Re: [meteorite-list] Quickie
Brilliant, Sterling! I believe you've just written the next verse for Monty Python's Galaxy Song. http://www.youtube.com/watch?v=buqtdpuZxvk http://www.youtube.com/watch?v=buqtdpuZxvk > From: sterling_k_w...@sbcglobal.net > To: nf11...@npgcable.com; meteorite-list@meteoritecentral.com > Date: Sun, 20 May 2012 14:53:01 -0500 > Subject: Re: [meteorite-list] Quickie > > 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 Gödel 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" > To: "Meteorite-List" > 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 questionif 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@meteoritecentral.com > > http://six.pairlist.net/mailman/listinfo/meteorite-list > > __ > > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list > __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Quickie
Ah, the wisdom of youth! If I could only reverse my accumulated clutter - Original Message - From: "Jim Wooddell" To: "Meteorite-List" Sent: Sunday, May 20, 2012 11:33 AM 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 questionif 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@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Quickie
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 Gödel 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" To: "Meteorite-List" 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 questionif 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@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
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 questionif 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@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Quickie
I thought so.. * Stuart McDaniel Lawndale, NC Secr., Cleve. Co. Astronomical Society IMCA #9052 Sirius Meteorites Node35 - Sentinel All Sky http://spacerocks.weebly.com * -Original Message- From: Sterling K. Webb Sent: Sunday, May 20, 2012 2:47 AM To: Stuart McDaniel ; James Beauchamp ; pshu...@messengersfromthecosmos.com Cc: The List Subject: Re: [meteorite-list] Quickie Pete, James, Stuart, List Long answer to a quick question. 1. The Moon DOES rotate on its axis. If it didn't, we on the Earth would have a slow month-long changing view of every spot on the Moon. There would be no "near" side and "far" side. If you were looking at what we call the near side tonight, in two weeks you would be looking at the "far" side. The sidereal (with reference to the stars, rotation period of the Moon is 27.321582 days. The orbital period of the Moon is 27.321582 days. In a word, the orbit is synchronous. That's relative to the stellar background. The synodic (relative to the Sun) orbital period of the Moon is different, 29.530589 days. In case that puzzles you, the cause of the difference is explained here: http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question32.html 2. James, the strength of the tides is determined by the Moon's MASS, hence its gravitational influence. Given the same orbit, the tides would be the same whatever the period of rotation, 27 days or 27 hours. Now, you may be referring to the fact that the Moon's center of gravity is displaced toward the Earth slightly, and if it rotated rapidly (or didn't rotate at all), it would slightly alter the gravitational pull and the tidal effect from it, but effect would be incredibly small. The center if gravity is only offset about two kilometers! 3. It has been hypothesized that without our large and prominent satellite, humans would have been a much longer time figuring orbital mechanics. Remember it was idly trying to figure out how fast the Moon was "falling" around the Earth that gave Newton his first push into the theory of gravity while he was back home to avoid the plague while a young student. The Moon's orbit is incredibly complex, full of tilts and wobbles of every kind. http://en.wikipedia.org/wiki/Orbit_of_the_Moon The full calculation of the equation of the Moon's orbit (where it will be at a specific time) is one of the most computationally intensive tasks ever done. Men have devoted their entire working life to it and still not finished the job. The last to do it was E. W. Brown: http://en.wikipedia.org/wiki/Ernest_William_Brown 4. But even IF the Moon had a new, non-synchronous rotation, tidal braking would slowly return it to its old synchronous rotational period. OR, if it had no rotation at all, tidal acceleration would spin it up again to the synchronous period. The full mathematical theory of tidal fiiction and the evolution of the lunar orbit was worked out by the XIXth century physicist George Howard Darwin (Charles Darwin's son). Brief explanation here: http://curious.astro.cornell.edu/question.php?number=124 5. The strength of tidal forces on the Earth's rotation and the Moon's recession (moving away from the Earth) is more dependent on the shape of the continents, the width of the continental shelves, and the depth of the oceans than any other factor. An Earth with many low-lying continents, broad ocean shelves, and shallow oceans would have been slowed to a "day" much longer than 24 hours by now. And the Moon would have ended up much further away than it is. In the past, the "day" was shorter and the number days in a year much greater than it is now. I appears that at formation, 4.5 billion yars ago, the year was about 800 "days" of nearly 12 hours each: ftp://ftp.ecgs.lu/public/publications/jlg/jlg90/JLG90_Denis.pdf 6. Tides are far from simple. In Tahiti, for example, the actual experienced tides are almost entirely a product of the Sun's gravity. You get a good approximation by ignoring the Moon altogether. There's a high tide at noon and midnight and lows at 6 am and pm. Why? http://tahitiexpeditions.typepad.com/travelblog/2010/07/tides-in-tahiti.html 7. We now have a short list of people on this List with nothing better to do on a Saturday night... I suppose especially me who wrote the longest. Sterling K. Webb --- - Original Message - From: "Stuart McDaniel" To: "James Beauchamp" ; Cc: "The List" Sent: Saturday, May 19, 2012 10:41 PM Subject: Re: [meteorite-list] Quickie I thought the Moon did rotate?? * Stuart McDaniel Lawndale, NC Secr., Cleve. Co. Astronomical Society IMCA #9052 Sirius Meteorites Node35 - Sentinel All Sky
Re: [meteorite-list] Quickie
Pete, James, Stuart, List Long answer to a quick question. 1. The Moon DOES rotate on its axis. If it didn't, we on the Earth would have a slow month-long changing view of every spot on the Moon. There would be no "near" side and "far" side. If you were looking at what we call the near side tonight, in two weeks you would be looking at the "far" side. The sidereal (with reference to the stars, rotation period of the Moon is 27.321582 days. The orbital period of the Moon is 27.321582 days. In a word, the orbit is synchronous. That's relative to the stellar background. The synodic (relative to the Sun) orbital period of the Moon is different, 29.530589 days. In case that puzzles you, the cause of the difference is explained here: http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question32.html 2. James, the strength of the tides is determined by the Moon's MASS, hence its gravitational influence. Given the same orbit, the tides would be the same whatever the period of rotation, 27 days or 27 hours. Now, you may be referring to the fact that the Moon's center of gravity is displaced toward the Earth slightly, and if it rotated rapidly (or didn't rotate at all), it would slightly alter the gravitational pull and the tidal effect from it, but effect would be incredibly small. The center if gravity is only offset about two kilometers! 3. It has been hypothesized that without our large and prominent satellite, humans would have been a much longer time figuring orbital mechanics. Remember it was idly trying to figure out how fast the Moon was "falling" around the Earth that gave Newton his first push into the theory of gravity while he was back home to avoid the plague while a young student. The Moon's orbit is incredibly complex, full of tilts and wobbles of every kind. http://en.wikipedia.org/wiki/Orbit_of_the_Moon The full calculation of the equation of the Moon's orbit (where it will be at a specific time) is one of the most computationally intensive tasks ever done. Men have devoted their entire working life to it and still not finished the job. The last to do it was E. W. Brown: http://en.wikipedia.org/wiki/Ernest_William_Brown 4. But even IF the Moon had a new, non-synchronous rotation, tidal braking would slowly return it to its old synchronous rotational period. OR, if it had no rotation at all, tidal acceleration would spin it up again to the synchronous period. The full mathematical theory of tidal fiiction and the evolution of the lunar orbit was worked out by the XIXth century physicist George Howard Darwin (Charles Darwin's son). Brief explanation here: http://curious.astro.cornell.edu/question.php?number=124 5. The strength of tidal forces on the Earth's rotation and the Moon's recession (moving away from the Earth) is more dependent on the shape of the continents, the width of the continental shelves, and the depth of the oceans than any other factor. An Earth with many low-lying continents, broad ocean shelves, and shallow oceans would have been slowed to a "day" much longer than 24 hours by now. And the Moon would have ended up much further away than it is. In the past, the "day" was shorter and the number days in a year much greater than it is now. I appears that at formation, 4.5 billion yars ago, the year was about 800 "days" of nearly 12 hours each: ftp://ftp.ecgs.lu/public/publications/jlg/jlg90/JLG90_Denis.pdf 6. Tides are far from simple. In Tahiti, for example, the actual experienced tides are almost entirely a product of the Sun's gravity. You get a good approximation by ignoring the Moon altogether. There's a high tide at noon and midnight and lows at 6 am and pm. Why? http://tahitiexpeditions.typepad.com/travelblog/2010/07/tides-in-tahiti.html 7. We now have a short list of people on this List with nothing better to do on a Saturday night... I suppose especially me who wrote the longest. Sterling K. Webb --- - Original Message - From: "Stuart McDaniel" To: "James Beauchamp" ; Cc: "The List" Sent: Saturday, May 19, 2012 10:41 PM Subject: Re: [meteorite-list] Quickie I thought the Moon did rotate?? * Stuart McDaniel Lawndale, NC Secr., Cleve. Co. Astronomical Society IMCA #9052 Sirius Meteorites Node35 - Sentinel All Sky http://spacerocks.weebly.com ********* -Original Message- From: James Beauchamp Sent: Saturday, May 19, 2012 11:31 PM To: Cc: The List Subject: Re: [meteorite-list] Quickie I would say less. The highest density of the moon stays on the earth side now, so the 1/r^2 magnitude of the gravity effect is maximized. If it were rotating, the average pull would always be less than it is now. Sent from my iPhone On Ma
Re: [meteorite-list] Quickie
I thought the Moon did rotate?? * Stuart McDaniel Lawndale, NC Secr., Cleve. Co. Astronomical Society IMCA #9052 Sirius Meteorites Node35 - Sentinel All Sky http://spacerocks.weebly.com * -Original Message- From: James Beauchamp Sent: Saturday, May 19, 2012 11:31 PM To: Cc: The List Subject: Re: [meteorite-list] Quickie I would say less. The highest density of the moon stays on the earth side now, so the 1/r^2 magnitude of the gravity effect is maximized. If it were rotating, the average pull would always be less than it is now. Sent from my iPhone On May 19, 2012, at 10:16 PM, wrote: I have a quetion. Would the moon's effect on the tides be more or less if the moon still had rotational spin? And why? Pete __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Quickie
I would say less. The highest density of the moon stays on the earth side now, so the 1/r^2 magnitude of the gravity effect is maximized. If it were rotating, the average pull would always be less than it is now. Sent from my iPhone On May 19, 2012, at 10:16 PM, wrote: > I have a quetion. > Would the moon's effect on the tides be more or less > if the moon still had rotational spin? > And why? > Pete > > > __ > > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Quickie
I have a quetion. Would the moon's effect on the tides be more or less if the moon still had rotational spin? And why? Pete __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
