The 1955 edition placed a capital "Y" here; it was replaced by "gamma" in all later Urantia Foundation printings. As gamma rays are clearly intended here, we have used that word. As to the origin of the "Y", it is likely that the Greek letter gamma was mistakenly transposed into "Y" at some point in the preparation of the original edition.

Original Paragraph:

^{P474:5, 42:5.1} In the superuniverse of Orvonton there are one hundred octaves of wave energy. Of these one hundred groups of energy manifestations, sixty-four are wholly or partially recognized on Urantia. The sun's rays constitute four octaves in the superuniverse scale, the visible rays embracing a single octave, number forty-six in this series. The ultraviolet group comes next, while ten octaves up are the X rays, followed by the Y rays of radium. Thirty-two octaves above the visible light of the sun are the outer-space energy rays so frequently commingled with their associated highly energized minute particles of matter. Next downward from visible sunlight appear the infrared rays, and thirty octaves below are the radio transmission group.