Nuclear Pasta: Strongest Material in Universe Discovered in Neutron Star Crust

The strongest material in the universe has been discovered: nuclear pasta from neutron stars. The material is so intense it could never exist on Earth—if somehow a tiny amount were transported here, it would explode like a nuclear bomb. Instead it can be found deep inside the crust of the smallest, densest known stars, scientists have discovered via computer simulations.

Matthew Caplan, a postdoctoral research fellow at McGill University, and colleagues have had their findings on nuclear pasta accepted for publication in the journal Physical Review Letters.

Neutron stars form when the core of a massive star collapses under the weight of its own gravity. What emerges is a star that has around double the mass of the Sun crammed into a 20km-wide sphere. According to NASA, a sugar cube-sized piece of a neutron star would weigh about the same as Mount Everest.

Because of the immense gravity, the outer layers of neutron stars freeze solid to form a crust that surrounds a liquid core. Below the crust, protons and neutrons compete and end up forming long cylindrical shapes or flat planes. These have become known as "spaghetti" and "lasagne"—or nuclear pasta.

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File photo: A neutron star is depicted. Getty Images

Scientists know nuclear pasta exists from observations of neutron stars—the pressure from the gravity is too high for anything other than a solid crust to form.

Caplan ran computer simulations where he stretched and squeezed nuclear pasta to see how it breaks. “These simulations allowed me to calculate the strength of nuclear pasta,” he told Newsweek. “The materials in neutron star crusts can't exist on earth, they only form when matter is under the kind of immense pressure that you can find on a neutron star, which is why we use computer simulations to study them.

“But if somehow a teaspoon of nuclear pasta magically teleported into the palm of your hand you'd die instantly because without the pressure of the star to hold it together it would explode like a nuclear bomb. Put simply, despite its strength, no one is going to build anything out of this stuff.”

According to, the nuclear pasta would be around 10 billion times stronger than steel.

File photo. Caplan said nuclear pasta comes in all shapes and sizes. iStock

Understanding the strength of nuclear pasta will help astronomers studying neutron stars to better understand their physical properties—allowing them to test out theories and models. It also opens up the possibility of observing gravitational waves.

At present, gravitational waves have only been observed coming from cataclysmic events—two black holes merging, for example. But isolated neutron stars with a “mountain” on it could also produce gravitational waves, Caplan said. “Knowing the strength of the neutron star crust is like knowing the strength of rocks on earth; it tells you about how big earthquakes can be and how tall mountains can get,” Caplan said. “On a neutron star, those 'starquakes' or breaking events can release light while 'neutron star mountains' can make gravitational waves, which are both things astronomers would like to observe.”

The researchers plan to continue to study neutron stars and their super-strong crusts. “This work only studied lasagna, but pasta comes in a lot of shapes. Maybe I'll try spaghetti next,” Caplan said.