What is a matter baby?

A matter baby is a theoretical concept in physics that is used to illustrate the principles of matter and energy in the universe. Essentially, a matter baby is the hypothetical result of combining matter and antimatter in equal amounts, which would theoretically produce a baby-like entity made entirely of energy.

The concept of a matter baby is typically used to explain the nature of particle-antiparticle interactions and the relationship between matter and energy in the universe. It helps to demonstrate the idea that matter and energy are interchangeable forms of the same underlying substance, according to Einstein's famous equation, E=mc^2.

While matter babies are purely theoretical constructs and have never been observed in reality, they serve as a useful thought experiment in the study of theoretical physics and the fundamental forces of the universe.