Upon learning about the work of George Johnstone Stoney

The Emergence of Natural Units


Dublin, Ireland.  Unique moments in time are the subject of historians. Judging the  significance of such events helps to qualify historians as historians. In an 1874 lecture for the Belfast Meeting of the British Association, “On the Physical Units of Nature,” Stoney shared his insights about natural units. In 1881, George Johnstone Stoney’s lecture was finally published. His rather unique methodology for measuring became a new concept, natural units. These are units of measurement that are independent of measuring devices or instruments or tools. Here fundamental physical constants are the base units. It should be observed that such physical constants are always relational. Their very definition recognizes the dynamic relation between two things. There was really no one day and moment in time when Stoney recorded his process of uncovering and discovering the relations between these fundamental physical constants. Yet, he started publishing his thoughts and formulas in 1881.

That was a special event within recorded history.

George Johnstone Stoney had been a professor at Queen’s University in Belfast yet during this period he was also serving as the representative authority for the university in Dublin.

References & Resources:


Natural Units Before Planck
Authors: Barrow, J. D.
Journal: Quarterly Journal of the Royal Astronomical Society, Vol. 24, P. 24, 1983
Bibliographic Code: 1983QJRAS..24…24B


“In physics the Stoney units form a system of units named after the Irish physicist George Johnstone Stoney, who first lectured in 1874 in Belfast about them, then published that account in 1881.

“Contemporary physics has settled on the Planck scale as the most suitable scale for a unified theory. The Planck scale was, however, anticipated by George Stoney.[5] Like Planck after him, Stoney realized that large-scale effects such as gravity and small-scale effects such as electromagnetism naturally imply an intermediate scale where physical differences might be rationalised. This intermediate scale comprises units (Stoney scale units) of mass, length, time etc., yet mass is the cornerstone.

“The Stoney mass mS (expressed in contemporary terms)[9]

m S = e 2 4 π ε 0 G =

where ε0 is the permittivity of free space, e is the elementary charge and G is the gravitational constant, and where α is the fine-structure constant and mP is the Planck mass.

“Like the Planck scale, the Stoney scale functions as a symmetrical link between microcosmic and macrocosmic processes in general and yet it appears uniquely oriented towards the unification of electromagnetism and gravity . Thus for example whereas the Planck length is the mean square root of the reduced Compton wavelength and half the gravitational radius of any mass, the Stoney length is the mean square root of the ‘electromagnetic radius’ (see Classical electron radius) and half the gravitational radius of any mass, m:

is the reduced Planck’s constant and c is the speed of light.

“It should be noted however that these are only mathematical constructs since there must be some practical limit to how small a length can get. If the Stoney length is the minimum length then either a body’s electromagnetic radius or its half gravitational radius is a physical impossibility, since one of these must be smaller than the Stoney length. If Planck length is the minimum then either a body’s reduced Compton wavelength or its half gravitational radius is a physical impossibility since one of these must be smaller than the Planck length. Moreover, the Stoney length and Planck length cannot both be the minimum length.

“According to contemporary convention, Planck scale is the scale of vacuum energy, below which space and time do not retain any physical significance. This prescription mandates a general neglect of the Stoney scale within the scientific community today. Previous to this mandate, Hermann Weyl made a notable attempt to construct a unified theory by associating a gravitational unit of charge with the Stoney length. Weyl’s theory led to significant mathematical innovations but his theory is generally thought to lack physical significance.[10][11]