The horizon problem is a problem with the standard cosmological model of the Big Bang which was identified in the 1970s. It points out that different regions of the universe have not "contacted" each other because of the great distances between them, but nevertheless they have the same temperature and other physical properties. This should not be possible, given that the transfer of information (or energy, heat, etc.) can occur, at most, at the speed of light. The horizon problem may have been answered by inflationary theory, and is one of the reasons for that theory's formation. Another proposed, though less accepted, theory is that the speed of light has changed over time, called variable speed of light.
Read more about Horizon Problem: Basic Concept, Inflation
Famous quotes containing the words horizon and/or problem:
“The whole world of thought lay unexplored before me,—a world of which I had already caught large and tempting glimpses, and I did not like to feel the horizon shutting me in, even to so pleasant a corner as this.”
—Lucy Larcom (1824–1893)
“The family environment in which your children are growing up is different from that in which you grew up. The decisions our parents made and the strategies they used were developed in a different context from what we face today, even if the “content” of the problem is the same. It is a mistake to think that our own experience as children and adolescents will give us all we need to help our children. The rules of the game have changed.”
—Lawrence Kutner (20th century)