China's Shenzhou 14 astronauts complete their 3rd and final spacewalk (video)

Can someone clarify what this fluoride study in public water sources is trying to say? From what I read, it’s implying that fluoride levels in public water sources is over the recommended limits that causes harm and has no benefit on reducing incidence of tooth decay.

Maryland, Oklahoma Students to Hear from Space Station Astronauts

World's first computer, the Antikythera Mechanism, 'started up' in 178 B.C., scientists claim