Our Orbit

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dillberg
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Our Orbit

Post by dillberg » Mon May 31, 2010 6:11 pm

Does our solar system revolve around another star every 24,000 years, that also revolves around the center of our galaxie and are we in an eliptical orbit around that star?

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Chris Peterson
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Re: Our Orbit

Post by Chris Peterson » Mon May 31, 2010 6:53 pm

dillberg wrote:Does our solar system revolve around another star every 24,000 years, that also revolves around the center of our galaxie and are we in an eliptical orbit around that star?
Our system is not in orbit around any other star, only around the center of the Milky Way.
Chris

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BMAONE23
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Re: Our Orbit

Post by BMAONE23 » Tue Jun 01, 2010 5:28 pm

Along the same lines...
Since most everything in space (the universe) seems to "Orbit" something, (the moon orbits the Earth orbits the sun orbits the galaxy) What is responsible for the suns travels through the galactic plane? We do seem to spend 13,000 or so years above the galactic plane and 13,000 or so below with the crossing (alignment) coming up in 2 years. What creates this movement of the solar system if not orbital in nature?
If we continually cross and recross the galactic plane every 13,000 years or so but take 200,000,000 years to orbit the galaxy, the solar motion through the galaxy would be a sine wave Image

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Chris Peterson
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Re: Our Orbit

Post by Chris Peterson » Tue Jun 01, 2010 5:55 pm

BMAONE23 wrote:We do seem to spend 13,000 or so years above the galactic plane and 13,000 or so below with the crossing (alignment) coming up in 2 years.
This is completely inaccurate. The Solar System has a small oscillation above and below the galactic plane that is related to its inclination and perturbations. The period of this oscillation is about 90 million years- we cross the galactic plane 2.5 to 3 times each orbit. And given that there is no well defined galactic plane, that crossing period lasts hundreds of thousands of years (and last occurred a few million years ago).

I think that you must be confusing an effect of axial precession (26,000 years for the Earth) with the Solar System crossing the galactic plane. Because of precession, the intersection of the galactic plane and the ecliptic shifts. Any given crossing point (such as longitude 0°) will be hit every 13,000 years. This has no dynamical significance.
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neufer
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Re: Our Orbit

Post by neufer » Tue Jun 01, 2010 6:03 pm

BMAONE23 wrote:Along the same lines...
Since most everything in space (the universe) seems to "Orbit" something, (the moon orbits the Earth orbits the sun orbits the galaxy) What is responsible for the suns travels through the galactic plane? We do seem to spend 13,000 or so years above the galactic plane and 13,000 or so below with the crossing (alignment) coming up in 2 years. What creates this movement of the solar system if not orbital in nature?
If we continually cross and recross the galactic plane every 13,000 years or so but take 200,000,000 years to orbit the galaxy, the solar motion through the galaxy would be a sine wave Image
We continually cross and recross the galactic plane every 13,000,000 years or so.
http://en.wikipedia.org/wiki/Nemesis_%28star%29 wrote:
<<Matese and Whitman have suggested that the supposed [26,000,000 year] extinction periodicity might be caused by the solar system oscillating across the galactic plane of the Milky Way. These oscillations may lead to gravitational disturbances in the Oort cloud with the same proposed consequences as the orbit of "Nemesis". However, the period of oscillation is not well-constrained observationally, and may differ from the needed 26 million years by as much as 40%.
Art Neuendorffer

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BMAONE23
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Re: Our Orbit

Post by BMAONE23 » Tue Jun 01, 2010 11:36 pm

Guess I was mistaken.
Thanks Chris and Neuf

Arrgy

Re: Our Orbit

Post by Arrgy » Sun Nov 07, 2010 5:37 pm

That there are so many different theories as to how often we cross the plane (dark rift) shows that we don't have a clue.

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neufer
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Re: Our Orbit

Post by neufer » Sun Nov 07, 2010 9:45 pm

Arrgy wrote:
That there are so many different theories as to how often we cross the plane (dark rift) shows that we don't have a clue.
No....It is determined solely by the average density of stars in our neighborhood.

A periodicity of 56,000,000 years (i.e., an extinction every 26 to 30 million years)
corresponds to an average density of one solar mass per (56,000,000)2 4π/3 AU3

or one solar mass per (56,000,000)2 4π/(3 x 64,2403) cubic light years

or one solar mass per 49.55 cubic light years

or one solar mass every (3.673 light years)3
which is probably a good estimate for the average density.

(The uncertainty here mostly involves the local density of dark matter.)
Art Neuendorffer

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