So I get that a Planck length is the smallest length measurement that we have. But why?
I know it has something to do with gravity and speed of light in a vacuum. But why? Is it the size of the universe as early as we can calculate prior to the Big Bang? What is significant about it?
All the videos I see just say it’s a combination of these three numbers, they cancel out, and you get Planck length – and it’s really really small. Thanks in advance!
In: Physics
Planck length and related constants, represent quantities beyond which the laws of physics as we currently understand them, kind of hit a wall and cease to give reasonable answers. Those laws say we can’t have EM radiation (aka “light”) whose wavelength is the Planck length, for instance, because at that wavelength, Einstein and Schwarzschild’s equations say the energy carried by a single photon, would be enough to collapse the photon into a black hole.
And because of all our laws which connect different physical units to each other, there’s a host of interrelated prohibitions which fall out of this. You can’t have matter that’s hotter than the Planck temperature, because if you did, then its thermal radiation would have a wavelength shorter than the Planck limit, and so on.
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