Google has just announced that it’s achieved “quantum supremacy” by using a quantum computer it built to perform a test computation that would take even the most powerful non-quantum supercomputers thousands of years to execute. It’s an early yet significant milestone in the development of quantum computers—one which Google refers to as the field’s “hello world” moment—because it stands as a proof-of-concept of the real-world applications of this technology, which will likely one day include everything from creating unbreakable encryption to modeling quantum systems to helping AI program itself.

Google made the proclamation of quantum supremacy on its blog, as well as in a YouTube video (above), with the caveat that the company is keeping in mind Nobel Laureate Richard Feynman’s wise words, “If you think you understand quantum mechanics, you don’t understand quantum mechanics.” The company even notes in its post that “In many ways, the exercise of building a quantum computer is one long lesson in everything we don’t yet understand about the world around us.”

The idea that Google researchers—who published their breakthrough in a paper in the journal Nature—are dealing with science and technology that’s just barely on the edge of humanity’s understanding isn’t hyperbolic in the least considering the complexity of quantum computers. At their core, quantum computers distinguish themselves from non-quantum computers thanks to their use of quantum bits, or qubits, of information. Unlike binary bits of information, which are made up of either zeroes or ones, qubits are “superpositions” of both zeroes and ones. This means that qubits exist in two equally valid states simultaneously.

A quick explainer of how quantum computers work. 

It’s difficult to grasp exactly what this means because, as Google itself notes, this kind of dual-state existence runs so counter to our normal day-to-day experiences. A big part of the reason the physical rules that govern the quantum world and quantum computing are so difficult to grasp is because we don’t have any useful references, or even metaphors, for the way the subatomic world works. (How often is your sandwich both there and not there in front of you at lunch?) But on the quantum scale, particles existing in a superposition of multiple states is the norm.

While this feature of the quantum world is totally counterintuitive to our everyday lives, it does make the existence of qubits possible, which are useful because their dual nature as both zeroes and ones means they can be used to perform much more complex calculations much faster than normal computers. In other words quantum computers can have exponentially more computational power relative to normal computers thanks to the fact that they have access to far more computations far more quickly.

For instance, if you have two bits of information, they can exist in four possible states (00,11,01,10) whereas two qubits of information would allow you to put those four possible states in superposition, meaning those four states, plus any variation of all four states, all exist simultaneously. In practice, this would mean performing calculations much faster thanks to the availability of exponentially more information, which is exactly what’s happened with this landmark quantum supremacy computation.

In the case of Google’s quantum computer, a 54-qubit processor named “Sycamore” has been deployed, which can simultaneously be in 2^54 possible computational states. Or—wait for it— 18,014,398,509,481,984 simultaneous computational states. Yes, this means quadrillions of simultaneous computational states.

Looking forward, there is an enormous amount of research to be done and an equally enormous number of breakthroughs to be made before quantum processors like Google’s Sycamore become widely available. No one source found while researching this article gave a concrete estimate in terms of when quantum computing will become commonplace, but the general consensus seems to be that it will take decades.

But once quantum computers like these do come online, Google says they’ll be able to help with everything from solving complex climate change problems to helping to find cures for diseases to coming up with more efficient battery designs to “simulating the world on a molecular level.” Which means this “hello world” moment is going to mean us saying hello back to worlds that we literally can’t yet imagine, but one day, with quantum computing’s help, will be able to.

What do you think of Google’s “quantum supremacy” moment? And where do you think quantum computing is going to take us in the decades to come? Let us know in the comments!

Images: Google