Today I found out about a man who fairly accurately estimated the circumference of the Earth well over 2,000 years ago: Eratosthenes of Cyrene.

Born around 276 B.C. in Cyrene, Libya, Eratosthenes soon became one of the most famous mathematicians of his time. He is best known for making the first recorded measurement of the Earth’s circumference, which was also remarkably accurate.  (And, yes, people at that point had known for some time that the world wasn’t flat, contrary to popular belief.)

Eratosthenes was able to accomplish this in part because of his education in Athens. There, he became known for his achievements in many different fields, including poetry, astronomy, and scientific writing. His activities became so talked about, in fact, that Ptolemy III of Egypt decided to invite him to Alexandria to tutor his son. Later, he would become the head librarian of the Library of Alexandria.

The mathematician must have been thrilled to have this opportunity. The Library of Alexandria was a hub of learning at the time, attracting scholars from across the known world. Eratosthenes was able to rub shoulders with the likes of Archimedes while continuing his own learning.

It was probably in the Library of Alexandria that he read about a curious event that took place in Syene (now Aswan, Egypt) at the summer solstice. Syene sat to the south of Alexandria. At high noon, the sun would shine directly overhead and there would be no shadows stemming from the columns. However, Eratosthenes realized that at the same moment in Alexandria, columns clearly did have shadows. Being a good mathematician, he decided to use this knowledge to do a few calculations to figure out the circumference of the Earth.

To do this, Eratosthenes measured the shadow of an obelisk on June 21 at noon. He discovered that the sun was about 7°14’ from being directly overhead. He realized that, because the Earth is curved, the greater the curve, the longer the shadows would be.

Based on his observations, he hypothesized that Syene must lie 7°14’ along a curve from Alexandria. Furthermore, he knew that a circle contained 360°, which meant that his calculation—7°14’—was roughly one fiftieth of a circle. Therefore, Eratosthenes thought, if he multiplied the distance between Syene and Alexandria by 50, he would have the circumference of the Earth.

The missing information was simply how far away Syene was from Alexandria. He measured the distance in stadia. There isn’t an exact modern day conversion to stadia, and it isn’t perfectly clear which version of the stadia Eratosthenes was using, but regardless, from what is known, his estimation was remarkably accurate.

There are two theories as to how Eratosthenes figured out the distance: first, that he hired a man to walk there and count the steps. Second, that he heard a camel could travel 100 stadia a day, and it took a camel about 50 days to travel to Syene. Whatever the case, he estimated the distance between Syene and Alexandria was 5,000 stadia. If that was the case, then using his formula, the earth was 250,000 stadiaaround.

Due to the uncertain distance that stadia represents (and particularly which stadia he was using), historians believe that Eratosthenes’ conclusion was between .5% and 17% off the mark. Even if the latter case was true, it was astoundingly accurate given the limited technology he was dealing with at the time. But many scholars think it likely that he was using the Egyptian stadia (157.5 m), being in Egypt at the time. This would make his estimate only about 1% too small.

There had been previous attempts at discovering the Earth’s circumference (which don’t count as “first recorded” because their methods didn’t survive, though we have references to them) which resulted in a 400,000 stadia figure, 150,000 more than Eratosthenes’—obviously far from accurate.

While finding the approximate circumference of the Earth was probably Eratosthenes’ largest contribution to scholarship at the time, it was by no means the only one. Eratosthenes is also credited with coming up with a way to map out the known world by drawing lines north-south and east-west—early latitude and longitude lines. However, these lines were irregular and often drawn through known places, meaning they weren’t entirely accurate. Nevertheless, it provided a precursor for maps we know today.

He is also remembered for the Sieve of Eratosthenes, a simple algorithm that makes it easy to find all prime numbers up to a certain limit. Though none of Eratosthenes’ personal work on the sieve survives, he was credited with the creation of the algorithm by Nicomedes in his Introduction to Arithmetic.

Not only that, but Eratosthenes estimated the distance to both the sun and the moon, and measured the tilt of the Earth’s axis all with amazing accuracy.

He also wrote the poem Hermes, correctly sketched the route of the Nile, and even gave a more-or-less accurate account of why the Nile flooded, something that had baffled scholars for centuries. He worked on a calendar that included leap years and he also estimated and corrected the dates of various historical events beginning with the Siege of Troy.

Despite these accomplishments and many more like them, Eratosthenes was often nicknamed “Beta.” Beta is the second letter in the Greek alphabet and referred to Eratosthenes being second-best in everything he did.

Eratosthenes died around 194 B.C. and is thought to have starved himself to death. It is believed that he started going blind in his later years and, unable to continue his work, he simply stopped eating.

Bonus Fact:

  • A man named Posidonius copied Eratosthenes’ basic method about a century later, using the star Canopus, Rhodes, and Alexandria as starting points. However, he didn’t measure the distance between Rhodes and Alexandria correctly, resulting in a circumference that was smaller than Eratosthenes’ estimation. It was this circumference that was recorded by Ptolemy in his geography treatise and later used by explorers looking for a quicker way to the Indies.



வாரம் ஒரு கவிதை ….” மழை நீர் போல …”


மழை நீர் போல …
வறண்டு கிடக்கும் பூமி …வானம் திறக்குமா கண் ?
மேலும் கீழும் பார்ப்பது உழவன் மட்டுமல்ல இன்று !
அடுக்கு மாடி கட்டிடக் குவியல் கூட்டில் குடி இருக்கும்
நகரத்துப் “பறவைகளும்” மழை தேடி வானிலை
அறிக்கையை காலையும் மாலையும் அலசும் அவலம் இன்று !
மழை நீரை முத்தமிட துடிக்கும்  வறண்ட பூமி நனையுது
மழை நீர் போல பெருகி வரும் உழவன் அவன் கண்ணீரில் !
குடிக்க நீர் இன்றி தவிக்கும் அடுக்கு மாடி “பறவைகள்”
வழி மேல் விழி வைத்து காத்திருக்குது  தினமும் ஒரு
லாரி தண்ணீருக்கு !
தண்ணீரும் பணமாக மாறும் காலம் இது ..மழை
நீர் சேமிப்பின் மதிப்பு உணராத மனிதன் கொடுக்கிறான்
நீருக்கு ஒரு விலை இன்று !
மழை வெள்ளம் வரும் நேரம் “இது என்ன பேய் மழை”
என்று அலறிய மனிதன் குரல் கேட்டு வானமும்
மனம் உடைந்து “கண்ணீர் ” விடவும் மறந்து போனதோ ?
தினம் தினம் தண்ணீர் தண்ணீர்  என்று மனிதன்
கண்ணீர் விட்டு என்ன பயன் இன்று ?
மாற வேண்டும்  மனிதன்… மாற்றி யோசிக்கவும்
வேண்டும் …வானமும் மகிழ்ந்து  தன் ஆனந்தக்
கண்ணீரால்  நனைக்க வேண்டும் இந்த பூமியை !
மனிதனுக்கும் புரிய வேண்டும்  எந்த நீர்
ஆனாலும்  மழை நீர் போல ஆகுமா  என்று !
in dated  13th August 2017

வாரம் ஒரு கவிதை ….” தூரத்தில் கேட்குது ….”


தூரத்தில்  கேட்குது ..
அம்மா உன் குரல் முதன் முதல் கேட்டேன்   தூரத்தில்…
உன் கருவில்  நான்  மலர்ந்து வளர்ந்த  போது !
இப்போதும்  உன் குரல் நான் கேட்கிறேன்
தினமும் …தூரத்திலிருந்தே !
அயல் நாட்டு மண்ணில் நான் இன்று  இருந்தாலும்
நம் நாட்டு  மண் வாசம் மறக்கவில்லையே அம்மா  நான் !
தூரத்திலிருந்து உன்  குரல்  நான் கேட்டாலும்
அம்மா..பாசமுடன் மண் வாசம் கலந்து ஒலிக்கும்
உன் குரல் நான்  அன்று  கருவில் கேட்ட
அதே குரலாக இன்றும் ஒலிக்கும் மாயம் என்ன அம்மா ?
தூரத்தில் கேட்குது உன் குரல் என்று என்னிடம்
இது வரை நீ சொன்னதில்லையே அம்மா !
எங்கே நீ இருந்தாலும் நீ இருக்குமிடம் என்
இதயத்தில்தான் என்று எனக்கு சொல்லாமல்
சொல்லுகிறாயா  அம்மா ?
Natarajan … dated 24th July 2017

This 30-Year-Old Indian Pilot Is the World’s Youngest Woman to Captain a Boeing 777!

Currently based in Mumbai, the young aviator had always dreamed of becoming a pilot and did so at the age of 19

“Since my childhood, I wanted to be a pilot. Other children used to make fun of me for this. Kids, at that time, were pushed to pursue engineering or become a doctor but not a pilot,” Anny told to HT.

Coming from an army background, one would think Anny must have had it easy. While she had rock-solid support from her parents, dissent often cropped up in form of family friends and relatives.

“Luckily, my parents never forced their choice on me. They were supportive and progressive in their thinking. My mother always used to encourage me. However, my relatives and my family friends were against my decision to become a pilot. Also, at that time, being a pilot was not considered as a profession for woman,” she said.

After her father took voluntary retirement, the family moved to Vijayawada, where Anny did her schooling. Hailing from a modest background, their family had their share of financial shortcomings. “Since I grew up in Vijayawada, I could write and read English but speaking English was a major challenge that I had to overcome,” Anny said.

Post her school education, the 17-year-old Anny made it to Indira Gandhi Rashtriya Uran Akademi (IGRUA), one of the premier flying schools in the country.

The cultural change from a small town to a big city was overwhelming for me. I had difficulty adjusting and speaking English. People used to mock me for my poor English and that hurt me a lot. At times, I had even thought of going back. However, backed with my parents’ support, I worked hard enough to win a scholarship,” she added.

Completing her training by the time she was 19, Anny bagged a job with Air India and since then, there has been no looking back. Post her training, she kickstarted her flying carrier with Boeing 737.

“When I turned 21, I was sent to London for further training. It was then when I started to fly Boeing 777. Since then, my life has changed. It’s been a great experience so far. I’ve got the opportunity to travel to various countries. My journey so far has taught me a lot,” Anny added.

When the going gets tough, the tough get going!

Source….LekshmiPriya .S  in




It was March 14, 1932 when George Eastman, famed inventor, philanthropist, and founder of Eastman Kodak, invited a few loyal friends over to witness the rewriting of his will. He had made the decision to give a good portion of his money and prized possessions, including his enormous mansion, to the city he called home for his whole life- Rochester. To this end, he bequeathed his house and a $2 million endowment (about $34 million today) to the University of Rochester. Eastman also donated a large sum of money to dental dispensaries across the city, attempting to ensure that no child in Rochester would go without proper dental work. Finally, he left $200,000 (about $3.4 million today) to his beloved niece, Ellen.

Cheerfully signing the will, he assured his friends this was just a matter of ensuring his wishes. Later, it was thought that he also wanted his friends to see him mentally alert so the credibility of the will wouldn’t be questioned. After all the t’s were crossed and i’s were dotted, he asked if everyone could excuse themselves for a moment. When they did, George took out paper and pen and wrote a note, which read,

To my friends,
My work is done.
Why wait?

Then, he took a pistol out from his nightstand and shot himself in the heart, ending his life at the age of 74.

So who was this captain of industry and why did he, quite cheerfully, suddenly choose to take his own life?

George Eastman, and his company, turned photography from a complicated, expensive, unwieldy, and potentially dangerous hobby (due the chemicals needed to develop the film) into one that, quite literally, a child could do. He was not only a genius inventor, but a brilliant marketer.

His story begins as it ended, in Rochester. The Eastmans always put a priority on education. In fact, George Eastman Senior founded Eastman’s Commercial College in 1854, the same year George Junior was born. The family was middle-class and living pretty comfortably, but this was short-lived. In 1862, when George was only eight, his father passed away from a “brain disorder.” His mother, Maria, was a now a widow with three small children, one of them (George’s youngest sister Katy) suffered from polio and other illnesses. Life was hard for the Eastman family after George Senior’s death and self-reliance became a necessary trait.

At age of 14, George dropped out of high school to support his family. He worked at a local insurance company and as a clerk at Rochester Savings Bank. Then, in 1870, tragedy struck again when his sister, Katy, passed away from complications related to polio. She was buried next to her father.

George, even at an early age, was meticulous, detailed, and controlling of every aspect of his own business. Starting when he got his first job at 14, he began keeping ledgers to detail his finances. Due to his careful planning and earning enough working at the bank, Eastman was able to afford certain luxuries. It was in one of these ledgers, under January 27, 1869 to be exact, that “photography” was first mentioned. As the months passed, besides helping to support his mother, George spent more and more money on “photos” or “photograph materials.”

In 1878, Eastman learned an important lesson – photography (at least at the time) was hard. The legend goes that he wanted to treat his mother to a vacation in Santa Domingo in the Dominican Republic (other sources say he was looking to buy land in the newly independent nation). Either way, to document his trip, he bought a photographic outfit. Cameras then are not what we think of cameras are today. An outfit included the camera (constructed from several parts that must be put together before taking pictures), a stand, a light, and wet glass plates (with chemicals) in order to preserve the picture. As Eastman later put it,

In those days, one did not ‘take’ a camera; one accompanied the outfit in which the camera was only a part. I bought an outfit and learned that it took not only a strong, but also a dauntless man to be an outdoor photographer.

Eastman, so fed up with everything he had to bring, not only didn’t take a camera, he didn’t take the trip at all. At this point, Eastman thought to himself that there had to be a better way.

For the next several years, while still working at the bank, Eastman developed a new kind of dry plate, one made out of gelatin (the same ingredient used in Jello, which would be invented twenty years later in a small town thirty miles from Rochester), not glass. Glass was heavy, fragile, and expensive. Gelatin was an improvement on all of these things. By 1880, he had patented a dry-plate coating machine made out of gelatin, making the process of preserving film negatives simpler, cheaper, and less dangerous.

While developing this process, he came across another innovation that would allow photography and, eventually, cameras to become something that wasn’t just for the professional. As described by Eastman,

I also made experiments by using paper as a temporary support and coating the Cellulose immediately upon the paper, and afterwards coating with the emulsion. I had no difficulty stripping the Cellulose from the paper, the cellulose adhered to the emulsion and separated from the paper.

He patented this film on March 4, 1884. That same year, Eastman and his associate William Walker developed a roll holder to hold the film. The invention of this revolutionary film wasn’t enough, though. What he really wanted to do was, “to popularize photography to an extent as yet scarcely dreamed of.”

In 1888, the name “Kodak” was thought up while playing with an anagram set with his mother. Eastman loved the word because it was simple, easy to pronounce and it started with a “K.” Said Eastman, “It became a question of trying out a great number of combinations of letters that made words starting and ending with ‘K.”

Kodak was officially incorporated as a company in 1890 and quickly rocketed to the top of the industry. Also that same year, Eastman introduced the first Kodak camera, equipped with his film. It cost $25 (about $640 today), but the most important thing was that the customer didn’t do the developing of film themselves- Kodak did. The customer would send the camera back (film and all) to the company for developing and processing. Their motto aptly illustrated this: “You press the button, we do the rest.”

He had now made it easy for anyone to take and have pictures developed. The next step was to change the camera from a luxury item or expensive hobby to something just about anyone could afford.

In 1900, the revolutionary Brownie camera, versions of which were so popular through the mid-20th century, was born. It cost only one dollar ($28 today) and was even marketed to children. For the next hundred years, George Eastman and Kodak would be synonymous with cameras and film.

For his entire 40+ years of heading up his own company, George Eastman was used to being in control. So, when he was diagnosed with a spinal condition in the late 1920s, forcing him to be confined to a wheelchair, it depressed him greatly. His mother, who lived with him until her death in 1907, was also in a wheelchair for the last years of her life. His baby sister was in a wheelchair until she died. He saw them suffer and Eastman did not want to go through the same long drawn out process. He also didn’t like that he felt this gave off an image of weakness. Eastman was used to being a man respected the world over, not an “invalid.” He mused greatly about death and illness, writing a friend,

God keep me from being like them (referring to family and friends who he had seen succumb to illness). Doesn’t it seem strange that the clearest minds I have ever known should be taken this way? That is the sad thing about illness.

So, by March 1932, he had enough. George Eastman wanted to go by his own hand, rather than the hand of illness and fate. So he tidied up all the loose ends of his life and, once complete, ended it immediately on his own terms.

Source… i


வாரம் ஒரு கவிதை …” சூரிய தாகம் “


சூரிய தாகம்
சுள்ளென்று எரிக்கும் சூரியனின் தாக்கம் தெரியும்
அது என்ன சூரிய தாகம் ? சூரியனுக்கே  தாகமா !
இல்லை  தாகம்,  சூரிய வெப்பம் தாக்கும் பூமிக்கா ?
தாகம் பூமிக்கு மட்டும் அல்ல …  சூரியனுக்கும் இருக்கு !
மண்ணில் உள்ள நீர் மனிதனுக்கு மட்டுமல்ல சொந்தம் !
விண்ணில் உள்ள மேகத்துக்கும் அதுதானே நீராகாரம் !
மண்ணிலிருந்து நீர் உறிஞ்சி வெண் மேகம் நெய்து
கொடுக்கும் கரு மழை மேக புத்தாடை  சூரியனுக்கு
ஒரு பட்டாடை ! கதிரவன் அவன் தாகம் தீர்க்கும்
தண்ணீர் பந்தலும் அதுவே !
விண்ணின் தண்ணீர் பந்தல் அள்ளி வழங்கும்
கொடையே இந்த மண்ணுக்கு துள்ளி வரும் மழை !
மண்ணுக்கு துள்ளி வரும் மழை நீரை வரவேற்க
ஏரி குளம் ஒன்றும் இல்லையே நம் மண்ணில் இன்று !
மண்ணுக்கு குடை பிடித்து கருமேக மழைப்
பொழிவை வழி காட்டி வரவேற்கும் மரம்,
கானகமும் கண்ணில் படவில்லையே இன்று !
வரிசை கட்டி வானம் தொடும் கட்டிடங்கள்தான்
தெரியுது கண்ணுக்கு எட்டும் தூரம் மட்டும் !
வீட்டுக்கு ஒரு மரம் வளர்ப்போம் ! ஏரி குளம்
அருமை புரிந்து நம்  மண்ணின் நீர் வளம்
காப்போம் !
மரம் வளர்த்து நீர் வளம் பெருக்கினால்
தீரும் அந்த சூரிய தாகம் !
சூரிய தாகம் தணிந்தால்  தீரும் இந்த மண்ணின்
தண்ணீர் தாகம்  தன்னால் !
Natarajan  in  dated 17th April 2017

Real story behind a King Cobra from Karnataka drinking water from a water bottle…!!!

The media is fired up about a video showing a 12-foot-long, parched King Cobra drinking water from a water bottle. The video first uploaded by a YouTube channel called ‘Uttara Kannada News’  shows a man in khaki giving water to the snake.

Mashable India, was one of the first to put the video out and said that severe drought prevailing across Karnataka had resulted in the cobra straying into a village and desperately looking for water.

Huffington Post, in its article, Thirsty King Cobra sips water from a bottle amid debilitating drought, draws much sympathy for the poor lost snake, being offered drinking water by a sympathetic man.

One of the men seen in the video giving water to the snake is CN Naykka, the Deputy Range Forest Officer of Karwar forest range. He had rescued the cobra along with snake expert Raghavendra

Though Naykka is surprised that the video has gone viral, he refuted claims of drought in the region and also said that such instances were common during summer months.

“The Kaiga Power Plant is located near the forest range. The snake had wandered into the Kaiga Township, located near the plant sometime in the morning. We spotted the King Cobra at around 12.30 pm and it was dehydrated due to the extreme heat. Hence, I offered it some water and took it to a rescue centre,” Naykka said.

The forest officer also said that this is the mating season and cobras wandering around the area was a common occurrence, which happens almost every year.

“Whenever a snake wanders into civilian-populated areas, we first offer it water. There is nothing sensational about it. The Kali River, which runs through the Karwar Forest Range is flush with water and so are the backwaters located near the Kaiga Power Plant. During summer, many different birds and animals come for water including cobras,” Naykka added.