Rotating Question Curious About Astronomy? Ask an Astronomer

When was the last time all 9 planets were aligned?

When was the last time all the planets were aligned and approximately when will they be aligned again?

When astrologers speak of the planets being aligned (something which doesn't really concern astronomers) they don't mean that the planets will actually all lie on a straight line at some instant of time. 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. All nine planets are somewhat aligned every 500 years, and are grouped within 30 degrees every 1 to 3 alignments.

If you'd like to read more, here's my source: National Solar Observatory Sacramento Peak page on planetary alignments.

March 1999, Dave Kornreich (more by Dave Kornreich) (Like this Answer)

Still Curious?

Get More 'Curious?' with Our New PODCAST:

More questions about Planets: Previous | Next

How to ask a question:

If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.

Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist

URL: http://curious.astro.cornell.edu/question.php?number=203
This page has been accessed 157556 times since September 12, 2002.
Last modified: September 22, 2002 2:23:17 PM

Legal questions? See our copyright, disclaimer and privacy policy.
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.

Warning: Your browser is misbehaving! This page might look ugly. (Details)