that even then, the process was “stop-and-go for about 2 billion years.”
“The simulation suggests that Earth now is nearly halfway through its tectonic life cycle.”
The team observed that after 5 billion years, plate tectonics ground to a halt as their simulation earth chilled.
The researchers were confident that the simulation was accurate, and a pioneering look into the way plate tectonics evolves over the Earth’s whole life span. Science News reports that “Even using a supercomputer and simulating only a two-dimensional cross section of the planet, the calculations took weeks.”
“Previous simulations were simplified and typically considered only snapshots of Earth’s history and missed how plate tectonics evolves over time…O’Neill and colleagues simulated Earth’s full tectonic life span, starting with the planet’s formation around 4.5 billion years ago and looking ahead to around 10 billion years in the future.”
Plate tectonics has a number of important functions: it regulates the planet’s climate by adding and removing carbon dioxide from the atmosphere, thus helping to maintain Earth’s habitability. Reporting Climate Science reports that the appearance of atmospheric oxygen on Earth was a consequence of plate tectonics and the formation of continents.
“Based on a new model that draws from research in diverse fields including petrology, geodynamics, volcanology and geochemistry, the team’s findings were published online this week in Nature Geoscience. They suggest that the rise of oxygen in Earth’s atmosphere was an inevitable consequence of the formation of continents in the presence of life and plate tectonics.”
O’Neill and his colleagues report that some “stagnant” planets — planets without moving plates — could be capable of supporting life, but that would depend on where they are in their life cycle. O’Neill was more optimistic about the early period when tectonics has not yet geared up, rather than the cooling period when tectonics is dwindling away.
“Stagnant planets, depending on when they are in their history, can be equally likely of supporting habitable conditions.”
Tectonics could be gearing up on other planets in our solar system, claims Julian Lowman, a geodynamicist at the University of Toronto. Thus, there is a chance that humans could relocate to a planet earlier in its life cycle if we are still around when cooling begins on Earth.
“There is a possibility that plate tectonics could start up on Venus if conditions were right.”
[Image via NASA/Apollo17 Crew: Wikimedia Commons/Public Domain]