The macro world as we know it is governed by Newton's laws of motion and gravity - what goes up, must come down.
But a team of physicists from Columbia University have put forward a theoretical paper that turns this idea on its head. They say there might actually be particles with negative mass - which under gravity, move up, instead of down - and they're all around us.
According to their paper, it's not any weird subatomic particle that has these properties, but the particles of sound we hear and produce every day - phonons - that are rebelling against the force of gravity.
So far, so strange, right? After all, sound isn't even a physical object, so how can the force of gravity have any impact on it?
This paradox is at the heart of the new hypothesis - what if, the researchers say, sound waves actually did carry mass. Negative mass. And that negative mass created its own tiny negative gravitational fields that push them up instead of down.
That's not to say they've found any physical evidence sound waves carry negative mass as yet, they've simply shown that if it was the case, it wouldn't break anything else in physics. this idea isn't actually that insane.
Read more: https://www.sciencealert.com/physicists-...-around-us