Physicists from Washington State University have now broken the mold, creating the only matter in the world with negative mass — mass that accelerates backward under pressure.
The phenomenon can be used to explore some of the more challenging concepts of the cosmos, according to Michael Forbes, a WSU assistant professor of physics and astronomy and an affiliate assistant professor at the University of Washington.
Scientists were hesitant to accept the reality of negative mass, as it would defy Einstein’s Theory of General Relativity. However, scientists such as Saoussen Mbarek and Manu Paranjape from the Université de Montréal in Canada claim they’ve found a solution to this theory that permits negative mass to exist without putting into question any essential assumptions. According to the scientists, these different positive and negative masses would form a plasma that could allow for space travel.
Newton’s Second Law of Motion is: force is equal to the mass of an object times its acceleration (F=ma)). “With negative mass, if you push something, it accelerates toward you,” says Forbes.
For their work, the physicists created negative mass — or mass that acts like it were a negative mass — by cooling rubidium atoms close to absolute zero, which created a Bose-Einstein condensate. Here, particles move extremely slowly, acting like waves. The team then used lasers to aggravate the atoms into spinning backwards. Upon the rubidium rushing out fast enough, it behaved as if it had negative mass. The atoms also synchronized and moved in unison like a superfluid — where no loss of energy occurs from the atoms flowing.
“Once you push, it accelerates backwards,” says Forbes. “It looks like the rubidium hits an invisible wall. What’s a first here is the exquisite control we have over the nature of this negative mass, without any other complications.”
This physicist-created negative mass can serve to test theories regarding everything from dark matter and black holes to astrophysics, and time travel.
“It provides another environment to study a fundamental phenomenon that is very peculiar,” says Forbes.
It’s certainly intriguing to think that, while we have assumed every single other physical object in the world does not accelerate backward under pressure, there is a mass that does. The phenomenon itself is known as the intuitive side of Neuton’s Second Law of Motion.