This experiment is the first of its kind and has created something quite interesting. The only known matter in the world with ‘negative mass’ has been created by physicists from Washington State University!
Scientists held previous assumptions that negative mass would require some sort of exotic particles that ‘did not exist in our Universe’ but were proven wrong. This assumption was held because if something like this did exist it would defy Einstein’s Theory of General Relativity. In order to create this negative mass, scientists cooled rubidium to absolute zero. This created a Bose-Einstein condensation in which particles are only able to move very slowly and behave more like waves. This is similar to how it is described in the famous double slit experiment.
After this point, scientists used lasers to kick atoms around until they begin spinning backward. You see, when the rubidium rushes out fast enough it behaves as if it had negative mass. This lab created negative mass can now be used to test out theories in regards to dark matter. This being because scientists have suggested in the past that dark matter and dark energy in itself should be considered negative mass.
Michael Forbes a professor from Washington State who took part in this says this about its creation:
“Once you push, it accelerates backward; 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 negative mass, if you push something, it accelerates toward you.”
According to scientists Saoussen Mbarek and Manu Paranjape from the University de Montreal in Canada, there is a solution to Einstein’s Theory of General Relativity that allows negative mass to exist without breaking assumptions that are essential. They have even hinted at these different positive and negative masses would create plasma of some sort that would eventually allow for space travel.