Okay, remember back when we talked about how Galileo thought that we could use the moons of Jupiter as a clock, and their location would help us find our location on Earth? Or how about when Nevil Maskelyne figured we could use the positions of the stars and planets to find out where we are—if we know what time it is?
Maskelyne put in a ton of night-time hours charting the courses of the stars and planets. How much easier it would have been if the heavenly bodies just told him where they are. Well, guess what? Right now, as you sit there eating your frooty kibble, there are over 19,000 moons—man-made satellites—orbiting the Earth that we shot up into space. Every last one of ‘em sends back a constant signal telling us where exactly it is, and the time.
This site shows you where every satellite is right now—https://maps.esri.com/rc/sat2/index.html
Quickie overview of satellites for kids with a charming young lady and a puppet constructed 10 minutes before showtime—https://www.youtube.com/watch?v=03pZdYVacaM