Why does the sun go up and down?

The sun not only orbits the center of the galaxy, but oscillates up and down, like the horse on a calliope?


The suns orbit around the galaxy is inclined relative to the orientation of the galactic plane. This means that the sun spends half of each orbit above the plane and the other half below the plane of the galaxy. AFAIK there’s no evidence for changes at a higher frequency than half a galactic year. The milky way was probably not so tightly organized 8 billion years ago as it is today, so many of the older stars have orbits that are at angles to the current galactic plane.

A horse on a carousel? A calliope is a “a keyboard musical instrument resembling an organ and consisting of a series of whistles sounded by steam or compressed air”.

And of course you weren’t talking about “a horse on Calliope”, the Greek muse of heroic poetry…no, no, the prospect is too hideous to contemplate, at least, not outside of a MPSIMS sex thread…


The sun’s plane of orbit around the center of the galaxy does not line up exactly with the galactic plane.

Too slow, doh!

Damn, I missed the calliope thing, :o and I was just listening to some old Manfred Mann too.

Why not? It would be highly unusual if it didn’t. It would be a fluke. Almost impossible.

The Sun Goes Up because heat rises.

The Sun Goes Down because whatever goes up must come down.
Sheesh! Do we have to explain everything?

Looks to me the sun just stays in one place but the earth rotates.

I’d try and straighten handy out, but he’ll never return, so what’s the use.

yeah why bother?

Is this the phenomenon that you are talking about? Analemma

Or are you talking about the sun’s position relative to the rest of the Milky Way?

Nope. Thanks, but not the analemma.

But the previously mentioned point about the sun’s orbit being slightly inclined to the the galactic ecliptic doesn’t answer the motion that was implied in the “Hyperspace” program, hosted by Sam Neill.

“The sun orbits the center of the galaxy about once every 200M years. It passes thru the more densely-populated disk about every 30M years.”

That was info mentioned in the program, so there’s still something I’m missing. A simple inclination would cause this to happen only once every 100M instead of 30M years.

The orbital period of the sun around the galaxy was recently determined to be ~ 226 million years. It’s doubtful that anyone has yet obtained evidence for anything as complicated as a periodic 30 million year variation in that simple orbit. You’ve got to wonder what sort of evidence there could even be for such odd behavior.
It seems more likely that the 30 million year figure touted by Sam Neill comes from the theory that periodic mass extinction events are caused by an companion star to the sun with an orbit of ~30 million years: Nemesis.

If you replace the hypothetical Nemesis, with an equally hypothetical passage through the plane of the galaxy, you end up with an equally satisfactory astronomical theory for periodic mass extinctions. All that’s needed then is a little data to distinguish between the possibilities ;).

For that matter, I would really like to know what the sun was doing at Fatima, Portugal, on October 13, 1917, before 70,000 eyewitnesses. Talk about “going up and down!”