The Universe, the solar system, the earth and its seasons, the moon and the tides, night and day… cycles are a natural phenomenon. The economy behaves in a similar way. Because of how our collective psychology work, we experience cycles in the economy. Markets go up and down, and right now we are experiencing what some people think is “The Perfect Storm” of downsides in cycles, meaning that many factors, many of them cyclic, line up at the same time to bring the economy to a standstill. For an introduction to economic cycles, read this article from Investopedia:

http://www.investopedia.com/articles/technical/04/050504.asp

Then check out the article on Stock Market Bottoms on Wikipedia:

http://en.wikipedia.org/wiki/Stock_market_bottom