[Data-modeling] Astronomy: Celestial Objects andNaturalSatellites

[Jeff Thompson]

Perhaps this is confusion caused because Freebase is designed to
let you attach a set of properties to a topic, and the properties
are supposed to contain the information about the topic.  But
(unfortunately?) the set of properties is called a "Type", so people
naturally assume that they should use the name of the "Type" as
they do in common language so that the name itself conveys the
information, not the properties.
Thus we have the types
http://www.freebase.com/view/basketball/basketball_player
and
http://www.freebase.com/view/baseball/baseball_player
where it is not a property but the name of the type which conveys
the meaning of what sport is played.  If "Type" had been called
"a collection of the properties which actually convey the information" this
would not have happened.

I think the same is happening in this case.  I like the fact
that you have moved the distinction between a natural and
artificial satellite from the type name to a property called
"Orbit type".  This way a query does not need to examine
the type name and guess its meaning.  It has to guess because
in Freebase we are not allowed to annotate a type with more information
needed to say how the name of the type distinguishes it from another.
But the "Orbit type" property points to a topic which can be
filled out with properties as needed so that the information is
in the properties, not obscurely hidden in a type name.

Danny, I've heard Roberts opinions on this, but I'm interested in
what you think about "tagging" a topic with a type where the
(unannotated) type name represents the knowledge.
- Jeff

Danny Hillis wrote:
> Going back to Gordon's original question, the proposal below would  
> imply that we replace the Moon(s) property with an Orbiting bodies  
> property of type Celestial Body.
> -Danny
> 
> On May 3, 2008, at 10:43 AM, Danny Hillis wrote:
> 
>> My concern is in adding too many types . Since all Celestial Objects
>> have  orbits, why don't we just put the orbit properties on those,
>> including "Orbit type"  and a property for "Orbits around" which
>> reciprocates as "Orbiting bodies". Artificial Satellite (which we
>> could just call Satellite) could include both celestial body and
>> Spacecraft. his would work for the Mars Reconnaissance Orbiter, and
>> satellites orbiting satellites, like Ranger-9. The Satellite schema
>> would have the other properties that currently on Earth Orbiting
>> Satellite, plus the few extra properties that are useful for
>> geosynchronous satellites, for example "Longitude (if synchronous)".
>> If get's to be too many, we could factor out Observation Satellite as
>> separate type.
>> -Danny
>>
>>
>> On May 2, 2008, at 8:39 PM, Ed Laurent wrote:
>>
>>> What about the Mars Reconnaissance Orbiter and other artificial
>>> satellites that orbit things besides Earth? I was thinking of
>>> Satellite as a very simple and generic type that could include an
>>> "Orbiting body" property, reciprocated with "Satellite(s)". Maybe it
>>> would have a couple other properties too? Many of the "Earth
>>> orbiting satellite" properties should probably be split into
>>> "Geostationary", "Sun-synchronous" and other orbiting types so that
>>> their orbits can be properly described.  Some of these types might
>>> be appropriate for any satellite. An "Artificial satellite" type
>>> might have a few more properties but would certainly be co-typed
>>> with "Spacecraft". Specialty artificial satellite types could then
>>> be co-typed depending on whether the satellite was used for
>>> observation or other purposes.
>>>
>>> Co-typing, naming, and descriptions would be key so that users don't
>>> get lost in these minutia when they're just trying to add some basic
>>> data to Io vs. Hubble vs. Landsat 7 vs. ....
>>>
>>> Too complex?
>>>
>>> -Ed
>>>
>>> On Fri, May 2, 2008 at 10:35 PM, Danny Hillis
>>> <danny at appliedminds.com> wrote:
>>> I like what you suggest about moving Discoverer,etc.
>>>
>>> One issue that we should consider is that almost any celestial  
>> object
>>> is orbiting around something, even is it is the black hole at the
>>> center of the galaxy. Maybe the idea of "orbit" is more useful for
>>> this than making the type Satellite too generic. We could keep
>>> Satellite as meaning as earth-orbiting artificial satellite and give
>>> all celestial bodies an orbit and (as you suggest) a set of orbiting
>>> bodies.
>>> -Danny
>>>
>>>
>>> On May 2, 2008, at 6:10 PM, Gordon Mackenzie wrote:
>>>
>>>> Metapsyche and I did some work a while back to add more useful
>>>> properties for his exoplanet type and I am considering moving most
>>> of
>>>> those properties to Celestial Object and adding planet as a co- 
>> type.
>>>> Celestial Object is our workhorse of a generic Astronomical Object
>>>> type that is included by Star, Planet, Natural Satellite,  
>> Asteroid,
>>>> Comet types. I'm unsure what specifically to retain within
>>> exoplanet,
>>>> pretty much most of the non-celestial object bound properties
>>> could be
>>>> placed within the Planet type. Exoplanet could be just a boolean
>>> true/
>>>> false for is this planet an exoplanet for that matter.
>>>>
>>>> So Celestial Object would have added specifically:
>>>>
>>>> Discoverer, Discovery Date, Discovery Method, Discovery status,
>>>> Discovery Institution/organization
>>>>
>>>> And then remove/move the data for the related discovery properties
>>> in
>>>> Planet/Asteroid/Comet  types to the equivalents in Celestial Body.
>>>> Planet type might have both jupiter and earth-based radius and  
>> mass
>>>> properties.
>>>>
>>>> One question I have is whether Natural Satellites should be
>>>> individually added as a property to Planet and Asteroid types or  
>> to
>>>> add as a single property to just Celestial Object. The latter is
>>>> simpler, but the former allows cleaner demarcation of moons of
>>>> planetary bodies and asteroidal moons.
>>>>
>>>> ~ Gordon
>>>>
>>>> <<< gordon at metaweb.com >>>
>>>>
>>>>
>>>>
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