Saturday, December 25, 2010

Delhi - Legacy of Lutyens and the Mughals – Personal Photo Album Part 5

The historic cities of Agra, Jaipur and Delhi form a ‘Golden Triangle’ of major Indian tourist attractions.  My earlier travelogues covered the first two and it is appropriate that I complete the triangle with a photo album of the third, the nation’s capital and one of the world’s largest and most ancient metropolises.
Since my first visit in 1963, I have visited Delhi innumerable times and seen most of its major attractions.  Practically all these visits were on official work, related to my employment with the National Council of Educational Research and Training (NCERT), whose headquarters is located in a sprawling campus adjacent to the Indian Institute of Technology (IIT) in posh south Delhi.  I have seen the transformation of a metropolis into a megapolis during this period.  Even after retirement from my service in the year 2000, I have visited the nation’s capital many times and all the photographs presented in this album were taken after 2005 with several digital cameras.  These photographs naturally represent only a very small and rather ill organized cross section of my collection. 

[All pictures in my posts can be blown up to their full size by clicking on a picture and opening it in a separate window]

Raisina Hill

Where else to begin my photo album than at the magnificent Rashtrapathi Bhavan and the nearby central government secretariat, perhaps the most visible handiwork of the legendary British architect Edwin Lutyens, located on Raisina Hill?  Here are two photographs symbolic of Lutyens’ Delhi.  Only a part of the north block of the secretariat is seen in the second photograph.

India Gate

The India Gate at the other end of the famous Rajpath starting from the Rashtrapathi Bhavan is as symbolic of Delhi as is the Gateway of India in Mumbai, the financial capital of the nation.  Here are two pictures showing the famous monument and its surroundings, the focus of special attention at the Republic day parade on January 26 every year:

Jantar Mantar

The Jantar Mantar in Delhi, located close to the busy and buzzing Connaught Circus, is a smaller version of the one in Jaipur built by the famous astronomer-king Maharaja Jaisingh II in early eighteenth century.  The complex itself is relatively quiet, well maintained and has an impressive collection of brick buildings and a variety of yantras (measuring instruments)Here is a view of the complex showing some of the red brick structures:

Teen Murti

The Teen Murti Bhavan is a great building dedicated to the memory of India’s first prime minister, Jawaharlal Nehru.  It houses a museum and a planetarium within a large and serene complex.  The entrance to the complex shown in the following picture has an impressive monument built as a war memorial.

The Lotus Temple

After the Taj Mahal in Agra, I rate the Baha’i House of Worship, appropriately called the Lotus Temple, as the greatest architectural marvel in the country.  Being the most visited sight in the capital, it appears to have attracted even more visitors than the Taj Mahal.  Shaped like a lotus flower, with beautifully symmetrical petals made of pure white marble, it is a breathtakingly beautiful sight from any vantage point, particularly from any aircraft flying overhead as I discovered several times.  It is located in a vast tract of greenery which in itself is a nature lover’s delight.  Here are three views of the structure in two of which I have tried to capture the surroundings as much as the structure itself.


Humayun’s Tomb

President Barak Obama of the USA is one of the very few high level foreign heads of state to have visited India without also having visited the Taj Mahal at Agra.  He sought to make up for the lapse by visiting what has been touted as Delhi’s equivalent of the famed monument, Humayun’s tomb.  Though the comparison is rather overstretched, Delhi’s monument is very impressive in its own right and one of several UNESCO designated world heritage sites in the city.  Unlike the Taj which is built from pure white marble, it is constructed mostly from red bricks.   It seems inappropriate that it was built in memory of someone like Humayun rather than his more illustrious predecessor Babar or successor Akbar.  Here are three pictures of it from my collection:

The Qutab Minar

The Qutab Minar in south Delhi is the world’s tallest brick minaret, standing 72.5 metres tall.  It is one of the earliest and most notable examples of Indo-Islamic architecture. The minaret is part of a complex, housing several ancient and medieval structures and ruins.  Here are two pictures showing the Qutab Minar:

The Red Fort

Located in old Delhi close to Chandni Chowk, one of the busiest places in the country, the Red Fort (Lal Qila) is another great landmark in the city.  As a very popular tourist attraction it springs into special prominence once every year when the Indian Prime Minister hoists the national flag and makes a speech from the ramparts of the fort to mark the nation’s Independence Day on August 15.  Here is the famous red brick facade of the fort:

Inside the Red Fort complex there are a number of buildings and structures, the most attractive of which is probably Diwan-i-Aam, much like its counterpart in the Agra fort.  Here is a picture showing the ornate inlay work and intricate carvings on its walls:

Birla Mandir

The Laxminarayan Temple, popularly known as the Birla Mandir, is a wonderful example of Indian temple architecture seen in many parts of northern India.  Here is a frontal view of it:

Raj Ghat

Located on the banks of river Yamuna, Raj Ghat marks the spot of Mahatma Gandhi’s cremation in 1948 on a black marble platform which is left uncovered.  It is a great place, befitting the memory of the father of the nation and superbly maintained.  Here are two pictures I took with the memorial seen behind each of two different trees which I found fabulously attractive and particularly appropriate to the situation.

Down Memory Lane

I round off my last blog post of this year with a picture that touches a personal chord.  Whenever I visited Delhi on official work I used to stay in one of the guest houses inside the NCERT campus in which the most attractive building is the Central Institute of Educational Technology (CIET), one of the institutions forming part of the NCERT.  It is a superb red brick building, apparently inspired by many of the red brick structures, old and new, dotting the city.  The best part of it however is the greenery surrounding it and the serene atmosphere it creates, something that I have always valued. 

Tuesday, November 30, 2010

Search for Extra Terrestrial Intelligence [SETI]


When astronaut Neil Armstrong took that small step on the Moon on 20 July 1969, it was indeed a giant leap for all mankind.  After the Apollo 11 lunar explorers’ return to earth, the then American President Richard Nixon went so far as to say, “This is the greatest week in the history of the world since Creation”.   This must have sounded like music to the ears of the creationists and their descendants, the intelligent design theorists, in the western world who visualize human life on earth as just a week’s handiwork performed by a super intelligent being.  Nature of course has been far less enterprising and taken millions of years to do the job through a long drawn out and complex evolutionary process.  Nixon may or may not have used the term ‘creation’ in its biblical sense, but he was not far off the mark if he implied that the event was the greatest since human life itself took firm root on planet earth, whenever this may have been.  To celebrate the next such momentous event in history we may have to wait until one of the most tantalizing questions of all time facing human civilization is answered definitively – is there intelligent life elsewhere in the universe?  If and when this is answered in the affirmative, an even more momentous event would be the establishment of contact with such intelligent life.  It could indeed be a tremendously long wait and very far into the future.

Since time immemorial, mankind has been fascinated by the possibility of intelligent life outside our planet earth.   While there has been no credible factual evidence of any kind whatever even up to the present day, writers of science fiction, movie makers and the modern media have given themselves unfettered liberties and let their imaginations run riot.   If their claims are to be believed, the earth is crawling with a plethora of uninvited extraterrestrial aliens deposited by UFOs (Unidentified Flying Objects) flying all around us, whose favorite pastime seems to be abducting or at least frightening hapless innocent earthlings!  Ufology has become nearly as popular as, but no more scientific than, Astrology.

With the discovery of innumerable stars having physical properties and chemical composition similar to that of our Sun in the last two centuries, wild imagination has given way to meaningful speculation about extraterrestrial life, including intelligent life as prevalent on earth.  It makes eminent scientific sense to expect at least a tiny fraction of these stars to have an earth-like planet with similar life forms, including intelligent life.

In the latter half of the twentieth century, scientists decided that the best way to approach the problem would be to scan the skies and ‘listen’ for non-random patterns of electromagnetic emissions such as radio or TV waves in order to detect another possible civilization somewhere else in the universe.  This is the essence of the ongoing worldwide SETI (Search for Extraterrestrial Intelligence) effort.

Radio SETI

Radio is believed by most scientists to be the best means we have for interstellar communication, considering the vast distances involved. Radio waves, like all electromagnetic radiation, travel at the speed of light – 300,000 kilometers per second. This is the fastest velocity possible, and yet even Proxima Centauri, the closest star to our own Sun, is so far away that light takes approximately four years to make the journey. In contrast to the speed of light, a typical fast spacecraft we have with current technology travels about 15 kilometers per second. At such speeds, it would take a spaceship about 80,000 years to reach our nearest neighbor!  In other words, interstellar travel by earthlings is virtually impossible for the foreseeable future even within our own galaxy.  We have to look for other, indirect, means to look for evidence of intelligent life elsewhere in our galaxy.

Radio waves are thought to be the optimum band of the electromagnetic spectrum for interstellar communication because they are relatively free of the absorption and noise associated with other areas of the spectrum.  Radio, visible light, and the near infrared are the only electromagnetic radiations able to penetrate the earth's atmosphere, and of the three, radio is not as easily absorbed by interstellar gas and dust. In addition, stars are generally ‘quiet’ in the radio frequencies. This makes radio a natural candidate for a ‘beacon’ by an advanced civilization, or for interstellar communication between such civilizations.

In late 1959 and early 1960, the modern Radio-SETI era began when Frank Drake conducted the first such SETI search at approximately the same time that Philip Morrison and Giuseppe Cocconi published a key journal article suggesting this approach.

Project OZMA

Project OZMA was the first systematic attempt to detect artificial radio signals from nearby stars. Named after the princess in Frank Baum's Wizard of Oz, it was the brainchild of American radio astronomer Frank Drake working at the Green Bank observatory in West Virginia, USA.  Drake began preparations for Ozma in 1959, the same year in which the seminal theoretical paper on SETI by Philip Morrison and Guiseppe Cocconi was published in the British journal Nature. These developments, although occurring more or less simultaneously, were quite independent of each other.  However, both concluded that the best chance of success would come from searching at a radio frequency of 1,420 MHz (corresponding to a wavelength of 21.1 cm) since the 21-centimeter line of neutral hydrogen in the Galaxy might represent a natural wavelength at which intelligent species would try to communicate. Although, after 150 hours of ‘listening’ from two nearby stars the effort proved futile, it was to be the forerunner for many more, increasingly sophisticated, searches which continue to this day at ever increasing pace.


Project SERENDIP (Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations) was the first major organized large scale effort, begun in 1979.  It underwent further stages of improvement.  SERENDIP IV consisted of 40 spectrum analyzers working in parallel to look at 168 million narrow (0.6Hz) radio frequency channels every 1.7 seconds.  It was effectively a 200 billion-instructions-per-second supercomputer. The equipment was installed piggyback, without affecting the primary work of the facility in any way, at the 1000-foot non-moving Arecibo National Radio Telescope Observatory – the largest radio telescope in the world – in Puerto Rico, USA, and managed by the University of California at Berkeley.  SERENDIP V, the most recent version of the project, began in 2009.  It employs a two billion channel digital spectrometer covering 300 MHz of bandwidth.


Most of the SETI programmes in existence today require fast computers that can analyze data received from the telescope in real time. None of these computers look very deeply at the data for weak signals nor do they look for a large class of signal types.  This is due to the limitation on the amount of computer power available for data analysis. To probe into the weakest signals, a greatly enhanced amount of computer power is necessary. It would take a monstrous supercomputer to get the job done. SETI programmes cannot afford to build or buy that computing power. There is a trade-off that they can make. Rather than a huge computer to do the job, they could use a smaller computer but take longer to do it.  But then there would be lots of data piling up. What if they used a huge number of small computers, all working simultaneously on different parts of the database? Where can the SETI team possibly find thousands of computers they would need to analyze the data continuously streaming from the Arecibo Radio Telescope?

There are already hundreds of thousands of computers that are available for use, owned by individuals and institutions all over the world. Most of these computers sit around most of the time accomplishing absolutely nothing and wasting electricity as well. This is where SETI@home comes into the picture. The SETI@home project harnesses the potential of such computers to get its job done.  It has built up a huge network of computers whose services are being volunteered by millions of users all over the world.  The user software can be run either exclusively during the idle time of a computer or continuously as an additional task while being used for other purposes as well (multi-tasking).  Most serious volunteers prefer the latter.

The SETI data analysis task can be easily broken up into little pieces that can all be worked on separately and in parallel. None of the pieces depends on the other pieces. Of course, there is only a finite amount of sky that can be seen from Arecibo through the fixed telescope. In the last two decades the entire sky as seen from the telescope has been scanned several times.

Breaking up the Data

Data are recorded on high-density tapes at the Arecibo telescope in Puerto Rico and sent to Berkeley. They are then divided into 0.25 MByte chunks (which are called ‘work-units’). These are sent from the SETI@Home server over the Internet to volunteers around the world to analyze. There are nearly 3 million such actively participating volunteers worldwide.

SETI@home looks at a width of 2.5 MHz of data, centered at 1,420 MHz. This is still too broad a spectrum to send to any one volunteer for analysis, so this spectrum space is broken up into 256 pieces, each 10 kHz wide. These 10 kHz pieces are now more manageable in size.  The SETI computer sends out about 107 seconds of this 10 kHz data in the form of a ‘work-unit.’
Sending the Data

SETI@home connects to the volunteer’s computer via the Internet when transferring data. This occurs only when the computer has finished analyzing a work-unit and wants to send back the results (and get another work-unit). The data transmission lasts just a few seconds with most common modems and disconnects immediately after all data is transferred.

The SETI staff keeps track of the work-units in the Berkeley campus of the University of California with a huge database. When the work-units are returned to them, they are merged back into the database and marked ‘done.’ Their computers look for a new work-unit for the volunteers to process and send it out, marking it ‘in progress’ in the database. 

What SETI@home looks for

The easiest way to answer this question is to ask what we expect extraterrestrials to send. We expect that they would want to send us a signal in the most efficient manner for them that would allow us to easily detect the message. Now, it turns out that sending a message on many frequencies is not efficient. It takes lots of power. If one concentrates the power of the message into a very narrow frequency range (narrow bandwidth) the signal is easier to weed out from the background noise. This is especially important since we assume that they are so far away that their signal will be extremely weak by the time it gets to us.  So, we're not looking for a broadband signal (spread over many frequencies); instead, we are looking for a very specific frequency message. The SETI@home screen saver program that displays the work in progress on the volunteer’s computer monitor acts like tuning a radio set to various channels, and looking at the signal strength meter. If the strength meter goes up, that gets our attention.

Another factor that helps reject local (earth-based and satellite-based) signals is that local sources are more or less constant. They maintain their intensity over time. On the other hand, the Arecibo telescope is fixed in position. So the sky "drifts" past the focus of the telescope. It typically takes about 12 seconds for a target to cross the focus (or ‘target beam’) of the dish. We therefore expect an extraterrestrial signal to get louder and then weaker over a 12 second period. We are looking for this 12 second ‘Gaussian’ signal within the 107 seconds of data. We can also expect the signals to be pulsed since this would be a very efficient means of coding information.

Because of the rotational motion of the planets, both ours and ‘theirs’, there is likely to be a ‘doppler shifting’ or changing frequency, of the signal because of our relative motions. This might cause the signal to rise or fall in frequency slightly over the 12 seconds. These are called ‘chirped’ signals.  In summary, we look for ‘chirped’ and ‘pulsed’ signals as indicated in the adjacent graph.

Signals that show a strong power at some particular combination of frequency, bandwidth and chirp are subjected to a test for terrestrial interference. Only if the power rises and then falls over a 12 second period (the time it takes the telescope to pass a spot in the sky) can the signal be tentatively considered extra-terrestrial in nature. Spikes (short radio bursts) above a threshold value, doublets and triplets are also recorded.

Depending on how the telescope was moving when the work unit was recorded, the computer will do between 2.4 trillion and 3.8 trillion mathematical operations (flops or floating point operations) to complete its work.  Depending on how powerful the volunteer’s computer is, the time taken for processing one full work unit may range from 3 to 50 hours! These calculations include a fast Fourier transformation of the signal data to yield a frequency spectrum.

The following is how a typical SETI@Home screensaver on the user’s computer screen may look like:

The initial software platform, now referred to as "SETI@home Classic", ran from May 1999 to December 2005. This program was only capable of running SETI@home.  It was later merged with BOINC (Berkeley Open Infrastructure for Network Computing), which also allows users to contribute to other distributed computing projects at the same time as running SETI@home. The more versatile BOINC platform (called SETI@home II) allows testing for additional types of radio signals.  Also, it covers an enhanced bandwidth of 50 MHz over 700 million channels. 

Project Phoenix

Project Phoenix is a complimentary SETI project involving the analysis of patterns in extraterrestrial radio signals. It is run by the independently funded SETI Institute of Mountain View, California, USA.  It  started work in February 1995 with the Parkes radio telescope located in New South Wales, Australia, the largest telescope in the southern hemisphere. Between September 1996 and April 1998, the Project used the National Radio Astronomy Observatory in Green Bank, West Virginia, USA.

Rather than attempting to scan the whole sky for messages, this Project concentrates on nearby systems that are similar to our own (i.e., those most likely to have planets capable of supporting life). It has concentrated on about 800 stars within a 200 light-year range.

The Project searches for radio signals as narrow as 1 Hz between 1,000 and 3,000 MHz, a broader bandwidth compared with the conventional SETI searches.

In March 2004 the Project announced that after checking the 800 stars on its list, it had failed to find any evidence of extraterrestrial signals. This may possibly mean that our solar system is located in a rather ‘quiet’ neighborhood.

Optical SETI@berkeley

In the Radio SETI@home project, the signals are assumed to be transmitted isotropically from the source, with just a tiny fraction of it being intercepted by earth based instruments.  The Optical SETI@berkeley project, initiated in 1997, is based on the assumption that a distant civilization might take recourse to sending highly focused pulses deliberately towards our solar system (This implies that it has already identified us as a potential intelligent civilization).  Such nanosecond-scale optical (laser) pulses are not known to originate naturally from any astronomical source.  The idea of looking for pulses in the optical band of the electromagnetic spectrum was suggested as far back as 1961 by Townes (a co-inventor of the LASER and Physics Nobel laureate) and Schwartz.

The optical pulse search employs a 30-inch automated telescope equipped with a super sensitive photometer system located at a University of California campus near Berkeley.  

Advertising our presence

Our attempts to discover ETI should be complimented by efforts to announce our own existence in the solar system to nearby systems that may be harboring extraterrestrial intelligence.  The first such attempt was due to Carl Sagan who persuaded NASA to include a plaque specially designed by him as part of the Pioneer deep space probes launched in 1972 and 1973.  The plaque shown here carries a coded pictorial message giving some basic information about ourselves and the planet we live in.  A much more complex and detailed message was included in the Voyager spacecraft launched in 1977.  It was in the form of a golden phonograph record containing sounds and images portraying the diversity of life and culture on earth.

The probability of a space faring civilization discovering and intercepting these messages is so ridiculously small that these efforts can only be viewed as symbolic gestures.  A more productive venture would be to send very strong radio signals or laser beams carrying coded information much the same way that we expect other ETIs to communicate with us.  This has been done in recent years though not in a very organized and systematic manner.  In any case, much of the radio and TV signals generated on the earth have leaked out into interstellar space over the last 60-70 years though the strengths of these signals are far too weak compared to what we ourselves expect from ETIs.  

One inherent assumption in any SETI effort is that the communicating civilizations must be sufficiently advanced to have mastered the technology of radio or other electromagnetic wave communications.  Obviously, if and when we discover such signals, the farther the location of the source the more technically advanced is the civilization we have to deal with.  It will almost certainly be far more advanced than we are on earth.  After all, our communicative capabilities are less than a century old.  We are only like a new born baby in a cosmic cradle. 

The Drake Formula for Advanced Technical Civilizations

The Drake Formula was developed by Frank Drake in 1961 as a way to focus on the factors which determine how many intelligent, communicating civilizations there might be in our galaxy.  The formula itself and the best estimates given by Carl Sagan, a SETI pioneer, are given in the appended texts.  It is amazing to think that under this estimate our galaxy alone has about ten million advanced technical civilizations!  The fundamental question facing humanity is therefore not whether anybody is out there but how to locate them and communicate with them.  The ‘search’ aspect of SETI naturally takes precedence over CETI (Communication, and later perhaps contact, with Extra Terrestrial Intelligence).

In the Drake Equation, N* represents the number of stars in the Milky Way for which a reasonable estimate is 400 billion. 

fp is the fraction of stars that have planets around them.  Thanks to great advances in opto-electronic technology in recent years, quite a number of (large) planets have been discovered.  A spate of new discoveries, including earth-like planets, is on the cards in the coming years.  Planetary systems appear to be much more common than believed earlier.

ne is the number of planets per star that are capable of sustaining life.  In our Solar System this number appears on current evidence to be just one. A more liberal value of two is used in Sagan’s estimate.

fl is the fraction of planets in ne where life evolves.  There is no reliable basis for estimating this.

fi is the fraction of fl where intelligent life evolves.  fc is the fraction of fi that develops into an advanced communicative civilization.  It is very difficult to estimate the two separately.  In Sagan’s estimate the product of the two factors is taken to be 0.01.

fL is the fraction of the planet's lifetime during which the communicating civilizations live or survive.  This is the toughest of the questions involved in Drake’s equation. If we take Earth as an example, the expected lifetime of our Sun and the Earth is roughly 10 billion years. So far we've been communicating with radio waves for less than 100 years. How long will our civilization survive? Will we destroy ourselves in a short period like some futurologists predict or will we overcome our problems and survive very long? Only the future holds the answer.

The true value of the Drake formula is not so much in the answer itself as in the questions that are thrown up when attempting to come up with an answer. Obviously there is a tremendous amount of guess work involved when estimating the variables. However, as Astronomy, Biology, and other sciences and technology march on, the answers to these questions will emerge with continually greater reliability.

Scale of the SETI@home effort

The SETI@Home project that has been running for about eleven years now has had over 5 million voluntary contributors, with about a third of them involved actively for much of this period.  Incidentally, I have been contributing significantly as a volunteer (see certificate appended) to this and other BOINC managed distributed computing projects and is among the top 6% of the SETI@home contributors worldwide (top 2% from India) since the year 2000. Billions of work units have been processed, analyzed and studied.  Over 5 million years of actual computing time has been invested in the effort, most of it coming from the volunteers all over the world.  It has already become the largest distributed computing project in history.

[Cobblestone (named after Jeff Cobb of SETI@home) is BOINC's unit of credit and is 1/200 day of CPU time on a reference computer that does 1,000 FLOPS based on the Whetstone benchmark]

Among the billions of work units processed so far only about 3000 have proved to be of potential interest. The rest of them have been found to be of terrestrial or natural origin.  No ‘signature’ has yet been detected of any extra terrestrial intelligence.  However, scientists recognize that a much greater effort needs to be mounted and run for several more decades before any definitive indicator can emerge.

Hunt for Exoplanets

It is just 15 years since the first extrasolar planet was discovered around an ordinary star in our galaxy.  More than 450 exoplanets have been identified since then and the number has been growing rapidly.  Understandably, most of the early discoveries were of giant Jupiter like planets.  However, with major improvements in earth-based detection techniques and the NASA Kepler spacecraft launched last year specifically for such a purpose, multiple planet systems and even earth sized planets are being added to the exoplanet population.  Preliminary findings indicate that one of them is inside the ‘goldilocks’ (potentially habitable) zone around its parent star.  With earth like physical conditions, particularly a ‘tolerable’ temperature range, likely to prevail, such planets are the most likely candidates for the existence of advanced life forms.  If their number grows at the expected rate, Carl Sagan’s estimate for ne in the Drake Equation, which has been considered by some as too optimistic, may not really be so. 
The coming years are poised for some tremendously exciting discoveries that may strengthen our expectations of ETI elsewhere in our galaxy, though not necessarily in our near neighborhood.


The question of ETI belongs at present to the realm of speculation/belief, but based on sound scientific foundation.  It is also based on the realization that the Laws of Science are truly universal, at both macroscopic and microscopic levels.
Evolution of life on Earth may be accidental (due to coincidence of a number of individually improbable events), but this ‘accident’ must have been replicated on a large number of planets in the cosmos.  From a philosophical, psychological and practical point of view it would be the height of egotism and stupidity, a throwback to the pre-Copernican geocentric era, to assume that we are alone in the vast universe.  As Carl Sagan has pointed out, such loneliness would be of a most profoundly disturbing character. In the deepest sense, the search for ETI would be a search for ourselves.

SETI involves finding powerful new ways to distinguish a genuine alien transmission from the vast earthly and cosmic background noise. It is like locating a needle in the cosmic haystack.   Many decades of sustained and systematic efforts are called for before the search leads us anywhere.  As of now, despite years of intense effort under SETI@home and other projects, we have not been able to find any definitive evidence of extra terrestrial intelligence. However, absence of evidence does not amount to evidence of absence.

Monday, November 15, 2010

Eton of India: Mayo College, Ajmer – Personal Photo Album Part 4

My visit to the pink city of Jaipur chronicled in my blog post dated 14th October this year was preceded by a 3-day stay in Ajmer on some official work.  I had enough time to go round the city and its neighborhood, especially the well known Pushkar Lake. I found most of the sights rather disappointing and very much unlike what I was to see in the pink city just a few days later.  But on the last day (8th March 2005), I found an oasis in the desert in the form of the Mayo College campus about which I had known practically nothing.   When my local contact arranged this visit, I was expecting to see nothing more than a well known local institution, but what I actually saw took my breath away.   It was reminiscent of some of the sights in Oxford and Cambridge I had seen in distant England twenty years earlier.  As I later learnt, the Mayo College was conceived on the lines of the historic and venerable Eton College that I had seen across river Thames from the famous Windsor Castle near London on one uncharacteristically bright and sunny afternoon in mid 1985.

The Roots

Following the rude shock they received in 1857 in India, the British rulers realized the urgent need "to create a class of people - Indian in blood and colour but English in opinions, in morals and in intellect".  In this plan the Indian princely class who had remained silent spectators to the turmoil in 1857 was identified as useful allies and a ‘stabilizing’ force.  The Mayo College founded in 1870 and conceived as the Eton of India by Lord Mayo, the then Viceroy of India, was primarily intended for them. Today it serves a different purpose but continues to be the preserve of the elite class, the very rich and the super rich.

Present Status

The institution is not a college in the sense of the term as generally understood in India today.  It is a combination of secondary and senior secondary schools currently affiliated to the Central Board of Secondary Education (CBSE) in India.  It has an exchange programme with a number of premier public schools, including the Eton College, in the UK.  Spread over a vast area and housing a number of ancient heritage buildings amidst very rich greenery, the campus is a sheer delight for the nature lover.  Richly endowed with infrastructural and instructional resources, one of its best assets is a great museum housing a superb collection of antique items and armoury.

The Visit

I enjoyed the hospitality of the vice-principal who first took me to his home and then spent a considerable amount of time showing me almost all the places inside the vast college campus.  It was a bright and sunny day and I could indulge in my favorite hobby of photography to my heart’s content.  The pictures taken with my recently acquired Nikon E8800 camera and presented here constitute only a small collection of my catch that day. 

[All pictures in my posts can be blown up to their full size by clicking on a picture and opening it in a separate window]

The Main Building

The stunning main building of the college, completed in 1885, is in the classic Indo-Saracenic style of architecture and easily among a handful of such buildings in the country.  Here is a frontal view of this building, with a statue of Lord May in the foreground:

Here is a zoomed-in view of the entrance to the main building highlighting the Mayo statue:

Here are two other views of the main building:

The most eye-catching part of the main building is the great clock tower (see below), with the clock showing the time at which this full-zoom picture was taken.

Other Buildings

The college consists of a number of ‘houses’ in contemporary architectural style.  Here are three of them, all surrounded by rich greenery:

I like the next picture as much for the antique styled bench in the foreground as the rich greenery in the background.  This bench, made of long wooden strips held together by an ornate iron framework, appears to be as old as many of the houses in the campus. 

My memory took me twenty years back to the great London parks where I had seen benches of similar style and antiquity.  Here is the photograph of one such amazingly well preserved antique-style bench I remember to have sat on in Kensington Park, London, relaxing and contemplating the serene surroundings for well over an hour.  I found the Mayo College campus that afternoon equally serene and inviting even if the bench itself was not of comparable quality.

The following picture shows another one of the buildings in the Mayo college campus with a spacious lawn and some great trees in the foreground:

Here is another great building punctuated by beautiful all round symmetry:

The classic style of the building in the following picture is somewhat spoilt by the trappings of modernity visible at the entrance.

The temple seen in the following picture is of more modern origin and reminiscent in some respects of the Birla temple in Jaipur.

I wind up my photo album of the fabulous Mayo College campus with a picture of a recently constructed building housing additional classrooms for the expanding institution.  Though quite impressive, this doesn’t blend well with the rest of the campus architecture.

Saturday, October 30, 2010

Triumph of Newtonian Mechanics – the Story of Neptune


As a teacher, I very much enjoyed teaching a one-semester course on the History of Science to undergraduate students in my college long ago and during just the few years when the subject was part of the curriculum. Later it was axed from the ‘syllabus’ mainly because no one else volunteered to teach it. Also, the curriculum framers did not appreciate the value of the subject as part of the repertoire of teacher competencies.  Thereafter I always tried to bring in a historical perspective to my teaching of Physics and the methodology of teaching science.
One reason for my love for the History of Science was the opportunity it gave me to highlight the main characteristics of the ‘Scientific Method’ underlying the evolutionary, and often revolutionary, discoveries in Science dating back to the times of Aristotle and Archimedes.  I have made a reference to these broad characteristics in my earlier post tilted “Is science education promoting scientific temper?”  I have also tried to illustrate some aspects of the scientific method embedded in an unfinished ‘detective’ work of my own, titled “An Enduring Enigma’, in a later post.

Somewhat simplistically, the scientific method consists in:  (1) observing something that draws our attention or interest, (2) coming up with a tentative explanation (hypothesis) that is consistent with the observations, (3) using the hypothesis to make plausible predictions, (4) testing these predictions by experiments or further observations and modifying the hypothesis in the light of the findings, and (5) repeating steps 3 and 4 until there are no discrepancies between theory and experiment and/or observations.  Of course there are numerous examples of scientific discoveries where these processes were circumvented or short-circuited and where serendipity, chance and even luck, have also played a major role.  The end result is often the formulation of a law or set of laws (such as Newton’s Laws of Motion) or a definitive theory (like the Theory of Relativity) or the establishment or confirmation of what may be termed a scientific fact. 
One of the finest examples of the scientific method is the long sequence of events leading up to the formulation of Newton’s Laws of Motion and their subsequent application to study the motion of heavenly bodies, culminating in the discovery of planet Neptune. This thrilling triumph of Newtonian Mechanics is the main theme of the present post.

Aristotelian Legacy

Apart from the Sun and the Moon, the planets (Mercury, Venus, Mars, Jupiter and Saturn) were recognized as a distinct class of celestial objects, setting them apart from a huge number of stars, since the dawn of civilization.  It was all too obvious for them to be seen as moving around the Earth.  This geocentric view of the universe, based on common sense, is a legacy from the times of the great Aristotle, vigorously upheld and defended by the Roman Catholic Church.  However,  the observation that the planets departed significantly from circular paths was a major irritant, particularly since the similar looking stars were all ‘well behaved’, holding their places firmly on a ‘celestial sphere’ rotating around the Earth like a well oiled machine.  The discrepancy with the misbehaving planets was sought to be overcome by a very intricate mechanism of ‘cycles and epicycles’ of planetary paths devised by Ptolemy and others to preserve geocentricity at all costs.  The Church was happy that, in the process, the human egocentricity was also being preserved and protected.  This feeling of snug satisfaction and status quo lasted well over a millennium during much of which, human civilization was in hibernation and passing through an utterly dark age.

The Copernican Revolution

Though a heliocentric view of the planetary system had been advocated by others, it was left to Nicolaus Copernicus (1473 – 1543), a Polish clergyman and astronomer, to project it with such powerfully convincing arguments that it began to attract serious attention in spite of strong resistance from the Church. Copernicus wrote a treatise called De Revolutionibus Orbium Coelestium setting out his case in considerable detail, but withheld its publication during his own lifetime for fear of adverse reaction from the Church.  It saw the light of day on his death bed and the Copernican system gained widespread acceptance in due course.  It marked a major revolution in the history of human thought.   It also signaled the beginning of an end to the long Dark Age and a renaissance in human civilization.

A Grand Synthesis

Tycho Brahe (1546 – 1601), an eccentric Danish nobleman and brilliant astronomer, realized the need for much greater accuracy and reliability in the measurement of planetary positions and built a gigantic astronomical observatory equipped with some highly sophisticated measuring instruments much before Galileo’s invention of the telescope.  He compiled a huge database of the shifting positions of planets and other celestial objects over a period of twenty years and hoped to use the observational data to actually support the old geocentric system and negate the Copernican arguments.  In this he was sadly mistaken.  His data was used by his German assistant, Johannes Kepler (1571 - 1630), an outstanding mathematician, to strike a death blow to the Ptolemaic system and provide conclusive evidence in favour of the Copernican system.

After an extensive mathematical analysis of Tycho Brahe’s data on planetary positions, Kepler extracted three empirical ‘laws’ governing the motion of the planets in the solar system and brought about a grand synthesis.  He showed that (i) the planetary orbits were actually elliptical, though the departure from circularity was very marginal except for Mars, (ii) an imaginary line joining any planet to the Sun at the focal point of the ellipse swept out equal areas in equal intervals of time, and (iii) there was a mathematical relationship between the periods of motion and the distances of different planets from the Sun.  The Copernican picture was provided a quantitative canvas by Kepler’s monumental work.

Though Kepler’s discovery showed how the planets moved around the Sun, it provided no answer to the central question of why they did so.  The answer had to wait a considerable time.  Yet, Kepler’s findings marked a major milestone in the history of Astronomy.  They meant that the motions of celestial bodies were highly predictable; if the position of a planet was known at one point of time it could be worked out for any other point of time, past or future, with considerable precision.  Astronomy was no longer an inexact science.

Galileo paves the way

Galileo Galiei (1564 – 1642) is credited with starting a scientific revolution of an unprecedented nature and regarded as the founder of the modern scientific method.  He underscored the crucial importance of observation and experimentation in deciding between conflicting ideas and practiced both throughout his illustrious life.  His invention of the telescope and its use in exploring celestial objects – the satellites of Jupiter, phases of Venus, the shape of Saturn, earth-type lunar features, etc., – marked the true beginning of Astronomy and its divorce from the clutches of blind authority and religious dogma.  His observations and discoveries relating to the solar family drove the final nail in the coffin of the geocentric, and egocentric, world view.  Though he incurred the wrath of the mighty Roman Catholic Church for his views and underwent insufferable ignominy and mental torture, he left posterity with the unmistakable message that truth is always the final victor in any intellectual conflict.

Galileo’s numerous experiments on the motion of objects on earth paved the way for an understanding of the root causes of such motion in the hands of his successor, Isaac Newton (1642 – 1727), who was born in England the same year that Galileo died in Italy.
Newton, not particularly known for his modesty, is reported to have said; “If I have seen further than others, it is by standing upon the shoulders of giants”.  The biggest of these giants was undoubtedly Galileo.

Let Newton be…

Newton’s impact on Science was so enormous it is best summed up by Alexander Pope’s famous epitaph:
Nature and nature's laws lay hid in night;
God said "Let Newton be" and all was light.

[Ironically, Newton’s (corpuscular) theory of light was a total flop]

Not since the advent of Einstein in 1905 was so much achieved in science by one individual.  Newton’s greatest contribution was the formulation of the laws of motion and the universal law of gravitation that laid a firm foundation for all of physical science and astronomy of future centuries.  For the first time in human history, fundamental questions relating to the why of nature’s behavior could be faced and answered through the application of Newton’s Laws at both macroscopic and microscopic levels.   They were shown to be truly universal until the early twentieth century when their applicability at the sub-atomic level was shown to be wanting.

Newton’s Laws are indeed laws in the fundamental sense of the term and not empirical ones like those of Kepler cited earlier.  According to these laws: (i) Any object preserves its state of rest or of uniform motion in a straight line unless acted upon by an external force, (ii) An external force applied to a body produces an acceleration (of the body) which is directly proportional to the applied force (the constant of proportionality is called the ‘inertial mass’ of the system), (iii) For every force acting on a body, there is always an equal and opposite force on the agency exerting such force (Law of Action and Reaction), and (iv) Every object in the universe attracts every other body in the universe with a force that is directly proportional to the product of the masses of the two bodies and inversely proportional to the square of the distance between the two (Universal Law of Gravitation).   These statements may sound rather obtuse to readers without a background of science. On the other hand, people with a background of Physics may find them lacking in rigour.  A great deal of discussion and illustration are necessary to understand these fully and it is really not necessary for the average reader to do this to appreciate the essential content of this post.  What matters most is that these laws hold the key to a complete understanding of the motion of planets in the solar system and indeed the motion of all heavenly bodies anywhere in the universe.

Motion in the Heavens

It is relatively easy to show that Kepler’s empirical laws of planetary motion follow as a logical consequence of the application of Newton’s laws of mechanics to celestial bodies.  All the hard work that Kepler put in would have been unnecessary if the laws of motion were known during his time!  This is just one illustration of the extraordinary power of Newtonian mechanics.
Newton’s second law of motion, together with the universal law of gravitation, can be used to calculate the orbital parameters of any planet in motion around the Sun.  The position of the planet can be calculated at any point in time and verified against observational evidence.  In operational terms, one has to solve a two-body problem (such as the Sun-Earth or the Earth-Moon) with appropriate input data and boundary conditions.  It is possible to obtain an exact solution to such a two-body problem.  In actual fact we have to handle a multi-body problem since the other members of the solar system are also involved in the gravitational interactions to varying, though small, extents. These are called perturbations. Exact solutions to such complex problems are impossible and one has to employ a variety of approximation techniques to obtain the desired results.
Mathematicians have perfected techniques for obtaining numerical solutions to such complex perturbation problems to any prescribed degree of precision.  The higher the precision required the more the number of steps in the calculation process.  In the olden days such calculations could only be carried out manually and extremely laboriously.  Months and even years of work were involved.  The advent of the computer in the second half of the last century changed all that.  Today, high speed computers can carry out millions of such calculations in the wink of an eye.  Even modestly priced home computers can be put to such uses if one has the necessary software.  One notable application of such techniques is the guidance and navigation of spacecrafts in real time, the bread and butter of the space age.

A Perturbed Planet

Mercury, Venus, Mars, Jupiter and Saturn are planets known to us since antiquity.  In 1781, William Herschel, an amateur astronomer and musician in England used his own telescope to discover Uranus, a new planet outside the orbit of Saturn. Visible even to the naked eye, it was just waiting to be discovered.  Herschel’s discovery catapulted him to fame and he went on to become a full-fledged astronomer of great repute.

The first accurate mathematical calculations of Uranus' orbital parameters were published in 1792. Within a few years, it was obvious that there was something wrong with the motion of the planet, as there was a small but distinct departure of the observed positions from the calculated ones.  As the accuracy of the observations was not in doubt, questions began to be raised about the calculations themselves, but these were found to be consistently reproducible.  So, there was a real problem on hand and a solution had to be found.  The ingenuity of the human mind began to work, especially in the minds of two very competent mathematicians – John Couch Adams in England and Urbain Le Verrier in France.  They both postulated the existence of an undiscovered planet outside the orbit of Uranus, producing a small residual perturbation in the path of the latter.  But, calculating the location and the orbital parameters of such a hypothetical planet was a formidable challenge and both of them, independently of each other, set out to solve the knotty problem. 

Predicting a Planet

What followed was one of the most enthralling and contentious episodes in the history of science.  In 1843, Adams was apparently the first to predict the expected location of the new planet and sent his calculations to the Astronomer Royal, George Airy, who appears to have just sat on the communication and made no attempt to discover the planet with the telescopes at his command.  Unknown to both, Le Verrier in 1846 completed his calculations, which turned out to be more precise that of the Englishman, and had the good sense to send the findings to Johann Galle of the Berlin Observatory when he found difficulty in arousing the interest of any of his own countrymen.


Galle and his assistant responded by successfully locating the predicted planet (later to be called Neptune) within hours of receipt of Le Verrier's communication on September 23, 1846. Neptune was discovered within 1° of where Le Verrier had predicted it to be, and about 12° from Adams' prediction.  The news created a sensation.  A bitter Anglo-French war of words followed on the question of who should get the bragging rights for the discovery.  Eventually, sanity prevailed and this amazing hare and tortoise race had a happy ending.  Both won! And the referee too! Historians of Astronomy decided to give equal credit to both Le Verrier and Adams.  Adams appears to have been distinctly lucky to share the spoils, but his positive role in the episode was never in question.

As a historian of science put it; “This was the high-water mark of Newtonian physics -- to be able, given the laws of physics and the peculiar motion of one object, to reach out into the depths of space and uncover a previously hidden object -- and caused an even greater sensation than the discovery of Uranus”.

Here is a rough sketch of the orbits of the outer planets of the Solar System.  Pluto, the outermost object shown here, was discovered only in the twentieth century.

Here is a recent photograph of planet Neptune taken with a spacecraft passing close by.  Through a small earth based telescope it will look just like any ordinary star.

Galileo and Neptune

This tale has an extraordinary twist to its tail.  The last word had not been said about the discovery of planet Neptune.  In 1980, Charles T Kowal and Stillman Drake reported a sensational discovery about a discovery attributable to the great Galileo.  They presented compelling evidence to show that Galileo had indeed observed planet Neptune accidentally as far back as 28 Dec 1612 when he was exploring the neighborhood of Jupiter in the night sky – a whopping 234 years before its officially credit discovery and 169 years before the discovery of Uranus itself!  He had marked its position very clearly and accurately in his notebook, but seems to have mistaken it for a star.  He had observed it on two more occasions the following month and during one of them he even seems to have suspected a barely perceptible shift in its position compared to a nearby star.  If only he had followed up on any hunch he may have had, planetary astronomy would have been at least two centuries older and who knows how far it would have progressed in subsequent centuries.  What an opportunity lost!

Last year (celebrated worldwide as the International Year of Astronomy, appropriately marking the four hundredth anniversary of Galileo’s invention and first astronomical use of the telescope), a University of Melbourne physicist, David Jamieson, unearthed some inconclusive evidence that Galileo’s suspicions about this ‘star’ which was actually planet Neptune went deeper than presupposed.  He has proposed a chemical analysis of some of the pages in Galileo’s diary which might point to an afterthought on his part.  It looks as if the last word is yet to be said on the discovery of Neptune.

History Re-enacted

This enthralling story of the discovery of Neptune was re-enacted when tiny unaccounted discrepancies in the calculated and observed positions of Neptune itself began to accumulate over a period of time, leading to the prediction of a trans-Neptunian planet.  After a long period of futile search lead by American astronomer Percival Lowell, Clyde Tombaugh of the Lowell Observatory in USA discovered this planet, called Pluto, in 1930.  This was so faint, so small and so far away from the Earth that special observational techniques had to be developed to find it.  Its discovery did not fully account for the residual perturbation of Neptune.

Pluto differs from the other planets of the solar system so much that it is no longer regarded as a planet.  It is now placed under a distinct class of objects, called the Kuiper Belt, lying beyond the orbit of Neptune.

A Wrap-up

I have narrated the story of Neptune’s discovery as a splendid example of the method of science inherent in most scientific discoveries and the predictive power of a well developed theory or law of nature.  The observations related mostly to planets and other celestial objects that displayed an unexpected behavior and drew special attention.  An initial hypothesis was the geocentric theory, but this did not survive the test of detailed observational evidence.  So it had to be given up in favour of a workable hypothesis in the form of the heliocentric system.  When the accuracy of observed data came into question, a whole set of measuring devices were designed and built to increase the accuracy many fold.  When the picture of circular planetary orbits failed to fit in with the more accurate and improved observations that became available, it was modified in favour of the more realistic elliptical orbits, a circular orbit being just a special and unusual case of an elliptical orbit.  Systematic analyses of the huge amounts of accumulated data lead to the formulation of a synthesized model of the motion of planets in the whole of the solar system.  The invention of the telescope opened up a whole new theatre of operations.  The resulting discoveries not only strengthened the heliocentric theory but also laid the firm foundation for a set of fundamental laws of nature.  These laws were successful not only in explaining a whole lot of observed phenomena but could also make testable predictions. These predictions were not only verified to place the laws on an even firmer pedestal, but they also led to many unforeseen and further verifiable consequences.  So the process has gone on, ensuring ever expanding horizons and an accelerated progress of science and technology.


Assuming that Galileo had observed and accurately recorded the position of Neptune as far back as 28 Dec 1612,  one can work backward and compare the calculated position on that day with the observed position as recorded by Galileo.  This has been done. Lo and behold, what is the outcome!  There is a small residual discrepancy which cannot be explained away as errors in calculation in this age of super computers.  Could it be an error in Galileo’s observations and recording?  It is a measure of the supreme confidence placed in Galileo’s extraordinary observational skills that, despite the poor quality of the telescopes used by him, astronomers simply dismiss this notion. In other words, the discrepancy is very real.  Part of it appears to have been accounted for by the discovery of Pluto in 1930, but the rest of it appears to be due to the recently discovered swarm of hundreds of thousands of small trans-Neptunian objects forming what is called the Kuiper Belt (Pluto is now regarded as the most prominent member of this belt).  The final verdict is yet to be pronounced.