What is the Planck Length, why’s it significant, and how could we even detect something that small?
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We don’t know of it is significant, it’s just the smallest theoretical measurable length. We can’t detect anything nearly that small, the last I read our technology remains 20 orders of magnitude away.
The length is 1.6×10^-35 meters, it’s significant because it’s the smallest measurable length. due to the heisenberg uncertainty principle (the one that says you can either measure speed, or momentum, but not both at the same time) it’d be impossible to have a more accurate measurement of length (unless you can break known physics)
It’s not so much a detection, more a calculation coming from combining a few constants in the universe (gravity, speed of light, electromagnetism, something called Coulomb constant, and a couple other things) to get an answer in Planck units, those units will be the same everywhere in every language, so they’re truly universal
To answer the question with the simplest answer first:
>how could we even detect something so small
We can’t, it’s purely theoretical.
The Planck length is part of the Planck units, which are units derived by combining the fundamental constants of the universe. In and of itself it has no real meaning (it’s literally a bunch of things multiplied and divided to get a predetermined result) but in various proposed models it is said to be the limit below which “our understanding of physics doesn’t make sense”.
To simplify it as much as possible (i.e. very inaccurately), because this is a topic that really can’t be properly explained without prior knowledge of physics: For example, that this is the where spacetime gets “foamy” due to quantum fluctuations, and defining a smaller distance isn’t possible. Others say that it’s because this is the size of the event horizon the energy of the vacuum itself would create, and therefore even speaking of a defined length stops making sense. There are more, but they’re so technical that I can’t even understand them enough to give a gist of the meaning.
Been a while since I’ve studied the Planck length, but will try to give it a go.
Instead of thinking of it as the small possible measurement of length, I’ve always thought of it as the resolution or “pixel” of the universe. For example you can stand in place and move forward one foot. You can say you made a journey of 1 foot in length. That means you started at point zero and ended one foot away. You moved through all the infinite points in between. You can also make a journey that is 1 inch long or 1 cm long….all the way down.
When you get to the Planck length you no longer can make such a journey. You start at point zero and move 1 Planck length away. You did not cross all the points in between. You teleported 1 Planck length away from your starting point.
Welcome to the quantum scale – where all the “rules” are wrong…and so much more exciting.
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