Max Planck demonstrated in 1900 that energy is directly proportional to frequency, expressed as E ∝ f. In my view, this fundamental principle surpasses any other laws established in the twentieth century in its significance.
In 1944, Planck stated:
"As a man who has devoted his whole life to the most clear-headed science, to the study of matter, I can tell you as a result of my research about atoms this much:
There is no matter as such. All matter originates and exists only by virtue of a force which brings the particle of an atom to vibration and holds this most minute solar system of the atom together…
Planck’s equation, E ∝ f, is universally applicable—not only in the presence of matter but also in pure energy states, such as the earliest moments of the universe when matter had not yet formed.
In contrast, relativity cannot be applied to such a primordial state. Instead, only fundamental vibrational principles, such as those in string theory, can extend beyond Planck’s frequency. In string theory, there are no elementary point particles (such as electrons or quarks); rather, everything consists of vibrating strings, where each vibration mode determines a particle’s charge and mass. Replacing point-like particles with vibrating strings leads to profound consequences for our understanding of fundamental physics.