:"The smallest periodicities (Δ''z'' = 72 km/s and 144 km/s) are due to parallel line segments of galactic clustering. The largest (Δ''z'' = 0.15) are due to circumferential circuits around the universe. Intermediate periodicities are due to other geometric irregularities. These periodicities or apparent quantizations are relics or faithful fossils of a real quantization that occurred in the primordial atom."<ref>{{cite journal | last1 = Sepulveda | first1 = E. |date=1987| title = Geometric Paradigm Accounts for All Redshift Periodicities |bibcode=1987BAAS...19Q.689S | journal = Bulletin of the American Astronomical Society | volume = 19 | issue = | page = 689 }}</ref>
===Hydrogen spectroscopy===
Various models propose that the quantization predicted by Karlsson's formula is related to the [[emission spectrum]] signature of hydrogen, described by the [[Lyman series]].<ref>{{cite journal | last1 = Moret-Bailly| first1 = J. | year = 2015 | title=Absorption spectrum of very low pressure atomic hydrogen | journal = Instrumentation and Methods for Astrophysics | volume = | issue = | pages = | doi = | bibcode=2015arXiv151208516M| arxiv = 1512.08516 }}</ref>
According to this explanation, redshift periodicity arises from the interaction between cosmic atomic hydrogen and [[electromagnetic radiation]] in the spectrum of visible light. As atomic hydrogen absorbs and emits energy in the form of electromagnetic radiation, it oscillates between higher and lower [[excited state|states of excitation]]. This transfer of energy redshifts the radiation it emits. Because the states of excitation are quantized in accordance with the Lyman series, the redshift is also quantized.
A limitation of this model is that the phenomenon described above can only arise in conditions where atomic hydrogen is within stringent parameters of low pressure and excitation, away from massive or highly radiant cosmological bodies such as galaxies and [[supernovae]].
