Great timing! A couple of us are about to do some refactoring of the <a href="http://www.freebase.com/view/spaceflight">Spaceflight</a> domain that is relevant to this discussion. One of the things we want to do is refine some of the properties currently included in the <a href="http://www.freebase.com/tools/schema/spaceflight/satellite">Satellite</a> type and move other properties to other types so Satellite describes the orbital characteristics of any satellite - natural or artificial. Hopefully it will be useful as a co-type on various celestial object types. Maybe the generic Satellite type would be better housed within your domain? <br>
<br>I'm planning to work on Satellite this weekend. I'll send a note out to this list with a link once I have something worth considering for your purposes. I'll make sure to look at your Celestial Object and Astronomical Object types while I'm modeling it. <br>
<br>-Ed<br><br><br><div class="gmail_quote">On Fri, May 2, 2008 at 9:10 PM, Gordon Mackenzie <<a href="mailto:gordon@metaweb.com">gordon@metaweb.com</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Metapsyche and I did some work a while back to add more useful<br>
properties for his exoplanet type and I am considering moving most of<br>
those properties to Celestial Object and adding planet as a co-type.<br>
Celestial Object is our workhorse of a generic Astronomical Object<br>
type that is included by Star, Planet, Natural Satellite, Asteroid,<br>
Comet types. I'm unsure what specifically to retain within exoplanet,<br>
pretty much most of the non-celestial object bound properties could be<br>
placed within the Planet type. Exoplanet could be just a boolean true/<br>
false for is this planet an exoplanet for that matter.<br>
<br>
So Celestial Object would have added specifically:<br>
<br>
Discoverer, Discovery Date, Discovery Method, Discovery status,<br>
Discovery Institution/organization<br>
<br>
And then remove/move the data for the related discovery properties in<br>
Planet/Asteroid/Comet types to the equivalents in Celestial Body.<br>
Planet type might have both jupiter and earth-based radius and mass<br>
properties.<br>
<br>
One question I have is whether Natural Satellites should be<br>
individually added as a property to Planet and Asteroid types or to<br>
add as a single property to just Celestial Object. The latter is<br>
simpler, but the former allows cleaner demarcation of moons of<br>
planetary bodies and asteroidal moons.<br>
<br>
~ Gordon<br>
<br>
<<< <a href="mailto:gordon@metaweb.com">gordon@metaweb.com</a> >>><br>
<br>
<br>
<br>
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</blockquote></div><br>