What is mass renormalization?

A simple explanation of mass renormalization:

The difficulties associated with an infinite rest mass can be successfully overcome in calculation of various effects with the help of mass renormalization which essentially consists in the following. Suppose that it is required to calculate a certain effect and an infinite rest mass appears in the calculations. The quantity obtained as a result of calculations is infinite and is consequently devoid of any physical meaning. In order to obtain a physically reasonable result, another calculation’ is carried out, in which all factors, except those associated with the phenomenon under consideration, are present. This calculation also includes an infinite rest mass and leads to an infinite result. Subtraction of the second infinite result from the first leads to the cancellation of infinite quantities associated with the rest mass. The remaining quantity is finite and characterizes the phenomenon being considered. Thus, we can get rid of the infinite rest mass and obtain physically reasonable results which are confirmed by experiment. Such a method is used, for example, to calculate the energy of an electric field.

– A. N. Matveev, Electricity and Magnetism, p. 16


emphasis | ˈɛmfəsɪs | noun (plural emphases | ˈɛmfəsiːz | ) [mass noun]

1 special importance, value, or prominence given to something: they placed great emphasis on the individual’s freedom | [count noun] : different emphases and viewpoints

2 stress given to a word or words when speaking to indicate particular importance: inflection and emphasis can change the meaning of what is said

vigour or intensity of expression: he spoke with emphasis and with complete conviction

Emphasis on something means that we want to highlight it from the rest. A common way to do this in text is to italicize or give a boldface or even underline the text. At times colour is added to text to highlight it or colour is added to the background of the text. All these elements of typography work when there is a common background against which these elements standout. Hence emphasise the words as required. But,

If everything is emphasised, the un-emphasised becomes emphasised.

But consider a block of text which is completely emphasised.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Thus we see that the appeal of the emphasis is lost! The only way emphasis will work is to create a background against which it stands out. Let us return to our examples above


Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.


For me, personally I have not used underline or the highlight. And recently have shifted to coloured italics as my choice of emphasis.

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.

Sometimes this produces very pretty results (at least I am very happy about them 🙂

(ETBB font with OrangeRed  (#FF4500) italics )

In some cases boldface colour also gives very good results:

Either the well was very deep, or she fell very slowly, for she had plenty of time as she went down to look about her, and to wonder what was going to happen next.


Further reading:

Elements of Typographic Style by Robert Bringhurst

Escher on Escher

Recently (read some years back) I read Escher on Escher – Exploring the Infinite. This book gives an insight on how Escher viewed himself and his work. How were his social relations with his family, friends and admirers. Fame and appreciation of his work by a wide circle of people came late to Escher, when he was past his 50s. Escher was a perfectionist, he had almost perfected his craft of making woodcuts, taking it to its limits
as far as his hands and eyes could take. But that was the mere mechanical part of his work, the real part was the idea of the graphic print. The ideas it seems struggled a lot in his mind, making the print itself was the easier part. The ideas came to him, but later he strived for something entirely new, and succeeded.

On of the part of the book “Lectures That Were Never Given” has notes from the talks that Escher was supposed to give in the US of Amerika, but could not because of health reasons. Other include translations of his articles that appear in many of the art magazines and journals. These articles tell us how Escher looked at the work he was doing, and his feelings about other artists works. But he was the most critical about his own work.

This is what he had to say about the ancient cave-painters:

# 12
But his will and his capacity to produce pictorial images were at the least just as strong as ours. Perhaps even stronger because he was in direct contact with nature, which we usually approach by the way of a cultural and educational system that, if not barring the was, certainly obstructs it for us.
# 13
Illustrations are consequently for the graphic artists (mostly) an indispensable link in the chain of activities, but never his goal. That is probably the reason why a graphic artists cannot suppress a feeling of dissatisfaction when presented with an illustration as end result. You see, I don’t give reasons, only statements.
# 15
The above-mentioned elements of repetition and multiplication is /not/ in conflict with this. On the contrary, order is repetition of units; chaos is multiplicity without rhythm.

Escher also talks about the influence Bach’s music had on his work. He says after hearing Bach’s Goldberg variation in a concert (this is from the acceptance address for an award which he gave to city of Hilversum):

# 20
That was to Bach to whom I have pledged my heart and my intellect at the same time. Such beauty, of composition as well as of execution, cannot be possibly expressed in words.

Maybe same is also true of Escher’s own work. And the inspiration that he got from Bach was at a deep level, maybe if Bach was a contemporary, Escher wouldn’t have felt that lonely in his life. He says:

# 20
Bach’s music may perhaps provide the occasion to say a few words about my work. I had better not expound on the affinity I seem to have discovered between the canon in polyphonic music and the regular division of a plane into figures with identical forms, no matter how striking it is to me that the Baroque composers have performed manipulations with sounds similar to the ones I love to do with visual images.

Allow me to say only that Father Bach has been a strong inspiration to me, and that many a print reached definite form in my mind while I was listening to lucid, logical language he speaks, while I was drinking the clear wine he pours.

And this is what he has to say about his own work:

# 21
I can’t keep fooling around with our irrefutable uncertainties. It is, for example. a pleasure knowingly to mix up two- and three-dimensionalities, flat and spatial, and to make fun of gravity. Are you really sure that a floor can’t also be a ceiling? Are you definitely convinced that you will be on a higher plane when you walk up a staircase? Is it a fact as far as you are concerned that half an egg isn’t also half an empty shell?
Such apparently silly questions I pose first to myself (because I am my own first observer), and then to others who are kind enough to come and observe my work. It is satisfying to note that quite a few people enjoy this kind of playfulness, and that they aren’t afraid to modify their thinking about rock-solid realities.

And about art itself and the feelings that it manifests in us he says:

# 21
To tell you the truth, I find the concept of “art” a bit of dilemma. What one person calls “art” is often not “art” for another. “Beautiful” and “ugly” are old-fashioned concepts that are only rarely brought into the picture nowadays – maybe rightfully so, who is to say? Something repellant, something that gives you a moral hangover, something that hurts your eyes and ear can still be art!

And he says about himself:

# 21
So I am a graphic artist with heart and soul, but the rating “artist” makes me a feel a little embarrassed.

Next in the book are the “Lectures That Were Never Given”. These are the notes accompanying the slides, the text tells us about the technique and thought and thinking about the work. Escher has interesting way of putting thoughts about his work and the creatures it contains. He suggests to us that the creatures have ideas and behavior of their own.

# 30
On Horsemen and Symmetry Work 67 (glide reflection) The left horsemen, as a creature, was exceptionally obliging and willing. It happens rarely that my subjects so meekly allow themselves to be portrayed in detail.

# 31
While drawing, I feel as if I were a spiritualistic medium, controlled by creatures that I am conjuring up, and it is as if they themselves decide on the shape in which they like to appear.

And the regular division of the plane is a theme which he calls “unusual mania” and its origins.

# 30
I often have wondered at this, for an artist, unusual mania of mine to design periodic drawings. Over the years I made about a hundred fifty of them. In the beginning, that was some forty years ago, I puzzled quite instinctively, apparently without any well-defined purpose. I was simply driven by the irresistible pleasure I felt in repeating the same figures on a piece of paper. I had not yet seen the tile decorations in Al-hambara and never heard of crystallography; so I did not even know that my game was based on rules that have been
scientifically investigated.

And on interpretations of his work, in which people find what they want, religious, spiritualistic and philosophical messages he says this:

# 47 (Reptiles)
I never had any moralizing or symbolizing intention with this print, but some years later one of learned customers told me that it is a striking illustration of the doctrine of reincarnation. So it appears that one can even be symbolizing without knowing it.

And on the self-portraits that he has something to say to us regarding ourselves, ( involving a bit of narcissism, I think) :

# 60 (Hand with Reflecting Sphere, Three Spheres II)
Your own head, or more exactly the point between your eyes, is the center. No matter how you turn or twist yourself, you can’t get out of that central point. You are immovably the focus of your world.

# 61 (Eye)
I choose the features of Good Man Bones, with whom we are all confronted whether we like it or not.

And on Print Gallery, (one of my personal favourites) he says:

# 67 (Print Gallery)
Thus having let our eyes rove in a circular tour around the blank center, we come to the logical conclusion that the young man himself also must be part of print he is looking at. He actually sees himself as a detail of the picture; reality and image are one and the same.

This is something that I can relate to. The life we observe is ultimately the print and we are actually observing ourselves in life as in young man in the Print Gallery. And on perspectives and absurdities of logical opposites he says:

# 73 (Another World)
It may seem absurd to unite nadir, horizon and zenith in one construction, and yet if forms a logical whole.

In form and function the idea of logical opposites forms, much of the basis for Escher’s work. Visit to Al-hambara had a special significance for Escher. Here he found that the Moorish artists had explored the regular division of
the plane, but he lamented that they restricted themselves to abstract geometric forms and not to the anything that is present in nature which he himself felt an urge for.

# 83
After that first Spanish trip in 1922, I became more and more intrigued by the fitting together of congruent figures according to the above-mentioned definition and by the effort to shape this figures in such a way that they would evoke in the observer an association with an object or a living form of nature. (emphasis in original)

# 88
With regard to my present work, this proves to what extent I feel liberated from the graphic arts simply for the sake of graphic arts.

About the graphic artist with which he identified:

# 90
The graphic artist, however, is like a blackbird that sings in the treetop. Again and again he repeats the song, complete in every copy he makes. The more copies people ask him to make, the better he likes it. He hopes the wind will spread his leaves over the Earth, the farther the better – not like the dry leaves in autumn but like feather-light seeds capable of germinating.

And I think Escher has attained this goal which he describes above very well. His works have germinated into new ideas to a new era of graphic artists and others. And on the old techniques of graphic art:

# 90
Consequently, the emphasis falls unjustifiably on process, and one hardly takes into account the actual goal of all that drudgery. No matter how much joy the exercise of a noble craft can bestow, let us not forget that it is a means of repeating and multiplying. Repetition and multiplication – two simple words. The entire world perceivable with the senses will fall apart into meaningless chaos if we could not cling to these two concepts.

On him being called an “expert.”

# 92
A feeling of helplessness comes over me now that I am faced with describing what is meant by this designation. To my unending amazement, however, this is apparently so unusual and in a sense so new that I am unable to identify any “expert” in addition to myself who is sufficiently comfortable with it to give a written explanation.


# 93
By doing this they have opened the gate that gives access to a vast domain, but they themselves have not entered. Their nature is such that they are more interested in the way the gate is opened than in the garden that lies behind it. Sometimes I think I have covered the entire domain and trod all the paths and admired all the views. Then all of a sudden I find another new way, and I taste a new delight.

On his explorations of the plane and its drawings

Because what fascinates me, and what I experience as beauty, is apparently considered dull and dry by others. A plane which one must imagine as extending without boundaries in all directions, can be filled or divided into infinity, according to a limited number of systems, with similar geometric figures that are contiguous on all sides without leaving “empty spaces.”

We don’t to master everything required to construct something in order to appreaciate it.

# 94
Just as I do not consider it necessary to know all the tricks of the graphic trade in order to appreciate prints, neither do I believe that one must master in detail the theoretical fundaments of division of planes in order to learn to value this and to accept that it can exert an inspiring influence, as I have experienced.

On the unending nature of many of creations.

# 95
I see it as a means of representing timelessness, the dimensionlessness, that existed before life commenced and that will return when life again ceases.

On the dynamic nature of his drawings and comparison to film and reading of a book.

# 98
The series of static representations achieved a dynamic character due to the time span that was needed to follow the whole story. In contrast to this cinematographically projected images of a film which appear one in the after the other on an immovable place, onto which viewer’s eye remains directed without moving. In the case of both the medieval story in images and the developing pattern of a regular filling of a plane, the images are located next to each other, and timing becomes a factor in the movements made by viewer’s eye as it follows the story from image to image. In this way, holding a strip of film in hand, one observes it image by image, reading a book is also done more or less in the same manner.


# 99
Is it possible to make a representation of recognizable figures that has no background? To see only a “figure” is not conceivable because something that manifests itself as a figure, that is, as “thing to be seen,” is limited, whether it is real or not. A limitation also means a separation with regard to something else. That “something else” is the background from which the figure (or object sensation) frees itself.


# 100

Imagination and inventiveness, not to mention tenacity, are indispensable for this work. They come to us from “somewhere out there” but we can facilitate their path to us and encourage and
cultivate them in various ways. Among others I found one in writings of Leonardo da Vinchi. This is
the fragment, translated as best I can:

“When you have to represent an image, observe some walls that are besmeared with stains or composed of stones of varying substances. You can discover in them resemblances to a variety of mountainous landscapes, rivers, rocks, trees, vast plains and hills. You can also seen in them battles and human figures, strange facial features and items of clothing, and an infinite number of other things whose forms you can straighten out and improve. It is the same with crumbling walls as it is with the sound of church bells, in which you can discover every name and every word you want.”

Despite all this conscious and personal effort the illustrator still gets the feeling that some kind of magic action is taking place as he moves his lead pencil over the paper. It seems as if it isn’t he who determines the shapes but rather that the simple, flat stain is guiding or impeding the movements of the hand that draws, as if the illustrator were a spiritualistic medium. In fact, he is amazed, not to say taken aback, at what he sees appearing under his hand, and he experiences with regard to his creations a humble feeling of gratitude or of resignation depending on whether they behave willingly or reluctantly.


EM Spectrum in Astronomy

EM Spectrum in Astronomy from Astrobites

I created a mindmap from the information above

  • Radio
    λ > 1 mm
    ν < 300 GHz

    • Objects
      • AGN JEts
      • Supernovae
      • Tidal Disruption Events
      • H II regions
      • Gamma ray bursts
      • Radio Galaxies
    • Processes
      • Synchrotron radiation
      • Free-free radiation
    • Observation
      • Ground based
    • Telescopes
      • Green Bank Telescope (GBT)
      • Five-hundred-meter Aperture Spherical Telescope (FAST)
      • Very Large Array (VLA)
      • Square Kilometer Array (SKA)
      • Low-Frequency Array (LoFAR),
      • Giant Meterwave Radio Telescope (GMRT)
  • Microwave/Sub-mm
    λ ~ 300 μm to 1 mm
    ν ~ 1 THz to 300 GHz

    • Objects
      • CMB
      • High energy phenomena
        • Relativistic jets
        • Cold dust
        • Cold gas
        • Galaxies at high z
    • Processes
      • Thermal (blackbody radiation)
    • Observation
      • Space
      • Ground
    • Telescopes
      • Space
        • Cosmic Background Explorer (COBE)
        • Wilkinson Microwave Anisotropy Probe (WMAP)
        • Planck
      • Ground
        • Submillimeter Array (SMA
        • Atacama Large Millimeter/submillimeter Array (ALMA).
  • Infrared
    λ ~ 300 μm to 2.5 μm
    ν ~ 1 THz to 120 THz

    • Far-Infrared
      λ ~ 15 μm to 300 μm
      ν ~ 20 THz 1 THz

      • Objects
        • Cool dust
        • Cool gas
        • star forming galaxies
        • young stellar objects
          • proto-stars
          • pre-main sequence stars
      • Processes
        • Thermal (Blackbody radiation)
      • Observation
        • Space
      • Telescopes
        • Infrared Astronomical Satellite (IRAS)
        • Infrared Space Observatory (ISO)
        • Herschel
    • Mid-Infrared
      λ ~ 2.5 μm to 15 μm
      ν ~ 120 THz 20 THz

      • Objects
        • Cosmic dust
          • surrounding young stars
          • protoplanetary disks
          • zodiacal dust
        • Solar system objects
          • planets
          • comets
          • asteroids
      • Processes
        • Thermal (Blackbody Radiation)
      • Observation
        • Space
        • Ground
      • Telescopes
        • Ground
          • Infrared Telescope Facility (IRTF)
          • United Kingdom Infrared Telescope (UKIRT)
        • Space
          • James Webb Space Telescope
          • Wide-field Infrared Survey Explorer (WISE)
          • Spitzer
    • Near-Infrared
      λ ~ 0.8 μm to 2.5 μm
      ν ~ 380 THz 120 THz

      • Objects
        • M-dwarfs
        • Cool stars
        • Low-mass stars
        • Galaxies
      • Processes
        • Thermal (Blackbody Radiation)
      • Observation
        • Space
        • Ground
      • Telescopes
        • Ground
          • 2MASS survey
          • Infrared Telescope Facility (IRTF)
          • United Kingdom Infrared Telescope (UKIRT)
          • Visible and Infrared Survey Telescope for Astronomy (VISTA)
        • Space
          • James Webb Space Telescope
  • Optical
    λ ~ 350 nm to 800 nm
    ν ~ 860 THz 380 THz

    • Objects
      • Ionized gases
      • Stars
      • Galaxies
    • Processes
      • Black Body Radiation (Thermal)
      • Non-thermal
    • Observation
      • Both Ground and Space
    • Telescopes
      • Ground
        • W.M. Keck telescopes
        • Very Large Telescopes
        • Southern African Large Telescope (SALT)
      • Space
        • Hubble Space Telescope
        • Gaia
        • Kepler
        • Transiting Exoplanet Survey Satellite (TESS).
  • Ultra-violet
    λ ~ 10 nm to 350 nm
    ν ~ 3e16 Hz to 860 Hz
    E ~ 120 eV to 3.5 eV

    • Objects
      • Thermal
        • O Stars
        • B Stars
        • white dwarfs
      • Non-thermal
        • AGN (continuous emission)
    • Processes
      • Blackbody radiation (thermal radiation)
      • Non-thermal sources
    • Observation
      • Ground (longest)
      • Space
    • Telescopes
      • AstroSAT (2015)
      • Galaxy Evolution Explorer (GALEX) (2003)
      • Hubble Space Telescope (1990)
      • Neil Gehrels Swift Observatory (2004)
  • X-Ray
    λ ~ 10 pm to 10 nm
    ν ~ 3e19 Hz to 3e16 Hz
    E ~ 120 keV to 0.12 keV

    • Objects
      • X-Ray binaries
      • AGN
      • Neutron stars
    • Processes
      • Thermal Emission
      • Free-Free emission
      • Accretion
    • Observation
      • From Space
    • Telescopes
      • Uhuru (1973)
      • Einstein (1978-81)
      • ROSAT (1999)
      • Chandra (1999)
      • XMM-Newton (1999)
      • NuSTAR (2012)
      • eROSITA (2019)
    • Gamma-Ray
      λ < 10 pm
      ν > 3e19 Hz
      E > 120 keV

      • Objects
        • AGN with Relativistic Jets
        • Gamma Ray Binaries
        • Gamma Ray Bursts
      • Processes
        • Gamma Decay
        • Pair-Annihilation
        • Shock Waves
        • Inverse-Compton Scattering
      • Observation
        • From Space
      • Telescopes
        • Compton Gamma-ray Observatory (1991)
        • International Gamma-Ray Astrophysics Laboratory (INTEGRAL) (2002)
        • Fermi (2008)

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Mysterious spiral shells

I have visited one of the most iconic sea forts in Maharashtra – the Sindhudurga at Malvan on the Konkan Coast twice. It is one of the most beautiful sea forts you will witness. The crystal clear waters and blue skies will be imprinted in your memories. The first time I had an analog camera with me, so I couldn’t take as many photos as I would have wanted (one of the analogue snaps is above c. 2001). The second time I had a really nice digital camera with me, so I did take a load of photos (all the ones below).

Maratha navy was a very formidable force on the Konkan coast. The maratha navy under the Angre’s was a force feared by the Portuguese and English alike. They ruled the waters from North of Goa to Colaba Fort (not the same as Colaba in South Bombay) with their capital at Gheria (Vijaydurg), in the later half of 1700s. Maratha navy ships were fastest and very agile in open waters and were absolute terror for the europeans. Anticipating the need for a strong navy as well, Sindhudurga was one of the first sea forts to be built by Shivaji. The fort is built on a rocky outcrop off the coast of Malvan. The fort played an important role after Shivaji as well. It housed Tarabai, the widower queen of younger son Raja Ram during the invasion Mughals. The fort has walls which have stood the test of time and are still standing well even after several centuries against sea water and constant barrage of waves. (though in the second visit we found parts of wall had collapsed). The architecture of the fort is amazing, though we only see the bastions and ramparts now. The fort walls are shaped smoothly when required (in the mathematical sense of continuity), unlike later european forts which are more angular in nature. The front gate is hidden inside a curved pathway between two bastions so that is not visible directly (hence cannot be hit directly with a canon. This mechanism is also seen in several other forts such as Raigad and Janjira. But so much about the fort, coming back to the topic of the post.

On the southern end of the fort there is a small door which opens to a patch of beach. This is one of the best spots on the fort if you are a nature lover. In this small patch there is clear water and beach.

From a bit far
A bit closer to the small door, Sindhudurga Sea Fort Malvan
A bit more close to the small door, Sindhudurga Sea Fort Malvan
Crystal clear waters at Sindhudurga Sea Fort Malvan

The beach sand is coarse, meaning most of it is actually made of seashells. This is a treat to see, myriad shapes, sizes and colours of seashells blended to form the sand. Sand is a fascinating mixture which results from erosion (air, water) and evolution over long time scales. Sand has both inorganic and organic content.

Waves, caustics and crystal clear water…


The sea shells are logarithmic in nature, with the nautilus perhaps being seen as exemplary. In many cases of shells the logarithmic spiral is obvious (see the photo), but in other cases as well it shows logarithmic growth.

Close up of the sand shell mix. In the center, Clypidina notata Linne, Size 23-30 mm.
Close up of the sand shell mix. What is this see weed by the way? Upper left white shell is most probably Cardita antiquata Linn  or Cardium sp.
A multishade rock in the sand shell mix
Close up of the sand shell mix, too
Our spiral shell standing out in the sand shell mix
Close up of the sand shell mix. A hermit crab residing in a Trochus radiatus Gmelin (Banded Torchus)
A view of the ramparts and bastion from the small beach
Close up of the sand shell mix, .
Close up of the sand shell mix
Close up of the sand shell mix. This lot needs a lot of identification!
Close up of the sand shell mix
Close up of the sand shell mix. Sundial (Architectonica laevigata Lamarck) with most probably Cardium asiaticum Bruguiere.
A quadrumvirate of hermit crabs in Dwarf turban (Turbo brunneus Röding) with copper legs in a tidal pool near Aguada Fort, Goa)
A company of pebbles (Anjuna beach, Goa)
A company of pebbles (Anjuna beach, Goa)

See a previous post on patterns in nature, this post is a sort of extension of that. For an extensive and excellent treatise on spirals see The Curves of Life by Theodore Cook. On a side note, you should also read Junijo Ito’s spiral themed horror manga Uzumaki.

I did collect a few noteworthy shells from this patch (there were so many to collect!), and these included a few approximately hemispherical ones which were flat on the other side. These shells had a nice logarithmic spiral on the flat side which was also relatively smooth. While the hemispherical side was comparatively rougher.

Now in all other shells, one could easily visualise where would the animal be that created the shell or how the animals used that shell. for example

Connus mutabilis (Reeve) showing excellent spiral structure, from Madh beach
Cantharus spiralis (Gray), from Madh beach
Turritella duplicata (Lamarck) along with a hermit crab, 
Natica didmya (Röding), Revdanda Beach
Burasa tuberculata (Brodip) Tuberculated Frog, Madh Beach
Surcula javana (Linne) Javan Turrid, Nagaon Beach
Mix of organic and mineral sand, Madh Beach
Mix of organic and mineral sand, Madh Beach
Variants of Umbonium vestiarium (Linne), Button shells
Variants of Umbonium vestiarium (Linne), Button shells, Nagaon beach
Variants of Umbonium vestiarium (Linne), Button shells (from Nagaon beach)
Our mysterious spiral shells
Our mysterious spiral shells.
Our mysterious spiral shells
Our mysterious spiral shells


But in case of these spirals I could not understand how or where the animal would be using this shell. There was no hole to hide or provide a protection to the animal, as it was solid. It was indeed a puzzle. The shells definitely belonged to an animal, but which one and how did it use it? I asked around but did not get any clear answers. Thus began a journey to unravel the mystery. The image search for spiral shell did not help, though I came to know that these shells are used in astrology oriented rings with silver. And apparently they are seen in jewellery shops.

The first thing we knew for sure was that the shell belonged to a marine animal. But how did that animal use this? It remained an unsolved question for a couple of years. I would ask around to anyone with some knowledge of zoology, but it didn’t get any answers. Then one day someone did faintly recognised, “Isn’t this an operculum?” Now a quick image search with this new term, operculum, I learned gave the answer to this mystery. And commonly it is also known as cat’s eye shell. And the long mystery was solved:

The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of “trapdoor” to close the aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. (wiki)

TODO: Identify all the shells in the photos..



Deepak Apte – The Book of Indian Shells (BNHS)



Free Graphics Illustration Resources and Repositories

Finding a good and accurate graphic or illustration for your need is something that we all struggle with. On top of that if the requirement is that the graphic resource has to be free (as in freedom) then it further narrows down the options. Sometimes you see the graphic you want, but its license terms are unknown or are not agreeable to your work as they are not released freely. So what do you do? Either you use an illustration which is not perfect fit or you use one which breaks your resource (in terms of license).  But the problems is also that there are many free resource repositories which are very well not known. I have personally come across great many graphic resources, only to be forgotten after their current need is finished. This post is an attempt to overcome this. This post is a collection of various free graphics and illustration resources and repositories that I have found useful over the years. It is also a sort of personal bookmark list of the these resources if and when I need them in the future. I hope this will be of use to others too. I will keep on updating this list with new resources that I find. If you know of any resources which are missing please do post in the comments.

The Internet Archive Image Search https://archive.org/details/image

Wikimedia Commons https://commons.wikimedia.org/

Open source illustrations kit https://illlustrations.co/

NYPL Public Domain Archive https://nypl.getarchive.net

David Rumsey Map Collection  https://www.davidrumsey.com/  also https://archive.org/details/david-rumsey-map-collection

Metropolitan Museum of Arts Public Domain Images also https://archive.org/details/metropolitanmuseumofart-gallery

Cleveland Museum of Art Open Access also https://archive.org/details/clevelandart

Brooklyn Museum also https://archive.org/details/brooklynmuseum


Unsplash Free Images

NASA Images

ESO Images

Vintage Ads

Vintage Australian Print Ads

Vintage British Print Ads https://archive.org/details/vintage-british-magazine-ads

Vintage American Print Ads https://archive.org/details/vintage-american-print-ads


Vintage Danish Print Ads https://archive.org/details/vintage-danish-print-ads





A library of microorganisms https://archive.org/details/cmpuj


National Gallery of Art also https://archive.org/details/national-gallery-of-art-images

Flickr Collections (there are several collections on Flickr which are openly licensed)

Flickr Commons

NOAA Photo Library https://flickr.com/photos/noaaphotolib/




On Stories

What is a story?

A story is a series of imagined sequence of events which may or may not be based on true events. The story takes place somewhen, somewhere. A story may take place in the past, or the present or the future. A story may take place in a real place, or an imaginary one (even the surface of a neutron star!). A story has characters and a narrator (can there be a story without either?). Sometimes the characters tell us the story. Sometimes the narrator tells us the story. Some stories are fun, some are dark, others are just boring. A good story is like a fishing hook. It will compel the listener, and keep them eager for what happens next. It is the anticipation of events, which makes a story interesting. What good would be a story if you knew exactly what is going to happen? They say don’t let facts ruin a good story. But facts themselves can make a great story. Reality is stranger than fiction. Reality is a fractal. More you look deeper you see. The mundane becomes the mysterious. Everyday thing becomes enigmatic.

Timeless stories

There are stories which endure time. They were perhaps told since humans acquired language. Perhaps the enormous capacity of language to express imagination was developed to tell the stories. Stories are culture. Stories give us identity. Stories give us rules and norms. Stories make us who we are. Stories tell us about gods, about demons, about magical beings, about kings, about heaven and hell.

Visual Stories

Not all stories have words. Some stories are told via images. Before the written word, images were the only permanent thing. The spoken word is ephemeral, while images endure. Spoken word is for people who are present then and there, the image can transcend time and distance. The images can be somewhen, somewhere other than where and when it was created. Spoken words live only in the present.

Variations on a Theme

Stories change. When a story is told from one person to another, while retelling the person will inadvertently make changes. Though core idea of the story may remain same, some of the details may change. Thus stories multiply. Language is not a barrier. Same story can be told in different languages. Characters, places may change but the stories remain the same. It is like a person wearing different outfits suitable for the local environment.


But how do stories get made? Who makes them? Well, we make stories.

Each one of us has stories to tell. Some people are good at telling them, some aren’t. The good stories stick around. They pass on. From person to person, from generation to generation. From parents to children. From elders to youth. From friends to friends. From teachers to students. Storytellers form a network. Stories link them to those who came before them and those who come after them.



Stories evoke emotions. Some make us laugh, some make us cry. Some us happy, some make us sad. Some take us on adventures we will never be able to go. Some make us confront our deepest fears and invoke terror in us. Some make us feel elated, and inspire us to do things. Some possess wisdom, some are just folly. Some stories are about mundane things. Some stories are about mysteries. Some stories you can readily identify with, some are so alien to our experience.

Stories are Everything

Without stories we are nothing. We relate to others via stories in which we are the characters. Everyone has at least one story to tell, their own story. Will your life be a story worth telling others?

Change and hiccups

The site was down for a while due to a technical hiccup while transfering from WP to AWS. But its up and running now, I guess change and transformation is a part of the process… So will start with regular posts, lets see at least once a week!



PS: thanks to @imsmubarak for helping setup the AWS and @alpesh for sorting the DNS and domain transfer issue…

Obedience and Conformity

Obedience can be understood as “a compliance with an order, request, or law or submission to another’s authority”, while one of the meanings of conformity is “behaviour in accordance with socially accepted convention“. Obedience to authority forms one of the basis of civilisation. Unless the citizens abide by some rules there will be a complete chaos. In early days, this was done by rulers in form of rules and edicts. Now we have the constitution. 

Obedience is essential and must be achieved by cunning…

We usually use obedience and conformity as interchangeable terms or having at least similar connotations. but they are not same. But both are forms of power and control over other humans. Here is how Orwell puts it forth in Nineteen Eighty Four.  

“The real power, the power we have to fight for night and day, is not power over things, but over men.” [O’Brien] paused, and for a moment assumed again his air of a schoolmaster questioning a promising pupil:

“How does one man assert his power over another, Winston?”

Winston thought. “By making him suffer,” he said.

“Exactly. By making him suffer. Obedience is not enough. Unless he is suffering, how can you be sure that he is obeying your will and not his own? Power is in inflicting pain and humiliation. Power is in tearing human minds to pieces and putting them together again in new shapes of your own choosing.”

Stanley Milgram made a distinction between the two and identified four major differences that distinguish the two. This differences tell us about the nature of obedience and conformity. The core of the difference lies in the person who is commanding obedience and the person who is following that in case of conformity usually the person following others is at equal status to them. Where is in the case of obedience there is a hierarchy between the commander and the commanded. This is the first difference: the hierarchy. In a classroom the teacher commands the students to follow certain task or to do some task. This is an example of obedience. When students try to follow each other in terms of the things they do or they dress outside of school or the games that play or the clothes they wear is closer to conformity. The in the first case is the clear distinction and difference in hierarchy in the second case it is not so.

The second major difference is imitation while obedience involves compliance with orders, confirmatory involves imitation and adoption of similar behaviour. If neighbours are beating the plates to make corona go away, so shall I, otherwise we will be seen as socially non-fitting.

The third difference is that in case of obedience the commands are more explicit whereas for conformity is more of an implicit thing. An unspoken rule which everybody around you follows. Conformity is more about following others who are your peers than following explicit commands so in case of confirmative their might be some elbow room to express yourself slightly differently than others. But in case of obedience that is not possible obedience is to the full and no lateral thinking is allowed.

Final difference is the voluntary nature of conformity as opposite to attribution to authority figures. In case of obedience there is no choice but to follow the orders.

Milgram’s experiment on obedience shows how suggestible humans are in presence of authority. 

Would you torture another human because someone in authority tells you to?

The experiment is setup as such. The subject let us call them X is called for doing an experiment in the lab. X is then introduced to the experiment. The experiment involves X teaching another participant Y word association using punishment for wrong answers. If Y does not give correct answer, X has to give Y a punishment in the form of an electric shock. X is given a mild shock to make them experience of the punishment, so that X knows what is the type of punishment and how Y would feel when punished. X has a dial which can control the amount of shock delivered to Y. Overseeing all this is a researcher Z in a white lab coat. A person wearing a white lab coat somehow represents authority figure for most. This is why you see doctors/scientists in advertisements wearing white lab coat: because it is a symbol of authority

Now, Y is actually part of the experiment and accomplice of the researcher. X does not know this. The test starts, and Y deliberately chooses to give wrong answers. Now according to the “rules” of the experiment X has to give “punishment” to Y for incorrect answers. The dial for controlling the shock, the “shock generator”, is calibrated with incremental levels of shock, finally going to 450 Volts. (Of course this is make believe, there is no real shock given, but let us keep this secret with us and not tell X.)

With each wrong answer X is supposed to increment the level of shock punishment to Y from the shock generator. Now, X knows that increasing the shock will cause incremental pain to Y. When X hesitates to increase, Z intervenes and tells X authoritatively (remember Z is wearing a white lab coat) that this is the rule: “With each wrong answer punishment must be increased.” This is where the crux of the experiment comes in. It is found that majority of X, under the influence from authority figure Z, obediently inflicts serious punishment to Y. This even when Y cries in agony, asks experiment to stop, but more X continue to punish Y.   

This is highly counterintuitive result. How so you would ask?  Consider the following gedankenexperiment. Suppose someone looking authoritative tells you to go and thrash someone. Would you do it? Most probably the answer would be no. Then why are the participants X so willing to inflict the incrementally harsh punishment? Because they start with something that is seemingly innocent – a mild shock. Once that threshold is crossed rest of the punishment becomes easy. And you adjudge yourself being not at fault as you are “just following the orders or rules”. This has large implications for how we as a society, every now and then, fall for authority figures and do things which we think we will not do. Perhaps in such cases, we think that since authority figure is telling us to do something, it must be for greater good and we let not our puny morals or conscience come in the way. Also, since we are obeying authority, it takes off our own personal responsibilities as such. This is a slippery slope and can lead to genocides and living hell for those Y who are at the suffering end. Just because Z is popular and in authority does not make following them blindly a right thing. But then the aspect of conformity sets in. If we don’t follow the current norms we are seen as outcasts in the society and that leads to further pressuring of conformity.

Moral is we should exercise our own set of morals and conscience as much as possible.  





Great Ideas in Psychology by Fathali Moghaddam

Nineteen Eighty Four by George Orwell

Nominal expertise

Expertise of Dr. Strangelove
Expertise of Dr. Strangelove

Who is an expert? What qualities in a person defines them as an expert? The dictionary meaning of an expert is

a person who is very knowledgeable about or skilful in a particular area

But how do we know if a person is knowledgeable or skilful in a particular area? A simple way to answer this question is “expert is one who has expertise!”. But this really does not tell us anything (or it does?) about the nature of expertise. One better way to characterise expertise would be if we know by some objective manner that a particular person is an expert. One such way can be to look at the educational qualifications of the person under question. For example, if someone says “You can ask her any question about stars. She has a PhD in stellar astrophysics.” you take on authority of the person telling you and the fact of having a PhD that the person is indeed an “expert”. This is because PhD requires detailed study (at least of a part of the subject area) and we assume that people who have this degree also have a sufficient expertise. PhD holders are highly educated is the claim. Hence most of the experts would be PhD holders in their respective fields. But having a PhD is no guarantee that the person indeed is an expert in the field of study. This is what Frederick Reif has to say about it in his article Interpretation of Scientific Concepts:

Quite a few physics graduate students, and even some physics professors, make mistakes and arrive at wrong answers. Indeed, some experts’ performance resembles that of novices. Such observations indicate that nominal experts (i.e., persons designated as “expert” by virtue of their degrees, A. titles, or positions) can differ very widely in their actual competence. (To paraphrase George Orwell, some experts are much more equal than others). This should be a warning about the interpretation of many cognitive studies where “experts” are selected by purely nominal criteria, without specifying adequately the nature of their actual expertise.

This I feel is a case for normative vs. descriptive dichotomy. The position or degree of a person gives them the virtue of being an expert, but it does not guarantee it. And when we decide our policies based on the expertise of the experts which may not be a true expertise or maybe inherently biased. Perhaps this is one of the reasons that we have flawed policies in the first place. Though, Dr. Strangelove (Dr. suggesting a PhD) was an expert!
But are there experts who do not have a PhD or educational qualifications? Yes! Not all knowledge or skills can be concretised in the form of degrees. Most of the knowledge is tacit in nature, which comes from experience. It doesn’t matter if you have a PhD in theoretical hydrodynamics, fixing that leaking tap requires a different type of skill and knowledge. Cooking is another area where knowledge is tacit. Unless you start cooking, you can’t be called an expert cook!