Recently I heard someone make the assertion that the visible spectrum only makes up approximately 2% of the entire EM spectrum. That to me seems like a horrible statement to make since the bounds of the EM spectrum seem to be undefinable. But it brought this question to mind: Is there a physical property that limits the highest theoretical frequency or is the highest frequency possible infinite. The same question in a different form: Is there any reason why an infinitely small wavelength isn't possible? And if so, why? Thanks.