Quote:
Originally Posted by Robert Tulip
1. Are many planetary systems aligned like ours, with their ecliptic plane including the galactic centre?
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I doubt it. The alignment is happenstance, since it will disappear as the sun moves along its orbit.
Quote:
Originally Posted by Robert Tulip
2. In the picture, does the leftward movement of the system spiral clockwise or anti-clockwise?
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I don't know about "spiral". The sun's movement is clockwise around the galaxy when viewed from galactic north.
Quote:
Originally Posted by Robert Tulip
3. How fast is it? (or, what is the distance and period of the path of the sun around the galaxy?)
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There are various estimates. The Local Standard Of Rest is moving at around 200 km.s
-1: that's circular velocity for our distance from the galactic centre. Relative to the LSR, the sun has its own velocity: 14 km.s
-1 faster around the galaxy, inwards towards the galactic centre at 10 km.s
-1, and towards galactic north at 7 km.s
-1. (Figures from Frank Bash; there are other estimates.) The sun will take about 240 million years to go once around the galaxy.
Quote:
Originally Posted by Robert Tulip
4. Is the upward component of the leftward motion due to the movement of the sun against the galactic plane?
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The sun is north of the galactic plane at present, and moving farther from it.
Quote:
Originally Posted by Robert Tulip
5. Have the period and amplitude of this up and down galactic motion been worked out?
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They have. The period is about 65 million years. The amplitude is about 200 light-years either side of the galactic plane.
Grant Hutchison