Will We Find Other Universes?

   

  There are several theories of the multiverse. One comes from the “many worlds” interpretation of quantum physics by Hugh Everett. In 1955, over a bottle of sherry while a student at Princeton University, Everett considered the implications of quantum physics. At the

     Elementary level (protons and electrons), each particle exists in a superposition of different locations, velocities, and orientations of its spin, but when measured by scientists there is a definitive result. Somehow our unique world emerges in a system that has a multitude of possibilities at the quantum, or nanoscopic, level. In this theory, every possible outcome in the universe exists simultaneously in other universes. For example, if you shoot a basketball and miss, there is a parallel reality in which your basketball slides rightthrough the net. This alternative universedoesn’t occupy a physical space, but isinstead a co-existing, abstract reality.

    However, for many physicists, understanding and proving this alternativereality is too far afield. Another type of multiverse is conceivable through a theory called inflation. In the first moments after the Big Bang, the universe expanded exponentially, traveling faster than the speed of light. Some theorists suggest that random quantum fluctuations in the early universe caused this inflation to stop in some regions but not in others. In places where inflation stopped, pocket universes formed, where atoms, stars, and even planets could assemble. Our universe may even be one of the myriad of pocket universes. Recently, this theory gained momentum as physicists behind the Bicep telescope in Antarctica found ripples in the space-time fabric of the cosmos called gravitational waves. The unique pattern in the sky reinforced the inflation theory. But traveling to one of these alternate universes may be impossible. Each pocket universe would exist as a bubble, with its own laws of physics. The bubbles are connected, but in between them, eternal inflation is still stretching space-time faster than the speed of light. Even if we could somehow travel faster than light, the journey would be rough. As Anthony Aguirre, a physicist at the University of California at Santa Cruz, explains, “You also have to survive the inflation in between that would want to inflate every atom in your body. It’s not very practical