"What (former Federal Reserve Chairman Alan) Greenspan called exuberance is just the fact that these sunspots were going up," he said. "If you really study it, (sunspot activity) is very regular."

Investors can check the NASA Web site for predictions regarding sunspot activity, Nenner added.

Markets are likely to "muddle" through until 2013 "then we will go in a major crisis based on the sunspot activity," he predicted.

Meanwhile, the euro is likely to keep depreciating against the dollar because the US economy is stronger than the euro zone's, Nenner said, adding that the European single currency was not a good idea.

"Everybody knows, but they're not telling you, that this whole European idea is going under," he said.

"What I think about politicians - and it's not going to sound nice - I think they made a major mistake creating these European markets and as long as they're in charge they're going to keep it going," Nenner added.

However, other analysts predicted that the euro will stay in place just because it would be too costly for the euro zone countries to break the monetary union.