Talk:Q2

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Relation to Solar System (Q544)[edit]

How should the relationship between Earth (Q2) and Solar System (Q544) be shown? parent astronomical body (P397) is set to Sun (Q525), so presumably it shouldn't be set also to Solar System (Q544). Maybe part of (P361)? That seems a bit too generic. --Yair rand (talk) 16:54, 1 July 2015 (UTC)

May be part of (P361) is too generic for some abstract notions, but for the planet it is just ideal, I think. --Infovarius (talk) 13:43, 2 July 2015 (UTC)

Wikidata has no property to describe the age of the Earth[edit]

The age of the Earth is computed in years of constant length, such as the years produced by atomic clocks or ephemeris time. Calendars count actual days, that is, a sunrise/sunset cycle. In the distant past days were much shorter than today. Thus calendar dates are not suitable for describing the age of the Earth. Jc3s5h (talk) 19:51, 4 July 2015 (UTC)

Todo list[edit]

Some things that need doing:

  • Needs more historic data, including start time (P580) and end time (P582) qualifiers to everything in has part (P527) (current and past continents, ocean, and geological components).
  • Some significant event (P793) statements of some major events in the planet's history.
  • Historical highest point (P610) and deepest point (P1589) statements, if possible.
  • Some more population (P1082) wouldn't hurt.
  • Is location data possible? coordinate location (P625) uses geographical coordinates by default, but other coordinate systems are possible. Would any celestial coordinate systems have a value that makes sense?
  • Chemical composition, but I don't think a property for that exists yet.
  • Moment of inertia factor.
  • When unit support becomes available (tomorrow, I think):
    • GDP, GDP per capita
    • (list copied from English Wikipedia infobox) Aphelion, Perihelion, Semi-major axis, Orbital period, Average orbital speed, Mean anomaly, Inclination, Longitude of ascending node, Argument of perihelion, Mean radius, Equatorial radius, Polar radius, Circumference, Surface area, Volume, Mass, Mean density, Surface gravity, Escape velocity, Sidereal rotation period, Equatorial rotation velocity, Axial tilt, Albedo, Surface temperature, Surface pressure.
  • There are probably some more instance of (P31) values which make sense. Besides for being an inner planet, Earth is habitable and covered in water.
  • Some which may or may not make any sense: color (P462), Unicode character (P487), time of discovery (P575), flag (P163), territory claimed by (P1336)...

--Yair rand (talk) 03:25, 2 September 2015 (UTC)

--Yair rand (talk) 23:15, 29 November 2015 (UTC)

Uncertainties of population[edit]

@Mfb:, what do you mean by "underestimation"? If we have a number of 2 755 823 000 people why an error "1000" is underestimation? I believe that this is obvious uncertainty which is ruled out from the number itself (and its signifying digits). --Infovarius (talk) 20:12, 29 October 2015 (UTC)

Worldwide population estimates generally have an uncertainty of the order of a few percent. Even in Germany, where every citizen should be registered which should make the official number accurate, the number had to be corrected by 2 percent in 2011 due to miscounting (German source). The last digits of that 2.8 billion number are just nonsense. --mfb (talk) 15:35, 30 October 2015 (UTC)