Stellar Thermonuclear Energy:
A False Trail?
RALPH E. JUERGENS
By now a full generation of highly trained specialists and theorists has
devoted its time, its talents, and a substantial share of the world's public
and private treasure to a search for the means to produce energy on Earth
the way the Sun is said to do it - by fusing together the nuclei of light
elements to form heavier ones, and in the process converting mass to energy.
The inspiration for this extended effort rose from the ashes of a world
war. As the pall of horror thrown up at Hiroshima and Nagasaki began to
clear, atomic scientists looked up at the Sun and imagined it to brighten
with promise: There shines the example to be emulated - controlled nuclear
fusion - energy unlimited from now till the end of time.
Of course, the violence of the fusion reaction was easily controlled by the
Sun. That body was big enough and massive enough to tame the prodigal
works, to beat back the fierce radiations, to shift them, sort them, convert
them, and delay them until they were winded and docile, and then to release
them in forms benevolent to life on Earth. But this need not mean that
similar results were beyond the reach of technology.
With the process scaled down to manageable size, why shouldn't controlled
fusion become a tool of man? The energy released in the conversion of
hydrogen - so abundant in the seas of Earth - to helium - a useful and
valuable element - could power the electric generators that man never seemed
to have enough of.
Plasma physics became the promised land where all this would come to pass.
In a remarkably short time thousands of young people with advanced degrees
in plasma physics and electrical engineering were streaming from campuses of
higher learning, primed and eager to get on with the business of harnessing
These enthusiasts disappeared into research laboratories and were seldom
heard from again. The fusion reaction, so straightforward in theory,
refused to be tamed.
Although the uranium-fission bomb of 1945 rather quickly led to a practical,
controlled-fission device for the production of energy, the hydrogen-fusion
bomb of 1952 led nowhere. The construction of a "clean" reactor based on
nuclear fusion is as far away today as it was in the early 1950's.
Always - by analogy with the Sun - controlled fusion has been conceived as a
two-part problem: A plasma of heavy hydrogen (deuterium and tritium) must
be heated to tens of millions, or even to 100 million degrees, so that its
component particles gain the speed and momentum needed to produce fusion
when they collide; and this hot plasma must be held together long enough for
such collisions to take place.
From the start the solution to the heating problem has been known;
driving electric current through the plasma could handle that. So all
these years of research have been devoted to devising a non-material
container for the plasma - one that would not instantly vaporize at the
required temperatures or chill the plasma to the point where fusion
could not come about. The non-material of choice has always been the
magnetic field, even though every proposal thus far advanced as to how
such a field ought to be structured to do the job has brought nothing
At every attempt, long before the plasma could be brought to
thermonuclear temperatures, it always managed to leak out of its
This thermonuclear "crisis" was recognized and acknowledged as early as
1960, as was pointed out by Hannes Alfven on the occasion of his
acceptance of the Nobel Prize for Physics in 1970:
". . . As you know, plasma physics has started along two parallel
lines. The first one was the hundred-years-old investigations in what
was called electrical discharges in gases. This approach was to a high
degree experimental and phenomenological, and only very slowly reached
some degree of theoretical sophistication. Most theoretical physicists
looked down on this field, which was complicated and awkward . . . it
was a field which was not at all suited for mathematically elegant
"The other approach came from the highly developed kinetic theory of
ordinary gases. It was thought that with a limited amount of work this
field could be extended to include also ionized gases. The theories
were mathematically elegant and when drawing the consequences of them
it was found that it should be possible to produce a very hot plasma and
confine it magnetically. This was the starting point of then-nonuclear
"However, these theories had initially very little contact with
experimental plasma physics, and all the awkward and complicated
phenomena which had been treated in the study of discharges in gases
were simply neglected. The result of this was what has been called the
thermonuclear crisis some 10 years ago. It taught us that plasma
physics is a very difficult field, which can only be developed by a
close cooperation between theory and experiments. . ."
Though Alfven's words received wide circulation, published as the lead
article in Science for 4 June 1971, they have been little heeded,
and theory continues to lead the way as the search for magnetically
contained thermonuclear plasma goes on.
Meanwhile, the same theories have been applied by astrophysicists trying
to understand the universe, again leading to much frustration. Alfven
discussed this, too, in his Nobel Address:
"The cosmical plasma physics of today is far less advanced than the
thermonuclear research physics. It is to some extent the playground of
theoreticians who have never seen a plasma in a laboratory. Many of
them still believe in formulas which we know from laboratory experiments
to be wrong. The astrophysical correspondence to the thermonuclear
crisis [,however,] has not yet come. . . [Nevertheless,] several of the
basic concepts on which the theories are founded are not applicable to
the condition prevailing in the cosmos. They aregenerally accepted by
most theoreticians, they are developed with the most sophisticated
mathematical methods; and it is only the plasma itself which does not
'understand' how beautiful the theories are and absolutely refuses to
obey them. . ."
Alfven's paper, of course, dates from 1970. In the years since then, it
appears, a problem has come up that may indeed signal the onset of a
thermonuclear crisis in astrophysics to match that in the search for
controlled nuclear fusion.
Surprisingly, this problem emerged in connection with the supposed
fusion reactions that power our Sun.
The certainty that the Sun generates its prodigious outpourings of
energy through thermonuclear reactions deep in its interior has been
with us about half a century. But now, suddenly, suspicions are being
voiced that this may not be the case after all.
Doubts have been raised by recent findings on several fronts.
Probably the most distressing of these discoveries concerns the
sub-atomic particles called neutrinos, which ought to be
showering down on us from the Sun but apparently aren't. Suppose we let
John N. Bahcall and Raymond Davis, Jr., two researchers who have
followed this trail for a long time, tell part of the story:
"For the past 15 years we have tried, in collaboration with many
colleagues in astronomy, chemistry, and physics, to understand and Davis
soon set about the construction of a similar device to search for solar
neutrinos. His was built almost a mile from the surface in the
Homestake Gold Mine at Lead, South Dakota.
By 1967 the detector was in operation, and the first, terse
announcement of results was released: "Solar neutrinos were not
detected in the first 48 days of exposure . (Science News,
September 30, 1967).
A few months later, on the basis of Davis' further inability to capture
solar neutrinos, F. J. Dyson of the Institute for Advanced Study at
Princeton, New Jersey, reported to the American Physical Society that
there was "something fundamentally wrong" with the theory of the Sun
("Doubts Are Cast on Theory of Sun," New York Times, February 1,
But dismay was slow in surfacing. After the first full year of
fruitless effort in the search for solar neutrinos, Science News
commented (July 20, 1968) that "it is a testament to the persistence of
the neutrino astronomers and to the strength of their theoretical base
that their intensive search for these ghost particles still goes on".
Another four years were to pass, the "intensive search" continuing
without interruption, before V. Trimble and Reines, discussing "The
Solar Neutrino Problem - A Progress (?) Report," would concede that "The
conflict between observation and theoretical prediction of the flux of .
. . neutrinos from the sun has advanced from being merely difficult to
understand to being impossible to live with" (Reviews of Modern
Physics 45, 1, January 1973).
At a meeting of the International Astronomical Union in Warsaw late in
1973, W. A. Fowler of the California Institute of Technology reported
that the status of the theory had gone from bad to worse. Instead of
detecting about one neutrino per day, as previously estimated - and
this only ten percent of the predicted number, the experimenters were
recording only about one per month, and even this one might well be of
extraneous origin. Actually, "the number of [solar] neutrinos reaching
the earth . . . may even be essentially zero" (Scientific American,
January 1974, p. 50).
Trimble and Reines, in their review article of 1973, remarked that "The
critical problem is to determine whether the discrepancy is due to
faulty astronomy, faulty physics, or faulty chemistry". It seems
likely, however, that the true "fault" for the present predicament of
solar physics will be found to lie not in astronomy, not in physics, and
not in chemistry, but in certain fundamental assumptions upon which all
research into the workings of the Sun and the stars has been built.
The null result of the solar-neutrino
experiments, which still go on, has been a fact of astrophysical life
for more than a decade. The theory that prompted this research has been
scrutinized, modified, fine-tuned, and polished, but the discrepancy
remains. At the very least, therefore, it can be said that neutrino
astronomy, by failing to find neutrinos coming from the Sun, has raised
serious doubt as to the validity of the "conventional wisdom" (Bahcall
and Davis) concerning stellar-energy production.
And some other recent observations raise the same kind of doubt.
Early in 1975, H. A. Hill of the University of Arizona reported that he
and several colleagues had found the Sun to be oscillating in brightness
with variable cycles lasting from a few minutes to nearly one hour.
Hill suggested that the oscillations might be due to mechanical waves
(similar to sound waves) delivering energy from the core of the Sun to
the surface in as little as 25 minutes. This is to be compared with
something like 30 million years for radiant energy, continually
obstructed by the high opacity of solar gases, to make the same trip.
Hill reasoned that if energy is being brought to the surface by such
waves, perhaps the Sun's core is cooler than supposed and,
particularly, too cool for neutrino-producing reactions to take place.
But there remained the possibility that mechanical waves might be
produced as a result of the more-or-less routine violence that
characterizes the atmosphere of the Sun. So Hill's findings, by
themselves, provoked little alarm over the health of the thermonuclear
However, in the British journal Nature for January 15, 1976,
pulsations of another kind were reported independently by research teams
from the Soviet Union and Britain. And this "new" effect, apparently a
regular expansion and contraction of the Sun with a period of 2 hours
and 40 minutes, strikes another blow at the accepted theory of the Sun.
A. B. Severny, V. A. Kotov, and T. T. Tsap of the Crimean Astrophysical
Observatory observed the Sun's magnetic fields and were surprised to
find evidence of a periodic rise and fall of the entire solar surface.
The amplitude of the oscillations was about 10 kilometers.
According to the investigators, "the simplest interpretation is that we
observed purely radial pulsations. The most striking fact is that the
observed period of 2 h 40 min is almost precisely the same as ... if the
sun were to be an homogeneous sphere". This is equivalent to saying
that the Sun pulsates as if, like a balloon, its gases were of uniform
density throughout its body. Such a condition, of course, differs
radically from almost any solar model one can imagine, for gravity could
be expected to increase the density enormously toward the center.
The Soviet team suggested two possible explanations for its findings:
"The first alternative is that nuclear . . . reactions are not
responsible for energy production in the Sun. Such a conclusion,
although rather extravagant, is quite consistent with the observed
absence of appreciable neutrino flux from the Sun . . ." The second
possibility is that the pulsations are not purely radial motions, but
are harmonics of a more fundamental gravity wave affecting the Sun. But
there seemed to be little enthusiasm for this latter suggestion: "It
seems strange, however, that this high harmonic [should be] dominant."
The British observers, J. R. Brookes, G. R. Isaak, and H. B. van der
Raay, of the University of Birmingham, discovered the same radial
pulsation of the Sun quite independently and by an entirely different
technique based on slight shifts in the positions of spectral lines.
Like the Soviets, they pointed out that "Current models predict a
period of [about 11 h corresponding to a steep density increase in the
solar interior, in marked contrast to the observed ... period, which is
consistent with a nearly homogeneous model of the Sun".
Two University of Cambridge theorists, J. Christensen-Dalsgaard and D.
O. Gough, who commented on the newly discovered pulsations in the same
issue of Nature, emphasized the unlikelihood that any model can
be devised for the Sun to accommodate both the observed radial
oscillations and the thermonuclear theory.
Nigel Weiss, a Nature scientific correspondent, added: "The
observers suggest that the [2-hour, 40-minute oscillation] is indeed a
fundamental radial pulsation of the Sun. If so, this measurement would
upset the established theory of stellar structure and, with it, many
And the story of upsetting new findings is not yet complete.
The steadiness of the Sun's radiance has been considered a certainty
for centuries. And it is remarkably constant, as repeated direct
studies have shown. But now it appears that there may be variations of
as much as a few percent in solar-energy output - variations that
further strain the credibility of the accepted theory of stellar energy.
In 1975, Lowell Observatory astronomer G. W. Lockwood reported
(Science 190, 560, 7 November 1975) on measurements of the sunlight
reflected back toward the Earth from several outer planets of the solar
system. Consistently, in observations extending from 1950 to 1966 and
renewed in 1972, "Brightness changes of Uranus and Neptune . . . were
highly correlated . . .". The most straightforward explanation seemed to
be that the changes were due to variations in solar light-emission.
As Lockwood noted, "No reasonable explanation . . . is evident that does
not involve the sun, directly or indirectly, as the causative factor".
He was careful, however, to mention the possibility that the observed
variations in reflected light might be related to actual variations in
the Sun's invisible radiation or in the solar wind, with resultant
effects on the reflecting powers of the planetary atmospheres. He noted
that "Such a large variation in visible output, if real, would be unique
for solar-type stars".
But the implications of the more obvious explanation did not go
un-noted. Science News commented (July 19, 1975, p. 37): "If the
variability is confirmed, solar physicists will have to build it into
their models, and these models are in enough trouble already predicting
things [neutrinos] that can't be found, that they don't need this
Yet another shock was still to come, this one at least as damaging as
any that had gone before. It was reported in late February, 1976, to
the annual meeting of the American Association for the Advancement of
Science by J. A. Eddy of High Altitude Observatory at Boulder,
Colorado. When he finished reading his paper, a colleague is reported
(Science News, March 6, 1976) to have remarked to the assembled
audience: "Maybe we've heard a turning point in the history of science."
Eddy's was a work of historical research, and what he found was that an
old idea - that the Sun has not always behaved as it does now - may
indeed be correct.
Kendrick Frazier's Science News account of the meeting would be
hard to improve on:
"The current dogma is that the sun is steady, dependable, constant. In
this view, its well-known 11-year sunspot cycle is the manifestation of
a smoothly running, well-ordered machine, clicking with regularity like
astrophysical clockwork. It is a comfortable view, the sun being
of some importance to us all here on earth.
"Now an astronomer with a historical bent has delved back through past
observational records and, by making numerous independent cross checks,
resurrected and made a persuasive case for an old hypothesis that the
solar cycle and the sun itself have changed in historic time.
The evidence shows that for a 70-year period from A.D. 1645 to 1715
sunspots were almost totally absent on the surface of the sun. Solar
activity was at a near-zero level, a true and strange anomaly...
"Eddy's conclusions imply that the often-discussed 11-year solar cycle
is of far less importance and concern than are longer term variations -
the overall 'envelope' of solar activity. That patterns of solar
activity have varied over historic time is interesting enough in
itself. But beyond that, Eddy believes that the long-term fluctuations
may be due to changes in the solar constant, the total radiative output
of the sun. Such an idea is of fundamental importance. Whether the
solar constant may vary, once considered improbable, is now being much
debated. . ." [emphasis added].
So the Sun fails to emit neutrinos in detectable numbers, it pulsates as
if gravity were of little influence on its internal structure, it
radiates less steadily than was long supposed, and even its "cycles" of
surface activity apparently are not rhythmical at all. Each of these
recent discoveries, in its own way, calls into question the assumption
that thermonuclear fusion is the source of solar energy. What are we to
think, then, of man's efforts to simulate merely hypothetical conditions
in the core of the Sun and thus achieve controlled fusion?
Could it be that the search for thermonuclear energy is a false trail
that has been followed all these years with no real hope of success?
If the Sun and the stars indeed succeed in fusing lighter elements to form
heavier ones, are the relevant activities carried out more or less in plain
sight - in their atmospheres?* -
Some years ago, R. Shapiro and F. Ward reported (J. Atmos. Sci.
19, 506-508, 1962) that, on the basis of their power spectral analyses,
relative sunspot numbers vary with a period of 25.7 months. Providing
the above citation, Kunitomo Sakurai of Kanagawa University in Yokohama
has recently suggested (Nature 278, 146, 8 March 1979) a
correlation between solar neutrino production and the activity
responsible for sunspots. The flux of neutrinos, while inexplicably
low, seems to vary with a similar period (he arrives at 25.3 months).
Although Sakurai favors an explanation for both phenomena in terms of
"some unknown process ... in the interior of the Sun ... [with motions
penetrating] into the region where the thermonuclear fusion is taking
place . . .", it would seem more straightforward to seek a cause of
sunspotting and a source of neutrinos (too few, in any case, to be
coming from postulated thermonuclear fires in the interior) much closer
to the visible surface of the Sun (see following article).
Space does not permit elaboration here. I would simply call attention
to the following: 1) The synodic period of Mars with respect to Earth is
780 days, or 25.7 months; 2) if the Sun is fired electrically from the
outside, one would expect electrically charged planets orbiting through
its current-carrying atmosphere (its electrical "discharge" - a
misleading term) to behave somewhat like "grids" in a vacuum tube, which
is to say, to interfere with the flow of current to varying degrees as
their relative positions change with time; 3) the most pronounced
depression of relative sunspot numbers in Sakurai's Fig. 3 coincides
very well with Mars' favorable opposition of August 10, 1971, when Mars
was closer to Earth and to the Sun simultaneously than it will be again
until 1986 or so. Of course, Mars and Earth are not alone in the inner
solar system, but it may be significant that the orbitings of these
slowest-moving inner planets seem to produce a signal discernible above
the noise raised by Venus and Mercury,
Ralph E. Juergens, June 1979
EDITOR'S NOTE (LMG):
At the present writing, those solar problems noted above remain
unresolved. "The continued negative results of a careful experiment to
detect neutrinos from the sun has led to a deepening scientific crisis.
If, as astronomers confidently believe, the sun generates its energy by
the proton-proton chain of reactions in which hydrogen is converted into
helium, then neutrinos should be liberated in great numbers deep within
the sun. Neutrinos are massless, uncharged subatomic particles that
travel at the speed of light, and interact so weakly with matter that
they can pass virtually unchecked through the sun and reach the earth"
(Sky and Telescope, November, 1976, p. 324).
An Earth-based experiment designed to catch solar neutrinos has shown
"that only 0.13 argon-37 atom was being formed per day, close enough to
the cosmic ray background rate of 0.09 atom per day to raise the
possibility that no solar neutrinos were being detected at all! ... The
neutrino counts are low enough to cause doubts that thermonuclear fusion
is in fact the sun's energy source" (S & T, Ibid.).
According to one author, writing in the February 1977 Analog (p.
31), "If even low-energy neutrinos are not being emitted from the
solar furnace, something is very, very wrong with our Sun. Is it
possible that our Sun will not peacefully continue evolving as a
main-sequence star, until it reaches the Red Giant stage? Maybe our Sun
is not, after all, 'an ordinary star'."
And the article concludes: "Perhaps the most frightening speculation
along these lines is that our Sun might have had an accident: it may
have run into a quite small black hole in the very recent past, which is
sitting on the core, gobbling up mass from the surrounding gases and
regurgitating energy. Radiation pressure keeps more than just a little
bit of matter at a time from falling into the hole, but eventually, say,
150 million years, the Sun will be eaten up from within by this cancer?
Nightmares, anyone?" (Analog, Ibid.).
In April 1978, Kendrick Frazier reiterated the astrophysical dilemma
posed by the Sun's perplexing behavior. "In the 1970s studies of the
sun have shown it to be filled with enigma and unanticipated possible
variations. . . . New mysteries have arisen. The lack of the expected
number of neutrinos reaching earth from the sun's interior has thrown
theories about basic stellar processes into confusion. The picture of a
regular, constant sun, apart from the long-known 11-year cycle, has been
dramatically assaulted from flanks at opposite time scales....
"If the confirmation of coronal holes in the 1970's solved one
long-discussed problem about the sun, the mystery of the missing
neutrinos has deepened throughout the decade to become one of the major
unsolved scientific problems of our time .... Only about a fourth of the
expected number of solar neutrinos - tiny particles produced in the core
of the sun as a byproduct of the fusion reaction - have been monitored
by a detector a mile beneath the earth in a gold mine in South Dakota.
Something is wrong....
"Astronomers' ideas about the interior structure of the sun may be
wrong. If so, our understanding of the evolution of stars may be in
error, and that would have far-reaching consequences.
"The apparent neutrino deficit could mean that some of the fusion
reactions in the sun's interior have switched off; perhaps it is at
heart a variable star....
"The missing solar neutrinos are a genuine and disturbing puzzle"
(Science News, Vol. 11 3, April 22, 1978, pp. 252-254).
In the same issue of Science News, Dietrick E. Thomsen echoed his
colleague's sentiments. "The orb we had once thought so regular turns
out to be more and more variable and unpredictable. Perhaps it was
inevitable that this should come to pass. Our impression of solar
regularity may have depended more on our inner need for a dependable
celestial parent - living in the neighborhood of a variable star is a
bit of a nervous strain - than it did on the facts.
"One recent contribution to the solar upheaval, which is still highly
controversial, but, if correct, extremely important, is that the sun
itself has the shakes, oscillations that go deep into its insides.... In
recent months the evidence that the oscillations are real and belong to
the sun has greatly increased ... this tends to alter our traditional
picture of solar steadiness, and it will have, if and when it is widely
accepted, profound effects on the theoretical physics of the sun....
"[Al change in the energy transport possibilities will alter the picture
of the nuclear reactions that must go on in the interior of the sun to
supply the observed flux of energy - especially in the convection zone
where heating churns up the solar material. For these reasons the
existence of the oscillations may also provide a solution to the solar
neutrino problem - why the sun does not produce the flux of neutrinos
that would be expected from the thermonuclear reactions that currently
accepted theory proposes take place in the sun's interior....
"In the end we may be discovering that we do not live in as quiet a
corner of the universe as we may have wished" (Science News, Ibid.,
By February 1979, scientific concern over solar behavior intensified.
As expressed by Science News (Vol. 115, February 17, 1979, p.
103) - "If the sun should fall, metaphorically and theoretically, that
is, the destruction in astrophysics would far outreach the loss of fish
if Skylab were to plunge into Lake Ontario with a thunderous hiss.
Astrophysicists' whole basic notion of how stars generate energy would
have to be redone.
"Such a fall of solar theory seems imminent. An experiment [referred to
above] that has been measuring the flux of neutrinos from the sun for
the last ten years indicates that something is drastically wrong.
Basically, the chain of thermonuclear reactions by which energy is
produced in the sun according to the ,standard theory' should produce a
certain flux of neutrinos as a byproduct. That flux is not being
recorded. If standard solar theory doesn't fall, it seems standard
neutrino theory must. The experiment is also based on that, especially
the belief that neutrinos are not subject to radioactive decay and
therefore all survive the 8-minute journey from the sun. If standard
neutrino theory goes, the repercussions in particle physics could take
an anti-textbook to list. Experiments are being proposed to find out
which is wrong."
In the words of one physicist: " 'Looking for neutrinos from the sun's
core is the first critical and direct test of the theory [which
was built on evidence from the surface]. Much to our consternation, the
experiment has failed to reassure us that the sun works in the way we
thought it did' " (Science News, Ibid. - last brackets and
emphasis in text).
Possible confirmation that the Sun pulses every 2 hours and 40 minutes has
dealt yet another blow to standard solar theory. Again Dietrick E. Thomsen:
"That the sun may vibrate to its own beat - possibly to several of its own
beats is a suggestion entered into the debate over solar physics in recent
years." That suggestion now gains credence via a report in the February 22,
1979 issue of Nature "intended to convince astronomers and physicists
that the vibrations are real".
"Such vibrations would proceed from deep inside the sun. They are a fast
way of transporting large amounts of energy from the interior to the surface
that is not envisioned in present theory. They could upset the
thermodynamics of the solar interior and so change expectations about the
thermonuclear processes that go on there. They could stir up the material
inside the sun, which current theory tends to see as well layered, and that
could affect the fusion dynamics. If they come to be generally accepted,
they will require a reworking of solar theory, and that carries in its train
a reworking of stellar theory generally. These vibrations could reverberate
throughout astronomy." (Science News, Vol. II 5, April 21,
1979, p. 270).*
[ADDITIONAL READING: Natural History, Vol. LXXXV, No. 9, November
1976, "The Turbulent Sun," edited by S. Lindsay, pp. 54-86.1