[leggomylibro]

You don't buy all at once, though - you can "dollar cost average" into the market by buying index funds in small chunks when there are big dips, and stop buying when it stops falling.

You won't predict the bottom, and you might not get all of your money in in time, but you'll still wind up ahead when the markets recover.

And they will recover, unless we somehow get to a point where the entire monetary system collapses. The only question is whether it will take a few weeks, months, years, or decades.

Pick your starting point depending on how long you can wait. Buying early makes you less likely to miss the dip, but it might take longer to start seeing green numbers. Buying late means that you stand to gain more in the short term, but you might not get all of your money in in time.

Personally, I think we're still straddling the "early" line around now, but your guess is as good as mine. This is what they call a 'roller coaster' :)