The battered U.S. stock market opened down sharply Thursday as traders continued to face the uncertainties created by last week's terrorist attack.

Stocks plunged right from the start of trading with the Dow Jones Industrial Average losing about two percent in the first 30 minutes. Technology stocks led the steep decline, but the drop was widespread as fears that massive layoffs in the airline and aircraft industries could trigger an economy-wide recession in the United States.

Market analyst Mary Farrell says uncertainty always triggers stock market selling. "The problem is that the market triggers off corporate earnings which trigger off the health of the U.S. economy and we truly do not know," she said. "This is unprecedented in scope and magnitude we just do not know what is going to happen in the near future."

Some analysts, although a decided minority, say now is a great buying opportunity because the stocks of so many high quality U.S. corporations have fallen so far. But they caution that buyers now should have a very long-term time horizon and not expect a substantial recovery any time soon.