What happens when all the planets align?

One calculation of alignments within around thirty degrees (about as close as they can get) shows that the last such alignment was in 561 BC, and the next will be in 2854. The eight planets plus Pluto are somewhat aligned every 500 years, and are grouped within 30 degrees every one to three alignments. read more

Another, more accurate, answer Think of a very simple alignment of two planets, Earth and Venus. This only occurs a little more than once a century. To add a third planet to this alignment would take many millennia. To have all eight planets aligned would require an infinite amount of time. Even so, the word for it is syzygy. read more

A true alignment can never happen in our solar system because all of the planets orbit at varying angles. This means that while they may line up on one axis, they will be off on another. For this reason, the whole debate of aligning planets as a factor in an apocalypse is an entirely superfluous concept. read more