Wolfram|Alpha is a web service whose goal is to provide access to all objective data. You can try it here.
You can use Wolfram|Alpha from Soulver to look up specific pieces of numeric data. Just type the name of the metric followed by = ?
distance to the moon = ?
After a second, Soulver will insert the metric if it's available via Wolfram|Alpha
distance to the moon = 365,519 kilometers
Some setup in Soulver's settings is required to use this feature (Settings > Calculator > Wolfram|Alpha).