Researchers at OpenAI said it took just days-and millions of dollars in computing power-to crack what is known as the Navier-Stokes problem. Navier-Stokes is one of the seven Millennium Prize Problems, a list of the hardest open questions in mathematics drawn up by the Clay Mathematics Institute. It concerns the equations describing how fluids such as air and water move, which are used in aircraft design, weather forecasting and the study of blood flow.

The company says it has cracked the physics of fluids using AI, solving one of the toughest puzzles in mathematics.

Mathematicians at OpenAI showed that the Navier-Stokes equations, which describe how fluids flow, can sometimes “blow up.” But the massive result is not without controversy.

Prior to the announcement, rumors were circulating online among mathematicians over the proof’s origins—OpenAI has denied all allegations