Explanation:

In theoretical physics, negative mass is a type of exotic matter whose mass is of opposite sign to the mass of normal matter, e.g. −1 kg. Such matter would violate one or more energy conditions and show some strange properties such as the oppositely oriented acceleration for negative mass.

Answer:

1)There are several proposed types of exotic matter: Hypothetical particles and states of matter that have "exotic" physical properties that would violate known laws of physics, such as a particle having a negative mass. ... Forms of matter that are poorly understood, such as dark matter and mirror matter.

2)By launching a tiny, atom-packed chip into space and blasting it with lasers, German scientists have for the first time created an exotic state of matter known as a Bose-Einstein condensate in space. Their findings could lay the groundwork for a new way to search for gravitational waves, or ripples in space-time.

3)Physicists have created a fluid with "negative mass", which accelerates towards you when pushed. In the everyday world, when an object is pushed, it accelerates in the same direction as the force applied to it; this relationship is described by Isaac Newton's Second Law of Motion.