Carbon dating laymans terms
If you draw a picture on the surface of a balloon, then if the balloon is dented somewhere or even turned inside-out, the picture remains the same (all the distances, angles, densities, etc. Point of fact: it may be that the balloon is a completely false metaphor for the universe as a whole, since the best modern measurements indicate that the universe is flat.
When you inflate a balloon the sides are obviously moving apart.The energy the object uses to bust metatarsals is equal to the distance it takes for it to come to a stop times the force that does that stopping. Of course, the distance over which the object slows down is much smaller than the distance over which it sped up.As a result, the stopping force required is proportionately larger.The distance at which this happens (where the rate at which the distance decreases because of the movement of the ant and the rate at which the distance increases due to the expansion of the balloon) is a kind of “ant horizon”.Any pair of ants that are already farther apart than this distance can never meet, and any pair closer than this distance may (if they want).You can use a rule (maybe a tape measure) and a stopwatch and you can say “dudes and dudettes of the physics world, the of expansion is ____”.
Even worse, when a balloon expands it expands into the space around it, which begs the question “what is the universe expanding into? But keep in mind, all that physics really talks about is the relationship between things of the balloon).
Kinetic energy is (average) force times distance; whether you’re winding a spring, starting a fire (with friction), firing projectiles, or crushing your foot.
The energy the object gains when falling is equal to its weight (the force of gravity) times the distance it falls.
This means that there is genuinely no way to describe the expansion of the universe in terms of a speed (there’s no “far side of the balloon” to reference).
It a falling object starts at rest and ends at rest, then it gains all of its energy from gravity, and all of that energy is deposited in your unfortunate foot.
Physicist: You’ll often hear that “the universe is expanding faster than the speed of light”.