What are the meaning, origin and usage of word ‘Canon’?

(Pronounced kan.uhn)

Meaning: A noun, canon refers to a generally accepted rule or principle by which something is judged. This 'canon' is spelt with one 'n' in the middle, whereas 'cannon' refers to a large artillery gun.

Origin: The term canon was derived from the Hebrew-Greek word kanon meaning "cane or measuring rod." It entered Old English from Old French or Late Latin canon meaning "church rule." The use of the word "canon" is said to have originated in reference to a set of Biblical texts regarded as scripture. The sense of the term as "a rule or principle" has been in use since the late 14th Century, and as a "standard of judging" since the 17th Century.

Usage: The recent actions by Russia violate all canons of international law, experts say.

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What are the meaning, origin and usage of word ‘Tenuous’?

(Pronounced ret-ro-spect)

Meaning: Looking back on or thinking about past events

Origin: The first known use of this word was in 1601. It comes from a combination of the Latin roots 'retro'(which stands for back or backwards) and 'specere' (which means looking).

Example: We all learn things in retrospect.

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How was the ball pen invented?

It was the Biro brothers who invented the ball-point pen in the late 1930s which changed writing forever

The ball-point pen or ball pen, as we know it today, was invented by Hungarian journalist and painter Laszlo Biro.

Biro hated the way fountain pens blotted and smudged on the paper. Once, when he was visiting a newspaper printing press, he saw them using quick-drying ink and rollers. The first thing he did was use the newspaper ink inside a fountain pen but found that the ink was too thick and slow to make it to the nib of the pen.

So he approached his brother, Gyorgy Biro, who was a chemist. Together, they created a rolling ball mechanism for the tip of the pen. This ball picked up ink from a cartridge as it turned in its socket and then rolled again to deposit it on paper. They also created just the right consistency of ink for this kind of nib. They patented their invention in 1938 and called the pen Biro. In some countries, the pens are still known by this name.

Unfortunately, the advent of World War II forced the Biro brothers to flee Hungary because they were Jews. They shifted to Argentina where they began selling their pen commercially under the brand name 'Eterpen'. That's how the ball-point pen was born.

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How was the ball pen invented?

It was the Biro brothers who invented the ball-point pen in the late 1930s which changed writing forever

The ball-point pen or ball pen, as we know it today, was invented by Hungarian journalist and painter Laszlo Biro.

Biro hated the way fountain pens blotted and smudged on the paper. Once, when he was visiting a newspaper printing press, he saw them using quick-drying ink and rollers. The first thing he did was use the newspaper ink inside a fountain pen but found that the ink was too thick and slow to make it to the nib of the pen.

So he approached his brother, Gyorgy Biro, who was a chemist. Together, they created a rolling ball mechanism for the tip of the pen. This ball picked up ink from a cartridge as it turned in its socket and then rolled again to deposit it on paper. They also created just the right consistency of ink for this kind of nib. They patented their invention in 1938 and called the pen Biro. In some countries, the pens are still known by this name.

Unfortunately, the advent of World War II forced the Biro brothers to flee Hungary because they were Jews. They shifted to Argentina where they began selling their pen commercially under the brand name 'Eterpen'. That's how the ball-point pen was born.

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Who invented artificial sweetener saccharin?

Did you know Russian chemist Constantin Fahlberg accidentally invented the first artificial sweetener saccharin while working on coal tar derivatives?

The first artificial sweetener to be invented was saccharin. Russian chemist Constantin Fahlberg is credited with this invention, which was actually pretty accidental. In the late 1870s,

 Fahlberg was working with another chemist, Ira Remsen. Together, they were studying substances derived from coal tar. One evening, Fahlberg returned home and sat down for dinner. As he bit into a roll, he found it sweet. He asked his wife about this, but she claimed that her rolls were perfectly normal. Fahlberg then tasted his fingers. They were sweet. He rushed back to his lab and began checking up all that he had done that day. He found that he had accidentally invented a substance that was as sweet as sugar, but had no fattening effects like sugar. He named this substance 'saccharin'

Fahlberg shared the news of the invention with Remsen, but he filed a patent claiming that he was the sole inventor of saccharin. Saccharin caught on commercially and Fahlberg grew rich. This upset Remsen who was a part of the discovery.

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What’s a binary star system?

When two stars orbit a common centre of mass, they are called binary stars. These stars are gravitationally bound to each other. It is said that 85% of stars are in binary systems or in multiple systems.

Did you know that the light that we observe coming from a star in the sky may not be produced by a single star? That the light emanating from the single point may actually be light coming out from two or even more stars that are orbiting together? These are called multiple-star systems.

The most common star system that you come across will be a binary star system that comprises two stars. When two stars orbit a common centre of mass, they are called binary stars. These stars are gravitationally bound to each other.

Did you know that most stars are in binary systems? It is said that 85% of stars are in binary systems or in multiple systems.

While the brighter star is called the primary star, the dimmer one is called the secondary. If the stars are of equal brightness, then the discoverer gets to decide on the designation.

Binary stars are very important from an astronomic point of view as they help in understanding stellar evolution. They help determine the masses and luminosities of stars.

But how are these binary stars formed? The most common way of formation of a binary star system is by a process called fragmentation.

According to this, the gas and dust cloud which collapses to form a star splits into two or more stars due to their instability or cooling/heating effects.

These fragments or stars then evolve separately and form the binary star system. But there are rare incidents when a massive star captures a passing one, as the star travels through the galaxy and thereby creates a new binary pair.

Binary pairs can be classified based on a number of factors. One such classification is on how they are observed viz. visual binaries.

They are called visual binaries when the two stars have a wide separation when viewed through a telescope.

The first binary stars to be ever spotted were visual binaries. In 1617, at the behest of a scientist, Italian astronomer Galileo Galilei used his telescope to focus on a star at the end of the handle of the Big Dipper, a constellation.

It was discovered that this wasn't a single star, but two stars which later turned out to be six. Sir William Herschel, who is known for cataloguing 700 pairs of stars, used the term binary for the first time in 1802 to refer to the double stars.

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Sci-fi novels that shaped reality

Science fiction (sci-fi) and scientific innovation have been intertwined since the creation of this genre. Here are five marvellous inventions that were inspired by sci-fi.

The Taser

The Taser stun gun is a hand-held electrical non-lethal weapon used by police and law enforcement officers around the world. Invented by Jack Cover, an American aerospace scientist in the 1960s-70s, this device takes inspiration from English writer Victor Appleton's young adult sci-fi novel ‘Tom Swift and His Electric Rifle (1911)’. The purpose of creating this device was to provide an alternative to the firearms that the air marshals were supposed to carry and use in case of a hijack. This invention was a solution to the concern that firing a gun on a plane could damage important and sophisticated machinery or pierce the fuselage.

Cover's invention pays homage to Appleton's book, and its name TASER is an acronym for Thomas A. Swift's Electric Rifle. The scientist is said to have added the 'A' to make the word easier to pronounce.

Liquid-fuelled rockets

The idea of rockets, space travel, and exploration might not sound exceptionally futuristic today, but for 16-year-old Robert H. Goddard coming across this idea for the first time in English novelist H.G. Wells's ‘The War of the Worlds’ (1898) was something right out of a dream. The famed father of rocketry invented and launched the world's first liquid-fuelled rocket in 1926, making space travel a reality. A few years after this momentous event, the NASA physicist penned a letter to Wells elaborating on the "deep impression" his novel made on the American inventor and motivated him to take this journey "aiming at the stars" both literally and figuratively.

World Wide Web

Millions of people across the globe use the World Wide Web every day. They access it through computers, phones and other digital devices. From ordering food to sharing one's location or some news and pictures with others, we use the Web all the time.

The first proposal for the World Wide Web was written by Tim Berners-Lee in 1989. Talking about the motivation behind this invention, the English computer scientist said, "I believe If you connect people up and you take away the national boundaries and you just leave humanity connected, it will naturally become better." He also credited Arthur C. Clarke's short story ‘Dial F’ for Frankenstein as the inspiration behind the World Wide Web. Acknowledging the impact of his story on Berners-Lee, the English sci-fi writer declared, "I guess I am the godfather of the World Wide Web."

Humanoid robots ASTRO BOY

Japan's Tomotaka Takahashi is one of the world's leading new-generation robot scientists. In 2013, his humanoid robot named Kirobo became the world's first talking robot sent into space to keep astronauts company. Talking about his passion for robotics in an interview, Takahashi said "When I was about six, I started reading the manga comic ‘Astro Boy’ after finding it lying around at home. My dream, from that moment on, was to become a robot scientist. I made my first robot around the same time, from a soapbox and duct tape complete with a robot face." Osamu Tezuka's ‘Astro Boy’ is a manga series that ran from 1952 to 1968. It chronicles the adventures of the titular humanoid. The Japanese scientist also admitted that his 13-inch-tall robot Kirobo's design and colour palette are heavily inspired by the friendly manga character.


Since the beginning of time, the idea of flying from one place to another in little time has been a fascinating topic. The helicopter is one of the many inventions that aimed to accomplish this. Russian-American aviator Igor Sikorsky is credited with inventing the modern helicopter. As a child, his parents exposed him to the technical drawings of da Vinci and encouraged him to pursue science. As a curious kid growing up in Russia, he was fascinated by Jules Verne's 1886 novel ‘Robur the Conqueror (which is also known as The Chipper of the Clouds)’. This book's description of a flying machine called the ‘Albatross’ inspired Sikorsky's design of the helicopter. Starting test flights in 1939, Sikorsky's aircraft was ready for larger production by 1942.

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What is the importance of elephants in the natural ecosystem?

Elephants are the largest land mammals, and also a keystone species, meaning they play a crucial role in keeping the natural ecosystem balanced. Despite such a significant function, the numbers of African elephants dwindled over the last few centuries due to European colonisation, poaching, and habitat loss. Now the species faces an additional challenge - drought. This climate change-induced drought in Africa can also affect more than one generation of these gentle giants. How? Come, let's find out.

Droughts in most African regions have become longer and more acute. Some have lasted for over two decades. And this can affect elephant populations in more ways than one. "Heat accumulates through an elephant's natural metabolism and physical activity, as well as being absorbed from the environment." But they cannot sweat it off the way humans do because they lack sweat glands. Further, their thick skin slows loss of heat. This is where water comes in; it helps regulate the animal's body temperature and keep it cool. Not just drinking, even swimming and spraying their skin with mud and water cools them down.

Without water, elephants can experience high internal temperatures, which "can disrupt the function of cells, tissues and organs such as the liver and cause them to become sick and die".

Importantly, drought "can also reduce the availability of food, causing elephants to starve. It can also mean young elephants die or don't develop properly, because their parched mothers produce less milk". This is to say, longer-lasting droughts can affect the next generation or even prevent the very existence of that generation.

The creation of artificial water sources for elephants could lead to denial of water to humans and also ecosystem damage due to animal congregation at a specific spot. So, the answer to saving the elephants could be in creating or restoring wildlife corridors.

Traditionally, these animals moved to other places in search of water during droughts. But this has been affected due to fences, fragmented habitats, etc.

Conservationists stress the need for finding such solutions. Because, if we don't find solutions, and quickly, at that, we risk losing not just this majestic beast but also so many other species that depend on it for their survival.

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What happens to the black box when a plane crashes?

When a plane crashes, the investigators search for the black boxes to determine the cause for the accident.

Recently, a plane crashed just before landing in Nepal's tourist city of Pokhara. To investigate the reason for the crash, the authorities soon rushed to the spot to search for black boxes. Do you know what they are?

Black boxes

Black boxes are large metallic boxes containing recorders kept on most aircraft, one in the front and the other in the back. They help in establishing legal liability and identifying causes of the accident and, hence, help prevent adverse incidents in the future.


Black boxes are usually referred to by aviation experts as electronic flight data recorders. Though these boxes are known as black boxes, they are painted in highly visible vermilion colour known as "international orange". The colour helps the crew at the crash site search for the black boxes.

Flight recorders consist of two functional devices the flight data recorder (FDR) and the cockpit voice recorder (CVR). Sometimes these devices are packaged in one combined unit. Digital recorders have enough storage for 25 hours of flight data but only two hours of cockpit voice recording, which is recorded over itself in a loop.

 FDRs are usually double-wrapped in titanium or stainless steel, and, hence, can withstand harsh conditions. Besides, the flight recorders have crash survivable memory unit (CSMU) wherein a memory chip stores data to allow recovery of data from wreckage.

Every flight data recorder has a tool called an underwater location beacon (ULB), which makes it possible for  investigators to find it if a plane crashes into a body of water.

While black boxes are virtually indestructable, planes are not made of the same material.

Building the entire plane out of the black box would make it too heavy to fly.


The FDR records more than 80 different types of information such as altitude, airspeed, flight heading, vertical acceleration, pitch, roll, autopilot status, etc. They are commonly carried in the tail of the aircraft, which is usually the part that is least affected in the event of a crash.


The CVR, kept in the front, records radio transmissions and other sounds in the cockpit, such as conversations between the pilots, and engine noises.

Besides, aircraft sounds audible in the cockpit are also caught on the recorder.


In 1939, French engineers François Hussenot and Paul Beaudouin invented a flight recorder, which could record altitude and speed information on a piece of photographic film.

During World War II, analysing crashes of military aircraft became important. As civil aviation developed in the years after World War II, "crash-survivable" flight recorders began to be developed.

An Australian scientist, David Warren designed the first combined FDR and CVR. During the 1960s, crash-protected FDRS and CVRS became mandatory on aircraft around the world. Australia was the first country to make black boxes mandatory.

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What are the phobias of literature?

Some fears seem less rational than others. Here is a list of literary phobias that you might find intriguing.

In the realm of writing and literature, where words flow like rivers and imagination dances on the page, there exists a shadowy undercurrent of fears and phobias that grip the hearts and minds of some individuals. While books and the written word have long been celebrated as gateways to knowledge, for a select few, they serve as gateways to a world of dread and irrational anxiety. Step into this labyrinth of ink-stained fears as we explore some literary phobias.

  • Bibliophobia is a specific phobia characterised by intense fear or aversion towards books. Individuals who experience bibliophobia may feel significant anxiety, panic, or discomfort when they are near books or even when the idea of reading is brought up.

The underlying causes of bibliophobia can vary from person to person. It may stem from a negative experience related to books, such as being overwhelmed or intimidated by the content, struggling with reading difficulties, or associating books with traumatic events.

  • Logophobia is a term used to describe the fear or aversion to words. This fear can make it difficult for individuals to read books, write essays, or even have conversations.
  • Scriptophobia is an extreme fear of writing in public. It can make everyday writing situations such as taking notes during a lecture or participating in group activities that involve writing, extremely challenging and distressing. The fear of making mistakes or being embarrassed in front of others becomes so overwhelming that it may cause one to avoid these situations altogether. It can hold one back from expressing their thoughts and ideas freely in public, hindering their academic and social growth.1`
  • Metrophobia is the fear of poetry. Individuals with metrophobia experience anxiety, discomfort, or fear specifically related to poetry or poetic expressions. It may manifest as a fear of reading, reciting, or engaging with poetry in any form.
  • Papyrophobia is an irrational fear of paper. Individuals who experience this phobia may feel intense anxiety or fear even when thinking about paper. They are often extremely anxious about touching paper, writing on it, or even the possibility of getting a paper cut. It is important to note that papyrophobia is relatively uncommon, with only a small number of people in the world have it.
  • Abibliophobia is a word that represents the fear or anxiety someone can feel when they do not have a book to read or when they cannot access reading materials.

People with abibliophobia have a strong emotional connection to books and reading. Books may provide them with an escape, knowledge, or a sense of companionship. When they do not have a book, they might feel lost or disconnected, which leads to a fear of being without the comfort and stimulation that reading provides.

It is important to understand that the intensity of abibliophobia can vary from person to person. For some, it might be a mild uneasiness, while for others, it can be a stronger fear that affects their daily lives. They might constantly search for books, feel anxious when they do not have one, or avoid situations where books are not available.

  • Hippopotomonstrosesquippedaliophobia, is the fear of long words. The humorous contrast between the fear and the cumbersome word used to label it adds an interesting twist to this particular phobia. It is important to note that it is primarily used for amusement.

Phobias such as "abibliophobia" and "Hippopotomonstrosesquippedaliophobia," were created with a humorous intent or are not officially recognised. However, it is crucial to acknowledge that there are real and debilitating phobias that can significantly impact individuals who have them.

Remember, it is important not to dismiss or trivialise someone's fear, regardless of whether it is a recognised phobia or not. Most of these phobias can be addressed through therapy and gradual exposure to the stimuli in a supportive and controlled manner. Offering understanding and support can make a significant difference in helping individuals navigate and overcome their fears, enabling them to lead happier and more fulfilling lives.

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Scientists have achieved the world's first X-ray signal (or signature) of just one atom

From medical examinations and airport screenings to space missions, X-rays have been used everywhere since its discovery by German physicist Wilhelm Roentgen in 1895. A group of scientists from Ohio University, Argonne National Laboratory, the University of Illinois-Chicago, and others, have now taken the world's first X-ray signal (or signature) of a single atom. The groundbreaking achievement could revolutionise the way in which scientists detect the materials.

One atom at a time

Before this, the smallest amount one can X-ray a sample is an attogram, which is about 10,000 atoms or more. The paper brought out by the scientists was published in the scientific journal Nature on May 31, 2023 and also made it to the cover of the print edition on June 1. The paper details how physicists and chemists used a purpose-built synchrotron X-ray instrument at the XTIP beamline of Advanced Photon Source and the Center for Nanoscale Materials at Argonne National Laboratory.

Specialised detector

The team involved picked an iron atom and terbium atom for their demonstration. Both atoms were inserted in respective molecular hosts. Conventional detectors were supplemented with a specialised detector by the research team.

This specialised detector was made of a sharp metal tip. It is positioned at extreme proximity to the sample, enabling it to collect X-ray excited electrons. This technique is known as synchrotron X-ray scanning tunnelling microscopy or SX-STM.

Apart from achieving the X-ray signature of an atom, the team also succeeded in another key goal. This was to employ their technique to find out the environmental effect of a single rare-earth atom.

The scientists were able to detect the chemical states of the individual atoms inside respective molecular hosts and compare them. While the terbium atom, a rare-earth metal, remained rather isolated and didn't change its chemical state, the iron atom interacted with its surrounding strongly.

Many rare-earth materials are used in everyday devices like cell phones, televisions, and computers. This discovery allows scientists to not only identify the type of element, but also its chemical state. Knowing this enables them to work on these materials inside different hosts, paving the way for further advancement of technology.

This team aims to continue to use X-ray to detect properties of a single atom. They are also seeking ways to revolutionise their applications so that they can be put to use in critical materials research.

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What are solar trees and solar canopies?

Solar trees and solar canopies are all about the idea of taking solar energy to another level. Solar energy is a renewable source of energy. It is cheaper, perennial, and environmentally friendly.

Tapping into solar energy is a revolutionary way to drive renewable energy production and reduce our dependence on fossil fuels which release harmful greenhouse gases and thereby lowers our carbon footprint.

And to promote the use of solar energy, sustainable, aesthetic-looking solar structures such as solar trees and solar canopies have come up. Here we harness the energy of the sun to generate electricity.

Ever seen the Supertrees in Singapore? Remember those colossal structures that look like trees right out of a science fiction novel. Those are solar trees.

A collection of 18 artificial Supertrees ranging in height upto 50 metres, were set up in Singapore at "Gardens by the Bay" (a botanical project). These solar trees also serve as vertical gardens with ferns and vines climbing up the steel framework.

So what are solar trees? A solar tree is a structure resembling a tree and generating solar energy using photovoltaic (PV) panels.

How does a solar tree work?

 In a solar tree, the photovoltaic "leaves" will capture the sunlight and convert it into electricity. This is then conducted down through the framework that resembles the trunk of a tree to an internal battery.

Some designs of solar trees feature rotating panels and these can move throughout the day and absorb more amounts of sunlight.

These are futuristic "trees" and can be set up even in rural communities or other off-grid locations. They can be used to supplement other methods of harnessing sunlight.

Why solar trees?

One of the main perks of setting up solar trees is that they help save land as they are vertical. Due to their towering height, they can also receive more sunlight than solar panels mounted on a lower ground.

If you were to take a look at the Supertrees in Singapore, you can see that the steel framework is covered by climbers and floral species, increasing the aesthetic value. Thus it also adds to the biodiversity of the urban locale. Moreover, these trees require less maintenance compared to other means of solar energy production. They also help cool the heat islands by reducing the thermal energy that gets reflected off surfaces. These structures can thus help offset the effect of climate change.

Solar canopy

Now what are solar canopies? A solar canopy is a structure that is designed to cover an outdoor area. They are rooftops that are used to harness solar energy using photovoltaic panels.

They also provide shelter in expansive areas. One can even say that the future of parking lies in solar canopies. They are slowly becoming popular in public places and businesses. These green roofs are mostly used as transportation infrastructure (bus shelters, or parking lots) or in recreational areas.

Solar canopies help in decentralised energy production and have an edge over huge grid-based power systems as these can help avoid grid failures and power outages. Despite their advantages the solar canopies are not that common. This is expected to change over time.

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When chemistry meets myth

Step into the captivating realm of chemistry, where elements bear the names of legendary figures from myth and folklore.


British mineralogist William Gregor made a significant discovery, in 1791, when he detected an unfamiliar metal in a black mineral known as menachanite. However, it was not named until four years later German chemist Martin Heinrich Klaproth independently identified the same metal in a different mineral called rutile. Upon learning about Gregor’s findings. Klaproth realised that the two metals were, in fact, the same. In honour of the Titans, a group of Greek deities known for their strength and power, Klaproth named the element "titanium." This name befits the metal perfectly, as it exhibits remarkable resistance to corrosion and possesses an impressive tensile strength, especially considering its low density.

Thorium & Cerium

 Jons Jacob Berzelius, a Swedish chemist, made an exciting discovery while examining mineral samples from Norway and Sweden in 1815. He named this newfound substance thorjord, meaning "Thors earth," in honour of the powerful Norse god of thunder. However, further investigation revealed that thorjord was, in fact, yttrium phosphate, an existing compound. Nevertheless, Berzelius later had the opportunity to pay tribute to Thor once again when he successfully identified a new element, which he named thorium in the late 1820s. Berzelius had a penchant for bestowing mythological names upon elements, and his naming of cerium was no exception. In 1803, while working alongside his colleague Wilhelm Hisinger, Berzelius discovered a silvery rare earth metal. Inspired by the recent sighting of the asteroid (now considered a dwarf planet) Ceres, they named the element cerium after the celestial body. The name Ceres, in turn, originated from the Roman goddess associated with agriculture and abundant harvests. It is worth noting that the word "cereal" is also derived from the name of this goddess.


Vanadium was discovered in 1801 by the Spanish-Mexican mineralogist Andres Manuel del Rio. He found a new mineral in a lead ore from a mine near Zimapan, Mexico. Del Rio initially believed that the mineral was a form of chromium, and he named it "panchromium" due to its ability to exhibit various colours when oxidised.

However, in 1830, Swedish chemist Nils Gabriel Sefstrom rediscovered the element independently while working with iron ores. Sefstrom recognised that the mineral previously identified as panchromium was a distinct element and named it "vanadium" in honour of the Scandinavian goddess Vanadis (also known as Freyja) Vanadis was associated with beauty and fertility, which Sefstrom felt was appropriate due to the many vibrant colours exhibited by vanadium compounds.


During the development of the atomic bomb as part of the Manhattan Project in World War II, American chemist Charles Coryell and his colleagues Lawrence E. Glendenin and Jacob A. Marinsky were involved in the identification of elements produced during nuclear fission of uranium. Surprisingly, they discovered an unknown rare earth metal during their research. Credit for the name of this radioactive element goes to Coryell's wife, Grace Mary. She proposed naming it after Prometheus, the Greek Titan who famously stole fire from the Olympians and gave it to humans. However, Prometheus faced severe consequences for his actions. He was bound to a mountain by Zeus, and every day an eagle would come to peck out his liver, which would then regenerate overnight. This punishment served as a reminder of the dangers associated with defying the gods.

When Glendenin described the name "promethium" in 1976, he explained that it not only symbolised the remarkable manner in which the element is created through the harnessing of nuclear fission energy but also served as a warning about the potential consequences and perils of engaging in war, as represented by the eagle punishing Prometheus.

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How soil came to be?

Soil is almost everywhere around us that we don't give it much thought. But it is so crucial that life as we know it will cease to exist without soil. Here's a peek into how soil came to be.

Though Earth is over 4.5 billion years old, the soil it holds is less than 500 million years old. Before soil came about, the continents of our planet were "dusty, barren and rocky landscapes similar to the surface of Mars". All that dramatically changed with the birth of soil. It was earlier believed that rivers weathering bare rock resulted in soil, but more recent research suggests that land plants are largely responsible for the formation of soil.

Freshwater algae gradually evolved to become land plants, which quickly gained complex forms. So quickly that 385 million years ago, there were forests the world over. These forests "sucked carbon dioxide out of the atmosphere at a rapid rate". This resulted in global temperatures falling and causing widespread glaciations. These "helped to grind down Earth's rocks". But there was also something else at play - roots.

There's evidence that early plant roots were not the way they look today. There were just thin stems covered in tiny hairs, which helped "anchor plants to the planet's rocky surface and absorb water and nutrients". The new hairy stems intertwined with decaying older stems to result in a thin-layered peaty soil enough to offer a foothold for more plants to grow. In about 20 million years, plant roots evolved and "drilled down over a metre in depth", transforming soils and letting plants gain access to deep reserves of water and nutrients. "This below-ground revolution provided an entirely new ecosystem for life to diversify into." From fungi and mites to roundworms and early arachnids, the soil was just bursting with life. Meanwhile, the penetration of roots into the ground also helped broad sheets of water on land to flow deeper to become what we now call rivers. It is said plant roots may have evolved further since then, impacting soil.

Given how important soil is for water, nutrients, and absorbing carbon, it is worrying that globally our soil is in peril due to several factors, including erosion. And this is a reminder that we must protect it.

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Why has the RBI withdrawn Rs. 2000 notes?

The Reserve Bank of India recently announced its decision to withdraw the Rs. 2000 notes from circulation. The public has been advised to deposit and/or exchange these banknotes on or before September 30. These notes were introduced in November 2016 as part of demonetisation. Let us know more about demonetisation.


On November 8, 2016, Prime Minister Narendra Modi announced the demonetisation of Rs. 500 and Rs. 1000. The move was made to prevent the accumulation and circulation of black money in the country.

The sudden decision to ban these notes caused anxiety and panic among the public. Banks and ATMS witnessed huge queues with people waiting for several hours to exchange / get their cash.

The case of Rs. 2000 notes

The Rs. 2000 notes were introduced in 2016 to meet the currency requirement after Rs. 500 and Rs. 1000 notes were withdrawn. The printing of Rs. 2000 notes was stopped in 2018-2019 once there were enough notes of other denominations. Recently, the RBI announced that in pursuance of the Clean Note Policy, the Rs. 2000 notes will be withdrawn from circulation.

There is a difference between demonetisation and withdrawal of currency. While demonetisation is the process of removing a monetary unit's legally accepted status, withdrawing a currency from circulation does not affect their legal tender status. This means that while Rs. 2000 will be valid for use in business and exchange transactions, the notes will be set aside when they arrive at banks to be deposited in the RBI and will no longer be distributed to the general public.

Clean Note Policy

The Clean Note Policy, first announced in 1999, seeks to provide citizens high-quality currency notes and coins with better security features, while removing worn-out notes from circulation. For instance, on Rs. 2000 notes, the security features include readable and windowed security thread alternately visible on the obverse with the inscriptions 'Bharat (in Hindi), '2000', and 'RBI'.

In 2018, a new Clean Note Policy was announced to make digital payments more secure.

In 2005, the RBI withdrew all banknotes issued before 2005 from circulation, as they had fewer security features than banknotes printed after 2005. The notes issued before 2005 do not have on them the year of printing on the reverse side.

In 2002, the RBI inaugurated Currency Verification and Processing (CVPS) Machines for checking numerical accuracy and genuineness of the currency notes.

The CVPS system is capable of processing 50,000 - 60,000 soiled notes per hour. The system, along with the Shredding and Briquetting System for destruction of soiled notes, helps faster withdrawal of soiled and mutilated notes from the market. These machines are installed at both regional and zonal RBI offices.

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