Categorized In: SciTech , Astronomy
Source: How often do the planets in the solar system all line up? - Yahoo! Answers | answers.yahoo.com
Description: The last "Great Alignment" meant that all planets were in the same 90 degree quadrant (not really in line), but even that is rare enough.
2 days ago, 12:28am
Planetary alignments of one sort or another happen all the time and have for 5 billion years, and they have no effect on the Earth
If you are talking about an "exact" line, it has never happened. Even having all 9 planets in a rough line is very infrequent!