The Pacific Ocean is getting smaller by about an inch every year as the tectonic plates on which America lies are moving westward. Now, thanks to calculations on a supercomputer, scientists say that this process will give rise to a new “supercontinent”: Amasia.

The modern world map with its recognizable pattern of continents and oceans is just one of the snapshots of our planet through time. During its 4.5-billion-year history, the Earth has tried on a wide variety of continental configurations, including periods when almost all of the Earth’s land mass was united into one giant supercontinent.

We now live on the wreckage of the supercontinent Pangaea, which formed 335 million years ago and broke up around the time of the dinosaurs. The existence of even older supercontinents, such as Rodinia and Columbia (Nuna), suggests that the Earth is locked in a “supercontinental cycle” that involves the formation and destruction of these huge landmasses on an approximate timescale of 600 million years. This cycle raises the question of what new supercontinent might emerge in millions of years, prompting scientists to propose future landmasses with names such as Novopangaea, Aurica and Amasia.

To shed light on this mystery, researchers led by Chuan Huang, a geophysicist at Curtin University in Australia, simulated the future of the Earth using a supercomputer. The results show that a new supercontinent, Amasia, will form when the Pacific Ocean fades into oblivion in about 200 million years, sending North America crashing into Asia, according to a recent study, published in the National Science Review.

The future emergence of Amasia (the merging of America and Asia) has been debated by scientists for more than a decade, but the debate continues as to whether this supercontinent will form “from the inside,” a process known as introversion, or “from the outside,” called extroversion. Introversion suggests the closure of younger post-Pangaean oceans, such as the Indian or Atlantic, while extroversion indicates the closure of the Pacific Ocean, which is the oldest ocean on Earth and is disappearing at a rate of about one inch per year.

“Earth’s known supercontinents are believed to have formed in vastly different ways, with two endmembers being introversion and extroversion,” Huang and his colleagues said. “The former involves the closure of the internal oceans formed during the break-up of the previous supercontinent, whereas the latter involves the closure of the previous external superocean.”

“With our simulation results, we suggest that the next supercontinent is likely to be assembled through the closure of the Pacific Ocean,” which would be extraversion, “or the Indo-Atlantic Ocean,” which would be introversion, the team added.

When Huang and his colleagues ran their supercomputer simulations, they noticed that the strength of the lithosphere, the rigid upper layer of the Earth that covers the crust and surface, is an overlooked variable in the emergence of the next supercontinent. The oceanic lithosphere weakens over time as the Earth slowly cools, a shift that clearly predicts the emergence of Amasia from extraversion or the closing of the Pacific Ocean.

A new study offers a look at our planet in 200-300 million years, when a huge land mass may merge into the ashes of the ancient Pacific Ocean. It is a reminder that humanity exists only for a fraction of a second in geological time, and that our planet in the distant past and distant future may turn out to be a foreign world to us.

“Earth as we know it will be drastically different when Amasia forms,” said Zheng-Xiang Li, a professor in Curtin University’s Earth Dynamics Research Group who co-authored the study, in his statements. “The sea level is expected to be lower, and the vast interior of the supercontinent will be very arid with high daily temperature range.”

“Currently, Earth consists of seven continents with widely different ecosystems and human cultures, so it would be fascinating to think what the world might look like in 200 to 300 million years’ time,” he concluded.