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Biographical Memoirs of Deceased Fellows
Originally prepared for publication as part of Bright Sparcs by the Australian Science Archives Project.
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Australian Academy of Science Biographical Memoirs of Deceased Fellows Originally prepared for publication as part of Bright Sparcs by the Australian Science Archives Project. |
![[Portrait]](gifs/bolton.jpg)
By J.P. Wild and V.R. Radhakrishnan
Since the Second World War astronomy has lived through its golden
age, undergoing a complete transformation. Before the war, astronomy
meant optical astronomy and observations were confined to the
use of the narrow range of visible spectrum capable of penetrating
the Earth's atmosphere - about 1 octave in all. Since that time
new advances have made it possible to observe at radio, infrared,
ultra-violet, X-ray and gamma-ray wavelengths covering a spectrum
of some 56 octaves. An exciting consequence of the new era has
been the discovery of new classes of galaxies with extraordinarily
high energy and luminosity, pushing back the limits of the observable
universe beyond all expectations.
What started this great revolution? It may be fairly said that
it all began in 1948 in Sydney, Australia, when a three-man team
led by a 26-year-old Yorkshireman named John Bolton discovered
that three distant objects, known from optical observations, were
extremely powerful emitters of radio waves. One, which Bolton
called 'Taurus A', was located in our own galaxy; the Crab Nebula.
The other two ('Virgo A' and 'Centaurus A') were external galaxies.
This discovery marked the beginning of the new era in which the
universe could be explored by means of its high-energy galaxies.
The pursuit of this subject became the main theme of Bolton's
scientific life.
Not only was Bolton one of the great pioneers of radio astronomy,
but to those who knew him personally, a friend of truly remarkable
individuality. With his unlimited courage and penetrating intuition,
and physically indefatigable when in intense pursuit of whatever
he was after, John Bolton was a phenomenon that had to be experienced
to be believed. So different was he from other scientists of his
eminence that it was almost as if he did not belong with them.
John Gatenby Bolton was born in Sheffield on 5 June 1922. After
going through his local grammar school, he won a scholarship to
Trinity College, Cambridge. He graduated in 1942 and joined the
Royal Navy as a Radar Officer, but was soon recruited into radar
research at the then secret Telecommunications Research Establishment
(TRE). Among other famous figures in radio astronomy who also
served time at TRE were Hey, Hanbury Brown, Bowen, Ryle and Lovell.
In 1944 Bolton did get to sea in the aircraft carrier Unicorn
in the Pacific where he even became involved in dangerous
flight testing and survived a forced landing in a naval fighter.
After the war Bolton settled in Sydney and joined the Council
for Scientific and Industrial Research (CSIR) - later to be renamed
the Commonwealth Scientific and Industrial Research Organization
(CSIRO) - whose Radiophysics Laboratory was directed by E.G. (Taffy)
Bowen, formerly a radar pioneer in Watson Watt's team. The Laboratory
was in the process of changing over from its secret wartime radar
work to peacetime programmes. Among the latter was the investigation
of radio emission from the Sun that had been discovered during
the war. The group led by J.L. (Joe) Pawsey included names that
would later become well known among the international astronomical
community: Mills, Christiansen, Piddington, Kerr, Bracewell, Wild
[1]
and numerous others.
To most of these scientists Pawsey was the much-loved father figure
of Australian radio astronomy. Not so for Bolton however, one
of whose first experiences was being ordered back to the lab by
Pawsey when the latter unexpectedly visited the site and found
the aerials not pointed at the Sun, because Bolton was looking
for other radio sources.
Bolton was reassigned to assist a colleague, Gordon Stanley, to
build equipment to go on an eclipse expedition to Brazil in the
following year. All equipment in those days was home-made and
very primitive by modern standards. It was a matter of great good
fortune for astronomy that the expedition was called off and Bolton
was 'released' to do what he pleased with the equipment they had
built, and to avail of Stanley's services as well. They lost no
time in moving the equipment out to the cliff-top site called
Dover Heights, and so began a period of epoch-making observations.
Although Bolton intended to work primarily on non-solar radio
sources, for his first observation at Dover Heights and his maiden
publication in August 1947, he took part in a pioneering solar
discovery. He and two colleagues (at another field station) took
observations at three well separated frequencies (60, 100 and
200 MHz) of the first identified solar outburst of Type II (as
later designated by Wild). Bolton and co-authors correctly attributed
the delays in arrival time with decreasing frequencies to the
passage of a physical agency upwards through different levels
of the corona. They estimated a velocity of almost 1000 km/s,
close to that of auroral particles, and noted that an aurora was
in fact observed in some parts of Australia a little more than
a day after the outburst.
Dover Heights had been a R.A.A.F. radar station, part of the wartime
defences of Sydney. It is located at the top of a sheer cliff
overlooking the Pacific, just to the south of the entrance to
Sydney Harbour. In the previous two years Pawsey and his colleagues
had used the site to make pioneering observations of the Sun.
As the Sun rose above the Pacific horizon, radio emission from
sunspots reached the cliff-top aerial along two paths, one direct
and the other reflected by the sea's surface. From the interference
pattern so generated it was possible to locate the source of the
emission (in one dimension) to an accuracy of a few minutes of
arc.
[2]
This 'cliff interferometer' (as Pawsey called it) was
the radio analogue of Lloyd's mirror in optics.
Bolton, with his colleagues Stanley and Slee, adopted the same
technique (which he renamed the 'sea interferometer') to search
for radio sources. At this time there was evidence of only one
discrete source in the sky other than the Sun. While surveying
the radio galaxy, J.S. Hey and colleagues in England noticed that
a region in the constellation of Cygnus showed fluctuations. They
concluded that such a variable source must be of small angular
size. Eventually it turned out that the fluctuations were not
intrinsic to the source but due to scintilla-tions caused by the
Earth's atmosphere, a phenomenon that also required the source
to be of small angular size. As Pawsey later put it, 'Hey came
to the right conclusion for the wrong reason, which is the mark
of a good physicist'. Anyway, the evidence was there, and so Bolton
and Stanley began their search in the Cygnus region.
After a period of negative results it happened! There before their
eyes on the recording chart was a beautiful set of fringes enabling
them to locate the source and set an upper limit to its angular
size of eight minutes of arc. Gordon Stanley has written of how
Bolton and he reacted:
The most memorable moment of our association occurred when we first saw interference fringes from Cygnus A. In a world now accustomed to inexplicable results from radio observations, it is difficult to comprehend the emotional impact of an observation which took us from partially explicable solar system and galactic radio emission phenomena, into the realms of phenomena with inexplicably high energy outputs, no matter where they were located. Neither of us ever approached such an emotional high again in our work.
It took several years for the optical identification of Cygnus
A and then it was found that this extremely strong source corresponded
to a very dim distant galaxy. This made everyone instantly realise
that the accessible radio universe would be far larger than the
visible one.
Then followed the discovery of the three sources mentioned at
the beginning. Determining their positions well enough to make
the identifications was no simple matter. It involved shipping
the equipment to New Zealand and towing it with an army truck
to more than one location with a cliff of adequate height and
appropriate orientation. Months of hard work later, there was
enough justification to write to three famous optical astronomers,
all of whom had an interest in the Crab Nebula - Jan Oort, Bengt
Strömgren and Rudolf Minkowski. The letters provoked enthusiastic
responses and led to co-operation and lifelong friendships. To
quote Bolton: 'The identification of the Crab Nebula was a turning
point in my own career and for non-solar radio astronomy. Both
gained respectability as far as the 'conventional' astronomers
were concerned.'
The other two sources were identified with what were initially
thought to be nebulae in our own galaxy (surely they couldn't
be extragalactic!): Virgo A with M87 and Centaurus A with NGC
5128. Within a year both were recognized as extragalactic; they
were elliptical galaxies. This then was the start of the radio
study of the universe. And despite a crowded and illustrious career
ahead of John Bolton, this, surely, was his finest hour. The remarkable
thing about Bolton's early identifications was his success despite
the crudeness (by modern standards) of the available data. He
had uncanny intuition and a propensity for being right.
By 1949 Bolton had been joined by Kevin Westfold, a radio astronomy
theorist, and the two of them turned their attention to making
a whole-sky survey of galactic background radiation at 100 MHz.
Meanwhile Stanley and Slee continued searching for sources with
increased sensitivity. Within a year they had brought the number
of sources detected at Dover Heights to 22.
At this time radio astronomy at the Radiophysics Laboratory was
being carried out under Pawsey's general direction by some seven
or eight groups of which Bolton's was one. The Sun, the Moon,
the galaxy and the cosmos were all being investigated and every
group was making a significant impact on the international scene,
though the Dover Heights source identifications were the jewel
in the crown. It is fair to say that at this stage Australia led
the world in radio astronomy. Recognition of Australia's position
was manifest by the decision of the International Union of Radio
Science (URSI) to hold its 1952 general assembly in Sydney - the
first time an international conference of any kind had ever been
held in the Southern Hemisphere. At this conference Bolton really
found his feet. He suddenly found that scientists with illustrious
names treated him as an international celebrity. And how he loved
it!
A project undertaken by Bolton that should find a place in any
account of his career is the 72-ft. hole-in-the-ground antenna
built in 1951 for a survey of the region near the galactic centre,
which at the latitude of Sydney passes directly overhead. The
excavation was done mostly by Bolton and Slee. Westfold also helped
to dig, and Gordon Stanley trucked loads of ash from a powerhouse
each week to stabilise the sand out of which the hole was formed.
The reflecting surface was made from steel strips formerly used
for binding packing cases, and performed adequately at the operating
frequency of 160 MHz. It was interesting however that the 'site'
for the hole was chosen not to be visible from the official working
area of the Dover Heights station. All of the digging etc. had
to be carried out in one's own time (lunch, after hours, etc.)
and in secrecy. Somewhere along the way Bowen was made aware of
this exercise and, predictably, supported it. To be fair to Pawsey,
after a first demonstration of the potential of this dish in early
1952, he too enthusiastically supported its upgrading to 80 ft.
in diameter and to 400 MHz in frequency. Observations with this
improved version, made with Dick McGee, led to Bolton's suggestion
in 1958 that Sagittarius A was the nucleus of our Galaxy. Three
years later the IAU ratified the view, making the position of
the (radio[3]) source the zero of longitude in the new system
of galactic coordinates.
By 1953 the glorious days of Dover Heights were drawing to a close.
The Lloyd's mirror technique could no longer compete with two
or multi-element interferometers. So Bolton found himself at the
crossroads - what next?
Dover Heights is today a public park - the 80-foot hole is a level
playing field. One of John's last public appearances was at the
unveiling of a memorial tablet there in November 1989 to commemorate
the 40th anniversary of the publication of the first
paper on identifications. One of us (JPW) was unable to be present.
Instead I sent a message, which was read out, saying that I had
a lifelong habit of associating special times with popular songs
of the day, and that I had always associated the great days of
Dover Heights with that well-known, haunting melody that introduces
Pinnochio; perhaps with the detection of Cygnus A in mind:
Like a bolt out of the blue
Fate steps in and sees you through
When you wish upon a star
As dreamers do.
At this time the work of the Radiophysics Laboratory comprised
two major programmes: radio astronomy and cloud physics, the latter
prompted by the desire to make artificial rain. Pawsey directed
the first and Bowen himself directed the second. It seems that
Bowen was not satisfied with the rate of progress in cloud physics.
He would dearly love a John Bolton to stir the group up. And it
came about that around August 1953, Bowen struck a deal with Bolton.
If Bolton would join the cloud physics group for two years or
so, Bowen would use all his influence (see below) to obtain for
Bolton the plum directorship of radio astronomy at the California
Institute of Technology which was about to enter the field.
[4]
So for eighteen months Bolton worked in cloud physics, His main
contribution was to investigate the effects of air temperature
and pressure on the decay of silver iodide (the favoured cloud-seeding
agent). This he did by injecting silver iodide into a cloud chamber
and counting the number of ice crystals generated. The results
were published in November 1954. He then turned his attention
to the development of silver iodide burners for rainmaking trials
in Queensland and Tasmania.
In January 1955 he left the group to start up radio astronomy
at Caltech, which operated the foremost optical telescopes in
the world.
Since the early (pre-war) pioneering days of Karl Jansky, the
father of radio astronomy, and Grote Reber, radio astronomy in
the USA had been taking a back seat compared to the activity in
Australia and England. We have already mentioned TRE in England
where Bolton worked for a while and where radar was developed.
The corresponding centre in the US, set up much later, was the
MIT Radiation Laboratories headed by Lee DuBridge. Here, work
on microwave devices and measurements was carried out by a battery
of distinguished physicists - Bethe, Dicke, Pound, Purcell and
Van Vleck, among hundreds of others. Taffy Bowen was one of the
key players in the drama of radar in the Second World War and
was personally responsible for carrying an early sample of a 'magnetron'
invented at Birmingham University across the Atlantic to the Radiation
Laboratories. We mention this visit and Bowen's subsequent stay
for some years at the Radiation Labs as it has a bearing on the
Bolton story. The links of friendship Bowen forged then were crucial
in obtaining generous financial support from foundations in the
US for the Parkes 210-ft. telescope to be built many years later.
In return, Bowen arranged for Bolton to spend time at the California
Institute of Technology where Lee DuBridge was now President.
As has been said, Bolton went to Caltech in January 1955 and in
the six years before be returned to Australia in 1961, created
the Owens Valley Radio Observatory which was quickly recognised
as a world centre and which provided a much needed boost to radio
astronomy in the USA. Bolton's crew in this exercise came from
all over the world - England, Australia, New Zealand, India, Canada
and Norway. The graduate students were American and included Barry
Clark, Ken Kellerman, Al Moffet and Bob Wilson. One of us (VR)
was the Indian and was hired to maintain the radio equipment that
Gordon Stanley had already built. In Bolton's own account of the
Owens Valley period he dwells on the education he received, from
the very first day, from Minkowski on the need for and importance
of accurate radio positions as the only way to make identifications
that would lead to progress.
The Caltech interferometer was unique and a forerunner of later
instruments in having as elements large dishes operating at a
frequency as high (at that time) as 1 GHz. It had the sensitivity
and baseline to resolve a substantial fraction of the sources
observed. Among the sources not resolved at the longest baseline
was 3C295, which was identified by Bolton with an object for which
Minkowski with the Palomar 200-inch telescope got a redshift of
0.46, roughly three times the highest then known and a record
which was to stand for fifteen years. There were many interesting
discoveries made by members of Bolton's group during his years
at Caltech, but his own interest in building the Owens Valley
Observatory was, as he has stated himself, 'to extend the observable
scale of the universe to look-back times as great as the oldest
stars in our own system'. It was a unique and unforgettable experience
to see Bolton go about this exercise in as cool and low-key a
manner as someone building a cattle shed or repairing a washing
machine. He gave people tasks about which they may not have had
a clue to start with. He never taught you how to do anything,
as if that would have been a presumption. But his example and
even more his expectation made people rise to heights that they
would never have dreamt possible.
The Caltech chapter of Bolton's story would be incomplete without
a mention of 3C48. Quite simply, 3C48 was the first identification
of a quasar,[5]
which was made public without a redshift in a
paper presented at the Christmas 1960 meeting of the American
Astronomical Society with the authors T.A. Matthews, J.G. Bolton,
J.L. Greenstein, G. Munch and A.R. Sandage, the chronological
order in which they were involved. Matthews, who was the Canadian
in the group, obtained a position for the radio source that beautifully
fitted a 16th magnitude star. Spectra werc obtained by Münch
and Sandage and measured by Greenstein. After considerable tuition
from Ira S. (not Taffy) Bowen, director of the Palomar Observatory,
Bolton arrived at a possible fit for the lines at a redshift around
0.37, but a four-angstrom discrepancy was unacceptable to the
spectroscopists and stopped matters dead for about three years.
It was hence poetic justice that, as will be recounted shortly,
Bolton played a vital part in the dramatic story of 3C273, hailed
by most as the first true identification of a quasar, and that
its very high redshift caused the high redshift of 3C48 to become
accepted.
Most of this section on Caltech is written as seen through the
eyes of one of us (VR) who was on the spot from early 1959 when
the action began at Owens Valley. However JPW can make a small
contribution. On a visit to Caltech in 1957 I spent a day at Mount
Wilson Observatory and watched Babcock measure solar magnetic
fields by observing the split of spectral lines by the Zeeman
effect. Next day I made the long drive to Owens Valley with John
Bolton. I said 'I wonder if it would be possible to measure galactic
magnetic fields by observing the Zeeman splitting of the hydrogen
line'. We talked about it, exchanging ideas in an exhilarating
conversation throughout the drive. Next day I wrote the Bolton
and Wild paper that incorporated the ideas of both of us. This
paper started a prolonged search in a number of observatories
and was eventually successful.
It is somewhat enigmatic that while Bolton was at Caltech, he
and Pawsey maintained an extensive and regular correspondence
on which way to go in radio astronomy. It was as though Bolton
felt isolated and needed someone experienced to talk to; and he
turned to his former director in spite of their earlier uneasy
relationship.
To the surprise and disappointment of everyone at Caltech, Bolton
announced abruptly in late 1960 that he was returning to Australia
to supervise the steelwork that had commenced on the 210-foot
telescope that Bowen had been planning for years. This he did,
not from the ground but from up on the structure. He also surveyed
and reset every one of the more than one thousand panels over
an acre of surface. The telescope was commissioned in late 1961
and Bolton took charge as Director of the Australian National
Radio Astronomy Observatory (ANRAO) to begin a third and equally
spectacular phase of his career. Parkes attracted astronomers
from all over the world including several who had worked with
Bolton in California. Major contributions were made in almost
every branch of radio astronomy of which there were now a large
number. Bolton's lifelong interest in the discovery, classification
and identification of radio sources found his greatest reward
in these years. The Parkes Catalogue, in the making of which Bolton
was the leading light, lists more than 8,000 sources including
several hundred quasars. He published more than 60 papers in this
field.
More than anyone else, Bolton brought radio and optical astronomy
together, through constant interaction with the best optical astronomers
of his time, through the use of optical telescopes himself for
identification purposes, and through efforts to set up major facilities
like the Anglo-Australian Telescope and the UK Schmidt Telescope.
He was among the earliest to recognise the unity of astronomy
across all wavelengths.
As hinted earlier, Bolton and the Parkes dish were essential elements
in the drama of the identification of the source 3C273 as a quasar.
Cyril Hazard, who at Jodrell Bank had pioneered the lunar occultation
technique of determining accurate positions for radio sources,
happened to be in Australia in Hanbury Brown's group at the University
of Sydney. He was invited by Bolton to take part in observations
at Parkes of occultations of the radio source RC273, several of
which had been predicted for 1962. It was typical of Bolton to
figure out that the most critical of these occultations would
require an extension of the existing zenith angle coverage of
the telescope, and that this could be achieved by grinding off
a considerable amount of metal from the bearing housings. We were
not there to witness it but, knowing John, we can picture him
with the grinder, hand-rolled cigarette hanging from his lip,
knee braced against a girder and grinding away in a shower of
sparks. In any event the observation was spectacularly successful
and, as a final touch to the drama, Bolton and Hazard each carried
a record and travelled on different planes to Sydney. Maarten
Schmidt of the Mount Wilson and Palomar Observatories in Pasadena
established a redshift as 0.158, considered astoundingly large
for an object that looked like a star.
This was the breakthrough and it led Greenstein and Matthews to
believe the 'redshift' of 0.37 obtained earlier for 3C48 and to
publish it in a paper following those on 3C273.
[6]
The Parkes telescope also played an important part in several
of NASA's Apollo missions. Not many may know that Neil Armstrong's
first steps on the Moon, seen all over the world, live on television,
came via Parkes. Another and unplanned occasion was when a sudden
emergency on another of the Apollo missions required Parkes to
come on line in a matter of hours. It so happened (that one of
us (VR) was to have observed that night, and quickly had to clear
the focus cabin of the pile of equipment that had taken all day
to assemble. In a situation of such urgency, kicking someone off
the dish required no effort but, to quote the London Times,
'Bolton, typically, left nothing to chance. With the Australian
sun beating down, he stood, stop watch in hand, rehearsing teams
of his perspiring staff in hand-cranking the axis gearing of the
1000-ton dish at rates correct to follow the spacecraft should
mains power fail',
Several changes took place at the Radiophysics Division in the
period 1971 - 72. Bowen retired as the Chief of the Division and
his place was taken by Paul Wild. John Bolton retired as Director
of ANRAO but continued at Parkes as Astronomer at Large until
1981 when after a heart attack he decided to retire and moved
to a coastal resort in the warmer climate of Queensland.
Bolton's contribution to astronomy was not only through his own
work but also through his influence on others. Many of his numerous
students went on to do great things. To mention a few: Ken Kellerman
was the moving spirit behind the Very Long Baseline Array with
antennas spread out over thousands of miles across the USA; he
also served as a Director of the Max Planck Institute for Radio
Astronomy in Bonn. Barry Clark was the system designer of the
most complex radio astronomy instrument in the world - the Very
Large Array in New Mexico; Ron Ekers became the first Director
of the VLA and later returned to his homeland to direct the Australia
Telescope; Jasper Wall became Head of the Royal Greenwich Observatory;
Marc Price became Director of the ANRAO at Parkes; Al Moffat became
Director of the Owens Valley Observatory; and Bob Wilson won the
Nobel Prize as co-discoverer of the 3º cosmic background.
No-one who came in contact with Bolton would have failed to notice
that determination was his main characteristic. This came through
in sports even more quickly than it did in other areas. Whether
at cricket, table tennis, snooker or golf, once he had decided
that he would win, it did his opponent little good being a much
better player in other circumstances. Bolton's power of concentration
was phenomenal and his resolve unshakeable.
Most people who have known Bolton paint him as harshly intolerant
of mediocrity and poor judgment. This may be true, but only if
it interfered directly with his plans or actions, when most of
us would react in the same way. Bolton was a fearless individual
who could be ruthless. He was especially harsh on administrative
staff who unnecessarily and bureaucratically interfered with his
operations. On one occasion an irritating directive from CSIRO
Head Office found its way on to a Parkes notice board. Within
a day there appeared, written in large letters diagonally across
the notice 'Head Office has no jurisdiction at this observatory,
JGB'. But Bolton was a fair and friendly person, rather shy deep
down, a person of great integrity and strength of character.
Letty, his wife for 43 years, cheerful, vivacious, outgoing, hospitable,
was the perfect partner for John. The two of them kept open house
for their staff, and John would have the same standards of perfection
in barbecuing steaks and providing fine wines for his guests as
he did for his astronomy. John was the devoted father of Letty's
two sons by her former husband, killed in the war. John maintained
his Yorkshire accent to the end, while Letty's uninhibited broad
Australian accent took California by storm.
During John's retirement his health deteriorated with heart trouble
and pneumonia but his mind remained as sharp as ever and he saw
many visitors. After a final attack of pneumonia he died at home
on 6 July 1993.
A one-day John G. Bolton Memorial Symposium was held at Parkes
on 10 December 1998. On this occasion the assembled company, including
Letty, gathered round a commemorative sundial and stood in silence
for a minute. In the ground, beneath the sundial, lay the ashes
of a very special man.
| 1951 | Edgeworth David Medal (Australia) |
| 1967 | First Karl Jansky Lecturer (U.S.) |
| 1968 | Henry Norris Lecturer (U.S.) |
| 1969 | Elected Fellow of the Australian Academy of Science [7] |
| 1972 | Elected Foreign Honorary Member of the American Academy of Arts and Sciences |
| 1973 |
Vice-President of the International Astronomical Union (1973-79)
Elected Fellow of the Royal Society of London Elected Honorary Fellow of the Indian Academy of Sciences |
| 1977 | Gold Medal of the Royal Astronomical Society |
| 1980 | Elected Foreign Associate of the U.S. National Academy of Sciences |
| 1982 | Commander of the Order of the British Empire |
| 1988 | Bruce Medal of the Astronomical Society of the Pacific (U.S.) |
[1]
Although I worked in a different part of radio astronomy (I
was a solar man) my background was strikingly similar to John
Bolton's. We were both born in the same city (Sheffield), within
a year of each other, both went to the same university (Cambridge),
both joined the Royal Navy as radar officers operating in the
Pacific, both emigrated to Australia after the war, both applied
for the same advertised job at the Radiophysics Laboratory, both
married Sydney girls (within a month of each other), both played
for the Radiophysics cricket team and were appointed joint vice-Captains;
when the two observatories of Radiophysics were founded (Parkes
and Culgoora) we were appointed the two Directors on the same
day.
[2]
A similar technique was used during the war by the British
Navy to determine the height of aircraft by radar.
[3]
The optical source is obscured by dust.
[4]
Jesse Greenstein, then in charge of Caltech's Division of
Physics, Mathematics and Astronomy, wrote (in 1993); 'The excitement,
generated by John Bolton and his team with their sea interferometer
at Dover Heights near Sydney in the early 1950s placed irresistible
pressures on U.S. astronomy'.
[5]
A quasar (or quasi-stellar object) is a starlike object with
luminosity some 1000 times that of a normal galaxy. Quasars are
thought to be compact galactic nuclei and to have a massive black
hole in the middle. They are the most luminous objects in the
universe and so include the most distant observable objects. The
number now known has reached four figures, many of them discovered
by Bolton.
[6]
It is interesting that despite Bolton's vital contribution
both to the successful recording of the occultation of 3C273 and
to the redshift identification of 3C48, his name does not appear
on either paper. These papers are respectively: Hazard, C., Mackey,
M.B., Matthews, T.A., Nature 197, 1037 (1963); and
Greenstein, J.L. and Matthews, T.A., Nature, 197,
1041 (1963). Those who have worked closely with Bolton would know
that this was not unusual.
[7]
Bolton resigned from the Academy in 1980, the only Fellow
to have done so in the history of the Academy. It appears that
the Sydney Morning Herald put pressure on the Academy to
express its public support for Andrei Sakharov, the dissident
Soviet nuclear physicist, human rights advocate and recipient
of the Nobel peace prize. Bolton appeared to object to the way
in which the Academy Council handled the matter. In his final
letter to the President he wrote: 'I have a very strong feeling
that scientists or scientific bodies should keep out of politics
except for those occasions when there is a concrete objective
to be gained and when their expertise will be respected'.
J.P. Wild, 4/1 Grant Crescent, Griffith, A.C.T. 2603 Australia
and 800 Avon Road, Ann Arbor, Michigan, 48104, USA.
V.R. Radhakrishnan, Raman Research Institute, Bangalore 560080,
India.
This memoir was originally published in Historical Records of Australian Science, vol. 10, no. 4, December 1995, pp. 381-91, and also in Biographical Memoirs of Fellows of the Royal Society of London, 1995.