space-age: Add precision in Earth estimate
@@ -12,7 +12,7 @@ Given an age in seconds, calculate how old someone would be on:
- Neptune: orbital period 164.79132 Earth years
So if you were told someone were 1,000,000,000 seconds old, you should
-be able to say that they're 31 Earth-years old.
+be able to say that they're 31.69 Earth-years old.
If you're wondering why Pluto didn't make the cut, go watch [this
youtube video](http://www.youtube.com/watch?v=Z_2gbGXzFbs).
