A false vacuum is a theoretical region of space that can exist as a type of bubble. Held together by surface tension, the walls of the false vacuum can expand by borrowing energy from the universe, a process called tunneling. If the walls were to break, or an object crossed over from one area to another, then the laws of physics could change. The energy of the bubble can also decay to a lower state, which may result in a change in the laws of physics for objects inside it. If the principles of physics and chemistry are different enough afterwards, according to the theory, then everything could be destroyed or cease to exist.
The process of tunneling can allow false vacuum bubbles to grow very large over time. If these collapse, the effects might not be noticeable, but it could also alter the charge of electrons, as well as change the kinds of particles that can exist. Theorists think that the Earth may be in a false vacuum, and some theories suggest that this may be an atypical form of one that has allowed the planets and stars to develop as they have.
A variation in the concept, which incorporates quantum mechanics, suggests that one world could survive while another doesn’t; this is called the "many worlds interpretation." Many scientists do not believe in the false vacuum theory and seek to disprove this concept as well. Another theory claims that the universe has already decayed into what is called a lower-energy vacuum state. A different one can form in the future, which could cause the universe to collapse based on some interpretations.
Many physicists believe that if a false vacuum were to form, the wall could move at the speed of light. Gravitational attraction could take the place of the current state of cosmic inflation, in which stars and galaxies typically move away from one another. The process may be too slow to observe over a reasonable amount of time, however. Some people believe that a particle accelerator can generate energy at a high enough density to decay a false vacuum, but researchers say because the energy of observed cosmic rays is much higher, such an event is unlikely.
Cosmologists often disagree as to whether observations are only possible in a false vacuum, or if they cannot occur in more general areas. The universe could be more typical, according to other beliefs. Science fiction has explored the concept of a vacuum bubble, and one book has portrayed a spaceship that can travel as fast as the edge of one and study it.