Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-02-10
BY N. WIENER AND d. J. sTRu1K,


ITO understand the bearing of the
new paper of Einstein in the
Sitzungsberichte der Preussischen
i Academic der Wissenschaften,
reprinted in The Star, we must
consider the whole development Of
physics in the present century. In the
eighties of the last century Michaelson
and Morley made their famous attempt
to detect the rate of drift of the earth
through the ether and achieved the sur
prising result that it Is always zero, ac-
cording to the accepted theories OF the
! time.
Lorentz built up very special modi-
| flcation of the existing physics OF the
| length of moving bodies to account for
his unbelievable state of affairs. when,
| about 1905, the young German physicist.
Einstein, already famous for his re-
searches on the Brownian motion, made
the suggestion that 1t is fundamental
property of the universe that uniform
motion is not to be distinguished from
rest Shortly afterward Minkowski
pointed out that this was tantamount
to assuming the geometry of the world
/ to consist in certain four -dimensional
| geometry of both space and time. and
| of type by no means unknown to the
pure mathematician.
Special Relatively Verified.
This theory, the so-called special rela-
tivity, has stood and still stands i'm
pregnable to all attacks. 1t has been
verified in a thousand ways by the as
| tronomer, by the experimenter in optics,
by the atomic physicist. It may, of
future occasion, but that day Is as yet
far off.
Special relatively is already classical;
the present interest In physical theory
is divided between two competitors for
attention, general relatively and guam
tum theory. Quantum theory Is the
older Of these and is decidedly the more
successful. It is of about the same age
as special relatively, and in its original
form deals with the emission and alb
sorption of light. Light seems to be
emitted and absorbed in Jumps or
quanta Of a size depending on its color.
This view of light was forced on US by
the investigations of Planck and Of
Einstein himself. On the other hand
the wave theory of light seems to be
unavoidable, in view of the phenomena
of interference, where two lights may
add up to make a darkness.
Bohr Expands Quantum Theory.
In 1912 Niels Bohr of Copenhagen
gave the quantum theory a new and
much more important turn. Ruther-
ford had previously considered atoms
as petty solar systems of nuclei and
electrons, but this theory was unable
to account for the distribution of lines
in the spectra of the different elements.
BY combining the Rutherford atom
with the ideas of Planck and Einstein,
nAt] xryau 14ln To L at%1r
accurate theory of the observed regu-
larities in the spectrum lines of hydro
gen and of certain other elements.
Notwithstanding its success, the theory
was characterized by a most unsatis-
factory and inconsistent wavering be-
tween the ideas of the classical New
ton mechanics and the essentially I'M
mechanical notions of Planck and Elm
stein.
Thus both light theory and atomic
physics were characterized for years by
great success in practice and total
lack of a satisfactory foundation
This continued until 1925, when the
brilliant work Of Heisenberg, Born,
Jordan and PAUL. opened the possible
ity of self-contained spectrum the
DRY, parallel to, but not dependent on
the old mechanics. Within year this
theory had produced the wave-atom
theory Of Schrodinger and the statisti-
cal theory of Born and Heisenberg, for
mally equivalent to one another, but
widely divergent in standpoint.
Views on Electrons Diverge.
Schrodinger followed the pre-Heisen-
berg work of de Broglie in conceiving
an electron as vibration phenomenon
filling all space. and the spectral lines
OF an atom as analogous to the simple
modes of vibration of a drumhead or
string. Born and Heisenberg. on the
other hand, regard an electron as To-
Gated at single point, which has
probability of distribution corresponding
to the density of the Schrodinger atom.
Thus the Heisenberg treatment, which
seems to be the more satisfactory, dis
cards determiniSm. and regards the
laws of nature as mere statistical aver
ages. Both forms of the theory approx
mate closely in their conclusions to the
Bohr theory, but where they depart
from it, depart in the direction of the
actual observations.
Just before the birth of the HeiSen-
berg theory. Goudsmit and Uhlenbeck.
now at Ann Arbor, found a physical
confirmation of the idea that an cleo
iron may spin like top. The harmon
ization Of this idea with the Heisen-
berg Schrodinger notions was not easy,
as both of these are unable to describe
an electron without an allusion to the
actual or probable state of affairs In all
space.
Within the last year Dirac has given
brilliant theory of the spinning elec-
tron on the new basis, which has met
with the most amazing experimental
confirmation. The new ideas have been
victorious all along the line, and Weyl,
whom we now have the honor to have
as guest In this country, has car
ried them on to new conquests in the
field Of the periodic table and Of chem
istry.
Accelerated Motion Like Gravity.
Quite apart from this movement. but
contemporaneous with it, the theory of
gravitational relatively has developed.
The fundamental idea of this is that
just as uniform motion is indistinguish-
able from rest In the special relatively,
so accelerated motion Is indistinguish-
able from gravity. We cannot tell #
we are attracted to the earth, or If the
ground is being pushed up at us with
increasing velocity. This idea was put
forward by Einstein in his famous 1918
paper. The mathematical tool for the
expression OF ideas of this sort had been
at hand for many years in the form of
Ricci's absolute differential calculus. To
specify the actual laws of gravitation.
Einstein had to establish his famous
field equations, to characterize the be-
havior of a curved and non Euclidean
space-time world. These equations were
practically forced on him. They were of
the second order and second degree. |
They form a generalization of Newton 5 ]
laws of motion. 1
Here we must interpolate some re-
marks on q skeleton In the closet Of |
the mathematician. A mathematical |
problem is called linear If. to put it |
crudely, added causes yield added eff
fects. Thus balance yields linear |
reading On the other hand, when |
the last straw breaks the camel's |