# Does the Sun orbit the Milky way in a (kind of) flat or inclined orbit or more of a sine wave? [duplicate]

I know it can't be a perfect ellipse or smooth orbit due to all the matter in every direction, and our Sun could be affected by a gravity assist of sorts if it passes close enough to another massive star. I also know that galaxy orbits are different than Solar System orbits because most of the mass is in the dark matter halo and as a result, the outer stars orbit faster than in a standard orbit, so there's a number of variables.

But, if we ignore gravity assists, is the sun mostly in a standard, or lightly inclined orbit around the center of the Milky way or more sinusoidal?

Reason I'm asking - see (attached and in my opinion, bad) article, and picture included.

I've seen pictures like this before that suggests that the Solar System moves in a kind of sine wave motion. I've seen estimates between 26 and 32 million years with the solar-system, rising above then below the plane of the Milky way with consistency (and perhaps, mass extinctions tied to this movement).

I can kind of see that happening, as the sun rises above it might have more gravitational pull below it drawing it back down and you kind of have a horizontal velocity to displacement cycle creating a sine wave in the orbit. That makes logical sense, but I'm wondering if that 26-32 million year sine wave type of movement is generally accepted or more somebody's imagination. Is anything definitive known about stars' orbits within galaxies?

• I'm confused by the title question. The Sun orbits in both: In an ellipse in the plane, and in a sinusoidal path above and below it. Commented Nov 15, 2015 at 1:08
• @HDE226868 that's a good point. To my thinking, A standard orbit rises above the plane and below the plane once every orbit (though above and below are obviously arbitrary). While sinusoidal path cycles above and below based on it's period. I probably should say standard inclination vs sinusoidal. My question was really on whether the Sinusoidal path is accepted or just a hypothesis. I tried to clear up the question. Commented Nov 15, 2015 at 1:12
• Answered barely 2 weeks ago. Commented Nov 16, 2015 at 7:29