ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
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  The Sciencenter in Ithaca, New York developed our 1.2 kilometer Sagan 
Planet Walk at a scale of 1 to 5 billion.  The planet models are much as 
David described below, with the correct spacing between their orbits. 
Our goal was to show the amount of emptiness in space, so we wanted the 
same scale in planet size and distance.  At each station we also have 
plaques with beautiful photos and some information.

It is still a big draw that brings visitors from the city's downtown 
center where the Sun station is, to the Sciencenter, where Pluto is 
located (in 1997 Pluto was still a planet!).  It's a perfect scale for 
an easy walk for families or school groups, and you get a sense of the 
space between planets while still seeing their relative sizes (the inner 
planets are a few millimeters in diameter, while the sun is about 28cm).

Lots of information and photos are at:

http://www.sciencenter.org/saganpw/

And we're going to make it BIGGER!  We'll be adding a new station for 
Alpha Centauri, our nearest star. It is four light-years away.  Anyone 
want to guess where it'll be located??  no peeking....  **

We also have developed a beautiful "Passport to the Solar System" as 
well that you can buy at stores at either end, and if you get it stamped 
at stores along the way you'll get free admission to the Sciencenter.
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**Here's a hint: all of our staff would happily volunteer to go help 
with the installation....
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** At the 'Imiloa Astronomy Center of Hawai'i, in Hilo on the big island 
of Hawai'i.

Kathy Krafft
Exhibitions Curator
Sciencenter
Ithaca, NY

David Smith wrote:

>ISEN-ASTC-L is a service of the Association of Science-Technology Centers
>Incorporated, a worldwide network of science museums and related institutions.
>*****************************************************************************
>
>One of the major points of the thousand-yard solar system models and things
>on a similar scale is to address the misperceptions people have from the
>common illustrations of the solar system in which the planet diameters are
>shown to be a non-trivial fraction of the orbital diameter.  If you show a
>solar system model in which, no matter the scale, you can see planets as
>anything significantly larger than a pinpoint when you are zoomed out far
>enough to see the whole model, then you are probably adding to this
>misperception.
>
>Simple rules of thumb to begin this planning process: Earth diameter is
>roughly 1/100th of the solar diameter and Earth is roughly 100 solar
>diameters from the Sun.  So if the solar diameter is 10 meters, Earth should
>be 10 cm diameter, 1 kilometer away. At this scale, Pluto would be roughly
>40 km  away and the Oort cloud would be more than one Earth circumference
>away!
>
>If you choose a 1 meter sun, Earth is 1 cm, which is large enough to
>carefully paint with some accuracy, and is 100 meters away, which might
>still fit within large science centers.  Pluto would be 4 km away, and the
>Oort cloud would be 5000 km away, only 1/8th of the way around the world.
>
>For a 1 km solar system (to Pluto) you would need a 25 cm sun
>(volleyball-sized) and a 2.5 mm (peppercorn-sized) Earth, 25 meters away
>from the sun.  We have walked this off as a teacher professional development
>activity.  We did it in the Fall and so we used plastic Trick-or-Treat
>pumpkins as the sun and used them to hold the other planets, too. Teachers
>love this activity and are always amazed at the true scale of the solar
>system.
>
>Dave Smith
>
>On Tue, Apr 12, 2011 at 5:40 AM, Lynn Baum <[log in to unmask]> wrote:
>
> 
>

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