Quote:
Originally Posted by Robert Tulip
Why is that? If you think of the solar system as like a snowplough pushing its way around the Milky Way, the blade has pitch of sixty degrees but zero yaw. Would continuing this setting mean the ecliptic will stay aligned to the galactic centre?
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But to continue that setting you'd need a force to precess the plane of the ecliptic at exactly the (variable) angular rate of the sun's orbit around the galaxy.
Quote:
Originally Posted by Robert Tulip
What I was asking is, if you take your picture, which is a static shot of the solar system against the galaxy at one moment in time, and extend it through time by depicting the planets as spirals around the cylindroid formed by the movement around the galaxy, then do the planets also go clockwise viewed from solar north?
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The planets go anticlockwise. And they describe a helix, not a spiral.
Quote:
Originally Posted by Robert Tulip
Thanks Grant, am I right to understand the unit of the 65 MY period is two halves of a sine wave, so the period is the time taken to return to the same position of a wave function? Does this mean the sun spends an equal amount of time north and south of the galactic plane? For example, over the 65 million years since the dinosaurs, has the sun been equally north and south of the galactic plane?
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The 65-million-year period is the cycle time of the sine wave, yes. So the sun spends equal time north and south in any period of that duration.
Grant Hutchison