on 2003-08-04 22.28, Howard Ressel at [EMAIL PROTECTED] wrote: <snip> > I was also in Ithaca, NY. "In November 8,1997 a unique, educational > monument and memorial was dedicated. Built, in part, to honor Ithaca > resident and Cornell Professor Carl Sagan, the Sagan Planet Walk is a > scale model of the Solar System in the midst of the City of Ithaca. The > model stretches from the center of the Commons in downtown Ithaca north > to the Sciencenter 1.2 km away" (from ScienceCenter Ithica web site). > > Each pylon gives facts and figures about the planet it represents. All > the information is given in SI only.
Dear Howard, Thanks for that information. You have inspired me � I must think about designing one of these for Geelong. I once built such a model for a rural high school at Orbost in eastern Victoria, Australia. My model was based on a scale of 1�millimetre to 10�000�kilometres, which meant that I could make the interplanetary distances and the size of the planets to the same scale. It appears that my model was half the size of the City of Ithaca model � and quite ameteurish. I worked from figures like these: Planet distance diameter Sun - 1 392 530 km Mercury 60 Gm from Sun 4 878 km Venus 108 Gm from Sun 12 104 km Earth 150 Gm from Sun 12 756 km Moon 384 Mm from Earth 3 476 km Mars 230 Gm from Sun 6 794 km Jupiter 780 Gm from Sun 142 800 km Saturn 1430 Gm from Sun 120 000 km Uranus 2870 Gm from Sun 51 800 km Neptune 4500 Gm from Sun 49 500 km Pluto 5900 Gm from Sun 2 500 km My scale sizes worked out something like this: Planet distance diameter Sun - 139 mm Mercury 6 m from Sun 0.5 mm Venus 11 m from Sun 1.2 mm Earth 15 m from Sun 1.3 mm Moon 384 mm from Earth 0.35 mm Mars 23 m from Sun 0.7 mm Jupiter 78 m from Sun 14.3 mm Saturn 143 m from Sun 12 mm Uranus 287 m from Sun 5 mm Neptune 450 m from Sun 5 mm Pluto 590 m from Sun 2.5 mm I used a softball for the Sun that I painted bright yellow (with dark spots). Mercury, Venus, Earth (and Moon), and Mars were lead shot, dipped into appropriate colored paint. Jupiter and Saturn were glass marbles; Jupiter was a milky one on which was painted a red spot, and Saturn was fitted with rings made from an ice cream container. Uranus, Neptune, and Pluto were ball bearings � they looked chilly. Each planet was fixed in the centre of a galvanised steel sheet and the planet was surrounded by information about the planet (Moon was on Earth's sheet). I made the sheets the same size as A3 paper to facilitate photocopying of information. The galvanised sheets were made so that they could be fixed to a (farmer's) fence conveniently behind the High School when they were in use, but they could then be taken back into the school, for storage and safety from vandalism, when they were not required. Small positioning markings were left permenently on the fence. I well remember remarks such as: 'It's a long way to Pluto'. Aren't all the little planets clumped close together'. 'Gee, the Earth is small. How do we all fit on a little thing like that'. Etcetera! Cheers, Pat Naughtin LCAMS Geelong, Australia Pat Naughtin is the editor of the free online newsletter, 'Metrication matters'. You can subscribe by sending an email containing the words subscribe Metrication matters to [EMAIL PROTECTED] --
