Until recently, it was accepted that mass can only be positive… that is to say, there can be no negative values for mass.
As they are so fond of doing, scientists have recently shown that this particular element of physics is not true.
Negative mass is essentially mass which, when it is pushed, goes in the opposite direction, completely defying Newton’s Second Law. In a way, it seems logical that mass could be both positive and negative, just like things such as charge; yet until now, we have only ever considered it positive.
This new concept was proven by a physicist Michael Forbes. He created a superfluidout of rubidium atoms, whereby particles move as one, acting like waves, and at very slow speeds. This was done by lowering the temperature of the atoms to just above absolute zero (nearly -273 degrees Celsius): at this point a Bose-Einstein condensate is achieved. Lasers were used to trap these atoms and alter their spin, and some of those released exhibited signs of negative mass.
Although physicists are unsure of how this idea can be used in the future, such as explaining wormholes, it is thought they will prove useful in providing a better understanding of astrophysical phenomena such as black holes.