SIR FRED HOYLE: HIS WORKS
The stars in the sky have consistently proved the enigma of the universe. Humans have always searched the skies above them out of both curiosity and wonder. Throughout the centuries, several people have studied celestial objects in hopes of discovering a bit more of not only the world but also the universe they live in. The fascination for such a topic has undeniably continued well into the 1900s. One of the most innovative astronomers of the twentieth century was an English astronomer, Sir Fred Hoyle. With a career spanning over six decades, Hoyle has become an eminent astronomer and recognized for his contributions to the field. He is principally remembered today for his involvement in the creation of the theory of stellar nucleosynthesis and his views opposing the theory of the “Big Bang” – an expression he himself had created. The purpose of this paper is to inform the reader of some of the main astronomical theories and works of Sir Fred Hoyle, > such as his work on star formation and interstellar structure, stellar nucleosynthesis, and his works on stellar structure and evolution, particularly those of red giants. It is also imperative to consider his cosmological work with the controversial Steady State Theory, which shall be done at the end of the paper. In addition to this, a brief overview of his life will be shortly discussed with other inputs not directly related to the astronomical field.
Fred Hoyle was born and raised in Gilstead, a village near the town of Bingley in West Yorkshire, England. Hoyle was born as the first son on June 24th, 1915, just before his father was conscripted into the British Army for World War One. His mother had a great passion for music, which allowed her to earn a living by working as the piano player for silent films at the local theatre. Although Hoyle was born into a modest family, his parents worked hard to earn money for the family.
During his earlier childhood years, Hoyle had some difficulties in school. After concluding his teacher was unable to count past five (for he brought in a flower with six petals and his teacher insisted there were only five), Hoyle shirked his responsibility of going to school. However, he was still keen on learning and taught himself concepts from a Chemistry book that the family had owned. His mother was adamant in giving a proper education for Hoyle and soon decided to enrol him at a primary school in a nearby village, Eldwick. He had flourished there and was granted acceptance into a well-known Bingley grammar school in 1926. During his years at the school, he prepared for the Cambridge scholarship exam, with the aid of a professor, Alan Smailes. Although he received no financial support, he did gain acceptance into Cambridge at the Emmanuel College in 1933, where he went on to complete his Bachelor of Arts in Mathematics three years later. Within those three years, Hoyle was awarded the Mayhew Prize for his top performance in applied mathematics. In July 1936, Hoyle was now a research student. He worked on an essay on Beta (β) decay, for which he was honoured with the Smith’s Prize in 1938. Seeing that this was a monetary award as well, it was sure to eradicate a good portion of his financial burden. It was also during this period when Hoyle met Raymond Lyttleton, a student at the St. John’s College working in astrophysics. Lyttleton at the time was researching the accretion of stellar matter. During one of Lyttleton’s seminars, Hoyle had met the senior student and through this episode, he had become interested in astrophysics. The concept of accretion was the first topic in the field that Hoyle had delved into for further research. In 1939, both the events of his marriage and World War Two took place. Hoyle and Barbara Clark married in December 1939, and shortly after went to work for a naval radar research establishment. Here he met another two of his future colleagues, Thomas Gold and Hermann Bondi. Bondi, Gold and Hoyle met while working at a naval radar research establishment in Chichester, England. It appeared that they shared similar principles that funded their involvement in the creation of the Steady-State Theory. Subsequent to the war, Hoyle returned to Cambridge and continued his research. The period following the war was one where Hoyle would have propounded some of his most important theories and works.
One of Hoyle’s first ventures in astronomy was through the study of accretion in the 1940s. Accretion is the term given to describe the creation of a celestial object by pulling together the encompassing objects and gases through gravity. Both Hoyle and Lyttleton had developed the concept that the accretion of stellar matter was vital to stellar evolution in two papers in 1939 and 1940. They had determined that if a star were to move in rectilinear motion through a cloud of gas initially at rest, the orbits of the gas particles would meet with the “accretion axis,” a line behind the star. Collisions on this line would reduce the momentum of the particles, which would leave them with negligible kinetic energy. With little energy, the particles are now unable to avoid being captured by the star and thus they become a part of that star. Bondi had also later worked on the concept of accretion with Hoyle, and because of this the Bondi-Hoyle-Lyttleton accretion problem was named after the three of them. The Bondi-Hoyle-Lyttleton accretion problem deals with the accretion rate of a body of particular mass that is moving at a constant velocity through a regular cloud of gas. Accretion is useful in possibly comprehending the creation of the first massive stars of the Universe, which were formed at redshifts of around z = 6-15 (z being the ratio and the 6-15 showing that they are of a great distance from us as a redshift indicates the object is moving away from us since a longer, red wavelength is detected). These stars are of interest as they probably produced the first heavy elements. Through computer simulation analysis, it was found to be probable that these stars first formed as a nucleus and then grew from the accumulation of intergalactic gas through accretion.
In the 1940 paper on accretion (Hoyle and Lyttleton), the problem that was dealt with was the cooling system of interstellar gas. Using a calculation by Arthur Eddington and the assumption that the interstellar matter had no chance for additional emission, the temperature of a pure hydrogen cloud was estimated to be 10000 K. This was too high for any significant accretion and through the paper, it was suggested that its cooling occurred through molecular hydrogen, H2. Two > options of cooling were considered: the free-free transitions (or Bremsstrahlung) in electron-to-proton collisions and the infra-red emission as a result of excited hydrogen molecules. The Bremsstrahlung (roughly translating to “braking rays” in German) is a term used to represent the process when a charged particle
decelerates when deflected by another charged particle, in which electromagnetic radiation is emitted. In the paper, it is explained that Bremsstrahlung does not reduce the temperature of the cloud to be of much consequence (after calculating the cross-section or the probability of the interaction to take place between those particles, as measured in barns). Through additional research, Hoyle and Lyttleton have concluded that between consecutive excitations of the hydrogen molecules, the molecules would have enough time to radiate away the energy that was obtained in the first excitation, thereby producing a cooling effect. Hoyle has been praised for his ability to have formulated the problem without laboratory assistance in determining cross sections. This paper was also the first to acknowledge cooling by molecular hydrogen.
During the 1960s and 1970s, Hoyle collaborated with Chandra Wickramasinghe in tackling the issue of the composition of interstellar grains. In 1962, their first paper on the subject proposed that the grains were composed of graphite formed in carbon stars and then, through pressure from radiation, emitted into the interstellar medium (ISM). This idea challenged the customary idea that the grains were mostly made of ice. A convincing argument to this theory is shown through the extinction curves for graphite and the normalized extinction curve (for interstellar grains). An extinction curve is also known as the interstellar reddening curve. Interstellar reddening is connected to the absorption (when the energy is consumed by matter) and the scattering (the deviation of the radiation when passing through certain objects) of electromagnetic radiation emitted by some object between the object emitting the radiation and the spectator. Interstellar reddening deals with the changes in the properties of the electromagnetic radiation spectrum (the range of all frequencies possible) and reddening will occur if light scatters off matter in the ISM. In the paper, an interstellar reddening curve for graphite flakes was calculated theoretically, which was shown to be quite similar to the observed interstellar reddening curve. This similarity suggests that the interstellar grains may indeed be composed of graphite, and not ice.
Both Hoyle and Wickramasinghe went on to further suggest that even more complex material composes interstellar grains and comets, including life in the form of bacteria. Hoyle was adamant in his belief that life did not originate on Earth as he viewed the probability of forming life from non-living materials on Earth is too small. The two also worked on the theory of panspermia, which states that the “seeds of life” already exist across the universe and life on Earth may have started through these seeds. Both Hoyle and Wickramasinghe have supported the theory and argued that the Earth is continued to be bombarded with various life forms, which may be responsible for epidemics and diseases.
Hoyle was the first to recognize that heavy elements can be produced in stars and then released into the interstellar medium by stellar winds or through various explosive methods from the stars. He also theorized that the massive stars, which have developed to have quite hot and dense centres, would generate the iron- peak elements (elements with 56 protons like Fe). This process was later named the “e-process,” with the “e” standing for equilibrium. It states that at temperatures greater than 5,000,000,000 K and with densities greater than 3,000,000 g cm-3, several collisions between the nuclei and the photons with great energy would occur. These collisions would disintegrate the nuclei and these pieces would then combine with other particles. In the long run, particles with iron-like properties would probably be trapped in the nuclei since the iron group of elements will have the largest binding energies. These elements would then be ejected into the interstellar medium by the means of an explosion (supernova explosion) as discussed in Hoyle’s 1946 paper.
Although the Nobel Prize for nucleosynthesis in stars was awarded to S. Chandrasekhar and Fowler in 1983, some believed that Hoyle should have been awarded it as well for his noteworthy contributions (including Fowler, an amiable colleague of Hoyle). Nonetheless, fourteen years later, the Royal Swedish Academy of Sciences awarded the 1997 Crafoord Prize in astronomy to both Hoyle and Salpeter for their contributions to stellar nucleosynthesis, a prize comparable to the Nobel Prize. Hoyle had initially done some work on red giants with Lyttleton throughout the 1940s. In their 1949 paper, the pair discussed the structure of inhomogeneous stars (stars without a consistent composition). However, Hoyle’s most celebrated collaboration on the subject was with Martin Schwarzschild in 1955. The pair calculated the development of Population II stars from the stars in the main sequence (like the Sun) to red giants, as shown through Hertzsprung-Russell diagram. Population II stars are stars that are said to have comparatively little metal, or “metal-poor” and are some of the oldest stars in the Galaxy (the Sun is considered a Population I star because it is metal-rich, therefore depicting that it is a younger star). These stars are found in spherical clusters and are more common near the centre of the galaxy where the bulge is located. When the two met at Princeton University, they realized that the problem in the past works of stellar evolution was that convection was disregarded in the previous calculations of red giant models. Convection is the transport of heat by grand-scale shifts of gas. The currents flow upward and downward while carrying the hot gas outward and the cool gas inward. The cooler gas is reheated and then carried upward again. This process was already thought to occur in red dwarfs but Hoyle and Schwarzschild revealed that it was also effective in the structure of both red giants and supergiants. In fact, their first models that were calculated with the convection considered were shown to be more analogous to the observed spherical-cluster colour-magnitude diagrams than any of the previous models, which did not consider convection. Colour-magnitude diagrams are graphs that show the relation between the brightness (magnitudes) and colours of stars, which correlate to their temperatures and spectral variations. As a result of Hoyle’s and his collaborator’s work, red giants are often described as stars that have inert, constant-temperature cores, thin hydrogen-burning shells (where helium is formed), extended regions inside it where convection occurs, and are about 10 billion years old.
Later in the early 1960s, Hoyle and Fowler noted that heavy elements are emitted through Type I and Type II supernovae. They correctly deduced in their 1960 and 1964 papers that Type I supernovae are results of explosions of degenerate matter (highly compressed, dense matter where its normal atomic structure has broken down, such as the kind found in white dwarfs) and Type II supernovae occur due to the implosion and then explosion of non-degenerate stellar cores. For further classification, Type I supernovae have three subsets: Type Ia, which are explosions of white dwarfs, Type Ib and Type Ic are similar to Type II, in which they are explosions of massive stars but the Type Ib and Ic supernovae are caused by stars that are stripped of their outermost hydrogen layer (and most of the helium layer as well for the Type Ic).
It is wise to now note the “onion-skin” model, as explained by Hoyle in 1946. It is a model that is still used today and shows the composition of a star in its pre-supernova stage. There are seven layers to the star, with the outermost layer being hydrogen, the second layer being helium, and the innermost layer (or core) consisting of the iron group of elements. This shows that the star is inhomogeneous and, therefore, a very old star.
In 1948, Hoyle, Bondi and Gold developed the Steady-State theory, which opposes the Big Bang Theory. Although largely disregarded today (especially after the discovery of cosmic microwave background radiation in 1964), it was a strong idea in the mid-20th century. The theory relies on the perfect cosmological principal stating that the universe does not change with time or space. The theory allows the universe to exist for an infinite time as the same universe. Since the theory was created after E. Hubble discovered that the universe was expanding, it did take into account this expansion through what Hoyle called the “C-field” (“creation field”). This field was one that created matter from nothing at exactly the required rate to keep the density of the universe constant, even amidst expansion (but at only about 1 atom per m3, every 10 billion years). The theory had obvious flaws but was revised (as evidence supporting the Big Bang grew) during the early 1990s. The new Quasi-Steady-State theory was created by Hoyle, J. Narlikar and G. Burbidge, which suggested a continuous series of big bangs (known as “little bangs”) instead of one, initial Big Bang. Although this theory takes into account the ejection from active galaxies (as the Big Bang Theory does not), it still does not have much support due to lack of cogent evidence.
Sir Fred Hoyle died on August 20th, 2001 in Bournemouth, England at the age of 86. He started his career as a lecturer at his alma mater, Cambridge University, and then as the Plumian Professor of Astronomy. In 1967, he created the Institute of Theoretical Astronomy at the university. Hoyle was also an author of science fiction and has written many books alongside his son, Geoffrey. One of his most familiar novels is The Black Cloud (1957), a tale concerning the threat of a large cloud in the solar system blocking the sun’s radiation and foreshadowing the demise of the Earth’s creatures. He also branched out his creativity into television and wrote the popular British science-fiction drama, A for Andromeda (1961). Hoyle has had a profound effect on many aspects of astronomy and this paper only provides some of his more major works during his life. There are still many fascinating concepts he helped develop and after going through many of them, one truly realizes the passion and dedication of the astrophysicists in the world. Hoyle has indeed left a legacy not to be forgotten.
COLLECTED INFORMATION – BOOKS
I. Gough, Douglas, ed. The Scientific Legacy of Fred Hoyle. New York: Cambridge UP, 2005.
II. Mitton, Simon. Conflict in the Cosmos: Fred Hoyle’s Life in Science. New York: Joseph Henry P,
2005.
III. Osterbrock, Donald E. Walter Baade – A Life in Astrophysics. New York: Princeton UP, 2001.
COLLECTED INFORMATION – WEBSITES
I. http://astronomy.swin.edu.au/cosmos/T/Type+Ib+Supernova
II. http://astrophysics.suite101.com/article.cfm/steady_state_cosmology
III. http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Hoyle.html
IV. http://www.chemistrydaily.com/chemistry/Triple-alpha_process
V. http://csep10.phys.utk.edu/astr162/lect/energy/triplealph.html
VI. http://www.aps-pub.com/proceedings/1474/470411.pdf
VII. http://www.pas.rochester.edu/~rge21/research/bhl/
VIII. https://www.amazines.com/B%C2%B2FH_related.html
IX. http://www.csi.uottawa.ca:4321/astronomy/index.html#nucleosyntheticreaction
X. http://csep10.phys.utk.edu/astr162/lect/supernovae/type1.html
XI. http://www4.nau.edu/meteorite/Meteorite/Book-GlossaryD.html
XII. http://www.britannica.com/EBchecked/topic/126761/colour-magnitude-diagram
XIII. http://adsabs.harvard.edu/abs/1977AJ…..82..337S
XIV. http://astro.elte.hu/astro/en/library/padeu/padeu_vol_17/padeu_vol17_sipos_etal.pdf
XV. http://www.shodor.org/refdesk/Resources/Activities/InterstellarExtinction/
XVI. http://www.ndt-ed.org/EducationResources/HighSchool/Radiography/bremsstrahlung_popup.htm
XVII. http://www.lbl.gov/Science-Articles/Archive/cosmic-microwave-background-anisotropy.html
February 1, 2009
Russian Novelist Aleksandr Solzhenitsyn Dies at 89
Short biographical sketch
Russian Novelist Aleksandr Solzhenitsyn Dies at 89
By Thamayanthi Giritharan
Aleksandr Solzhenitsyn is a recognizable name to those of the literature world. He recently passed away on August 3rd, leaving behind a great legacy. For those of you not familiar with him, Solzhenitsyn was primarily a Russian novelist, even receiving a Nobel Prize for his works (in the field of literature – of course).
Solzhenitsyn (Dec 11 1918 – Aug 3 2008) was immersed in a world of academics since a very young age. His family was well educated. He ended up going to the University of Rostov-na-Donu and graduating in mathematics. He also studied literature at Moscow State University. He not only witnessed WWII, but fought in it and eventually earned the rank of captain of artillery in 1945. He was soon after arrested for criticizing Joseph Stalin, which led to eight long, dim years in prisons and labour camps. One should think eight years is a good enough period for punishment, however, he was then forced to undergo three more years of exile. Finally, eleven years after the war ended, Solzhenitsyn was able to resettle in Russia. He became a mathematics teacher and it was at this time is passion for writing flourished.
In 1962, Solzhenitsyn had his short novel Odin den iz zhizni Ivana Denisovicha (One Day in the Life of Ivan Denishovich) published in the Soviet Union’s top literary journal Novy Mir (New World). His novel became an instant hit, giving him a sort of celebrity status. Solzhenitsyn had based this story on his own experience as an inmate of a labour camp during Stalin’s epoch. This piece was a new force to be reckoned with in the Soviet Union at the time. It created waves in politics and literature both in and outside of Russia. He continued to publish more works and more criticism followed. He then resorted to self-publishing his works and circulated them in secret and abroad.
In subsequent years, Solzhenitsyn had cemented his international literary standing with many published novels, like V kruge pervom (The First Circle) and Rakovy korpus (Cancer Ward). Several stories were somehow related to his life. For example, the first was obliquely based on his years as a mathematician working in a prison research institute. The latter was based on his treatment for terminally diagnosed cancer while being exiled in Kazakhstan in the fifties.
Solzhenitsyn was awarded the Nobel Prize for Literature in 1970 but didn’t want to leave to accept it in apprehension of not being allowed back into the Soviet Union. He did end up in possession of the award four years later – when he was exiled from the Soviet Union. (He was readmitted twenty years later)
Solzhenitsyn continued to produce great works which have expressed his views and beliefs. He was never one to shy away from articulating his thoughts – even if it meant being exiled and pounced upon by the Soviet press. He has become a great literary icon over the years and is sure to be a remembered literary icon for the years to come.
Information gathered from
http://www.almaz.com/nobel/literature/Solzhenitsyn.html
Short Story: Thanks! By: Thamayanthi Giritharan
Short Story: Thanks!
By: Thamayanthi Giritharan
Downtown Toronto. It’s an extremely busy area. People of all kinds go this way and that; going to work, going to school, going anywhere to continue a blessed life. Have you ever observed all these people? Yes, I know it seems a bit nosy and meddlesome but I can’t help myself! There are so many people that comprise this city – people from all corners of this blue and green ball (it’s known as Earth). All these people have somewhere to go and something to do with life. Well, almost all; some aren’t as fortunate.
I walk on the cracked road in downtown while going to school. Just like everybody else, I’m going somewhere and I cannot be late – but it looks like I am going to be (again). Cars are honking while smoke is puffing out like mad; looks like another traffic jam. Hopefully, I am not late for school; hopefully I haven’t forgotten my homework (again). *Sigh* It sure is a humid day and it’s so hot – hey!
“Sorry miss. Here’s your backpack. You better get to school if you don’t want to be late!”
“Thank you,” I respond to a man of no interest. He looks like a businessman; another busy person in this hustling city. Hmm, there’s a man sitting on the street. I wonder why he’s sitting on the pavement on such a hot and sunny day (it’s 34 C you know!).
As I near the man I find he has no shoes. His clothes seem so tattered and aged. He’s wearing sunglasses – I wish I had some, it is super sunny! Next to his bare feet is a cane and a small baseball cap with a couple of quarters in it. Poor man, he must be homeless. It breaks my heart to see someone with no home and unprotected, yet virtually everyone passing by is living safely.
“Oh, Tessa! It’s a homeless guy! Don’t go near him – he might have a disease! Run away from him!” a little girl secretly and loudly whispers to her friend. I wonder how he must feel when he hears these things. He must be hurt but will never show it. I unzip my bag and search for some loose change. A loonie, three toonies and a couple of quarters, that’s all I have today.
“Hello. Um, I have something to put in your cap,” I timidly state. I briskly drop the coins into the cap and didn’t say another word. I patiently wait for a while to hear anything he might respond.
“Thanks,” is all he says. I nod politely and leave for school (even though I’m already much too late). He then says something else loud enough for me to hear but quiet enough so no one else would, “Now I have money to buy a decent meal to last for a couple of days.” I wonder how he walks with no shoes.
Today is another day; another busy day. I promised myself (and my teacher) that I wouldn’t be late today. However, I’m early enough to have a little chat.
“Hello. I have a bit more money today. You can buy a great meal of Chinese food with this,” I say to him without sounding too corny.
“Do you pity me?”
I was in jolt, “Uh, I just want to help you sir.”
“Ah, don’t say ‘sir!’ Call me Jacob.” He gestures a handshake and I accept. “It’s obvious to say you’re a girl; your hands are smooth and well moisturized – not like any self-respecting guy I know!” he heartily laughs. I was a bit perplexed. “Would you like to come in and buy food with me?”
I respond, “I’m sorry but I have school. Maybe some other day.”
“Yes, I remember when I was in school. I used to be a math professor, you know.” Wow, a math professor! Why is he on the street now? I decide its best not to inquire.
“Bye Jacob. By the way, my name is Terry. I hope to see you tomorrow!” I say.
“I might not see you, but you’ll definitely see me.”
Today I decide to visit Jacob again. I walk down the cracked road on my way to school and find Jacob sitting there once again on this hot and sunny day. Well, at least he has his sunglasses. Although, I went to a store and did pick up something.
I greet, “Hey Jacob!”
“Hello. What’s in the bag?”
“I wanted to get you something so I bought some –”
“Terry, before you say anything I want to ask if you can donate this money to a charity of any kind.”
“Yeah, do you really want to give this money away?”
“Yes.” He gave me $10.00 for charity. It may not be much but it’s all he has. Even in the midst of being homeless, he still has the heart to help other unfortunate beings.
“Don’t worry Jacob, I won’t disappoint you. Well, I bought some shoes for you. I know it’s not Nikes® or anything fancy, but I hope you like it!”
Jacob tried them on and looked very pleased. His face shone and happily said, “Oh thank you so much! It’s the nicest thing anyone has ever done for me in a long while! These shoes are comfy!”
I then ask out of curiosity, “Do you like the style?”
“Terry, I’m sure the style is wonderful but you see, I’m afraid I cannot enjoy it. I’m blind.”
I was in awe. With his kind heart and little supplies, he still gets through his life of hardships. I cannot believe how he survives, but I’m glad he does.
“You know what Terry, one day I’d like to have my job back.”
“Don’t worry, I’m sure you will soon.” I unzip my bag come across a five-dollar bill. “Here’s some cash to turn your dream into reality.”
He gently smiles with a twinkle in his eye. “Thanks.” I leave for school hoping to see him another day.
Courtesy: ‘Scarborough Youth Writers’, A collection of Short stories selected from the Short story Competition 2006, published by Scarborough Writers Association (Canada) with the support of Scarboroug Arts Council (Canada).
