My Science School

• Denmark was the first country in the world to enact an environment law. Its capital, Copenhagen boasts of a unique collaboration of its residents, institutions and government in making it one of the world’s most environmentally friendly cities in the world. It aims at becoming carbon neutral by 2025 by increasing the use of renewable energy sources.


• About 40 per cent of its population uses bicycles to commute over its 350 km long network of bicycle paths. To further facilitate fast, safe and pleasant bike rides, the municipality is building ‘greeways’ (interconnected bicycle routes) which cover more than 100 km from one end of the city to the other.


• The large offshore wind turbine farm generates 4 per cent of the city’s electricity. The city is harnessing solar and sound energy as well.


• Organic food is very popular – one in every ten purchases is organic, accounting for 45% of all food consumption in the city.


• Copenhagen is one of the few places in Europe where the inner harbor allows people to swim in its waters which are effectively cleaned by sewage treatment plants.

In June 2010, the municipality enforced a mandatory green roof policy which requires vegetation and soil to cover the roofs of all new buildings.

 

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          Lunar craters were first noted by Galileo. He thought these craters to be volcanic in nature. For most of that time, various varieties of the volcanic theories were used to understand lunar craters. This was before the discovery of asteroids.

          After the discovery of asteroids, it came to be thought that cosmic collisions could have formed lunar craters. Richard Proctor was one of the first astronomers to talk about impact craters in his book that came out in 1873.

          In 1893, the American geologist G. K. Gilbert seconded Proctor’s findings after a couple of experiments; he considered the impact of cosmic collisions as the most likely reason for the formation of craters. These findings led to the development of lunar stratigraphy in the 1950s.

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          For the last 20 years of the 18th century, the German astronomer Johann Hieronymus Schroter studied the surface of the Moon. He produced two volumes of Selenotopographische Fragmente. The books contained individual studies of five distinct lunar regions and features.

          These drawings contained details like ridges, numerous rills and domes, and tall mountains. Schroter found out that large craters were proportionately more shallow and flat-floored than smaller bowl-shaped ones.

          However, the first modern investigation of the lunar surface appeared with the publication of a detailed map and book by Wilhelm Beer and Johann Madler.

          The work was titled Der Mond and was released between 1834 and 1837. They succeeded in showing that the Moon was very different from the Earth. They also proposed that the Moon had no atmosphere, and hence no water. Their findings contradicted some of Galileo’s postulations.

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          The nature of the studies about the Moon and other celestial bodies began to change in the 1600s. Galileo Galilei designed a telescope to closely observe the Moon.

          Galileo Galilei was one of the first astronomers to make telescopic drawings of the Moon; his drawings are compiled in his book titled Sidereus Nuncius. He discovered that the Moon’s surface was not as smooth as it appeared to be.

          The 17th century was a period of telescopic mappings. Later, Giovanni Battista Riccioli and Francesco Maria Grimaldi worked out the system of naming the lunar features. Their lunar terminology is in use even today. This was followed by the trigonometrically accurate studies about lunar features, like the heights of several mountains.

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          The excited shriek ‘Eureka’ is the first thing that comes to our mind when we think of Archimedes. Archimedes was one man with many thoughts and curiosities. He made significant contributions in the study of astronomy as well.

          Archimedes designed a mechanical planetarium. Much of what we know about this mechanical planetarium comes from Cicero’s writings. This device could calculate the motions of the Moon and other objects in the Solar System, including eclipses. It demonstrated the daily movements of the Moon and five other planets. Archimedes designed this mechanical universe in a glass globe.

          The glass sphere representing the universe contained the motions of the stars around the Earth, the eclipses of the Sun and Moon, and their movements along the elliptic path.

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          Aristotle brought out a philosophical description of the universe. In it, the Moon was described as a border element, a boundary between the Earth and other imperishable stars. This philosophical view dominated the thoughts about the Moon for centuries.

          Some important studies about the Moon and its movement came out in the second century BC. Seleucus of Seleucia studied and theorized tides and tidal movements. He found out that tides were formed due to the attraction of the Moon, and that their height depended on the Moon’s position relative to the Sun.

          Aristarchus is credited with another important finding. He computed the size and distance of the Moon from the Earth. According to his findings, the distance from the Earth to the Moon is almost twenty times the radius of the Earth. Ptolemy studied and improved these values further.

For centuries, the colour purple has represented royalty, power and wealth. The Persian emperor Cyrus, wore a purple tunic as his royal uniform. In fact, some Roman emperors even forbade commoners from wearing purple clothes, failing which they would be condemned to death.

The colour enjoyed an elite status for long because the dye that was used to make this colour was very rare. It came from the trading city of Tyre in Phoenicia (now in modern-day Lebanon). More precisely, it was derived from a species of sea snail called Bolinus brandaris, found only in the Tyre region of the Mediterranean Sea. To obtain it, dye-makers had to crack open the snail’s shell. The mucus inside was milky but would turn an intense purple when exposed to air. More than 9000 molluscs were needed to produce just one gram of Tyrian purple. The result was that clothes made from the dye were extremely expensive – a shawl made from Tyrian purple. Silk cost its weight in gold. Hence, only imperial could afford to buy purple-coloured fabric. Purple was also linked to spirituality because monarchs were usually thought to be of divine origin.

Synthetic dyes of purple became widely available only after English chemist William Henry Perkin created a synthetic purple compound by chance, while trying to synthesize the anti-malaria drug quinine in 1856.

 

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A legally blind person is someone who would have to stand 6 metres from a particular object to see it with the same degree of clarity that a person with normal normal vision can from a distance of 60 metres. The visual field of a legally blind person is also limited to 20 degrees or less. A person with normal site has a field of vision measuring 180 degrees.

Normal visual acuity is termed as 20/20 (or 6/6). If the second number is smaller (say 20/18 or 6/5.4) it means the person has better than normal vision. Conversely, if the second number is larger (say 20/22 or 6/6.6), it means the person has worse than normal vision.

Governments all over the world have had to define legal blindness in order to decide eligibility for special benefits. For instance, legally blind person in the US can receive disability payment, take help of note takers and writers in college and avail of Seeing Eye dogs and white canes.

Marla Runyan, an American marathon runner, was the first legally blind athlete to participate in the Olympics–at Sydney in 2000.

 

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Hurricanes and tropical cyclones in the Atlantic Ocean have been named since 1953 when Miami’s National Hurricane Centre started the practice. This was then maintained and updated by the World Meteorological Organisation (WMO), a Geneva-based agency of the United Nations. The name is suggested by member nations by turn.

The countries of South Asia in West Asia chose not to name their cyclones until 2004 when the World Meteorological Organisation brought about agreement between eight countries in the region, namely, India, Pakistan, Bangladesh, Maldives, Myanmar, Oman, Sri Lanka and Thailand. This group came up with a list of 64 names, eight from each country, for cyclones - Hikka and upcoming ones.

As of September 2019, 58 of the 64 names have already been used! The cyclone that recently formed was called Hikka (Maldives), and this will be followed by Kyarr (Myanmar), Maha (Oman), Bulbul (Pakistan), Pawan (Siri Lanka), and Amphan (Thailand).

 

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Since the 1950s, when the space race began, a number of countries, most notably the US and the former Soviet union, as also India, have been sending manned and unmanned missions to the moon and other planets. When the missions end, the probes are inevitably crash-landed on the heavenly body they were investigating.

This means that not only has man filled his home planet with trash , he has also left tonnes of debris strewn on planets and their satellites across the solar system. The moon in particular has nearly 180,000 kilos of man-made material lying on it.

Litter on the lunar surface includes wreckage of spacecraft–more than 70 vehicles in all. Other objects include geological tools, shovels , rakes, plaques , flags, golf balls, dozens of pairs of boots, 96 packs of faeces, urine and vomit, empty food packets, TV cameras, magazines, backpacks, medals, pens, a silicon disc with messages from 73 world leaders, an Eagle feather and even a golden olive branch!

Astronauts from the Apollo missions alone left over 50 tonnes of litter.

Is there a law to prevent countries from littering space? The 1967 Outer space Treaty does require explorers to ‘avoid harmful contamination of the moon and other celestial objects’. But since it bans territorial claims in space, there is no central authority to enforce law against littering or anything else.

NASA keeps a list of all human-introduced garbage on the moon but it also tries to protect remains of the Apollo missions citing their ‘historical and scientific value’!

 

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          The temple astronomers of Babylon had observed the skies for centuries and had recorded their observations in astronomical diaries, and other catalogues. Their predictions are almost accurate to this day.

          In fact, the Assyrians and Babylonians regarded lunar eclipses as evil omens. They believed that eclipses were directed against their kings. This was one reason why they studied more about the Moon. They studied the length of the synodic month, the period between two full moons. Their observations were almost error free. Using these data on the synodic month, the Babylonian astronomers were able to predict lunar eclipses and solar eclipses later.

          They also recorded the 18-year Saros cycle of lunar eclipses. A Saros cycle is the period of 223 synodic months-18 years and 11.3 days- after which lunar and solar eclipses repeat themselves. The predictability of the lunar eclipse made it possible for the Babylonians to appoint substitute kings who would bear the burden of the wrath of the gods.

 

The report highlights the supposedly high standards of living in the Sangam era. It talks about the excavation having unearthed well-laid floors made of fine clay, along with roof tiles. The finger groove impressions on the roof may have been used to drain water, the report says.

Other excavations include a terracotta pipe that might have run through several quadrants over a stretch of many metres before ending in the soak jar. The pipe and the soak jar attest to the advanced sanitation system of the people who lived here.

Another brick structure, which look like a tank/trough, had an inlet and outlet. A covered drain was found below this. A small structure with a stone slab on top, perhaps meant for washing clothes, was also one of the artefacts excavated.

 

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This Indus valley civilization existed between 5000 BCE and 1500 BCE in the north-western part of India. When it declined, its people started moving towards East and South. The script that was used by the people of the civilization has been termed the Indus script. Exports have speculated that it could be that of a Dravidian language.

Now, the ‘graffiti marks’ on the artefacts obtained from the Keezhadi excavation site point to link between the scripts of the Indus Valley civilization and Tamil-Brahmi.

According to the report: One kind of script that survived in the time with the period between the disappearance of the Indus script and the emergence of the Brahmi script has been referred to as graffiti by the scholars. These marks, they believe, have evolved or transformed from the Indus script and served as a precursor to the Brahmi script. Therefore, these graffiti cannot be dismissed as mere scratches. Besides, like the Indus script, this also could not be deciphered till date.

Among the scripts are available with India, the Indus script is considered to be the earliest. After the decline of the script and before the emergence of the Brahmi script, there seem to be a gap. Researchers note that this graffiti could fill that gap.

 

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The Sangam period refers to a period in the history of ancient Tamil Nadu, Kerala, the southern parts of Karnataka and Andhra Pradesh, and northern Sri Lanka, spanning from sixth century BCE to first century CE. It is known for scholarly congregations in and around the city of Madurai. The period is considered the golden age of Tamil literature and culture as many of its epics were composed during this time.

The Tamil Sangam was an academy of poets and bards who flourished in three different periods and in different places under the patronage of the Pandyan kings. It is believed that the first Sangam was attended by gods and legendary sages, and its seat was Ten Madurai. All the works of the first Sangam have perished.

The seat of the second Sangam was Kapatpuram, another capital of the Pandyas. It was attended by several poets and produced a large mass of literature, but only Tolkappiyam (the early Tamil grammar) has survived.

The seat of the third Sangam was the present Madurai. It has also produced vast literature, but only a fraction of it has survived. It is this fraction which constitutes the extant body of Sangam literature. The Age of the Sangam is the age to which the Sangam literature belonged. The Sangam literature constitutes a mine of information on conditions of life around the beginning of the Christian era.

 

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Excavations at Keezhadi, an archaeological site in Sivaganga district near Madurai, Tamil Nadu have brought to light significant details about the Sangam era. The report on the fourth face of the archaeology survey, undertaken at the site in 2018, was released by the Tamil Nadu Archaeological Department (TNAD) last month. It describes the findings are turning point in the cultural historiography of the ancient Sangam era.

As many as four phases of excavations have been carried out in Keezhadi, while the fifth one, which began in June 2019, is underway. The first three faces were conducted by the Archaeological Survey of India (ASI) and the fourth and the fifth phases are under the ambit of the TNAD.

In 2013-2014, the ASI begin exploration in Tamil Nadu, along the banks of the river Vaigai. More than 290 sites were identified in Theni, Dindigul, Madurai, Sivaganga and Ramanathapuram districts for excavation, Keezhadi, a village 12 km south-east of Madurai in Sivaganga district, was one of them.

In Keezhadi, the first phase of excavation begin in 2015. The site began yielding rich artefacts such as potsherds with Tamil-Brahmi inscriptions, deep terracotta ring wells, big storage pots, pots with spouse, decorated pots, white-painted black ware, black and red pottery and beads made of semiprecious stones. Further excavations at the Pallichanthai Thidal in Keezhadi pointed to an ancient civilisation that thrived on the banks of the Vaigai.

Major findings mentioned in the latest report

The Sangam area could be 300 years older than thought. Culture deposits on earth date back to a period between sixth century BCE and 1st century CE. This is the first time the date has been officially announced by the TNAD.

The Keezhadi site provides overwhelming evidence of the presence of an urban settlement. The artefacts suggest that urbanisation took place on the Vaigai plains in Tamil Nadu around 6th century BCE, making it contemporary to the Gangetic plain civilization. The discovery of brick structures with classical features such as platforms, ring wells, rectangular tanks, square tanks with extended structures, and channels vouches for the presence of an urban culture there.

Sangam people may have participated in recreational activities as many as 110 dice made of ivory have been unearthed.

The Keezhadi findings push back the date of the Tamil-Brahmi script to another century, i.e., 6th century BCE.

Fifty-six Tamil-Brahmin inscribed potsherds have been recovered from the site of excavation undertaken by the TNAD alone. These suggest that the residents of the Sangam era attained literacy or learned the art of writing as early as 6th century BCE.

There are also other markings alongside the Tamil-Brahmi symbols which apparently suggest a connection with the Indus Valley civilization. Artefacts with ‘graffiti’ or ‘markings’ establish a possible link between the scripts of Indus Valley Civilization and Tamil Brahmi, which is the precursor to modern Tamil.

Skeletal fragments of  animals were used to predominantly for agricultural purposes.

Pottery specimens confirm that water containers and cooking vessels were shaped out of locally available materials.

 

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