Solar system motion

QuestionEdit

How fast (miles per day, hour, min or sec) is the solar system moving in it's up and down 26k year cycle relative to the motion we also experience in the spiral arm of our galaxies rotation? And how far do we move up and down during this cycle? Thank you.

AnswerEdit

Hi Kevin, Some of these numbers are only approximate as it seems each reference has their "pet" set of numbers, because no one knows exactly.

But in general, we the Solar System are moving around the Milky Way galaxy at about 220 km/sec (~130 mps) relative to the center of the Milky way. It takes from 225-250 million years to make one trip around the galaxy, so we, in 4.6 billion years of existence, have made between 18-22 laps around the galaxy. (And just as obvious, it's not 'deadly' as we lifeforms are still here.) And of course, the Milky Way is moving relative to the Local Group and the Local Group is orbiting around the Virgo Supercluster in Virgo...I believe we are heading toward the Leo/Hydra border at a velocity of some 600 km/sec (360 mps) relative to the center of the Virgo Supercluster. This value comes out pretty close to our velocity relative to the CBR too (Cosmic Background Radiation), again, see http://en.wikipedia.org/wiki/Milky_Way In effect, we are 'cutting new space' every second of every year, never to return to a pre-set starting point, because everything moves relative to everything else. There is no such thing as absolute rest.

We describe a very shallow sine wave, never leaving the north or south side of the galaxy, which is estimated to be about 5000 lightyears thick, hitting the mid-center passages about 2.7 times during one trip. (I read that somewhere).... See http://en.wikipedia.org/wiki/Milky_Way

{So I don't know where you get the 26k year cycle... Our up-down motion around the galaxy is measured in many tens of millions of years}. Perhaps you are confusing our precession of the Earth's axial tilt, which is close to 26k years, 25,800 years to be exact, so Polaris will once again be our North Star in 2105 AD + 25,800 = 27,905 AD. (2105 AD is our closest approach of our Earth's axis to Polaris, at 1/2 degree; we're currently in 2009, about 3/4 of a degree from Polaris). But all this has nothing to do with our motion around the Galaxy.

Oh, I've once read somewhere where we only vary our up-down motion by a few hundred lightyears, so we never exit the galaxy or even come close. We may not even know the exact values of our slight sine-wave up-down motion.

If you are trying to develop some catastrophic cataclysm here, good luck. My feeling is....we are still here, so all this business of up-down around the galaxy, geo-magnetic polar shifts which occur every several thousand years, and other metaphysical "stuff"...just doesn't hold water because we've been through it all before, many times in fact, and we (and many of the other lifeforms)...are still here. So how come we're not all dead already?? That's my take on it. Clear Skies, Tom Whiting Erie, PA USA