When will the planets align?

I was watching Lara Croft Tomb Raider, and I have heard of something to the effect that at some point in our lifetime (other yahoo answer people are saying 12/21/12) that the planets will align. When I asked this question a few days ago, everyone said the palnets will never be in exact alignment. So my question... show more I was watching Lara Croft Tomb Raider, and I have heard of something to the effect that at some point in our lifetime (other yahoo answer people are saying 12/21/12) that the planets will align. When I asked this question a few days ago, everyone said the palnets will never be in exact alignment. So my question is if the Tomb Raider movie is at all accurate, what do astronomers mean when they say that there will be a planetary alignment in December of 2012? Does this mean that all 9 (or 8) planets will be in perfect alignment if only for a few seconds causing a total eclipse, or does it simply mean that only the inner or outer planets will align with the Earth's orbit? I'm just curious. Thanks.
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