[meteorite-list] Quickie
From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Sun, 20 May 2012 14:53:01 -0500 Message-ID: <1A94743C10F24CCAA3E57C397D1BC8B8_at_ATARIENGINE2> Jim, List, Whoops! The Sun revolves around the center of our galaxy at about 220 km/sec which suggests a period of about 240,000,000 years. That's the current estimate, although the range of calculated values runs from 225 million years to 250, so the Sun has made 20 orbits so far. Oddly, it's a retrograde (backwards) orbit. What isn't known is the ECCENTRICITY of that orbit. If it's reasonably eccentric, has the Sun plunged down through the Galactic Core region 20 times? The Core is incredibly crowded with stars and dust and molecular clouds and weird sh-..., er, stuff of every kind. It's really crowded in that neighborhood. Look at a picture of a spiral galaxy and you'll see what I mean. The prospect of that particular joyride is a little daunting, at least to me. Every time I read that some geologist or other has detected a 250 million year periodicity in major change on Earth (like orogeny), it bothers me. Now, you know that eight-year-old is going to ask the next question, "What does the Galaxy go around?" The answer is the barycenter of the Local Group, which is itself in orbit around the barycenter of the Virgo Supercluster, which is itself heading a some good speed toward the Great Attractor, about which we know little... or maybe nothing, except it must be a whopper. If he's the eight-year-old I think he is, he will then ask, "Does the Universe go around anything?" Sheesh. In 1949, Kurt G?del published an exact and perfect alternative solution of Einstein's equations in which the Universe rotates (but doesn't have an axis). It also has a number of other truly spooky properties that give me a headache. http://en.wikipedia.org/wiki/G%C3%B6del_metric Since then, others have published other exact and perfect solutions of Einstein's equations all of which show rotation. None of these solutions are testable, at least not so far. But you can cut off the eight-year-old with "The universe is everything there is, so there's nothing else for it to go around." Sterling K. Webb -------------------------------------------------------------------------------- ----- Original Message ----- From: "Jim Wooddell" <nf114ec at npgcable.com> To: "Meteorite-List" <meteorite-list at meteoritecentral.com> Sent: Sunday, May 20, 2012 1:33 PM Subject: Re: [meteorite-list] Quickie > It was science week at an elementary school. > A third grade teacher was teaching the young kids in his class about > the solar system. He came in early one day and moved all the desks to > the side of the classroom on each wall. He proceeded to set up the > sun and planets using various sized styrofoam balls on stands that > represented our sun, planets and moons. It took several hours to set > up and filled the center of the class room. > > Later that morning, after the children arrived, he walked around > explaining the orbits, and how things worked. > Afterwards the children could ask questions. > > One young girl asked how the moon went around the earth. So he > grabbed the moon and showed her how it went around the earth. > > Another young student asked how the earth went around the sun. So > with the help of the young girl the asked the first question, he show > the earth going around the sun at the same time the moon was going > around the earth! It took some coordination! > > One of the brighter students then asked the question....if all these > planets go around the sun, then what does the sun go around?? The > teacher looked around the room, paused and said, "Good Question"! > > > Are we having fun yet? > Cheers! > > Jim > > > Jim Wooddell > http://k7wfr.us > > > > > > ______________________________________________ > > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list at meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list Received on Sun 20 May 2012 03:53:01 PM PDT |
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