D. The Monopole Problem
At early times in the expansion (z > 1000), the physics of the universe is described by particle theory. Many of these theories predict the creation of topological defects. These defects arise when phase transitions occur in particle models. Since the temperature of the universe cools as the expansion proceeds, these phase transitions are natural consequences of symmetry breakings that occur in particle models. Several types of defects are described briefly below [22, Chapter 10].
Out of all these defects, monopoles are the most prevalent in particle theories. It becomes a problem in the hot Big Bang model, when one calculates the number of monopoles produced in events, such as the electroweak symmetry breaking. One finds they would be the dominate matter in the universe. This is contrary to the fact that no monopole has ever been observed, directly or indirectly, by humans. These monopoles would effect the curvature of the universe and in turn the Hubble parameter, galaxy formation, etc. Therefore, unwanted relics, such as monopoles, remain an anomalous component of the hot Big Bang theory.
17 Also note that these are not visible objects,
they are distortions in the space-time fabric. Back.
17 Also note that these are not visible objects, they are distortions in the space-time fabric. Back.