Turns out the resolution to that paradox is that our universe is quantized, which means there’s a minimum “step” that once you reach will probabilistically round up or down to the nearest step. It’s kind of like how Super Mario at extreme float values will snap to a grid.
Wait, isn’t space and time infinitely divisible? (I’m assuming you’re referencing quantum mechanics, which I don’t understand, and so I’m genuinely asking.)
Disclaimer: not a physicist, and I never went beyond the equivalent to a BA in physics in my formal education (after that I “fell” into comp sci, which funnily enough I find was a great pepper for wrapping my head around quantum mechanics).
So space and time per se might be continuous, but the energy levels of the various fields that inhabit spacetime are not.
And since, to the best of our current understanding, everything “inside” the universe is made up of those different fields, including our eyes and any instrument we might use to measure, there is a limit below which we just can’t “see” more detail - be it in terms of size, mass, energy, spin, electrical potential, etc.
This limit varies depending on the physical quantity you are considering, and are collectively called Planck units.
Note that this is a hand wavy explanation I’m giving that attempts to give you a feeling for what the implications of quantum mechanics are like. The wikipédia article I linked in the previous paragraph gives a more precise definition, notably that the Planck “scale” for a physical quantity (mass, length, charge, etc) is the scale at which you cannot reasonably ignore the effects of quantum gravity. Sadly (for the purpose of providing you with a good explanation) we still don’t know exactly how to take quantum gravity into account. So the Planck scale is effectively the “minimum size limit” beyond which you kinda have to throw your existing understanding of physics out of the window.
This is why I began this comment with “space and time might be continuous per se”; we just don’t conclusively know yet what “really” goes on as you keep on considering smaller and smaller subdivisions.
The paradox holds in an infinitely dividable setting. Take the series of numbers where the next number equals the previous one divided by 2: {1, 1/2, 1/4, 1/8, 1/16…}. If you take the sum of this infinite series (there is always a larger factor of two to divide by) you are going to get a finite result (namely 2, in this instance).
So for the real life example, while there is always another ‘half’ of the distance to be travelled, the time it takes to do so is also halved with every iteration.
Turns out the resolution to that paradox is that our universe is quantized, which means there’s a minimum “step” that once you reach will probabilistically round up or down to the nearest step. It’s kind of like how Super Mario at extreme float values will snap to a grid.
Wait, isn’t space and time infinitely divisible? (I’m assuming you’re referencing quantum mechanics, which I don’t understand, and so I’m genuinely asking.)
Disclaimer: not a physicist, and I never went beyond the equivalent to a BA in physics in my formal education (after that I “fell” into comp sci, which funnily enough I find was a great pepper for wrapping my head around quantum mechanics).
So space and time per se might be continuous, but the energy levels of the various fields that inhabit spacetime are not.
And since, to the best of our current understanding, everything “inside” the universe is made up of those different fields, including our eyes and any instrument we might use to measure, there is a limit below which we just can’t “see” more detail - be it in terms of size, mass, energy, spin, electrical potential, etc.
This limit varies depending on the physical quantity you are considering, and are collectively called Planck units.
Note that this is a hand wavy explanation I’m giving that attempts to give you a feeling for what the implications of quantum mechanics are like. The wikipédia article I linked in the previous paragraph gives a more precise definition, notably that the Planck “scale” for a physical quantity (mass, length, charge, etc) is the scale at which you cannot reasonably ignore the effects of quantum gravity. Sadly (for the purpose of providing you with a good explanation) we still don’t know exactly how to take quantum gravity into account. So the Planck scale is effectively the “minimum size limit” beyond which you kinda have to throw your existing understanding of physics out of the window.
This is why I began this comment with “space and time might be continuous per se”; we just don’t conclusively know yet what “really” goes on as you keep on considering smaller and smaller subdivisions.
The paradox holds in an infinitely dividable setting. Take the series of numbers where the next number equals the previous one divided by 2: {1, 1/2, 1/4, 1/8, 1/16…}. If you take the sum of this infinite series (there is always a larger factor of two to divide by) you are going to get a finite result (namely 2, in this instance). So for the real life example, while there is always another ‘half’ of the distance to be travelled, the time it takes to do so is also halved with every iteration.