赤方偏移の量子化
This redshift requires energy at Lyman alpha frequency, and the redshift renews this energy up to a shift of Lyman beta or an other line written in the spectrum to Ly alpha frequency. -b) in its atomic ground state. There is no redshift because there are no 2P atoms, the 1420 MHz quadrupolar resonance is too high to allow an ISRS. However, atoms pumped by short frequencies to high levels, or 2S, 2P atoms resulting from a decay from these levels provide a small redshift which allows to reach energy at Ly alpha frequency, so that case a may be reached. Thus output from case b to case a requires high frequency light which disappears fast in thermal radiation.