“I much prefer the sharpest criticism of a single intelligent man to the thoughtless approval of the masses.” -Johannes Kepler, 1601
It’s easy to think of some things as eternal, even though nothing truly is. The Sun is long lived, and it has another 7 billion years (or so) to go before it runs out of fuel, but eventually it, too, will die. But surely gravitational orbits will outlast us all, right?
As it turns out, even the simplest system you can set up — of a single small mass orbiting a large one — will decay over time. But is this something that would come out of Newton’s laws, or would you need to go beyond that to understand this phenomenon?