In the movie there is an alignment that only happens every 1,000 years between their 3 suns and they call it the great conjunction. Ever since I saw the movie I have wondered, on what day will all of our planets align? The rest of the planets have a slightly tilted orbit in comparison to ours. However, inevitably they will all lie on 1 plane at some point; when will that occur, including the planets not visible to the naked eye? I’d like to find out without coding an orrery program, but will do it if necessary.
Do you want them to be on the same plane or on the same plane + lined up with one another? The second is significantly more difficult.
I think what the OP means by the same plane is a plane perpendicular to the ecliptic. In other words, lined up as well as they can given the different inclinations of their orbits.
There was a silly scare back in the 70s/80s about how the planets would all lineup and cause something bad to happen. Earthquakes or something. Total silliness, but someone wrote a book called the Jupiter Effect promulgating it.
The thing is, in the Jupiter Effect scenario, the planets are not lined up. They were more-or-less in the same quadrant. Or a bit less lined up than the players in a baseball game. This kind of line up happens every so often (several times per century) and is not especially remarkable. Line ups with them in a narrower angle, say less than 45 degrees, are much rarer, perhaps happening every 10,000 years or so.
“When the Moon is in the Seventh House…”
If you define the plane infinitely, it will never happen, so you will have to define an angle that’s allowed.
I remember that Jupiter effect thing. It was pretty silly.
Well, the Harmonic Convergence has come and gone, and the universe appears still to be here (without the predicted love and unity).
I seem to recall an entry in Dave Barry’s annual recap in which he described the True Believers celebrating the event by chewing on the ends of their straitjacket straps.