In the usual world when exposed to the object any power he begins to move in the direction of application of this force. This phenomenon is described by Newton's second law.
Theoretically, matter can have negative mass — in the same sense that electric charge can be positive or negative. Physicists call this phenomenon the "exotic matter".
Professor Peter Engels from the University of Washington and his colleagues managed to cool atoms of rubidium to a temperature of almost absolute zero (-273 degrees Celsius), creating a so-called condensate Bose-Einstein.
In this chilled condition, a sufficiently large number of atoms turns out to be in their lowest possible quantum States, and quantum effects begin to manifest at a macroscopic level. The atoms move extremely slowly and they behave like waves. They also move synchronously, forming the so-called superticket that flows without losing energy.
Rubidium atoms cooled by laser and kept the sample as long as high energy particles have not moved beyond the laser trap. At this point, the atoms still behave like normal particles with positive mass: if the force that kept the atoms together, came to an end, atoms would be dissipated in different directions under pressure from the Central atoms.
To make the rubidium atoms behave like a substance with negative mass, the researchers sent them on another set of lasers, with which you can change the spin of some atoms.
Comparing the calculated data with the experimental, physicists have come to the conclusion that at least some of the atoms in a laser trap began to accelerate in the opposite direction of application of force of the atoms, which occupied a Central position in the trap, however, this occurred only for a very short time, after which the atoms quickly return to the behavior characteristic of particles with positive mass.
"If you push a substance with negative mass, it is accelerated in the opposite direction, — explains one of the researchers Professor Michael Forbes. It is reminiscent of the collision of rubidium atoms with an invisible wall".
The results of this experiment may clarify the nature of some of the observed astronomical objects and phenomena, e.g., neutron stars, black holes and dark matter.