Physicists at Washington State University (WSU) created a fluid with negative mass — and, yes, it’s as crazy as it sounds.
A negative mass fluid is unlike any other physical object in the world. Normally, pushing something moves it away from you, but if you push something with negative mass, it moves in the opposite direction.
“That’s what most things that we’re used to doing,” Dr. Michael Forbes, a WSU professor of physics and astronomy, said in a press statement. “With negative mass, if you push something, it accelerates toward you.”
Forbes and his colleagues created negative mass by cooling rubidium atoms in a small bowl to almost absolute zero, creating what is known as a Bose-Einstein condensate. In this state, particles move extremely slowly and behave like waves. They also synchronize and move in unison, allowing them to flow without losing energy.
Researchers used a second set of lasers to change the way the rubidium atoms spun, then broke the bowl, giving the atoms a push.
“Once you push, it accelerates backward,” Forbes said. “It looks like the rubidium hits an invisible wall.”
Negative mass phenomena can only rarely be created in laboratory conditions but is useful in studying several strange concepts in astronomy.
The study suggests such methods can be used to examine analogous astrophysics, like neutron stars, and cosmological phenomena like black holes and dark energy. Experiments to study on such distant phenomena would be impossible without the negative mass.