In astronomy, the Zenithal Hourly Rate (ZHR) of a meteor shower is the number of meteor an observer would see in one hour under a clear, dark sky (limiting apparent magnitude of 6.5) and if the radiant of the shower were in the zenith.
The rate which can effectively been seen is always lower and decrease as the radiant is closer to the horizon.
... carbon dioxide plus water plus light (energy) yields oxygen plus sugar. In animal bodies, this is exactly reversed: oxygen plus sugar yields carbon dioxide plus water ...