Earth's Biggest Volcano Discovered

On the floor of the Pacific Ocean lies a giant that has been sleeping for 145 million years.



The Pacific Ocean floor hosts Earth’s largest volcano — Tamu Massif, at 120,000 square miles.

William Sager’s 20-year hunch has paid off in a very big way.

In September, the University of Houston geophysicist and his team announcedthat Tamu Massif, an underwater volcano about a third of the way from Japan to Hawaii, is by far the largest volcano on the planet.

For two decades, using sonar and other undersea mapping methods, Sager has been studying an oceanic plateau in the northwestern Pacific called Shatsky Rise. Over several expeditions, he began to suspect that the subtly dome-shaped formation at Shatsky’s south end, which he named Tamu Massif, might be an enormous volcano.

To confirm his theory, Sager’s team drilled core samples and bounced seismic waves through Tamu’s layers to determine its composition. They discovered Tamu’s 120,000 square miles were made of massive lava sheets, up to 75 feet thick, that had erupted from a single summit about 145 million years ago.

In square miles, Tamu Massif is larger than Arizona. Its single summit dwarfs multi-volcano complexes, also known as composite volcanoes, on Hawaii and Iceland. With 75 percent of the volume of Mars’ gigantic Olympus Mons, Tamu ranks as the second-largest known volcano in the solar system.

Sager believes it’s possible that we may one day find even greater volcanic giants beneath the waves. For now, however, he is savoring a sweet moment 20 years in the making. 

“As scientists, we spend our lives doing research,” says Sager. “We get maybe one moment when we can make people look up from their smartphones and be reminded of the wonder in the world.”

Amplituhedron May Shape the Future of Physics

This multidimensional shape can simplify certain quantum equations — and possibly also revolutionize physics.

Physicists have long struggled to understand exactly what happens after subatomic particles collide. For decades, the best tool involved basic sketches (called Feynman diagrams) of each possible result. For all but the simplest scenarios, this method fills pages with drawings and equations. 

A new computational insight in 2004 dramatically reduced the amount of paper required to describe a collision, and these new formulas combined multitudes of Feynman diagrams into a single mess of math. Last year, Princeton physicist Nima Arkani-Hamed was analyzing the formulas in search of a better way to simplify these quantum calculations. Using only pen and paper, he discovered a new kind of geometric shape called an amplituhedron — one that hints at a new way of seeing the universe.

Arkani-Hamed noticed the formula could be rearranged and still yield the same answer. Like paleontologists brushing away dirt to reveal a fossil, he and his colleagues found the pieces of a shape within the math — pieces that together form a multidimensional amplituhedron. The shape’s dimensions — length, width, height and other parameters (hence “multidimensional”) — represent information about the colliding particles, and the equation describing its volume also describes the particles that emerge from the collision. 

This result, the volume, is a single term that fits on a space the size of a napkin.

Unlike the older methods for exploring particle collisions, the amplituhedron is not rooted in a world where a particle starts in one place and time before moving to the next location and moment. That is, the shape does not exist in space-time — it does not rely on a conception of the universe that theoretical physicists suspect might be incorrect. (When they try to knit together large-scale and small-scale forces, such as gravity and those that hold atoms together, the assumption of space-time leads to mathematical inconsistencies, a clue that something’s amiss with current assumptions about the universe.) 

“We’ve known for decades that space-time is doomed,” says Arkani-Hamed. “We know it is not there in the next version of physics.” Though the collisions described by the amplituhedron still occur in space-time, the object itself is outside it, providing a possible way to imagine a world not woven of this fabric.

The new shape is intriguing, says physicist Lance Dixon, a pioneer in the field of particle collisions, but he cautions that so far it can only describe particle collisions within a simplified version of quantum theory — the results don’t yet translate to the real world. Arkani-Hamed acknowledges it is a “baby example”; he calls it “step zero” in the journey to create a new kind of physics — a project on par with the discovery of the probabilistic particle collisions themselves. 

For now, the amplituhedron offers a hint of what this strange new world could look like.