Consequences of a negative mass universe

AI Thread Summary
In a hypothetical universe with negative mass, all mass would repel each other, leading to significant implications for the laws of physics. Negative mass would challenge established equations like F=MA and E=MC², potentially resulting in nonsensical outcomes such as negative acceleration and energy. The discussion highlights that gravity would become repulsive, complicating the formation of stable matter. Participants note that if mass is negative, traditional forces would behave unpredictably, suggesting that such a universe would lack the conditions necessary for existence as we know it. Ultimately, the concept of negative mass raises fundamental questions about the nature of physical laws and their applicability.
olso4051
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If a universe existed where all the mass was negative but everything else was the same as our universe in terms laws of physics what would happen? To be more specific it appears that all the mass would repel each other, would negative mass atoms form, would these particles absorb or emit light? What else might be interesting about this universe?
 
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What is "negative mass" ? Anti-matter, which is the only thing I can think of that you might mean, does not have negative mass.
 
Well right it would be a hypothetical situation, and you're right it would not be anti-matter. In every equation you can think of the mass would have a negative value, what would happen?
 
If unicorns existed, they would have horns.

I mean, really ... if you want to just make stuff up, then make up whatever characteristics you like. It has nothing to do with physics.
 
olso4051 said:
Well right it would be a hypothetical situation, and you're right it would not be anti-matter. In every equation you can think of the mass would have a negative value, what would happen?

It's important to realize that our equations describe the real universe. I wouldn't expect negative mass to still use the equation F=MA do relate force, mass, and acceleration. For example, if you put -M in there, does that mean you are applying a negative force now? What does it physically mean? Is the acceleration negative?

E=MC2, how could you possible have negative energy? What does that even mean?

See what I mean? It just leads to nonsense.
 
Gravity would be repulsive, kind of...

F=GmM/r2 so if both masses were negative then F would still be positive, however...

F=ma so a=F/m

F would still point downward but since m is negative a would be negative so an object would accelerate in a direction opposite the force, so upward.

I suspect the same logic would apply to the other forces which hold stuff together so stable matter would not be possible in a universe with negative mass. In such a universe there would be no one to wonder what would happen if the sign of mass were opposite.
 

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