Since 9/11 and the 2008 economic crash, I have become quite the skeptic and I now question everything.
Then stop worrying about earth's shape and prepare for the crash of 2015. Its going to be much worse.
Monetary policy since 2008 has been a disaster. The market was flooded with liquidity from central banks across the world and interest rates were lowered to 0%. This has caused huge asset bubbles and mal investment. The S&P 500, FTSE100, Dax and pretty much every stock exchange are at record levels and the underlying economy is not there to support those prices. The P/E ratios are ridiculous. Real estate valuations are similar. This is because 0% interest causes investors/banks to make poor decisions. If you can borrow at 0%, when you work out your profit/investment you are dividing by 0!
You can't invest in bonds, guilts and government treasuries. You get next to no return. If you had bought bonds in the last 5 years you would have lost wealth based on inflation. You can't buy commodities because they are inversely proportional to stock values which go up unless a crash occurs. So all the funny money has driven bubbles in stocks and real estate.
But now there are harbingers. The UK just had the first ever month of deflation in 60 years. US unemployment is rising again. The central banks need to act to stop another crash. But they have painted themselves into a corner. If they print more money, they can't monetise it because no one wants government bonds at 0%. And they can't raise interest rates because that will trigger a real estate collapse as people can not afford interest payments on mortgages they got out at 10:1 of annul wage. So they default, that lowers the housing price and starts the panic. Investors will want out of property and fire sale assets to protect wealth pushing more people into negative equity on high mortgages. That bubble will pop. Central bank failure to do anything, will cause a huge issue to the stock market that is overheating. Something like a Greek default could be a trigger. The crash will be from record levels to the lowest of the low.
The end of the financial world is upon us. This could be the death of the dollar as its value crumbles overnight and international holders look to get rid of it. A system based on exponential debt, will collapse when there is no one left willing to monetise more of it.
In short, buy commodities, sell stocks, rent don't own a house til after the crash and stock up on shotgun bullets and tinned food.