08.11.2021 : The Economic Connections..

I hated history in school. So did most of my contemporaries. So do most of today's children. (Can't envisage any change there unless history teaching goes for a complete overhaul.) Not surprisingly, it is the popular culture that has helped shape the perceptions of history for many of us. In fact, my interest in history was seriously piqued, for the first time, by Name of the Rose by Umberto Eco (almost singularly responsible for ruining the summer internship work of a capricious masters student)!

Notwithstanding the academic debacle, medieval mysteries (and other such entertaining reads) have since been my standard go-to for historical perspectives. So, it was a pleasant surprise when yesterday's late night indulgence turned out to be based on a little piece of WWII physics history. The Catcher Was a Spy, a little known eponymous film (2018) based on a biographical book by Nicholas Dawidoff, narrates the story of Morris Berg (1902 – 1972).

Berg was a catcher in American Major League Baseball and later spied for the Office of Strategic Services (OSS) of the USA. Primarily because of his academic background (Princeton, Columbia) and linguistic proficiency, he was tasked (1944) with interviewing European physicists and trying to convince them to move to the US. The primary goal of this was to prevent Germany from making The Bomb before Manhattan project succeeded in doing so.

Though a great number of German (mostly Jewish) scientists had fled from Germany once Nazis came to power, there was no doubt about the calibre and capability of Heisenberg and other remaining German scientists to produce an Atomic Bomb. However, whether they had the resources to do that and/or had the willingness to do so were questions the Allied Powers were most keen to know the answers of. 

The climax of the film (as also of Berg's career, I suppose) took place in December, 1944 when Heisenberg traveled to Zurich to deliver a lecture on the invitation of the Swiss physicist Paul Scherrer. Berg's brief was to gauge the status of Germany's nuclear weapons program and to kill Heisenberg if they appeared to be close to success. Heisenberg lived, because Berg (correctly) assessed that the German efforts were not close enough!

Such an irony of fate! In the early 1930s, it was Heisenberg who was labeled as a White Jew (German Christians sympathetic to or in good terms with the Jewish people)! He was persecuted, his career suffered and things only improved through personal intervention from a family friend (Heisenberg's mother was a friend of Himmler's wife). Yet, because Heisenberg elected to stay back in Germany (many non-Jewish scientists left because of their differences with the Nazis) and because of his aforementioned family connections, he was never trusted by the scientists of the western bloc. At the end of the war, Heisenberg, von Weizsacker, Otto Hahn and other scientists working on German nuclear program were picked up by the British and interned at Farm Hill to investigate their wartime work. (https://sushan-konar-musings.blogspot.com/2021/06/28062021-of-different-era.html)

Almost exactly twenty years ago, I had an opportunity to visit the University of Leipzig where Heisenberg was a professor of theoretical physics (since 1927). He was awarded the Nobel prize (1932) while at Leipzig, and also met (1937) his future wife Elisabeth Schumacher at a musical evening there. Elisabeth was the sister of Friedrich Schumacher (1911 – 1977), the famous statistician and economist and author of Small Is Beautiful: A Study of Economics As If People Mattered (1973) - a must-read for our generation!

This book made economics in general, and Schumacher's ideas in particular, accessible to a wide audience. Schumacher argued that our technological progress must take into account the fact that the natural resources (like fossil fuel, coal) are finite. This coincided with the emergence of environmental concerns (which has now taken centre-stage of world policy-making, as is evident from the ongoing COP26 being held in Glasgow).

Schumacher had a deep connection with many Asian countries and had also served as a consultant to the Planning Commission of India for a while. However, a long time has passed since then. As Sanjeev Sanyal, our current Principal Economic Advisor says, the economics of today is adopting the dynamical world-view appropriate of a complex system (instead of the deterministic world-view of Newtonian physics). Indeed! Giorgio Parisi, theoretical physicist who pioneered the study of complex systems, is one of this year's physics laureate! (https://sushan-konar-musings.blogspot.com/2021/10/25102021-value-of-science.html) 

The personal economics of many of our persuasion (academic scientists, that is) may not be something to write home about, but it suits a physicists ego very well to imagine that our discipline is still defining the rules of the game! 😎

[The morning program of a Calcutta-based TV channel reminded me that it's Usha Uthup's birthday today. For me, her unusual voice, her unusual story, has always epitomised the many fights women must fight to find their own space, on their own terms. Because, despite all the odds she has been able to define her own space. Here's one song that I loved listening to in my younger days, and is rather appropriate for all those WWII references. The import of the song remains true even today. Because, the threat of violence is never very far from human endeavours. 
https://www.youtube.com/watch?v=4k9K088qTII (a recent stage performance)
https://www.youtube.com/watch?v=65adlW50S-w (original recording)]

16.08.2021 : The Martian

 It was the 15th of August yesterday. For the second time in a row, our schools stayed empty and silent on an Independence day.

Independent India was in her thirties when our generation attended school. In most schools, like my own, this used to be the biggest celebration of all. For an entire month we would prepare for the day - every class practicing their special song, fierce competition raging between groups making India-themed charts, or splashing tri-colour decorations all around...

Things haven't changed much in the intervening decades, it appears. A few years ago, the young one showed me a poem that they were learning for the Independence Day program. It was "Jhansi ki Rani" by Subhadra Kumari Chauhan, the well-known poetess, born on this day in 1904 [Today's Google Doodle is in her honour.]. It is perhaps no casual coincidence that Chauhan happened to be the first woman Satyagrahi to court arrest for protests against the British rule, while Rani Laxmibai has been an iconic symbol of resistance in India's first fight of independence against the British 'colonial' rule.

Throughout history, explorations for resources has one of the major reasons behind colonialism. Given the trend of population growth, our exponentially increasing requirement for a vast array of resources and given the limited resource reserve of planet Earth - space is quite obviously the new frontier. Clearly, we are about to enter the era of 'space-colonisation'.

For long, asteroid mining (for precious minerals) and terraforming (of other planets) have been standard science fiction fare. Recent space-exploration developments seem to suggest that the colonisation of Mars could just be around the corner. Serious suggestions are being tabled for terraforming (creating an Earth-like or habitable environment) of Mars.

Even though Earth is similar to Venus in composition, size and surface gravity, Mars has certain advantages for a long-term human habitation. Consider the following similarities -
a) A Martian day is 24 hours, 39 minutes and 35.244 seconds.
b) A Martian year is about twice as long as an Earth year.
c) Mars has an axial tilt of 25.19°, hence seasonal variations are similar.
d) Mars has water (ice) and other elements (carbon, oxygen, nitrogen, phosphorous, sulphur etc.)

Despite these, it would not be an easy task to terraform Mars. The current Martian atmosphere is too thin, the pressure being just 0.6% of the average atmospheric pressure on Earth. And it is also rather cold. Terraforming Mars would therefore entail - building up the atmosphere, and raising the temperature. And even if an adequate atmosphere is created it would be difficult to retain that, because Mars does not have a global magnetic field (which deflects solar wind and stops it from stripping the Earth's atmosphere). We also have no idea about the long-term health effects in such a low surface gravity (about 40% of Earth's) environment.  

A recent study by NASA suggests that it may not be possible to terraform Mars using current technology. However, space-agencies, both public (NASA, ESA, Roscosmos, ISRO, CNSA, UAE) and private (SpaceX, Lockheed Martin, Boeing), are now engaged in activities to test the feasibility of setting up small, self-sustaining, sealed enclosures on Mars for limited time human habitation. [Yep! Just like in the movie 'The Martian'. Last month, in a lecture organised by the HAPP Centre (Oxford), Jim Green of NASA explained how the movie was made with close collaboration with NASA scientists and how much of what was shown could be achieved in not too distant a future.]

However, space exploration is not only about science. According to the UN 'Outer Space Treaty' (1967) no country may make absolute claim over an extra-terrestrial space or its inhabitants. But, given the participation of commercial entities (like the Space-X) in these ventures, such legal documents would require a thorough rewrite. There would also be ethical issues, as discussed recently by Nicholas Dirks (Scientific American, 10 August 2021). Dirks raises very valid points regarding the ownership of the regions, mining rights and so on.

However, our explorations have not yet discovered any large life forms on Mars (or Moon, or the asteroids that have been investigated), though search for micro-organisms continue. Therefore, worrying about the impact of our explorations on 'resident life-forms' seems a bit of an overkill. Rani Laxmibai and Subhadra Chauhan fought against `imperialistic colonialism'. It is perhaps somewhat disingenuous to transpose the 'colonialism' lexicon (and its implications from the European experience on Earth) unqualified onto near-future space-explorations.

 

 

09.08.2021 : The Bomb connection..

 The 2020 Olympics, concluded yesterday in Tokyo, has almost been like a symbolic rise of the resilient human spirit after the devastation caused by and the 'clear and present danger' of the Covid-19 pandemic. Japan has presented the world with an exciting fortnight and we should all be grateful for that. However, we can't really move our focus away from Japan just yet.

Seventy-six years ago on this day (9 August 1945) the Japanese city of Nagasaki was completely destroyed when the US army dropped an atomic bomb on it. The city has since been rebuilt but the scars remain, so does our firm entry into the age of nuclear armament.

[But the political significance of 9th August goes way back. A British charter of 1683 (granted on 9th August) effectively gave 'sovereign' power to the East India Company over Asian territories, and sowed the seeds of British Empire. Then, close to 250 years later to the date (9 August, 1925) a group of dedicated freedom fighters (Ram Prasad Bismil, Ashfaqulla Khan, Rajendra Lahiri, Chandrashekhar Azad..) robbed a train (carrying money for the British treasury) in Kakori, near Lucknow, to fund the movement to free India from the clutches of that selfsame empire.]

This day also saw the birth of the noted physicist, Alladi Ramakrishnan (9 August 1923 – 7 June 2008), a couple of years before the Kakori incident. Ramakrishnan, son of the famous lawyer Alladi Krishnaswami Iyer (who took a prominent role in drafting the Indian Constitution), made significant contributions to stochastic processes, elementary particle physics, matrix algebra, and the special theory of relativity.

After completing his studies at Presidency College, Ramakrishnan worked with Homi Bhabha at the Tata Institute of Fundamental Research (TIFR) and then moved to the University of Manchester to work under M. S. Bartlett. He joined the physics department of the University of Madras (where crystallographer G. N.  Ramachandran was the head) upon returning to India (1952).

A few years later, Ramakrishnan met Robert J. Oppenheimer, the father of the atomic bomb, and went on to spend a year (1957-'58) at the Institute of Advanced Studies, Princeton at Oppenheimer's invitation.

Inspired by this visit he became desirous of inducting talented students into theoretical physics. In particular, he wanted to expose them to the latest advances through seminars given by scientists working at the frontiers of the field. Because he considered such seminars to be “the essence of intellectual activity, where there is as much desire to imbibe as there is to impart, where opportunities are provided for a clash of intellects which would produce creative ideas”.

Ramakrishnan used to invite eminent scientists from all over the world for these seminars and hold the seminars at his Madras home. Niels Bohr visited in 1960 and recommended the creation of an institute of advanced research. Bohr's recommendation, steadfast political support from C. Subramaniam, and (last but not the least) Ramakrishnan's enthusiastic students directly petitioning the prime minister paved the way for setting up of such an institute. The Institute of Mathematical Sciences (Matscience) was launched on January 3, 1962 and Ramakrishnan served as its director for 21 years till his retirement in 1983.

Today, Matscience is counted as one of the top research institutes of India, in the field of mathematical sciences. It is a curious coincidence that this institute of eminence had its origin in a private seminar series, born out of Ramakrishnan's connection with the 'father of the atomic bomb'!

28.06.2021 : Of a different era..

Many neutron star theorists spend their working lives delving into the intricacies of nuclear physics. While nuclear theories allow astrophysicists to interpret faint signals coming from exotic neutron stars; these celestial objects, in turn, act as unique laboratories (unlike any that can be built on Earth) for the nuclear physicists. Recently, my friend Sarmistha Banik organised a meeting to discuss such interconnections (between nuclear physics theory and neutron star observation) and to celebrate the sixtieth birthday of Prof. Debades Bandyopadhyaya (her academic guru) who has been working in this area for a very long time.

But neutron stars arrived later (discovered in 1967) on the scene. Nuclear Astrophysics has been walking hand-in-hand with nuclear physics since the beginning of the twentieth century. The last century decidedly belonged to physics. Even the world wars were fought on the back of physicists. Not surprisingly, many (or perhaps most) of the nuclear physicists (as well as nuclear astrophysicists) were involved in the process of Bomb making.

German-American Maria Geppert-Meyer (28.06.1906 - 20.02.1972) was one such nuclear physicist, whose nuclear shell model, explaining the properties of atomic nuclei, earned her the Nobel prize. [In the entire history of the Nobel Prize (1901 - 2021), only FOUR women physicists have been honoured - Marie Curie (1903), Maria Geppert-Mayer (1963), Donna Strickland (2018) and Andrea Ghez (2020). Though Geppert-Mayer had to wait for sixty long years after Curie, the last two have come in a quick succession and one hopes that the future would be reflective of the mores of our own times.]

Geppert-Mayer worked at Gottingen University for her doctoral thesis and moved to the US (after marrying Joseph Edward Mayer) in the 1930s. Then war came and she worked at Columbia University on the separation of uranium isotopes for the atomic bomb project. At around the same time Carl Friedrich von Weizsäcker (28.06.1912 – 28.04.2007), exactly six years younger than Geppert-Mayer and a former student of Gottingen, was also working on the atomic bomb project, albeit on the `wrong' side of the Atlantic.

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Weizsäcker, was a prominent member of the team (headed by Warner Heisenberg) that worked on the German Bomb-making project. In August 1939, Albert Einstein wrote to U.S. President Franklin D. Roosevelt to say - "the son of the German Under-Secretary of State, von Weizsäcker, is attached to the Kaiser-Wilhelm-Institut in Berlin where some of the American work on uranium is now being repeated". Uranium-enrichment was one of the key steps of the Bomb project.

Heisenberg and Weizsacker, 1933

The opinions have been divided about the nature of Weizsacker's (and others') participation in the Bomb project. Robert Jungk's Brighter than a Thousand Suns, based on post-war interviews with Weizsacker, suggested that they intentionally held the program back. But letters and documents appearing later have hinted at a somewhat different version of the story. Even now, the story intrigues people urging modern playwrights to interpret the events in their own way. Farm Hall by David Cassidy and Operation Epsilon by Alan Brody are two such efforts in recent years. 

Who knows? Perhaps politics was in von Weizsäcker’s blood. His father was a career diplomat and his younger brother, Richard von Weizsäcker, was that West German president who presided over the reunification of Germany in 1990.

Nevertheless, after the war Weizsacker joined a group of prominent German physicists to protest against the nuclear armament of West Germany and in later life moved to philosophical and ethical issues - a behaviour not very different from many of the physicists who participated in the Manhattan Project. 

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Notwithstanding his war efforts (or lack thereof), von Weizsäcker would be remembered for his pre-war work on nuclear physics. Like Geppert-Mayer, he too worked on the atomic nuclei and developed (1937) a method, now known as the Bethe–Weizsäcker formula, to estimate the mass and other properties of atomic nuclei from the number of constituent neutrons and protons.

Weizsäcker also developed a theory of the Solar System formation with the important implication that other stars like our Sun are also likely to have planetary systems similar to our own. This theory was later corroborated by Russian-American physicist George Gamow (and others) after the War.   

However, I feel the most significant work of von Weizsäcker has been his discovery of the CNO cycle, in which carbon, nitrogen, and oxygen act as catalysts in a sequence of nuclear reactions that leads to the conversion of hydrogen into helium. Later (1939), Hans Bethe corroborated this through a more detailed work and the process came to be known as the Bethe–Weizsäcker cycle. Interestingly, Bethe's family had moved to Kiel in 1912, where Weizsacker was born that year. Bethe left Germany in 1933, but their intellectual endeavours converged again and again.

CNO cycle is one the two known processes through which the stars convert hydrogen into helium, and is expected to be dominant in stars that are somewhat heavier than our Sun. It is only in 2020 that the Borexino collaboration has finally detected the neutrinos from the Sun that bear distinct signatures of the CNO-cycle (Nature, 2020, 587, 577).

The Borexino neutrino detector lies deep under the Apennine Mountains in central Italy, patiently waiting for astrophysical neutrinos. Let us hope that such exciting detections from the "India-based Neutrino Observatory" (INO), planned to be constructed under the Bodi West Hills in Tamil Nadu, are not too far in the future.  

[Today also happens to be the birth-centenary of P. V. Narasimha Rao (28.06.1921 – 23.12.2004), the 9th Prime Minister (1991 - 1996), who opened up the Indian economy ushering in the vibrancy we have become so used to in the last few decades. But that is a completely different story requiring a completely different kind of storyteller. 😁]

13.04.2020 : From one crisis to another..

As the world-wide pandemic locks human society down - unusual images of clear sky, clean water-bodies (apparently, Ganga water has become fit for drinking at Haridwar!), animals reclaiming urban spaces emerge all over social media - showing us the terrible impact our everyday activities have been having on the planet. Unfortunately, most of us are totally unaware of the effect this very act - sharing a colour photograph on internet - actually has.

About a decade ago, Radio Astronomers were proudly advertising the observational capability the Square Kilometer Array (SKA - the biggest radio telescope being built in two different location of South Africa and Australia) using the fact that it would generate an Exabyte (Exa = 18 zeros after 1) of data per day - equal to the total internet traffic of the entire world per day, at that point of time. The internet traffic has increased manifold since then and we, the internet consumers, are generating almost 8 Exabytes of data per day.

Such huge amount of the data needs to be stored somewhere, necessitating creation of gigantic data-centres which store millions of circuit boards. Amazon, Microsoft, Google, Facebook.. are some of the top companies maintaining these data centres. This development is rather recent. It was only in 1998 (almost to the day) two young students (Sergey Brin, Lawrence Page) of Stanford University published a 10 page paper titled 'The Anatomy of a Large-Scale Hypertextual Web Search Engine' and the abstract said - "In this paper, we present Google, a prototype of a large-scale search engine... and produce much more satisfying search results than existing systems. ... Also we look at the problem of how to effectively deal with uncontrolled hypertext collections where anyone can publish anything they want." Not only did the paper herald the birth of Google, our omniscient Big Brother, it also had a prophetic premonition for the future.

Now, with easy access to internet - anyone CAN and IS publishing anything they want.  And we are generating 'data' thereby. Whether it's a 'like' on Facebook, watching a movie on Netflix, posting a message on twitter - every internet activity involves data generation which needs to be stored for use at any and every future time-point. Hence, the data-centres. And energy is required to maintain these data-centres, the environmental cost of which is not insignificant.

These data centres – the repositories for billions of gigabytes of information – used an estimated 400 terawatt hours (TWh) in the 2018-2019 fiscal year. To put this number into perspective - the total electricity generation of India was 1547 TWh (of which about 35% renewable) during the same period, India being the world's third largest producer and third largest consumer of electricity. It is well known that electricity generation is a significant contributor to greenhouse gasses. That is not all. The information and communications technology (ICT) ecosystem as a whole — encompassing personal digital devices, mobile-phone networks and televisions — accounts for more than 2% of global emissions, same as the carbon footprint of the aviation industry!

At present, around 10% of the world’s total electricity consumption is being used by the internet. However, given the current growth (of internet usage) trend, the prediction is that the electricity usage by ICT could exceed 20% of the global total by 2030. It appears that use of efficient storage techniques and a large-scale shift to renewable energy may not sustain this rate of growth beyond the next 10 to 15 years.

Projection for ICT energy usage

It is obvious that increasing internet connectivity in everyday life has fostered new, more energy-intensive, forms of demand that is counterbalancing all our energy saving strategies. Mobile devices have come to support and overwhelmingly control our everyday behaviour. We need them and we are obsessed with using such devices while waiting for the bus, waking up in the morning, going to sleep at night and even while watching TV or having a social get-together.

The way we are going it might be impossible to prevent a catastrophic runaway climate change before we could make a complete transition to renewable energy. Perhaps cutting back on our thirst for data might be the ultimate way to prevent energy use going into hyperdrive. Would we be able to do that in time? Then again, humankind has always lived from one disaster to another, surf-riding on the crest of one innovation to the other. Perhaps this is the right time to start thinking about it - when we are completely dependent on the smooth running of the internet traffic through extended periods of lock-down. Perhaps it is time to incorporate this foreknowledge into the paradigm shift that is being brought about by the current crisis.

06.04.20 : The Departure

I believe, humankind never really recovered from the two devastating wars in the first half of the twentieth century. Only that could have explained our obsession with the third one. The next war, they said (from futuristic fiction writers to serious pedants), would be fought over water (not improbable it seemed). But majority talked about biological warfare, fought with terrible bio-weapons. Suddenly, it seems, we are bang in the middle of that third war - fighting against an invisible enemy. It appears to have been precipitated by human intervention (intentional or otherwise) - causing certain virus to jump across species.

In the midst of this pandemic, which has already claimed an unbelievable number of precious lives, there have also been other departures. Stalwarts, who played important roles in shaping the world of physics in the years following the WWII, completed their innings here, leaving us fighting the third war.

After Freeman Dyson (15 December 1923 – 28 February 2020) and Phil Anderson (13 December 1923 – 29 March 2020), today we lost the grand dame of modern Astrophysics - Eleanor Margaret Burbidge (12 August 1919 - 6 April 2020). She was born in the year Eddington observationally verified Einstein's theory of Relativity for the first time, and lived on to witness the detection of gravitational waves (a direct consequence of that theory).

People familiar with Margaret Burbidge's life would readily agree that her long innings in Astrophysics significantly influenced two arenas - first, our understanding of nuclear astrophysics and second, the practice of science in terms of gender equity.

During the war years she studied Astronomy at University College (London) and met Geoffrey Burbidge, with whom she would later embark on a lifelong personal and scientific journey. She received her PhD in 1943 and they moved to USA afterwards. However, realising the potential of Burbidges’ research expertise, William Fowler invited Geoffrey and (a pregnant) Margaret to Cambridge to work on Fred Holye's theory of 'Stellar Nucleosynthesis' (creation of chemical elements in stars) in the mid-fifties.

Geoffrey Burbidge, Margaret Burbidge, William Fowler

The result of that collaboration was a 108-page paper titled 'The Synthesis of the Elements in Stars' (Reviews of Modern Physics, 1957). This pathbreaking paper (now known as B2FH for Burbidge, Burbidge, Fowler, Hoyle) explained how various chemical elements are produced at different stages of stellar life cycle, and laid the foundation for the theory of stellar nucleosynthesis. The paper did receive the recognition it deserved when Fowler was awarded the 1983 Nobel, thought it was not clear why his co-workers were left out.

For Margaret, though, such unfair treatment was not new. She was turned down a Carnegie Fellowship, at the Mount Wilson observatory, in 1945. Because only men were allowed to use the observatory. Many years later, she recounted this story to us (a bunch of wide-eyed Astrophysics aspirants at IUCAA). Apparently, when she pressed the issue the authorities informed her that the observatory premises (located on top of a hill) did not have a rest-room facility for women! Ten years later (when, in 1955, Geoffrey Burbidge received the Canegie fellowship), she gained access to the observatory posing as her husband's assistant, concealing her pregnancy while climbing up and down the hill!

In 1968, Burbidges joined the University of California at San Diego (UCSB). But both of them could not be hired in the same department (IIT-K indeed copied the rules from overseas) and initially Margaret was hired in the chemistry department. Mercifully, the rules changed after a while and she could move back to Physics.

Then, in 1972, she became the director of the Royal Greenwich Observatory. Since, the establishment of the observatory three-centuries ago, this was the first time when the director was not chosen to be the Astronomer Royal (the post went to Martin Ryle instead).

Finally though, Margaret decided to speak up. In 1972, she turned down the prestigious `Annie Jump Cannon Award' of the American Astronomical Society (AAS) because it was earmarked only for women. She said - "It is high time that discrimination in favour of, as well as against, women in professional life be removed". This sparked a conversation about gender bias and eventually led to the formation of the AAS Committee on the Status of Women.

Margaret Burbidge with Jayant Narlikar at IUCAA (Courtesy : Somak Raychaudhury)

19.08.2019 : Of periodic tables..

Carl Sagan,  one of  the most  charismatic figures  of later-twentieth century Astrophysics,  has been the first  to inform the common  man that - "Our Sun is a second-  or  third-generation star.  All  of  the rocky  and  metallic material we stand on, the iron in our blood, the calcium in our teeth, the carbon  in our genes  were produced billions  of years ago  in the interior of  a red giant star.  We are made of  star-stuff (The Cosmic Connection: An Extraterrestrial Perspective, 1973)".

Yes, starstuff. Quite literally. According to the currently accepted cosmological models, the Universe started in an incredibly hot and dense state, about 14 billion years ago in a singular event known as the `Big Bang'. As the Universe expanded, it cooled and within the first three minutes matter, as we know it, formed. However, it was mostly hydrogen (76%) and helium  (24%), with a rather small fraction of other material like lithium etc.  It was not till the first stars were born that heavier elements could be formed through fusion of lighter elements in a process now known as 'stellar nucleosynthesis'.

Even though this appears to be rather obvious now, there was considerable uncertainty regarding stellar nucleosynthesis in the early part of the twentieth century when scientists were not sure if stellar interiors were hot enough for such fusion processes. Eventually, the day was won and Arthur Eddington proclaimed from Cambridge - "We do not argue  with the critic who urges that the stars are not hot enough for this  process; we tell him to go and find a hotter place (The Internal Constitution of Stars, 1926)". The story would be completed a couple of decades later by another Cambridge man, Sir Fred Hoyle, when he and his collaborators would work out the details of stellar nucleosynthesis in the celebrated BBFH (Burbidge, Burbidge, Fowler, Hoyle, 1957) paper.

However, stellar nucleosynthesis goes only as far as iron and nickel. Manufacturing elements heavier than iron require other more energetic processes like - a supernova explosion or merger of neutron stars. Jennifer A. Johnson of Ohio State University has now created a rather clever 'astrophysical' periodic table to indicate the origin of all the elements we commonly (or not so commonly) encounter around us.

But this is just for the show. :) In reality, astrophysicists mostly refer to another, far less complex version of the periodic table. Because, we basically deal with only three elements - Hydrogen, Helium and everything else. And in an ingenuous fashion this 'everything else' is called 'metal'. This is not as crazy as it sounds. This 'astrophysical' periodic table actually reflects the composition of the Universe, the fractional amount of a particular elements being proportional to the area under its symbol.

Dmitri Ivanovich Mendeleev, father of the periodic table, used a balloon to ascend above the cloud cover to observe an eclipse on this day in 1887. I am sure, when he dabbled in his passion for Astronomy, he had no inclination that one day his periodic table would become such a favourite of Astronomers. :)

24.06.2019 : Remembering Sir Fred..

Thirty years ago I spent the better part of a summer night reading a science fiction story. Nothing remarkable about that. Next morning though, I faced the said author's disciple, chairing an interview panel for PhD admission and asking me questions about our Solar System. The interview didn't work for me but I got that particular question right because of my extra-curricular reading the previous night. The interviewer was Prof. Jayant Vishnu Narlikar and the author of the book was none other than his PhD advisor Sir Fred Hoyle, who found time to write science-fiction stories besides being a prolific and brilliant astrophysicist.

Sir Fred, born on this day (24 June 1915) in early twentieth century England, spent most of his working life in Cambridge (1945-1973), except for his service to Britain's radar project during the war years. Apparently, discussions with some of his (physicist) colleagues during this radar phase was responsible for leading him towards astrophysics, which ultimately resulted in him formulating the theory of stellar nucleosynthesis in the 1950s.

His pioneering work on nucleosynthesis (creation of the nuclei of heavier material from fusion of lighter nuclei through nuclear fusion) taking place in stable stars and during supernova explosions has laid the foundation for the entire paradigm of stellar nucleosynthesis. This work would be followed by a comprehensive paper in 1957, authored by Margaret Burbidge, Geoffrey Burbidge, William Fowler and Fred Hoyle. Famously known as B2FH, this would go on to become the most influential paper in this area of nuclear astrophysics.

In 1983, Fowler would win the Nobel prize (with S. Chandrasekhar) for his work on nucleosynthesis and generate considerable controversy about Hoyle's exclusion. Controversy, of course, was a constant companion to Sir Fred. Though the story of 1974 Nobel (discovery of the first neutron star) is well known now, it was Sir Fred who first remarked about Jocelyn Bell's non-inclusion (the Nobel was awarded to her PhD advisor Anthony Hewish).

That has not been all, however. He held controversial views about a number of purely scientific issues too. In particular, he was opposed to the "Big  Bang" (a term coined by him on a BBC radio show) theory, in which the Universe itself begins its existence at some time in the past. Instead, he believed the Universe to be in a "steady state" and went on to formulate the Steady State theory. Though his theory did conform with the observations available then, it could not explain later observations.

Nevertheless, Sir Fred remained one of the most influential modern astrophysicists, mentoring several important figures like Leon Mestel, Jayant Narlikar, Donald Clayton.. He was also instrumental in establishing the Institute of Theoretical Astronomy (later rechristened as the Institute of Astronomy, Cambridge) which enjoys being one of the finest astrophysics research centres till date.

Sir Fred Hoyle with his Indian (academic) family : IUCAA, Pune

Sir Fred's story remains incomplete without mentioning his Indian family. It seems this month we are in the business of claiming kinship to legends. The man of our house traces his academic lineage directly to Sir Fred, through the Hoyle-->Narlikar-->Padmanabhan route. 😁 In fact, Sir Fred has left quite a large Indian family of astrophysicists, acquired through Prof. Narlikar. The accompanying photograph bears testimony to a happy family gathering (about three decades ago) showing Sir Fred with his student, a number of grand-students and very many great-grand-students (courtesy Debi Prasad Duari ).

04.02.2019 : Billboards on the Sky

Astronomy, because of its very nature, has been one of the ancient branches of knowledge. The sky has guided humans on their daily endeavours since the dawn of civilisation (perhaps even before) and we have looked up at the sky in wonder pondering about our own origin and that of the Universe. That sense of wonder has given rise to this vibrant field of study today. Unfortunately, that early beginning is also the reason the practitioners find it difficult to disentangle their scientific study from the soothsaying practise of Astrology in popular perception.

The trouble does not end there. Astronomy is the only physical science where it is not possible to set up one's own laboratory experiment. Instead we must make do with the information coming from the sky in the form of electromagnetic waves (and the awfully-difficult-to-detect gravitational waves). It takes the whole of known physics (and then some) to decode these signals. Also, we can only 'see' the visible light and the radio waves from our ground-based observatories, everything else (X-ray, gamma-ray..) gets completely messed up by our atmosphere.

Optical (visible light) Astronomy has become progressively difficult with the advent of big cities. Light pollution has ended the career of many a research observtories of yesteryear, relegating them to the status of outreach or student project instruments.

And now the sky is up for sale. It is the next frontier for the advertising world. Coca-cola and McDonald would now jostle for space up there. The children of future would have to take a space shuttle to the orbit to get his/her first glimpse of the Orion or the Great Bear. The new age grandmothers and mothers would no longer tell their young ones the story of the seven sages that mark the constellation of 'Saptarshi' (as Great Bear is known in India) - stories connecting the sky to the mytholoical beginning of human culture. Astronomy is going to change; so is our cultural perspective. 😔

Picture Courtesey : Daily Mail, UK