Planet Earth is spinning at a rate of 0.0007 rpm. Easy to calculate: One revolution per day, divided by 24 to get revs/hr and then by 60 to get revs/min = rpm. As for linear speed, it depends on where ...

The Romans needed a holiday in midwinter as they didn't do Christmas or New Year and followed the agricultural year, as did the Jews. The new moon told them when another month had passed. So they ...