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E.R.A. Report 5275
Successful Predictions of the Electrical Discharge Theory of Cosmic
Atmospheric Phenomena and Universal Evolution
By
C. E. R. Bruce
M.A., D.Sc. (Edin.) F.I.E.E., F.Inst.P. F.R.A.S.
(Research Physicist in The Electrical Research Association from 1924 to
1967)
1968
*The Electrical Research Association*
Contents
*Summary*
*(1) Introduction*
*(2) The Sun*
* (2.1) Solar Prominences
* (2.2) Solar Atmospheric Electric Fields
* (2.3) Solar Flares
o (2.3.1) Crochets and Bal mor Line Widths
o (2.3.2) Flare Energy
o (2.3.3) Pressure in Flares
o (2.3.4) Gas Jets and Magnetic Storms
o (2.3.5) Thermal and Non-Thermal Sources
o (2.3.6) Forbush Decreases
* (2.4) Sunspots
o (2.4.1) Explanation and Structure
o (2.4.2.) The Evershed Effect
o (2.4.3) Sunspot Magnetic Fields
* (2.5) Solar Discharge Temperatures
*(3) The Stars*
* (3.1) Extended Atmospheres
* (3.2) Long Period Stars
o (3.2.1) Electric Field Generation
o (3.2.2) Veiling
o (3.2.3) Epoch of Appearance of Emission Lines
o (3.2.4) Periods
o (3.2.5) Duration of Bright Line Spectra
o (3.2.6) Variations of Period
o (3.2.7) Variation of Spectrum with Epoch
o (3.2.8) Change of Spectral Type
o (3.2.9) Gas Velocities
o (3.2.10) Gas Velocities in AX Persei
* (3.3) Cometary Nebulae
* (3.4) Gas Velocities in P Cygni and [chi] Cygni
* (3.5) Planetary Nebulae
o (3.5.1) Two-Armed Structures
o (3.5.2) Gas Movements
o (3.5.3) Feast's Data on Gas Velocities
o (3.5.4) Zanstra's Stellar Temperature
* (3.6) Stellar Rotation
o (3.6.1) Dependence on Temperature
o (3.6.2) Stars of Types B and Be
o (3.6.3) Flare Stars
o (3.6.4) Current Theories
* (3.7) Low stellar atmospheric Density Gradients andl Apparent Loss
of Matter ... 20
* (3.8) g Cassiopeiae
o (3.8.1) Rotating Four-Armed Nebula ...
o (3.8.2) Variation of Emission Line Widths
o (3.8.3) Relation Between Intensities and Velocities of the
Emission Line Component
o (3.8.4) Interchange of Line Components
* (3.9) Novae
o (3.9.1) Line Broadening in Initial Stages
o (3.9.2) Current Wave Shape
o (3.9.3) Pinching of the Discharge
o (3.9.4) Two Discharges
*(4) Galaxies*
* (4.1 ) Galactic Evolution
o (4.1.1) Hubble's Scheme
o (4.1.2) Type S0
o (4,1.3) Type SBa
o (4.1.4) Radio Galaxies
* (4.2) Atmospheric Electric Field Building
o (4.2.1) Existence of Grain
o (4.2.2) Galactic Size - Type, Relation
o (4.2.3) Argument Against Continuous Creation
* (4.3) Discharge Channels
o (4.3.1) Two-Armed Spirals
o (4.3.2) Barred-Spirals
o (4.3.3) Gas Jets in NGC 1097
o (4.3.4) Irregular Galaxies
o (4.3.5) Discharge Temperature
o (4.3.6) Discharge Duration
o (4.3.7) Magnetic Fields in the Arms
o (4.3.8) Interacting Galaxies
* (4.4) Stellar Populations
o (4.4.1) Location
o (4.4.2) Atomic Constitution
o (4.4.3) Energy Radiated By a Radio Galaxy
* (4.5) Optical. and Radio Sources
* (4.6) Quasars
o (4.6.1) Their Absence a Theoretical Difficulty
o (4.6.2) Optical Characteristics
o (4.6.3) Duration
o (4.6.4) Pinching of the Discharge
o (4.6.5) Association with Dust
* (4.7) Two Populations of Galaxies?
List of References
*Summary*
The object is to show that all cosmic atmospheric phenomena can be
explained as deriving from electrical discharges, resulting from the
breakdown of electric fields generated by the asymmetrical impacts
between dust particles, such as are effective in terrestrial electrical
sand and dust storms and in thunderstorms. These electrical discharges
form, for example, the solar photosphere at 6,000°K, superposed on an
atmospheric background temperature of less than 4,000°K at which solids
can and do form. Isolated discharges form the solar prominences and
solar flares. The electrical discharge theory of the latter led to the
prediction (1959) that they must emit X-rays before these were observed
by the first U.S.N. satellite observations in 1960 and observations of
the transverse magnetic fields surrounding two flares in 1966 by Severny
have confirmed that the flares are, in fact, electrical discharges.
Despite over 50 years of observations of longitudinal magnetic fields in
the umbra of sunspots and of gas velocities limited to around 2 km per
second in the Evershed effect, Severny confirmed that the former are
actually transverse and Bumba confirmed that the latter reach 8 km per
second, each in accordance with the theory's predictions.
The theory led to the view that, much of what has been regarded as due
to stellar rotation is not due to the rotation of the star, as is now
generally agreed, but to rotation of balls of gas emitted from
discharges and this in turn led to a new theory of ball lightning which
seems to explain all the observations. It also explains the photographs
of barred spiral nebulae and of flashovers of insulator strings, in
which the same escape of gas occurs at the sudden bends in the
discharges at the ends of the bars and at the bends in the crinkled
discharges over insulator strings in the laboratory.
The theory explains the origin of the cosmic atmospheric magnetic fields
and relativistic electrons which have to be postulated by all other
theories of radio galaxies; also of the gas jets which explain solar
magnetic storms and the movements observed in the planetary nebulae,
novae, and many extra-galactic nebulae. These discharge-generated gas
jets derive from the same claracteristic of electrical discharges which
renders arc welding possible.
The theory led to the value of 10^60 ergs for the total energy liberated
by a radio galaxy before this value was confirmed by Heeschen's study of
all the available data. It explains the separation of the stars in a
galaxy into two Stellar Populations and the observed differences in
their average atomic constitutions and the two-armed structure of both
stellar (planetary) and extra-galactic nebulae.
The introduction of atmospheric electric fields would appear to do for
cosmic atmospheric astrophysics what the introduction of gravitation did
for dynamical astronomy.
*(1) Introduction*
A few years ago in a lecture to the British Association^(1) Bondi
emphasized the desirability that a theory should "live dangerously" by
making predictions which could be verified by observation or experiment.
The study of terrestrial lightning may be said to have been initiated by
one of the tersest examples of this procedure when Benjamin Franklin
ended his entry in his "minutes" on the lightning flash with "Let the
experiment be made", and the Philadelphia experiment, as it was called
in Europe, was successfully made, first by d'Alibard in France in 1752
and later by Franklin himself.
Unfortunately in proposing a step of even greater ratio in the extension
of the field of electrical discharges in gases to cosmic atmospheres the
writer has seldom been able to put his predictions in such a direct
relation to possible experiments. What he has been able to do frequently
is to suggest that the available observations, or even, and often, those
not already available, should be studied from the point of view of their
having originated in electrical discharges. Few theories can have lived
more dangerously in this way and survived than has the electric field
and discharge theory of cosmic atmospheric phenomena and universal
evolution. It predicted^(2.1) , for example, the existence of two-armed
nebulae on a stellar, as well as a galactic scale, when no one seemed
able to confirm the existence of such a nebular structure -- not even
theose who had worked for many years on planetary nebulae. It
predictcd^(2.2) the existence of temperatures of over 100,000,000°K in
electrica1 discharges in the solar atmosphere -- soon verified^(2.3) by
U.S.N. satellite observations; of velocities of up to 8 km/sec in the
Evershed Effect^(2.4) despite over 50 years of observations limited to 1
to 2 km/s. Perhaps; the most remarkable success of all was the deduction
that the magnetic fields in the umbra of sunspots must be
transverse^(2.5) despite the fifty years of observations at Mount Wilson
Observatory and elsewhere purporting to show that they are not
transverse but vertical. All the evidence would thus seem to indicate
that these last predictions are incorrect in view of the accounts of
sunspots and the Evershed Effect given in every text book on astronomy
during the last fifty years or so. But possibly even more striking was
the prediction of the existence and approximate duration^(2.6) of what
have since been discovered and called quasars, at least, four years
before their discovery.
These and. many other successful predictions of the theory are described
in the present account. As each contributes to the significance of its
fellows, it seemed desirable to collect them together with those not
already discussed. This has been done under the heads of solar, stellar
and galactic phenomena. It might have been more logical to have
collected them under such headings as electric field building, discharge
characteristics, discharge-generated gas jets, thermal and non-thermal
cosmic energy sources, etc., but the present arrangement will probably
appeal more to those who specialize in solar, stellar or galactic phenomena.
(2) The Sun
*(2.1) Solar Prominences*
The theory may be said to have started with a successful
prediction during Sydney Chapman's Kelvin lecture^(3.1) on the sun
to the Institution of Electrical Engineers on 8th May, 1941, when
he referred to a solar prominence which had reached a height of a
million miles in an hour. It seemed to the writer that this could
only mean that the phenomenon must be a solar lightning flash and
that, therefore, a million miles an hour must be equivalent to 3 x
10^7 cm/sec, the velocity of propagation of the lightning
leader-stroke since the velocity of propagation of breakdown in a
gas should be independent of the density. A little mental
arithmetic in the darkness corroborated on a scrap of paper when
the lights went up, verified that this first prediction was
approximately correct and the electrical discharge theory was
launched. It soon appeared^(2.7) that this prominence could not be
an isolated electrical discharge but that all the solar "surface"
phenomena must be electrical; that the granulations of the
photosphere, the spicules of the chromosphere and the rays of the
corona, form a hierarchy of electrical discharges at decreasing
gas densities and increasing discharge temperatures.
This general conclusion had been the more easily reached as the
writer was at the time working on the lightning discharge and had
shown^(2.8,2.9) that the electric field required to cause a
lightning flash is only about 1% of that which C.T.R. Wilson had
suggested^(4.1) as necessary and which earlier theories had taken
for granted ^(5,6) . The' onset of instability and breakdown was
shown to be marked by the transition in the field-maintained
corona or glow discharge of St. Elmo's fire having a positive
characteristic to the thermally ionized channel of the arc
discharge, possessing a negative characteristic. So far as the
writer is aware all subsequent criticisms of that theory, and of
the corollary that lateral corona currents must flow from the
leader-stroke channel, have since been answered^(2.6,2.10) , and
Pierce later found that the theory enabled all the observational
data obtained at Cambridge to be correlated "with no major
inconsistencies"^(7) .
It will be evident that the theory at once explained one of the
outstanding problems presented by the study of the solar surface,
namely its "fibrille" or "granulated" structure, the individual
granules being individual discharge channels. It is supported by
the very careful study of the formation and life of individual
granules made by Bray and Loughhead who write that "in general a
granule develops from a vague patch of diffuse bright material,
which originate's in a hitherto dark area."^(8.1) . (The
underlining is the present writer's).
The first publication in a scientific journal appeared in "The
Observatory" in April, 1946 (Ref. 2.10a) and summarized those
characteristics of solar prominences which were at once seen to
conform with the expectations of the discharge theory, including
their extreme thinness, which had often been commented on, the
fact that some are initiated as much as 150,000 km above the
"surface" of the sun, and that these downward developing
prominences on occasion show tho leader-return stroke mechanism of
the lightning flash, and that one prominence can exert an
influence on others over 250,000 km away. They also on occasion
simulate lightning flashes in that successive strokes follow one
anothor along the same discharge channel. As Ellison had written
"one gets the striking impression that the trajectory is a
conducting path, quite distinct from the prominence material which
is constrained to move along it".
It was also pointed out that "the very fact that such streamers
can be initiated as much as 150,000 km above the surface of the
sun itself support the writer's conclusion^(2.7) , reached on more
general grounds, that the sun and stars must be surrounded by
extensive tenuous atmospheres, and has been so interpreted by
Pettit himself" (Ap.J., 98, 1943, p.6) who first, recorded this
type of corona prominence.
*(2.2) Solar Atmospheric Electrical Fields*
The above quotation from Bray and Loughhead leads naturally to the
question of the setting up of the electric fields which lead to
the development of bright granules in these dark, low temperature
areas. Chapman has written^(3.2) recently "Bruce agrees that the
sun offers his ideas perhaps their greatest challenge, because of
the very high electrical conductivity of the solar material at all
levels".
On the contrary, the solar atmosphere offers one of the best
checks of the theory and confirms a prediction which has been
implicit in the theory since 1955, when a possible explanation of
these atmospheric electric fields was put forward^(2.11) . Till
then the necessary electric fields were merely, like so many of
their magnetic counterparts, a hypothesis. Unlike these latter
hypotheses, however, the electric field was the one hypothesis
which made the whole universe kin, so to speak, and obviated the
need for the many other hypotheses including those concerning the
magnetic fields themselves.
Since 1955 the discharge theory inevitably led to the tacit
prediction that a surface of discontinuity must exist in any
stellar atmosphere when that temperature is reached at which
solids begin to form, i.e., at temperatures of around 4,000°K. At
these temperatures hydrogen is far below its dissociation
temperature and still further below the temperature required for
appreciable thermal ionization. The theory itself supplies the
convection currents even if they were not there in the absence of
the electrical discharges, so all the factors are available to
lead to electric charge separation and field building, thanks to
the observations which can be made in the absence of the
discharges, i.e., in sunspots. In these, when we can see further
down into the solar atmosphere in the temporary absence of the
photospheric arcs, this thermal background is exposed to view and
is at the temperature predicted by the theory, 3,700°K or 3,800°K
(Ref. 8.2), more than 2,000°K less than that of the discharges. It
is only when this last temperature, about 6,000°K is reached,
i.e., that required for thermal ionization of the gas, that the
setting up of electric fields becomes impossible.
It may be emphasized too that de Jager^(9.1) has given this same
temperature, around 4,000°K, as the background temperature of the
chromospheric discharges.
It is thus fortunate that we are able to see the details of the
sun's atmospheric structure in sunspots, and verify that it
conforms to the picture which the discharge theory had led us to
expect; that is, a general background atmospheric temperature of
around 4,000°K in which electric fields can be built up by
asymmetrical impacts between solid particles, just as occurs in
terrestrial sand and dust storms and in the ejectamenta above
volcanoes. When these fields reach the values required for
electrical breakdown, then the latter results in those
temperatures being reached which are necessary for thermal
ionization of the gas, the 6,000°K of the photospheric arcs. When
the field in its neighbourhood is neutralized, then the arc is
extinguished, the gas cools, and the process is repeated.
Bray and Loughhead in the passage already referred to^(8.2) note
that "the dissolution of a granule appears to occur by the reverse
process, although occasionally a granule loses its identity by
coalescing with another granule", which is not surprising since
these parallel currents will tend to attract one another, just as
has been observed in solar prominences.
*(2.3) Solar Flares*
*(2.3.1) Crochets and Balmer Line Widths*
Crochets are those sudden variations in the earth's magnetic
field caused by the occurrence of solar flares and it seemed
to the writer that they might be the atmospherics radiated
by the solar lightning flash, especially as some of those
delineated by Newton^(10) had a wave form similar to those
of terrestrial atmospherics^(2.12) . As the writer had just
then developed a method of calculating the latter based on
his theory of the leader-return stroke mechanism in which
lateral corona currents flow from the discharge channel
during both these phases of the lightening flash, the same
calculation could be applied to calculate the atmospheric
radiated from a solar flare^(2.13) The values of the current
and current density obtained, 10^14 amperes and 10^-3 to
10^-5 A/crn^2 respectively, seemed quite reasonable, as did
the total rate of energy radiation from the discharge, 10^-5
of the sun's total output. There seemed to be one
insuperable difficulty, the theory led to the conclusion
that the magnetic fields in the discharge channel itself
must reach 10^4 to 10^5 gauss, and no one had previously
mentioned the existence of such fields though fields of
several thousand gauss had been observed in sunspots.
However, it was verified that magnetic fields of this order
will tend to Ha line widths between 0.8 and 8A, and a search
of the literature brought to light Ellison's^(11) observed
range of 1 to 16 A, in good agreement with the theoretical
values.
Until quite recently there remained one other apparent
difficulty. The maximum magnetic fields associated with
solar flares observed with Babcock's solar magnetometer^(12)
only reached 1000 or 2000 gauss. The writer has shown^(2.14)
that this is due to an instrumental limitation, so to speak,
since the instrument uses the lines of neutral iron. The
spectra of solar flares contain lines of levels of
excitation up to Si XII, i e., up to levels of the order of
500 eV, to say nothing of high energy X-rays^(9.2) .
Applying the "ionization potential thermometer" to which the
writer drew attention in an earlier note^(2.15) , this means
that the discharge temperature must reach values of the
order of 500,000°K. As this temperature is higher than any
mentioned in his earlier notes, it may be pointed out that
the "readings;" on this thermometer have since been checked
up to discharge temperatures of around 3,000,000°K in
laboratory electrical discharges^(2.16) , and they do not
depend on the nature of the heating process of the gas^(13) .
Theory and observation thus lead to a conception of a solar
flare as possessing an axial temperature of the order of
around 500,000°K to 1,000,000°K, a diameter of the order of
50,000 km, and a magnetic field of 10^4 to 10^5 gauss at its
surface, i.e., at, a radius of 10^3 to 10^4 km. In relation
to this description the pertinent characteristics of the
solar magnetometer are, first, that it mainly uses the
Zeeman effect in the lines g5250 and g4486 of the _neutral
iron atom_, and second that it averages the field oven
distances of the order of 10^5 km. At distances of this
order the magnetic field will have fallen to the values of
10^3 gauss recorded by the magnetometer and it is doubtful
if there will be any neutral iron atoms to record a Zeeman
effect much within this distance. So far as they go,
therefore, the recordings on the solar magnetometer would
appear to support the fields deduced from the discharge
theory of solar flares.
The theory as developed in 1949 will be seen to lead to two
obvious predictions: (1) the atmospheric radiated by the
discharge and observed at the earth will be greater if the
flare occurs at the limb and not at the centre of the sun;
(2) the atmospheric will be greater the greater the current
in the discharge, and hence the greater the magnetic field
and the width of Ha in the flare's spectrum. In confirmation
of these two deductions from the discharge theory Smith and
Smith write^(9.3) in the discussion of Dodson and Hedeman's
observations: (1) "Smaller flares near the limb are more
likely to produce crochets than are small flares near the
centre of the disk"; (2) "Crotchet-associated flares appear
to have a greater average maximum Ha line width than do
other flares". The discharge theory would thus appear to
answer the "challenge to interpretation" which Smith and
Smith write on the same page is presented by "this peculiar
distribution of the crochet flares".
*(2.3.2) Flare Energy:*
Another difficulty which the same 1949 theory clears
up^(2.13) is that found by Smith and Smith in their
discussion^(9.4) of large energy density of solar flares,
0.5 to 5.0 x 10^3 erg/cm^3 , which they contrast with the 1
to 10 erg/cm^3 of the undisturbed chromosphere. However,
just as in a lightning flash much of the pre-discharge field
energy is liberated in the discharge channel, and in a
laboratory spark discharge much of the energy stored in the
apparatus is released in the discharge channel, so the
energy of the pre-discharge field is similarly concentrated
in the flare.
The figures obtained in the 1949 note^(2.13) were, for the
current, 10^14 A, electric field, 8 x 10^-2 V/cm, and the
flare radius was taken as 10^3 to 10^4 km. Comparison with
Ellison's observed line-widths indicated that either the
current was greater than 10^14 A or the radius was less than
10^3 km. If then we take the values given we may expect a
lower limit for the energy density. The value so obtained is
about 2 x 10^3 erg/cm^3 which again agrees well with these
subsequent observations referred to by Smith and Smith.
*(2.3.3) Pressure in Flares:*
In 1937 Bellaschi^(14) showed that the axial pressure in an
electrical discharge carrying a current I with a current
density i would ultimately be increased by a factor10^-8 Ii.
With the values of current and current density in a solar
flare obtained in 1949 this led to the prediction that the
pressure in the axial regions of a flare should ultimately
be increased by a factor of between 10 and 1,000 according
as the current density is 10^-3 or 10^-5 A/cm^2 . In 1961
Jefferies and Orrall^(15) confirmed this deduction from the
discharge theory when they found that "the gas pressure must
have been ten times higher at the centre of the flare than
20,000 km out", since the value they thus quote for the
radius of the flare corresponds to that which gave the
smaller current density in the 1949 note on solar flares
already referred to^(2.13) .
*(2.3.4) Gas Jets and Magnetic Storms:*
One of the great advantages of the electrical discharge
theory has been referred to in the previous section. It has
built into it the most powerful known atmospheric
aggregative force^(2.17) . When it operates as it does in
all electrical discharges from the welding arc to those
which form the arms of the galaxies, gravitation cease's to
have any significant effect. This leads to a second great
advantage possessed by the theory^(2.18) , for this
aggregative force varies with the current and the current
density in the discharge which both vary along these
discharge channels. Beyond some point both will decrease
radially outward from the sun and will, therefore, result in
a pressure gradient and hence a flow of gas along the
flare^(2.19) . It is this plasma jet which is responsible
for the main phase of the magnetic storms which are observed
to begin suddenly at the earth about a day after the
commencement of the solar flare^(2.20) . This represents a
mean velocity of about 1,000 km/sec and H atoms have
actually been observed entering the earth's upper atmosphere
at velocities of up to 3,500 km/sec (Ref. 16), The
velocities of these discharge-generated jets can often be
used to determine the temperature of the gas^(2.21) , and it
was pointed out^(2.22) that these velocities indicate that
the temperature of the solar flare discharge reaches values
of the order of 1,000,000°K. This prediction had not long to
wait for confirmation by satellite observations^(2.23) .
*(2.3.5) Thermal and Non-Thermal Sources:*
Recently^(2.24) the writer developed a suggestion he put
forward many years earlier^(2.25) to account for non-thermal
cosmic ray and other sources. It in turn was the development
of a still earlier suggestion of C.T.R. Wilson^(4.2) that
the soft cosmic rays might be runaway electrons accelerated
in the electric fields of thunderstorms. In 1941 the writer
had shown that the over-all electric fields postulated by
Wilson do not exist in thunderstorms but in 1952 he showed
that the mechanism might be operative in the
field-concentrations built up during the propagation of
these cosmic leader strokes. Since the temperature of the
discharge in solar flares reaches more than 10^8 °K, the
velocity of the H atoms reaches about 2 x 10^8 cm/sec and
the velocity of the electrons reaches more than 40 times
this or about 8 x 10^9 cm/sec. If the solar electric field
is positive relative to the gravitational field, like the
field in a thundercloud, then some of these high speed
electrons can be pulled out in the field concentration ahead
of the plasma jet and further accelerated. They will then
account for the soft cosmic rays which arrive at the earth
within half-an-hour of the start of a flare, indicating an
average velocity from sun to earth of around 10^10 cm/sec
and an acceleration in the field by a factor of only about,
1.25.
Further support for this suggestion is afforded by the
results of the study of the corresponding characteristic of
galactic discharges in Section^(4.5) .
*(2.3.6) Forbush Decreases:*
Coincident with the arrival at the earth of the discharge
and plasma jet some 24 hours after these cosmic rays, the
earth will become enveloped in the discharge's magnetic
field. This will have two effects: it will prevent soft
cosmic rays from reaching the earth, and so account for the
observed Forbush decreases in cosmic ray activity observed
to accompany rnagnetic storm^(17) . it, will also explain
how the charged H atoms of the solar stream reach much lower
levels in the earth's field and atmosphere than they
otherwise would, without having to make the quite drastic
assumption of Akasofu's theory(18) of magnetic storms that
atoms of gas can travel at these velocities and yet be
unionized.
*(2.4) Sunspots:*
*(2.4.1) Explanation and Structure*
Whereas most astrophysical theories were and probably still
are embarrassed by the observation of the low temperatures
of sunspot's in which we are able to see further down into
the sun's atmosphere, this relatively low gas temperature
naturally confirmed one of the discharge theories earliest
tacit predictions, that, the temperature of the atmosphere
surrounding the photospheric arcs must, be much lower than
that of the discharges themselves.
It was suggested in the original summary of these
ideas^(2.7) that the cause of the extinction of the
photospheric arcs is the occurrence of a much larger
discharge or facula which neutralized the electric field in
their immediate neighbourhood. It was then emphasized in
support of this view that, "sunspots are _always_
accompanied by faculae, and are in fact preceded by them",
as had been then determined at Greenwich and as is generally
agreed^(19.1) .
The existence of the penumbra too was readily accounted for
and followed from the attraction on one another of parallel
currents. The current decreases outwards in these
atmospheric discharges since the current passing any point
has to maintain the lateral corona currents beyond that
point. It follows that the the discharges near the "surface"
of the photosphrere will be pulled outwards from the centre
of the spot and downwards so that a vertical section through
a spot will have the form shown in Fig.1, in which the width
of the individual arc channels represents diagrammatically
the magnitude of the current.
Diagram of vertical section through a sunspot
*Fig.1: Diagram of vertical section through a sunspot*
*(2.4.2) The Evershed Effect:*
Each of the arc channels in Fig.1 will have associated with
it an axial jet of hot gas its velocity depending on the arc
temperature. It followed^(2.26, 2.27) therefore that there
should be jets of hot gas moving along these bent discharge
paths at the velocity of sound in ionized atomic hydrogen at
6,000°K or 8 km/sec. Evershed^(20.1) had observed the flow
of gas, which the theory leads us to expect, in 1909, but
its velocity as observed by him and his successors in the
following fifty years and more had been 1 to 2 km/sec. The
writer had enquired at Oxford, where these velocities had
been studied for ten years or more, whether they had found
evidence of the higher velocities which the theory
predicted. They could not but the higher velocities up to 8
km/sec have since been observed by Bumba, as was announced
by Severny^(21.1) at an I.A.U. Symposium on cosmic gas
dynamics in 1961.
*(2.4.3) Sunspot Magnetic Fields*
One of the outstanding difficulties faced by the discharge
theory during its whole life, has been the divergence
between it and. observations on the magnetic fields of
sunspots during the last 50 years or so at Mount Wilson and
other observatories and the resulting "classical picture" of
sunspot magnetic fields illustrated in every text book on
astronomy. For it will be obvious from Fig.1 that the
magnctie fields, being at right angles to the photospheric
arcs, must be transverse through-out the umbra, and that
only over the surrounding rim, or penumbra, of the spot
should there be a vertical or longitudinal component. Much
effort had been expended by the writer during the last
twenty-five years in an endeavour to make the theoretical
transverse fields longitudinal but to no avail, and the
effort turns out to have been entirely wasted, as
observations made by Evershed^(20.2) in 1941 would have
demonstrated had the writer but known of their existence.
It was gratifying and surprising^(2.28) to read in Bray and
Loughhead's recent book on "sunspots" at the end of a long
section describing the "classical picture", "that the
observations of Evershed and Severny^(21.2) thus suggest a
field of configuration very different from the classical
picture. On the new view a predominantly transverse field in
the umbra is surrounded by a large vertical field in the
penumbra". Severny finds zero vertical field in some spots,
in which the field is entirely transverse, and that vertical
fields are observed only over the penumbra of spots, all
exactly in accord with the predictions of the electrical
discharge theory since its initiation in 1941.
*(2.5) Solar Discharge Temperature*
In all stellar atmospheres, that of the sun included, the
discharges are usually propagated outwards, that is they are
propagated down a density gradient. It was emphasized^(2.17) that
these long atmospheric discharges act 1ike "energy pumps".
We see the same effect in a lightning flash. The electrical energy
is generated five to ten kilometres up in the thundercloud, but
the leaderstroke short circuits the field between cloud and earth,
and the largest current flows just outside the earth's surface.
Just so, in these stellar atmospheric discharges the leaderstroke
short circuits the electric field so that energy generated lower
down in regions of higher density in the star's atmosphere is
liberated further out in regions of lower density and longer mean
free path. It is, therefore, to be expected that the discharge
temperature will increase as the discharge is propagated outwards.
The 6,000°K of the photospheric arcs becomes the 10,000°K to
20,000°K of the chromospheric glow discharges and this in turn
becomes the 1,000,000°K or 2,000,000°K of the discharges of the
corona. It was, therefore, not altogether surprising when the
conclusion already mentioned^(2.22) had to he drawn that the
discharges associated with solar flares actually reach
temperatures of over 100,000,000°K.
A similar rise in temperature is observed when discharges are
propagated outwards in the denser atmospheres of the
combination-spectra stars but having a lower density gradient when
the 5000°K to 10,000°K of the initial discharges increases after a
period of the order of 100 or 200 days to temperatures of hundreds
of thousands of degrees and lines of Fe X and Fe XIV appear in
their spectra^(2.11) .
*(3) the Stars*
*(3.1) Extended Atmospheres*
When the general conclusion was reached in 1941 that all cosmic,
atmospheric phenomena derive from electrical discharges, a
conclusion at once followed which was disturbing to one who knew
little about the results of astronomical research. If the
outbursts in the long-period variable stars which last for about a
year and if the nova outbursts which can last for ten years or
more, are the result of electrical discharges, then, since the
velocity of propagation of an electrical discharge is independent
of the gas density, it followed that stars must exist with
atmospheres which can contain such discharges. The velocity of
propagation of the lightning leader-stroke is about 3 x 10^7
cm/sec, so the stellar atmospheres required must be of the order
of 10^14 or 10^15 cm in depth, i.e., of the order of our whole
planetary system. This seemed likely to remain a considerable
theoretical stumbling block until the writer read of the existence
of such stars in a supplementary note at the end of Russell, Dugan
and Stewart's "Astronomy"^(22) Fortunately such stars as e and z
Aurigae, which are of this type, are members of binary pairs
revolving in the line of sight, the other star being a small hot
star. Some considerable time before the latter star goes into
complete eclipse behind the larger star absorption lines begin to
appear in its spectrum due to the passage of its light through the
extended atmosphere of the other star, demonstrating the existence
of just such extended atmospheres as the theory had predicted. An
apparent stumbling block thus became a correspondingly strong
argument in the theory's support.
The "new" observation was not entirely unexpected for it had
seemed most improbably that the Sun could go on for 10^9 year,
emitting the jets which had been postulated to account for
magnetic storms without giving rise to an extensive tenuous
atmosphere which the discharge theory of magnetic storms also
required. The explanation of these extended atmospheres is given
in section (3.7).
*(3.2) The Long-Period Variable Stars*
*(3.2.1) Electric Field Generation:*
If, as was seen in Section (2.2), the conditions for the
build-up of electric fields are met in the solar atmosphere,
by so much the more are they met in the atmospheres of the
long-period variable stars. Even their "surface"
temperatures reach only 1,500° to 4,000°K and the light from
these surfaces in passing through their outer atmospheres is
subject to considerable absorption by such molecules as TiO
and ZrO which dissociate at around 1,600°K and 2,500°K
respectively. Furthermore, the Doppler displacements of the
emission lines when they appear during the outbursts show
that gas movements of up to about 10 km/sec occur in their
atmospheres. The conditions for the generation of electric
fields as discussed^(2.11) in 1955 are, therefore, seen to
be amply met in their atmospheres.
*(3.2.2) Veiling*
This conclusion is confirmed by the explanation offered to
account for a large part of the variation of the stars'
light. The addition of the bright emission lines in their
spectra, which denote the occurrence of the discharges in
their atmospheres and which lead to their detection as
long-period variables, account for a part of their variation
in brightness, but much of the variation is due to veiling
of the stars at minimum by the increased dust in their
atmospheres^(23.1) .
*(3.2.3) Epoch of Appearance of Emission Lines:*
Merrill writes^(23.2) that "Displays of bright lines near
minimum light are specially curious" and for this reason
refers to them later as "the bizarre emission lines". On the
contrary the emission lines appear in the spectra, of the
long-period variable stars just when the theory predicts
that they should^(2.11, 2.29) . As the general atmospheric
temperature falls after a "thunderstorm season", then the
amount of dust in the atmosphere will increase and with it
the rate of electric field generation. In the absence of any
other cause of energy liberation this will go on until the
field builds up to the breakdown value. It follows that, the
latter will occur with the resulting emission of the bright
line spectrum somewhere around light minimum.
*(3.2.4) Periods*
The periods of light variation in the long-period variable
stars will depend mainly on the time required for the
electric field to build up to the breakdown value. A rough
comparison^(2.11) with the time required for this process in
thunderclouds, taken as 10^2 sec, taking into account the
main factors involved, namely gas density and velocity, and
the gravitational field, predicted that the times required
would lie between 10^6 and 10^9 sec. The observed periods of
these stars lie largely between 100 and 600 days or 10^7 to
10^8 sec.
*(3.2.5) Duration of Bright Line Spectra*
Similarly the theory predicts that the bright emission lines
will be emitted for a time obtained by dividing the
atmospheric dimensions, 10^14 to 10^15 cm, by the velocity
of propagation of electrical discharges, 3 x 10^7 cm/sec or
the order of 10^7 sec. As the bright lines are emitted for
times of the order of half the stars' periods, the theory's
prediction is again in good agreement with observations.
*(3.2.6) Variations of Period*
In putting forward the new theory of the lightning
discharge^(2.9) this writer showed that it accounted for the
considerable variation observed in lightning currents. The
occurrence of these long atmospheric electrical discharges
depends on the coexistence of two factors: (1) an average
field adequate to maintain the discharge when once it is
initiated by the transition from a field-maintained corona
type of discharge to a thermally ionized discharge column;
(2) in this low average field there must exist a
field-concentration adequate to initiate this transition. In
New York, for example, this transition occurs readily at the
top of the Empire State Building, which initiates upward
leaderstrokes^(24) . In purely atmospheric discharges or
discharges from cloud to earth it will be effected by
elongatod volumes of space charge in the thundercloud. The
smaller the field-concentration the longer will breakdown be
delayed, and the greater will be the current in the
discharge when it does occur. Just as this consideration
accounts for the observed variation in lightning currents,
so it leads us to expect^(2.30) that the maximum brightness
reached in these stellar thunderstorms and the
period-duration will also vary and this is observed.
*(3.2.7) Variation of Spectrum with Epoch*
From the general consideration that the time required for
the electric field to build up to breakdown will be less the
greater the density and the greater the gravitational force,
breakdown will start low down in the star's atmosphere, and
the discharges will be propagated out towards its
periphery^(2.11) . When the emission lines first appear,
therefore, the light; will be subject to maximum absorption,
and the effects of this atmospheric absorption will decrease
as the period progresses, on the present view of these
outbursts. This is in fact what is observed to happen^(23.3)
. Groups of lines, such as the Balmer series of hydrogen,
and smaller groups, or multiplets, in the iron spectrum, for
example, have definite intensity ratios in laboratory
spectra. When the bright lines first appear around the time
of minimum light the relationships between these line
intensities are found to be considerably modified by the
differential absorption to which they are subjected on the
way out by the molecules of metal oxides, etc., in the
atmosphere. This mutilation of the customary relationships
gradually decreases as the outburst continues, until,
towards its end, their ratios approach those observed in the
laboratory.
*(3.2.8) Change of Spectral Type:*
At any point in the evolutionary progress of one of these
stars the occurrence of the discharges in its atmosphere
followed by a period of cooling and field-building will
cause its general mean atmospheric temperature to vary
between two approximate limits. If the whole atmosphere is
gradually cooling, for example, a condition in which carbon
particles (freezing point ~3,500°K) are formed at minimum
and vaporized at maximum brightness, will be followed by a
phase in which, say, zirconium oxide (freezing point
~2,500°K) plays a corresponding role. When the mean
temperature falls by another 1,000°K or so, ZrO will be
replaced by TiO. There are in fact three types of these
long-period variable stars, and they are distinguished by
the appearance in their spectra of the absorption bands of
these three molecules. Stars of the two Classes R and N show
the bands of C_2 and CN; Class S stars show the bands of
ZrO; and Class M those of TiO. These differences have
usually been attributed to differences in the chemical
constitution of the stars' atmospheres, but for the above
reasons the writer suggested that they may instead be due to
differences in the physical conditions^(2.29) . This
suggestion, or prediction, is also subject to observational
check. On the earlier chemical explanation, it would be
quite impossible for one star to change type during an
outburst, whereas on the discharge theory's physical
explanation it would be quite possible for all the molecules
of TiO, say, to be dissociated during an unduly high
maximum, so that its bands would disappear from the star's
spectrum, and at the same time sufficient particles of the
normally solid ZrO could be vaporized, so that its bands
would replace those of TiO. Fortunately such stars do exist.
c Cygni is one whose spectral class occasionally changes
from M (bands of TiO) to S (bands of ZrO) as the result of
specially great outbursts^(25) .
It would thus appear that these stars are not necessarily in
conflict with the general uniformity of chemical
constitution of matter observed throughout the universe, as
they were generally considered to be, nor do they
necessarily indicate a trifurcation of the stellar
evolutionary sequence in the way they are generally regarded
as doing.
*(3.2.9) Gas Velocities*
The gas velocities observed in these stars afforded the
first extra-terrestrial application of the gas-velocity
thermometer^(2.18) . It had been shown^(2.6) that the jets
of gas generated when a lightning flash hits the earth
account for metal atoms being carried half to five meters up
the channel during the times available and thus explained
Isräel and Würm's observation of metal lines in lightning
spectra, up to heights of about two metres^(26) .
The appearance of emission lines of hydrogen and ionized
metals in the spectra of the long-period variables together
with the ionization potential thermometer indicated
discharge temperatures of 5,000°K to 10,000°K, so the theory
suggested^(2.18) that the gas velocities should lie between
the velocities of sound in ionized atomic hydrogen at these
two temperatures, or between the values of 8.5 and 12
km/sec. No satisfactory explanation for this outward flow of
gas had previously been offered and considering the whole
range of observed gas velocities up to thousands of km/sec
this was a very narrow theoretical target, yet it contained
the two mean values of 11 km/sec, which Merrill^(23.4)
obtained from a group of 72 long-period variables, and 9
km/sec, which his colleague at Mount Wilson, Joy^(27) ,
obtained from a group of closely associated irregular variables.
(3.2.10) Gas Velocities in AX Persei
Though AX Persei is not a long-period variable but a
"combination-spectra" star it is sufficiently close to the
former for the gas velocity of 110 km/sec observed in it by
Merrill^(23.5) to come as an unpleasant shock. Since the
velocity of sound only increases as the square root of the
temperature, this increase by a factor 10 in the velocity
implied that the discharge temperatures in AX Persei must
reach much higher values than they do in the long-period
variables. This conclusion is confirmed by the
observation^(28) that the lines of highly ionized atoms, for
example, 9 times ionised iron, Fe X, and 6 times ionized
calcium, Ca. VII, appear in the spectra of AX Persei and
associated stars such as CI Cygni.
*(3.3) Cometary Nebulae*
The existence of cometary nebulae such as that associated with the
star R Monocerotis, Hubble's Variable Nebula show the result of
the aggregative force of earlier discharges, probably of the nova
type, in their atmosphere. In this region of increased density
discharges are practically continuous and account for the
variability of the light of the nebula. This view suggested an
explanation for Beals' observations on the well-known star P
Cygni^(29) .
*(3.4) Gas Velocities in P Cygni and c Cygni:*
The diagram (Fig.2b) of the conditions in the discharge in the
star P Cygni are taken from an earlier paper^(2.31) and the
discharge channel is assumed to be towards us in the line of
sight. The only point at which the gas should have the velocity of
sound in ionized atomic hydrogen is in the throat of the expanding
nozzle formed by the discharge channel, where the temperature is
greatest. Beyond the throat the gas cools and accelerates, the
flow becoming more and more supersonic. The highest level of
excitation is 47 eV of the CIII and NIII ions, indicating a
temperature of 47,000°K. The theoretical velocity is, therefore,
28 km/sec and this is precisely the velocity of the CIII ions
observed by Beals. This was the first application of the
ionisation potential thermometer to determine these discharge
temperatures.
Hubble's Variable Nebula (R Monocerotis) *Fig.2 (a): Photograph of
Hubble's Variable Nebula
(R Monocerotis).*
*Fig. 2(b): Diagram of the discharge channel in the atmosphere of
P Cygni.* Discharge channel in the atmosphere of P Cygni
In c Cygni the levels of excitation and the gas velocities
observed by Merrill are both much lower^(2.15) , but show a
similar increase in velocity with decrease in the level of
excitation, and the lowest gas velocity is again close to the
expected value appropriate to the highest level of excitation.
*(3.5) Planetary Nebulae*
*(3.5.1) Two-Armed Structure*
As mentioned in the introduction one of the most surprising
conclusions to which the theory led was that two-armed
nebula should exist on a stellar atmospheric scale quite
analogous to their counterparts on a galactic scale and that
photographs of them very probably existed in view of the
existence of such photographs as that of Hubble's Variable
Nebula. It was almost equally surprising that even those who
had worked on planetary nebulae for many years were unable
to refer the writer to them until Merrill wrote that the
likeliest place to look for them was in a paper published 42
years earlier by Curtis at Lick Observatory(30), and there
indeed they were found.
Two-armed planetary nebulae
*Fig.3: Rough sketch of expected form of two-armed planetary
nebulae.*
The prediction derived^(2.1) , first, from the explanation
given for the spectrum of P Cygni, and its success naturally
helps to confirm that explanation and, second, from the
observation that stars like g Cassiopeiae exist in which
there are not only emission lines displaced to the violet,
but pairs of emission lines, one displaced to the violet,
the other to the red. These could obviously be explained if
double nebulae existed as in the diagram. If the two arms
were in the line of sight then the two discharge-generated
jets would give rise to the two emission components.
Merrill 's suggestion immediately led to the confirmation of
the success of this prediction, as will be seen from the
examples in Fig.4, taken from Curtis' paper.
NGC 2371/2 (Gemini or Peanut Nebula)
*NGC 2371/2* NGC 2392 (Eskimo Nebula
*NGC 2392* NGC 3587 (Owl Nebula)
*NGC 3587*
NGC 2452 Nebula
*NGC 2452* NGC 6853 (Dumbell Nebula) (M27)
*NGC 6853* NGC 4361 (Lawn Sprinkler Nebula)
*NGC 4361*
NGC 6058 Nebula
*NGC 6058* NGC 6563 Nebula
*NGC 6563*
NGC 6543 (cat's eye nebula)
*NGC 6543* NGC 6778 Nebula
*NGC 6778*
*
Fig.4: Photographs of planetary nebulae showing pairs of
discharge channels (Curtis: Lick Observatory).
* Note: The images of nebulae from this original article
were too poor to reproduce, and have been replaced by
alternative images from a variety of sources. The captions
remain unchanged
*(3.5.2) Gas Movements*
A more detailed study (Ref. 2.32, Figs.4 and 6) of the gas
movements in two of the ten nebulae which had entirely
baffed Campbell and Moore^(31) showed that they are at once
separable into two jets, straight in NGC 2392, the type
nebula of the group of ten and spiral, as its photograph
suggests, in NGC 6543. Both spiral and barred-spiral
discharge channels occur on a stellar as well as a galactic
scale, but so far no irregular stellar nebulae have been
photographed so far as the writer is aware. It may be that
the small scale does not allow for the development of
irregular nebulae, that there is always sufficient remnant
angular momentum of the gas to lead to the development of a
diametral rotational and, therefore, electrical plane.
*(3.5.3) Feast's Data on Gas Velocities*
The writer's friend, D.R. Barber, ex-Superintendent of the
Norman Lockyer Observatory, very kindly drew his attention
to the close agreement of the gas velocities observed by
Feast^(32) recently in a number of planetary nebulae, with
those to be expected from the discharge theory. The mean
level of excitation of the lines used by Feast is 36.2 eV,
indicating a mean discharge temperature of around 36,200°K
and, therefore, a mean gas velocity of about 23 km/sec. Tlie
mean velocity observed by Feast is 22 ± 7 km/sec.
Zanstra 'stellar' temperatures
*Fig.5: Zanstra "stellar" temperatures estimated from
intensities of spectrum lines of different energy levels.*
*(3.5.4) Zanstra's Stellar Tempuratures*
Zanstra^(33) has also put forward a theory of planetary
nebulae which is based on two fundamental hypotheses: (1)
the nebula is a more or less uniform ball of gas; (2) it
shines by fluorescent radiation deriving from the light of
the central star.
Observations would seem to show that neither of these
hypotheses is correct. On the discharge theory it is a
two-armed structure shining by the light of the discharges
still going on in it.
Two simple tests can decide between the two theories. In the
first place photographs show that the nebulae are two-armed
in accordance with the discharge theory's prediction. Those
which give the impression of a star surrounded by a luminous
ring are those in which we are looking along a discharge
channel. They are those in which the gas jets are in the
line of sight. Secondly, Zanstra's theory leads to a
determination of the temperature of the central star from
the intensity of the bright emission lines in its spectrum,
so obviously the values so derived for any one star should
all be the same. On the contrary on the discharge theory the
result must depend on the temperature of the gas where the
spectrum line is emitted and, therefore, the value obtained
should be linearly correlated with the level of excitation
of the line used in its determination. (See Fig. 11)
The writer, therefore, plotted the "stellar temperatures"
given to illustrate Zanstra's theory in Ambartsumian's
"Theoretical Astrophysics"^(34) against the level of
excitation of the lines, and it can be seen in Fig.5 that
all the points fall reasonably close to the writer's
theoretical line.
*(3.6) Stellar Rotation*
*(3.6.1) Dependence on Temperature*
Throughout this investigation, right from its initiation,
there has been a close link up with laboratory and
terrestrial electrical discharges. The origin of cosmic gas
jets, for example, is the same as that of those which
King^(35) showed render arc welding possible. The
ionization-potential-thermometer has been checked up to much
higher temperatures in laboratory discharges than those to
which it has been applied in cosmic electrical
discharges^(2.16) The discussion of what has been regarded
for over 80 years as the effect of stellar rotation on line
broadening is yet another good example of the inter-relation
of phenomena of widely different magnitudes.
It seemed to the writer^(2.33) that in all probability what
is actually rotating at these very high speeds is not the
star itself but huge volumes of gas escaping from the
discharge channel. Again a simple test of this hypothesis is
immediately available, as will be apparent from the diagram
in Fig.2(b). If the gas escapes from the channel where lines
of CIII are in emission its velocity would be 28 km/sec, Hd
lines should show 189 km/sec and Ha lines 280 km/sec. D.R.
Barber was, therefore, consulted as to whether he could
supply examples of the widths of say the Balmer lines of
hydrogen varying along the series. He replied immediately
with the data obtained by Pottasch^(36) from the spectrum of
g Cassiopeiae given in the Table and it will be seen from
the Table that another prediction was immediately successful.
*Table
Gas Velocities from Hydrogen Line Widths in the Spectrum of
g Cassiopeiae.*
Line Hg Hd He H8 H9 H10 H11
Width (km/sec) 1900 1650 1480 1310 1150 940 850
*(3.6.2) Stars of Types B and Be*
Since on the electrical discharge theory the addition of the
e in the denomination of stellar types indicates the
existence of discharges in the atmosphere of that particular
star, a comparison which immediately suggested itself was
between the "rotational" effects observed in stars of types
B and Be. Fig.6 (Slettebak^(37) ) again shows how well the
expectations of the theory are fulfilled. The "rotational
velocities" of Be stars are considerably higher than those
of B stars.
*(3.6.3) Flare Stars*
Another type of star in which similar effects might be
expected are the flare stars, the flares denoting the
occurrence of huge discharges in their atmospheres. These
stars also show much wider lines than are normal for their
spectral type and this increased width has hitherto been
attributed to high rotational velocities of the stars
themselves^(38.1) .
*(3.6.4) Current Theories*
In "Stellar Atmospheres" there is a long chapter on stellar
rotation by Huang and Struve the last page of which tends to
throw the whole subject into the melting pot^(38.2) . In
contrast to the writer's experience in seeking out evidence
of the observed relationship between "rate of rotation" and
gas temperature in support of the discharge theory's
prediction, the authors are quite non-plussed by the finding
of this evidence and write "since it is difficult to suppose
that there is a correlation between stellar rotation and
surface temperature or pressure, we again conclude that the
observed line widths in super giant stars are not due to
rotation". The suggestions they have to offer in the next
two paragraphs, the last in their chapter, all point in the
direction of the theory put forward herein. For example:
"The nature of the mass motions in super giants probably
resembles prominence activity", and "the motions observed in
stellar atmospheres may be related to the ejection
phenomenon", but these are all phenomena which only receive
logically inter-related explanations on the discharge theory.
The explanation afforded by the theory for these broadened
spectrum lines led to a theory of ball lightning^(34.2, 35)
which explains all the available data, and is supported by
copious photographs of the lightning, long-spark and other
laboratory discharges.
Comparison of rotational velocities of stars of Types B and Be
*Fig.6: Comparison of rotational velocities of stars of
Types B and Be (Slettebak)*.
*(3.7) Low Stellar Atmospheric Density Gradients and Apparent Loss
of Matter*
In first emphasizing the possible use of the Doppler shifts of the
lines in their spectra as the basis of a cosmic gas-velocity
thermometer in 1956, it was pointed out^(2.17) that this
characteristic of electrical discharges would account for another
well known characteristic of many stars, namely that the density
gradients in their atmospheres are remarkably small; more than ten
times less than can be accounted for when all account has been
taken of all known factors, including turbulence.
A corollary to this general explanation of the physical process by
which these atmospheres are extended by the discharge-generated
gas jets is that the theory also throws a new light on those
phenomena which have usually been regarded as demonstrating the
continuous loss of matter from these stars in the outer
atmospheres of which electrical discharges are occurring. The
matter is not necessarily being lost to the star, but is merely
being pushed further out in its atmosphere, which last will
ultimately bring it to rest.
*(3.8) g Cassiopeiae*
*(3.8.1) Rotating Four-Armed Nebula*
McLaughlin^(39) , one of the leading authorities on these
emission-line stars, five years ago wrote that "the
behaviour of g Cassiopeiae violated almost all my
generalizations" so its vagaries would appear to form a good
test for the application of the discharge theory. A full
account of this application will be found in a paper
published in the following year^(2.31) , so only a few of
the main agreements between theory and observation need be
outlined here, for far from proving a difficult subject,
this star provided a number of confirmations of the theory's
predictions in addition to that discussed in Section
(3.6.1). The general conclusion reached was that g
Cassiopeiae is the central star of a four-armed nebula which
rotates in a period of 4 years, the arms being in the plane
of sight so that there is a partial eclipse of the star by
one of the arms of the nebula every year, each of which
reduces the star's light, by about a fifth of a
magnitude^(2.31) (Fig.6). From a study of the past behaviour
of this star D.R. Barber has found evidence that outbursts
occur in each pair of arms successively in an overall period
of 11 years, the intervals between successive outbursts
being 7 and 4 years respectively.
*(3.8.2) Variation of Emission Line Widths*
During each outburst, such as that studied in detail by
Baldwin^(40) from April, 1935 to November, 1938, there are
discharges in each of one pair of arms and hence two
diametrically opposed jets of hot gas. When the jets are in
the line of sight, as happens every two years, the emission
lines are broadened, the velocities of the jets being ±150
km/sec around J.D. 2428200. When the arms involved are at
right angles to the line of sight, around J.D. 2428800, the
two bright emission components merge into one undisplaced.
narrow line but the star's luminosity is high^(2.31)
(Fig.5). The components again separate to reach velocities
of ±120 km/sec around J.D. 2429100.
*(3.8.3) Relation Between Intensities and Velocities of the
Emission Line Components*
The velocity indicated by the Doppler shift of each of the
two components, R (red) and V (violet), should be linked
with their intensities. Increase in the line intensity
denotes an increase in the current in the discharge and in
its temperature, which will lead to an increase in the
velocity of the jet. That this expected relationship is
observed is indicated by the Table:
*Period* *Intensity of R and V Components* *Velocity of R
and V Components V_R and V_V *
*1935-6* R > V V_R > V_V
*1936-8* V > R V_V > V_R
*1936-9* R > V V_R > V_V
*(3.8.4) Interchange of Line Components*
The 1955 outburst was also studied by W.J.S.Lockyer^(41) at
the Norman Lockyer Observatory and it is interesting that
one of his conclusions, which was subject to criticism, was
that after the emission components had come together when
the lines were at right angles to the line of sight, they
had interchanged when they again separated, so that what had
been the R component was now the V component, and vice
versa. It will be seen that Lockyer's conclusion was correct.
*(3.9) Novae*
*(3.9.1) Line Broadening in Initial Stages*
In presenting for publication the results described in
Section (2.3.1) the writer emphasized^(2.13) that the
spectra of novae should show even greater line broadening
than is observed in the spectra of solar flares, since the
nova outburst is much greater than any solar flare. In
accordance with this expectation it was recalled that the
lines in the spectra of supernovae are so widened as almost
to give the impression of a continuum.
It came as no surprise, therefore, to find that Stratton's
measurements of the widths of the Balmer lines in the early
spectra of Nova Herculis are proportional to the square of
the wavelength, and not simply to the wavelength^(2.36) ,
i.e., their broadening is the result of Zeeman effect and
not, as was usually supposed, of Doppler effect. When the
note based on this observation was sent to "Observatory" one
of the Editors wrote that it was interesting that the
writer's theory led to the expectation of a broadening dl
[proportional to] l^2 *, since this law had earlier been
observed by Wright^(42) in the early stages of N.
Geminorum,1912. Though at that time Stratton was strongly
opposed to the existence of the l^2 -law, in later years he
actually advised the writer to "plug at your l^2 problem",
as no one had any alternative explanation to account for it.
*(3.9.2) Current Wave-Shape*
All atmospheric discharges will have similar current
wave-shapes. A relatively rapid rise to peak current will be
followed by a somewhat slower decline and a long tail, the
form we are familiar with in the lightning discharge. This
is for example the wave-form shown by the broadening of the
Ha line in solar flares. It is also a well-known feature of
the spectra during the initial stages of novae and efforts
have been made by many investigators to explain it in terms
of a rapid acceleration of the luminous gas followed by an
almost equally rapid deceleration. As this part of the
wave-form coincides with the period during which the
line-broadening, dlal^2 , is that of the Zeeman effect, it
is at once explained by the rise and fall of the current in
the discharge.
*(3.9.3) Pinching of the Discharge*
Attention was recently directed to another interesting
link-up between discharge phenomena on the terrestrial,
stellar and galactic scales^(2.37, 2.38) , and this proved
yet another example of the elucidation of terrestrial
discharge phenomena from a study of their cosmic
counterparts. Many novae, such as N. Aurigae, 1891 and N.
Herculis, 1934 (Fig.7) have been practically extinguished
soon after maximum magnitude or peak current. The light of
both stars fell abruptly by _nine magnitudes_. This can only
be accounted for by pinching out of the discharge.
Photographic evidence of the occurrence of this phenomenon
has been obtained in a lightning flash, and in a galactic
discharge^(2.30) (Fig.3).
This suggestion led to a search of the literature for
oscillographic evidence of pinched lightning discharges
which brought to light the oscillogram shown in Fig.8 (Ref.
2.39), in which the lightning current wave is shown on two
different time scales. The cause of the pinching is
discussed in a recent note^(2.37) It results from the
increase in pressure due to both the temperature rise and
the aggregative force of the discharge. In the lightning
discharge the combined effect will be to raise the pressure
to well over 100 atmospheres. It has been found that the
voltage gradient required to maintain a discharge increases
as the square root of the pressure^(2.40, 2.41) so that
while the initial field may be adequate to maintain the
leader stroke or the initial stages of the nova or galactic
discharges, it may be inadequate to maintain the discharge
in these later high pressure stages.
Light curve of Nova Herculis 1934
*Fig.7: Light curve of Nova Herculis 1934.*
*Fig.8: Oscillogram of high lightning current wave (Berger
and Vogelsanger). Curve shown on two time scales*
Oscillogram of high lightning current wave
*(3.9.4) Two Discharges*
In R Monocerotis (Hubble's Variable Nebula, Fig. 2a) and in
others of the cometary nebulae the originating nova outburst
had taken the form of a single discharge. Most planetary
nebulae, however, as we have seen in Section (3.5.1) are
two-armed as are their counterparts on a galactic scale. In
an E.R.A. report in 1958 (Ref. 2.42) the writer explained
how this will come about on the electrical discharge theory.
Though there will in all probability be one initial and main
discharge, it is quite probable that conditions will
approach breakdown elsewhere in the stellar or galactic
atmosphere, and that the ultra-violet and thermal radiation
from the initial discharge will trigger off other discharges
in both hemispheres. Those in the same hemisphere as the
major discharge will be electromagnetically attracted to it;
those in the opposite hemisphere will be repelled to the
diametrically opposite point in the atmosphere.
In confirmation of this expectation Pearson^(43) found that
the observations on N. Aquilae, 1918 could best be explained
on the hypothesis of two diametrically opposed gas jets and
in the "Encyclopaedia of Astronomy" of Rudaux and de
Vancouleurs it is stated^(19.2) as a generalization that "In
fact, it is known that the gases are not expelled uniformly
by a nova, but primarily in two favoured and diametrically
opposed directions". This is also confirmed by the detailed
descriptions of individual novae given in Cecilia
Payne-Gaposchkin's "Galactic Novae".
The main difficulties in the way of recognizing planetary
nebulae as later stages of novae have been: (1) the much
lower gas velocities in the nebulae, and (2) the relatively
small number of planetary nebulae. However, the difference
in the velocities is simply explained by the reduction in
the discharge temperature toward the end of the discharge.
The discharge-generated gas jet has become a pale shadow of
that generated in the high current phase, when to judge from
its velocity, the discharge temperature must on occasions
have reached millions or hundreds of millions of degrees.
Secondly, the final stage of a planetary nebula will be
invisible, when the discharge ceases, so we do not expect to
find as many planetary nebulae as there have been novae in
our galaxy.
*(4) Galaxies*
*(4.1) Galactic Evolution*
*(4.1.1) Hubble's Scheme*
The theory seemed to offer a satisfactory background on
which Hubble's scheme of galactic evolution, Fig.9 (Ref.
44.1) could be explained. The atmospheric electric field is
built up during stages E0 to E7; breakdown occurs at around
Type S0 when the discharge channels form the spiral or
barred spiral arms. We have seen that in a large proportion
of the analogous stellar outbursts the discharges remain
straight. In galaxies this is less common, though barred
spirals, those in which the two discharges have remained
straight for an appreciable proportion of their life, are
about as common as spirals. If one discharge is deflected
from the radial direction by a random aggregation of space
charge to one side or the other ahead of it, then the change
in the electrostatic field at the advancing tip of the other
discharge will be such as to make it turn off in the other
direction and so spiralling of both discharges is initiated.
It was disconcerting when for about a decade attempts were
made to reverse Hubble's scheme of galactic evolution for
reasons which the writer considered to be quite erroneous.
However, it was reassuring to see that a movement back to
Hubble's original scheme was initiated by Massevich^(45) and
others at a recent I.A.U. Symposium.
Hubble's sequence of nebular types
*Fig.9: Hubble's sequence of nebular types.*
*(4.1.2) ) Type S0*
Hubble wrote^(44.2) that there is evidence for some
"cataclysmic action" at S0. The occurrence of two
discharges, the temperature of which reaches as we shall see
four or five hundred million degrees, and which go on
extending at 2,500 miles per second for ten or a hundred
million years, certainly fulfils this requirement.
The discharges occur well inside the galaxy's dusty
atmosphere, so that they have proved difficult to
photograph. They only become generally visible as a result
of the aggregation on to them of a large proportion of the
galaxy's atmospheric matter after they have been long
completed, which accounts for Hubble's repeated comment that
the arms are never seen in process of formation but become
visible as a whole at Type Sa or SBa (Ref. 44.2). However,
this is no longer true. In view of the special interest of
the apparently normal globular nebula NGC 4486 which is also
the radio source Virgo A, efforts were made by careful
filtering of its light to see what is going on, and the
nearer of the two discharge channels was photographed. (See
for example Ref. 2.30, Figs.2 and 3).
Diagram illustrating formation of Hubble's nebular type Sba
*Fig.10: Diagram illustrating formation of Hubble's nebular
type Sba*.
*(4.1.3) Type SBa*
Hubble's galactic type SBa will be seen to be quite
different from types SBb and SBc, but to resemble rather
more those planetary nebulae in Fig. 4 in which the
discharges have also remained straight. This form will be
understood from Fig.10.
As the discharge approaches the perimeter of the star's or
galaxy's spherical or rather oblate spheroidal or
"elliptical" atmosphere the electric field ahead will be
reduced but the lateral field will be high and the
encircling magnetic field will be reduced, so that lateral
breakdown, which this magnetic field had tended to prevent,
will become possible. This will be seen to lead to a form
having some similarity to the Greek letter q on both
galactic and stellar nebular scales and the general
breakdown throughout the peripheral regions of the whole
atmosphere has given rise to the idea that the whole nebula
has a spherical form. This impression is increased in a
stellar (planetary) nebula if the discharges are viewed end
on as in Fig. 11, when the effect is as though the nebula
were a uniform ball of gas illuminated by the light of the
central star.
Planetary nebula with arms in the line of sight
*Fig.11: Photograph of planetary nebula with arms in the
line of sight.*
Note: The images of the nebulae from this original article
was too poor to reproduce, and has been replaced by
alternative images from another sources. The captions remain
unchanged
*(4.1.4) Radio Galaxies*
When radio galaxies were discovered five years after the
initiation of the discharge theory, it was immediately
realized that they must be those galaxies in which the
discharges are in progress, so that they must be either of
type S0 or of late E types around E7. This conclusion has
been confirmed by the statistical survey of the types of
known radio galaxies discussed by Biermann and by Minkowski
at a recent International Astronomical Union (I.A.U.)
Symposium^(46) from which 16 out of 24 radio galaxies are
seen to be of type S0 or neighbouring types. It is also
supported by the more recent investigations of Matthews,
Morgan and Schmidt ("Quasi-Stellar Sources and Gravitational
Collapse" Ed. Ivor Robinson, Alfred Schild and E.L.
Schucking, University of Chicago Press, 1965, p.105).
*(4.2) Atmospheric Electric Field Building*
*(4.2.1) Existence of Grains*
In all the discussions of the building up of these cosmic
atmospheric electric fields and in extenuation of their
inadequacy at the present time, it should be kept in mind
that an agreed answer to the question of the physical
processes involved in the charge separation and
field-building in thunderclouds a few miles above our heads
is still lacking despite over 200 years of researches with
kites, balloons, manned and unmanned, aeroplanes and radar.
It is hardly to be expected that one can give a satisfactory
explanation of the build-up of cosmic atmospheric electric
fields at the present juncture.
We have seen, however, that the main requirement is dust or
grains which can become charged and so act as electrodes
applying the field to the gas. So it was significant that
van de Hulst wrote "Where gas collects grains collect"^(47)
. He went on to describe four main roles played by the
grains in gaseous atmospheres, but in the writer's opinion
omitted that role which far transcends all others in
importance, they become charged on impact and can be
separated in a gravitational field in which there exists
another radial force such as radiation pressure or
convection currents and so set up an electrostatic field. It
is no general argument against the theory to say that space
is infinitely conducting. It is also infinitely insulating,
and if there are any free electrons they will be swept onto
one of the grain electrodes. When all free electrons are
swept out in this way there can be no further increase in
the current until ionization by collision occurs and
discharges are thus initiated.
The main question is, therefore, do the grains required by
the theory exist in galactic atmospheres despite their
extremely low densities -- one atom cm^-3 , as against the
10^9 molecules cm^-3 in the earth's atmosphere? The ratio of
these grains to gas atoms in a galactic atmosphere is
actually a million times greater than the ratio of even the
Aitken nuclei to molecules in our own atmosphere^(48) . So
the electrodes are there to apply the field to the gas and
the general coherent account of galactic phenomena, as well
as stellar, to which the theory leads, offers fairly
conclusive proof that the fields are built up to break down
in electrical discharges. It is also known that the grains
are needle-shaped and are oriented in one direction in one
region of our galaxy as they would be were they dipoles
oriented in an electric field, since they polarize star
light coming from that region of the galaxy.
*(4.2.2) Galactic Size -- Type Relation*
There is, however, one check on the theory. It leads to the
conclusion that small galaxies will evolve faster than will
large galaxies, so that we should expect that small galaxies
will pass relatively quickly along the evolutionary path
from left to right (Fig.9) leaving the large galaxies behind
among the E types. This expectation has been found to be
fulfilled in recent years^(49) .
*(4.2.3) Argument Against Continuous Creation*
The explanation which the theory affords for the observed
size-type relationship will be seen to afford a categorical
argument against the theory of continuous creation^(2.43) .
If past time had been unlimited then there would have been
time to build up the electric field to break down even in
the largest galaxies. The whole theory is based on a process
of universal evolution, each step from universe to galaxies,
galaxies to stars, stars to planets, being accelerated and
governed by the electromagnetic aggregative force in the
universal, galactic and stellar discharges. It is of
interest, therefore, that the contradictory theory of
continuous creation has had to be abandoned for other
reasons as well.
*(4.3) Discharge Channels*
*(4.3.1) Two-Armed Spirals*
The explanation of the two-armed structure^(2.42) , first
put forward to account for this characteristic of galaxies,
has already been discussed in Section (3.5.1) since it
equally well explains this structure on a stellar
atmospheric scale.
*(4.3.2) Barred-Spirals*
Hubble's type SBa has already been discussed in Section
(4.1.3). They are galaxies in which the discharges remained
straight throughout the whole process of electrical
breakdown^(2.44) . Types SBb and SBc are those in which the
discharges departed from the radial direction sooner or
later^(2.45) .
*(4.3.3) Gas Jets in NGC 1097*
One prediction immediately followed from the conclusion of
the previous section^(2.32) If the slit of a spectrograph is
set along the bar of a barred-spiral galaxy, then if there
are bright emission lines in its spectrum they ought to be
displaced in opposite directions along the two halves of the
bar owing to the outward flow of the discharge-generated
jets of gas along each half of the bar. This has actually
been observed in the barred spiral galaxy NGC 1097 by
Burbidge and Burbidge (Fig.12) (Ref. 2.32, Fig. 7). Along
each half of the bar the velocity is constant to within ±25
km/sec, but the two jet velocities differ by about 415
km/sec, a value which will depend on the inclination of the
bar to the line of sight.
Two lines in the spectrum of the barred spiral galaxy NGC 1097
*Fig.12: Two lines in the spectrum of the barred spiral
galaxy NGC 1097 (Burbidge and Burbidge).*
*(4.3.4) Irregular Galaxies*
At first it was not easy to understand why these galactic
discharges remain in one plane till it was realized that
just as there is a rotational diametral plane, so also will
there be a diametral electrical plane in which the radial
electric field will be a maximum^(2.42) . The neutralizing
electrical discharges will be initiated in and confined to
this plane, while lateral corona discharges will gradually
neutralize the rest of the field.
However, if there is insufficient remnant angular momentum
in the gas to cause it to show an oblate spheroidal or
"elliptical" form, then there will be no preferred
electrical plane either; the discharges will be governed by
random accumulations of space charge and will be quite
irregular. Apart from their shape they should otherwise be
similar to those in spiral galaxies.
There are thus formed the 1% or so of irregular galaxies,
which the theory prepares us to expect, which are similar as
regards contents of arms and background to the more normal
spirals and barred spirals. Their existence would seem
entirely to preclude rotation as the root cause of the arm
formation, though it is the basis of all other theories.
*(4.3.5) Discharge Temperature*
The temperature of these discharges cannot go on increasing
indefinitely with their size and current^(2.30) . Ultimately
those temperatures will be reached at which thermonuclear
processes will be induced, when the rise in gas pressure due
to the release of this energy in it will balance the
electromagnetic aggregative force. This will presumably
occur somewhere between 10^8 °K and 10^9 °K, so that the
maximum velocity of the jets of gas formed by the discharges
should lie between the velocity of sound in ionized atomic
hydrogen at these two temperatures, i.e., between 1,750 and
5,400 km/sec.
Seyfert^(50) has investigated the gas velocities in those
galaxies which show an emission line spectrum denoting the
occurrence of discharges^(2.7) and has found velocities up
to 4,500 km/sec in accord with these theoretical
expectations. On the contrary the reason for the existence
of this upper limit to cosmic gas velocities was otherwise
merely the subject of a question at a recent I.A.U.
Symposium^(51) ; was it hydrodynamic? No, it is
thermonuclear and clearly.
*(4.3.6) Discharge Duration*
The considerations in the preceding section led to a new
theory of discharge propagation under these
conditions^(2.30) , since the velocity of these jets of hot
gas in the advancing leader stroke, 4.5 x 10^8 cm/sec,
exceeds by a factor of more than ten that of voltage
breakdown, about 3 x 10^7 cm/sec. When the discharge
temperature reaches about 10,000,000°K the jet velocity will
exceed this latter value and the jet will take over the
propagation mechanism.
From this velocity of propagation and the total length of
the spiral arms we can calculate the duration of the
discharge -- and hence of the radio-galaxy-phase of a
galaxy's life -- as about, 10^7 or 10^8 years, a value which
agrees with that derived from statistical surveys of galaxies.
*(4.3.7) Magnetic Fields in the Arms*
The discharge theory of necessity introduced circular
magnetic fields in and around the spiral arms from its
initiation in 1941. Twelve years later Chandrasekhar and
Fermi^(52) introduced magnetic fields _along_ the arms in an
attempt to explain the energy of cosmic rays but as
Cowling^(53) emphasized in his "Magneto-hydrodynamics", this
does not get us very far without an origin for these
magnetic fields. After two papers based on Chandrasekhar and
Fermi's fields Hoyle and Ireland^(54) in a third in 1961
changed the fields to circles to agree with those the
discharge theory introduced twenty years earlier and showed
that such fields will equally well serve the theorist's purpose.
These suggestions concerning the magnetic fields, together
with the changes suggested in the process of galactic
evolution, Section (4.1.1) amply demonstrate the complete
lack of knowledge of the physical processes involved and the
need for such a theory as that discussed herein.
Fig. 13: Interacting galaxies (Mount Wilson and Palomar
Observations). (NG.C 3187, NG. C 3190)
*Fig. 13: Interacting galaxies (Mount Wilson and Palomar
Observations). (NG.C 3187, NG. C 3190)*
*(4.3.8) Interacting Galaxies:*
When a speaker who had suggested at an I.A.U. Symposium that
the tilts in the galactic plane obviously caused in some way
by the Magellanic Clouds might be a tidal effect, he was
asked if they could be explained quantitatively in this way.
His reply was illuminating^(55) : "... the distortion
observed ... is too large by about two orders of magnitude
to be explained by gravitational effects. But really I am
not surprised. We see such enormous distortions in many
galaxies and bridges between galaxies, and also more fancy
things which cannot possibly be explained by gravitation,
neither in order of magnitude nor even qualitatively in shape".
Figure 13 shows one of the "fancy things" which the speaker
probably had in mind, for the effect of the upper on the
lower galaxy is obviously not such as can be explained by
gravitational effects. However, at least "qualitatively in
shape", it is certainly in accord with what is to be
expected on the discharge theory. For, if large currents
flow in the spiral arms or discharge channels of the large
upper galaxy, while the discharges were also in progress in
the smaller lower galaxy, then the currents in the latter
would be constrained to flow along the magnetic field due to
the former and account for the right angled turns taken by
the discharges in the lower galaxy.
*(4.4) Stellar Populations*
*(4.4.1) Location*
In the original short account of the work^(2.7) it was
suggested that the stars in a galaxy should be separable
into two populations though so far as the writer was then
aware, no one had previously suggested this. However, though
this prediction was right, the reasoning was wrong. The
correct explanation for the observed separation would,
however, appear to have been given by thc discharge
theory^(2.42) . The older stars of Population II are those
formed from the primordial gas of the original galactic
atmosphere contemporaneously with the building up of the
electric field in the remainder of the gas. They are
unaffected by the discharges when
they occur. The effect of the latter is to aggregate much of
the remaining gas and dust on to the spiral arms. In these
regions of considerably increased density a second
population of younger stars is formed relatively quickly,
Population I.
*(4.4.2) Atomic Constitution*
This suggestion is subject to numerical checks^(2.47, 2.48)
. In the first place the gas which goes to the formation of
Population I stars has been subjected to "thermonuclear"
discharge temperatures of around 5 x 10^8 °K for a period of
the order of 10^7 years and its constitution must have been
affected thereby. They should, therefore, contain a higher
proportion of heavy atoms than do Population II stars
despite the latter being by far the older. This difference
is in fact observed: the heavy atom content of Population I
stars is about 3%; that of Population II stars is only about
0.3%.
*(4.4.3) Energy Radiated. by a Radio Galaxy*
The effect of the discharges is two-fold: (1) during their
propagation the galaxy acts as a radio galaxy; (2) they
effect this change in the chemical constitution of the gas.
In these two processes the amounts of energy involved must
be the same. In other words during its phase as a radio
galaxy an amount of energy is radiated equivalent to about
10^-4 of its mass, since at out 3% of its matter loses about
1% of its mass. The mass of a galaxy is about 10^43 to 10^44
gm, so an amount of energy equivalent to about 10^39 to
10^40 gm, or about, 10^60 to 10^61 ergs, is radiated during
the radio-galaxy phase. This estimate was higher than that
available for comparison at the time, 10^58 ergs (Ref. 56)
derived from observations on the energy radiated by Virgo A,
but has since been confirmed by Heeschen's fuller study of
many radio galaxies, which yielded a value of 10^60 ergs
(Ref. 57).
*(4.5) Optical and Radio Sources*
The suggestion discussed in relation to solar flares in Section
(2.3.5) is at once applicable to galactic discharges^(2.24) . It
is to be expected that all these thermonuclear electrical
discharges will be preceded in space by regions containing these
non-thermal high speed electrons. Since the latter have velocities
reaching at least 40 times the velocity of the H-ions and hence of
the discharges themselves, we should expect these non-thermal
extensions ahead of the visible discharges to reach dimensions of
the order of 10 to 100 times those of the latter. Two quotations
from a paper by Shain^(58) to an I.A.U. Symposium on radio
astronomy confirm these predictions of the discharge theory. About
Virgo A he writes "It has been known for some time that at least
the greater part of the radio emission from this source originates
in a region about 5 minutes of arc in diameter and is associated
with the main body of the nebula NGC 4486. More recently, Baldwin
and Smith have given evidence for a faint extended source about,
50 minutes of arc in diameter surrounding the small bright source
.... Observations now suggest that this conclusion needs
modification. It appears that together with but not surrounding,
the main "point" source there is a much fainter component,
extending for between 0°.5 and 1°.0 on the preceding side ... The
interest in this observation lies in the fact that the general
direction of the extension is the same as that of the "jet" which
optical observations have shown issuing from the nucleus of NGC
4486". This will be seen to coincide exactly with the theoretical
expectations. Later in the same paper he writes, "when angular
sizes of a number of radio sources are determined, any optical
search for associated galaxies must extend to galaxies having
diameters down to one-tenth or less of the radio diameters".
Just as in Section (2.3.5) theory and observations are thus in
accord as to both the juxta-position of thermal and non-thermal
sources or in this case optical and radio sources and as to their
relative sizes.
*(4.6) Quasars*
*(4.6.1) Their Absence a Theoretical Difficulty*
In marked contrast to the impact which the discovery of
quasars had on other theories, the absence of any reference
to observations of such bodies had proved embarrassing to
the discharge theory prior to their discovery^(2.38) , and
the writer had had to conclude that their radiation must be
largely in the unobservable regions of the spectrum, e.g.,
X-rays or g-rays.
The current wave-forms of all atmospheric electrical
discharges must be similar. A rapid rise to peak current
will be followed by a somewhat slower decline and a long
tail. We see this wave-form delineated by the broadening and
subsequent narrowing of the Ha line in the spectra of solar
flares and novae, and in the rise and fall of brightness of
the latter throughout the naked eye phase. Where were the
"naked eye phases" of galactic discharges? There ought to
have been radio galaxies radiating an inordinate amount of
energy analogous to these naked eye phases of novae, but no
one had reported them prior to the discovery of quasars.
*(4.6.2) Optical Characteristics*
In the original account of this work^(2.7) the writer called
attention to those galaxies which Hubble had found to be
emitting an emission line spectrum and suggested that they
probably fulfil the theory's requirement. These galaxies,
which were studied in more detail by Seyfert^(50) , have
turned out to be quasars, and this emission line spectrum,
underlined in 1944, is still their only optical
characteristic referred to in a recent review article on
quasars(59).
*(4.6.3) Duration*
It is of interest that the writer roughly estimated the
duration of this phase of a galaxy's life in a paper
presented to the second U.S.A.F. Conference on Atmospheric
Electricity in 1958 (Ref. 2.6) still four years before their
discovery. He pointed out that this phase of a lightning
current wave lasts for m sec or tens of m sec of a solar
flare for minutes and of a nova for days. In view of the
similarity between the geometry of the nova and galactic
outbursts we may assume that the peak current phase will
last for similar proportions of the total life of the
discharge in both cases. This leads to an estimate of the
duration of the quasar phase of 10^4 to 10^5 years, which
agrees well with Greenstein's^(60) range of values of 10^3
to 10^7 years.
*(4.6.4) Pinching of the Discharge*
A quite unexpected characteristic of quasars is the rapidity
with which their energy output varies. The writer has
suggested that this may result from pinching of the
discharge for which there is some evidence in the well-known
photograph of Virgo A (Ref. 2.30, Fig.3), which shows that
the discharge channel is pinchied into three "sausages".
Analogous photographs have been obtained of a pinched
lightning flash, and this prompted the writer to search for
confirmation of such a process in published oscillograms of
lightning current waves, with the satisfactory result^(2.39)
shown in Fig.8. It will be seen that the current rose
rapidly to 180 kA, fell still more rapidly to a mere 10kA,
i.e., the discharge was practically extinguished and rose
again more slowly to about 50kA. An explanation for such
occurrences has been given in terms of the writer's theory
of the leader-return stroke relationship^(2.49)
The corresponding phenomenon in the nova outburst was
referred to in Section (3.9.5). (4.6.5) Association wish Dust
In view of the important role which atmospheric grains or
dust have played in the theory since 1955, it is interesting
that in the final section of a paper on "Theories of the
Origin of Radio Sources" beginning "Let us collect together
the Observational facts that a successful theory of radio
sources has to account for", Burbidge and Burbidge^(61) end
by stressing "the role played by dust in radio sources".
"The presence of dust", they go on, "in an otherwise
normal-looking galaxy has come to be accepted as a good
indication that a tentative identification with a radio
source was in fact correct (M84 (Wade 1960) is an example).
The broad dust lane in NGC 5128 has already been referred
to. The dust pattern in the radio source NGC 1316 (Formax A)
is another good example ... Among the Seyfert galaxies, a
curious dust bar near the centre can be seen in NGC 3227.
The very chaotic and remarkable dust structure in M82 is one
of its most striking features".
This last confirmation may be one of the discharge theory's
most striking features.
*(4.7) Two Populations of Galaxies?*
The theory suggested^(2.7) that occurrences on a galactic scale
have probably been preceded by a similar history of events on a
universal scal