Question

Does negative mass or negative energy exists? as in -E=-mc2

Answer 1

Negative energy is acceptable. Potential energy is negative for attracting bodies. Negative kinetic energy is not acceptable classical physics implying imaginary velocity or negative mass. Mass in classical physics is never negative. By that I mean classical physics a negative mass has no meaning by itself but negative mass does come up when for example studying a possible nuclear reaction for example a deuteron bombarded by a photon going to a neutron and a proton. you find in applying conservation of mass that the mass of the initial state is less than the final state implying there is missing mass (negative mass must be added to the initial state to balance the equation). This negative mass means that that the photon must supply energy equal to this negative mass equivalent for the reaction to occur.

In the latest gravitational and cosmological physics negative mass and energy are considered acceptable but way too advance for me to explain.

Answer 2

In the 4 current forces of the universe, only 1 type is known to have both attractive and repulsive forms. So there is not much inspiration from there that mass should have a negative identity as well.
What would it infact mean when we say 'negative' of a physical property ?
it means different for different things, its our own conventions.
for example, we attibute electric charge to be positive or negative depending on the observed physical property of attractive or repulsive action it contributes to on another charge.
what would be the meaning of positive/negative for the physical property i.e. mass
Are we saying that our 'normal' mass bends space time in one way and thus generating gravity. Then would a negative mass mean it would bend space-time the other way round and generate an 'opposite' gravity ? would that be a repulsive gravitational field.
I don't know.
Lets first define what would negative actually mean for the property mass.

Answer 3

meh

Answer 4

Actually negative mass is absurd apart as told by so great guys up above...
mass is anything that arises from certain position in space comprising of bulk.
Curvature of space is nothing but viewing our world from above the dimensions
for instance currently we are imagining our world using 3 measurable dimensions
i.e. X Y Z . for more info dimensional theory of universe

Answer 5

'meh'-ing anyone won't really get you anywhere anytime mate. Atleast not here in this western spiral arm of the galaxy.
its very good that you ask questions. but..
when you ask something....have the guts to accept feedback on what you're asking.
In the end, questions are a quest for truth, not glory.