Three scientists are getting a $3-million US prize for coming up with supergravity, a theory that suggests how to bring together the gravity that governs huge things like galaxies and the quantum physics that describes very tiny things like atoms.

The Special Breakthrough Prize in Fundamental Physics, announced Tuesday by the selection committee, goes to:

Sergio Ferrara of CERN (the European Organization for Nuclear Research).

Daniel Z. Freedman of the Massachusetts Institute of Technology and Stanford University.

Peter van Nieuwenhuizen of Stony Brook University.

The committee described their work, which was published in a 1976 paper, as "a highly influential" theory "that successfully integrated the force of gravity into a particular kind of quantum field theory."

It's a very elegant theory. It's mathematically beautiful. - Rob Myers, Perimeter Institute

"This award comes as a complete surprise," said Ferrara in a statement released by CERN on Monday. "Supergravity is an amazing thing because it extends general relativity to a higher symmetry — the dream of Einstein — but none of us expected this."

The theory is an extension of two other theoretical physics breakthroughs in the 1960s and early '70s:

The Standard Model of particle physics, which describes three of the four fundamental forces (the electromagnetic, weak and strong force) and classifies all known elementary particles, but doesn't include the fourth fundamental force — gravity.

Supersymmetry, which fills in some gaps in the Standard Model by creating an explanation for the relationship between particles of matter, such as electrons and quarks, and force-carrying particles such as photons of light. But it still didn't include gravity.

Ferrara, Freedman and van Nieuwenhuizen used computer calculations to help generate a theory based on supersymmetry that includes gravity through two kinds of particles: the "gravitino," which has mass, and the force-carrying "graviton" — bringing together all four fundamental forces of physics.

"It's a very elegant theory. It's mathematically beautiful," said Rob Myers, director of the Perimeter Institute for Theoretical Physics. He recalls that one of the first things he read as a graduate student at Princeton University was, in fact, a paper on supersymmetry by van Nieuwenhuizen, and the theory has since infiltrated many areas of theoretical physics.

Myers said a "central challenge" in theoretical physics is the question of how to bring together the physics of the very small (quantum mechanics) with the physics of the very big (gravity and space-time as described by Einstein's theory of general relativity).

Inspiration for future physics

"What supergravity is saying is that all of those different ideas and forces should be intertwined or could be intertwined in a consistent way," he added.

While supergravity alone doesn't explain the physics we see in the real world, Myers said, "it inspired physics to move forward from there… It's not a full answer, but it's an important building block in our quest to understand the physical universe."

That's what the Breakthrough Prize is recognizing, he added: "The importance toward solving these big problems" rather than the more direct applications for which the Nobel Prize in Physics is awarded.

This is the fifth Special Prize in Fundamental Physics awarded since the Breakthrough Prizes were founded in 2012 by Yuri Milner, a former theoretical particle physicist and founder of the technology investment firm DST Global.

In addition to the special prizes, which can be awarded at any time for discoveries made at any time, there are regular $3-million Breakthrough Prizes awarded annually for recent discoveries in fundamental physics, life science and mathematics.

The prizes are judged by former winners and funded by Milner and his wife Julia, along with a number of other tech tycoons, including: