Multiverse Possibilities

The observable universe may be just one patch of a far larger cosmos. Cosmic inflation theory suggests that the rapid expansion in the first fraction of a second may have created regions far beyond our observable horizon with potentially different physical properties.

Some versions of inflation predict an eternal multiverse — an infinite collection of universe "bubbles," each with its own physics. This idea is controversial because it may be fundamentally untestable. If other bubbles exist beyond our cosmic horizon, no signal from them can ever reach us.