*Originally posted by sonhouse*

**But according to that video, you would have to confine the light to a volume 1000 times smaller than a proton. That would seem to limit the lower frequency of light that would be able to be packed in such a volume. Can electromagnetic radiation even exist at that wavelength? So doing the arithmetic, the formula would be M=E/c^2 .**

The catch is that one would need more than one photon. The Compton wavelength of a particle is given by h/mc where h is Planck's constant (unreduced), c the speed of light and m the

*rest mass* of the particle. This is roughly the dimension of the volume of space one would expect a particle to occupy. The Schwartzschild radius of a black hole is 2GM/c^2. If the Compton Wavelength of the particle is smaller than its Schwartzschild radius then it is a "single particle black hole" candidate, at least at this handwaving level of description. We get a "single particle black hole" if M^2 > h/2Gc. This is the Planck Mass. It is

**huge** and photons are massless. So one would need several photons whose wavelength is smaller than the region to be in the region at the same time, the "photon ball" has a mass

*assignable* to it. To put it bluntly, you'd need to focus something like a second's power output of a star into a space the size of a proton to hope to create something like this.