Category Social Sciences

What type of lake is Crawford Lake?

Sediment deposited at Crawford Lake in Ontario, Canada, provides solid evidence that Earth entered a new human-driven geological chapter-the Anthropocene epoch- some seven decades ago, a team of scientists said recently. The members of the Anthropocene Working Group plan to submit the evidence to the international scientific body responsible for naming geological chapters in Earth’s history. The scientists conducted research at a dozen sites worldwide and cited Crawford Lake as the location that provided particularly persuasive geological markers that the Anthropocene epoch- essentially the age of humans – had arrived in the 1950s.

ANTHROPOCENE – – ETYMOLOGY

The word Anthropocene is derived from the Greek words “anthropo” for “man” and “cene” for “new”.

The idea of the Anthropocene was proposed at a science conference more than 20 years ago by the late Nobel Prize-winning chemist Paul Crutzen.

Teams of scientists have debated the issue since then and finally set up the working group to study whether it was needed and, if so, when the epoch would start and where it would be commemorated.

THE LAKE IN CANADA AND THE FINDINGS

From climate change to species loss and pollution, humans have etched their impact on Earth with such strength and permanence since the middle of the 20th century that a special team of scientists says a new geologic epoch began then. Called the Anthropocene, this epoch started sometime between 1950 and 1954, according to the scientists.

While there is evidence worldwide that captures the impact of burning fossil fuels, detonating nuclear weapons and dumping fertilizers and plastics on land and in waterways, the scientists are proposing a small but deep lake outside of Toronto, Canada – Crawford Lake to place a historic marker. “It’s quite clear that the scale of change has intensified unbelievably and that has to be human impact,” said University of Leicester geologist Colin Waters, who chaired the Anthropocene Working Group.

The  scientists aims to determine a specific start date of the Anthropocene by measuring plutonium levels at the bottom of Crawford Lake. The lake which is 79 ft deep and 258,333 sq ft in area was chosen over 11 other sites because the annual effects of human activity on the earth’s soil, atmosphere and biology are so clearly preserved in its layers of sediment. That includes everything from nuclear fallout to species-threatening pollution to steadily rising temperatures. There are distinct and multiple signals starting around 1950 in Crawford Lake – showing that “the effects of humans overwhelm the Earth system,” said Francine McCarthy, a committee member who specialises in that site as an Earth sciences professor at Brock University in Canada.

‘The remarkably preserved annual record of deposition in Crawford Lake is truly amazing,” said U.S. National Academies of Sciences President Marcia McNutt, who wasn’t part of the – committee. “If you know your Greek tragedies you know power, hubris, and tragedy go hand in hand,” said Harvard science historian Naomi Oreskes, a working group member. “If we don’t address the harmful aspects of human activities, most obviously disruptive climate change, we are headed for tragedy.”

DID YOU KNOW?

Geologists measure time in eons, eras, periods, epochs and ages.

The scientific working group is proposing that Anthropocene epoch followed the Holocene Epoch, which started about 11,700 years ago at the end of the Ice Age.

They are also proposing that it starts a new age, called Crawfordian after the lake chosen as its starting point.

* The reason geologists didn’t declare the Anthropocene the start of a bigger and more important time measurement, such as a period, is because the current Quaternary Period, which began nearly 2.6 million years ago, is based on permanent ice on Earth’s poles, which still exist. But in a few hundred years, if climate change continues and those disappear, it may be time to change that. AGENCIES

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What makes country Georgia special?

Georgia is a country located at the crossroads of Eastern Europe and Western Asia. It is part of the Caucasus region, bound by the Black Sea, with Russia. Armenia, and Azerbaijan as its neighbouring countries. Even though it is quite small, the country has a lot to offer. It boasts of ancient cities, vibrant culture, and breathtaking landscapes. It is also referred to as ‘Sakartvelo’, as Georgians call themselves Kartavelians- meaning “land where Kartavelis Live”.

The Georgian kingdom has been under the hegemony of various regional powers, including the Mongols, the Ottoman Empire, and various dynasties of Persia. It was later invaded and annexed by the Soviet Union until the country got its independence in the early 1990s. Tbilisi is the current capital and largest city. It gets its name from an old Georgian word “tbili” which means “warm”. This old town features narrow streets and a variety of architectural styles, reflecting the influences of the various empires. making it feel like a journey through time. Most of the architecture consists of churches. monasteries with fine metalwork representing the Byzantine style

Georgian is the official language spoken, which is one of the oldest languages in the world. Strongly influenced by the Greek and Persian, Georgian evolved around 5th century. The interesting fact about the language is that it does not use gender or capital letters. It has 33 alphabets, with many dialects. Other Caucasian languages are also spoken in minority.

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How do crystals form?

Rocks are mixtures of different minerals. All minerals are crystals, but not all crystals are minerals. These solid substances are found naturally in the ground. But do we know how they are formed?

How do crystals form?

Scientifically speaking, the term “crystal” refers to any solid that has an ordered chemical structure. This means that its parts are arranged in a precisely ordered pattern, like bricks in a wall. The “bricks” can be cubes or more complex shapes. I’m an Earth scientist and a teacher, so I spend a lot of time thinking about minerals. These are solid substances that are found naturally in the ground and can’t be broken down further into different materials other than their constituent atoms. Rocks are mixtures of different minerals. All minerals are crystals, but not all crystals are minerals.

Most rock shops sell mineral crystals that occur in nature. One is pyrite, which is known as fool’s gold because it looks like real gold. Some shops also feature showy, human-made crystals such as bismuth, a natural element that forms crystals when it is melted and cooled.

Why and how crystals form

Crystals grow when molecules that are alike get close to each other and stick together, forming chemical bonds that act like Velcro between atoms. Mineral crystals cannot just start forming spontaneously – they need special conditions and a nucleation site to grow on. A nucleation site can be a rough edge of rock or a speck of dust that a molecule bumps into and sticks to, starting the crystallization chain reaction. At or near the Earth’s surface, many molecules are dissolved in water that flows through or over the ground. If there are enough molecules in the water that are alike, they will separate from the water as solids – a process called precipitation. If they have a nucleation site, they will stick to it and start to form crystals. Rock salt, which is actually a mineral called halite, grows this way. So does another mineral called travertine, which sometimes forms flat ledges in caves and around hot springs, where water causes chemical reactions between the rock and the air. You can make “salt stalactites” at home by growing salt crystals on a string. In this experiment, the string is the nucleation site. When you dissolve Epsom salts in water and lower a string into it, then leave it for several days, the water will slowly evaporate and leave the Epsom salts behind. As that happens, salt crystals precipitate out of the water and grow crystals on the string. Many places in the Earth’s crust are hot enough for rocks to melt into magma. As that magma cools down, mineral crystals grow from it, just like water freezing into ice cubes. These mineral crystals form at much higher temperatures than salt or travertine precipitating out of water.

What crystals can tell scientists

Earth scientists can learn a lot from different types of crystals. For example, the presence of certain mineral crystals in rocks can reveal the rocks’ age. This dating method is called geochronology – literally, measuring the age of materials from the Earth. One of the most valued mineral crystals for geochronologists is zircon, which is so durable that it quite literally stands the test of time. The oldest zircon ever found come from Australia and are about 4.3 billion years old – almost as old asour planet itself. Scientists use the chemical changes recorded within zircon as they grew as a reliable “clock” to figure out how old the rocks containing them are some crystals, including zircon, have growth rings, like the rings of a tree, that form when layers of molecules accumulate as the mineral grows. These rings can tell scientists all kinds of things about the environment in which they grew. For example, changesin pressure, temperature and magma composition can all result in growth rings. Sometimes mineral crystals grow as high pressure and temperatures within the Earth’s crust change rocks from one type to another in a process called metamorphism. This process causes the elements and chemical bonds in the rock to rearrange themselves into new crystal structures. Lots of spectacular crystals grow in this way, including garnet, kyanite and staurolite.

Amazing forms

When a mineral precipitates from water or crystallizes from magma, the more space it has to grow, the bigger it can become. There is a cave in Mexico full of giant gypsum crystals, some of which are 40 feet (12 meters) long – the size of telephone poles. Especially showy mineral crystals are also valuable as gemstones for jewellery once they are cut into new shapes and polished. The highest price ever paid for a gemstone was $71.2 million for the CTF Pink Star diamond, which went up for auction in 2017 and sold in less than five minutes. (The author works at University of Montana.) THE CONVERSATION

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Have you heard about multilateralism?

During the recently held Group of Twenty (G20) Foreign Minister’s meeting. Prime Minister Narendra Modi said multilateralism is in crisis today as global governance has failed in preventing wars and upholding international cooperation. Let us learn more about multilateralism.

What is multilateralism?

 Multilateralism is the process of organising relations between groups of several states. It is usually associated with the period after the Second World War as numerous multilateral agreements were signed, though led primarily by the U.S. Indivisibility is the core principle of multilateralism. For instance, if a war is declared against a state, then all the states in a multilateral set up are considered to be at war against the opponent.

Multilateralism helps in developing a bond among nations, discourages unilateralism, enables small powers to voice their opinions, and empowers them to exercise their rights.

Organisations embodying the principle of multilateralism include World Health Organisation (WHO), World Trade Organisation (WTO) and North Atlantic Treaty Organisation (NATO). They provide the global framework for peace and stability.

Multilateralism vs. unilateralism vs. bilateralism

The basic difference between unilateralism, bilateralism, and multilateralism is that unilateralism supports one-sided action.

Bilateralism means coordination between two countries, and multilateralism is coordination among more than three countries.

Multilateralism requires states to follow international norms in contrast to unilateralism, where a single state can influence how international relations can be conducted.

Multilateralism vs. multipolarity

Multilateralism is an institutional form that coordinates relations among three or more states on the basis of generalised principles of conduct.

Multipolarity is the system where more than two competing nations have almost equal power and influence on the global economy, society, culture, and military. The concept came about after the Second World War as it became clear that the U.S. would no longer be the single great power globally (during the Cold War it was a bipolar world led by the U.S. and the U.S.S.R).

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The making of the Sydney Harbour Bridge

The Sydney Harbour Bridge was officially opened on March 19, 1932. An iconic structure in Sydney and one of the best recognized, photographed, and loved landmarks of the world, it is the world’s heaviest steel arch bridge.

There are some human-made structures that are readily identified and immediately associated with the place in which they are located. Taj Mahal is one such structure that people world over connect with India. Similarly, there are two landmarks in Sydney- the Sydney Opera House and the Sydney Harbour Bridge- that have turned out to be prominent structures that people globally link with Australia.

Spanning the Sydney Harbour and connecting Sydney with its northern suburbs, the Sydney Harbour Bridge is about 1,150 m in length, with the top of the bridge standing 134 m above the harbour. Apart from having two rail lines and eight lanes for vehicular traffic, the bridge also has a cycleway for bicycles and a walkway for pedestrians.

An old idea

The site of the Sydney Harbour Bridge (both sides of the harbour) was home to Eora people (Aboriginal Australians) before the arrival of the Europeans in 1788. While the bridge came about only in 1932, the desire to span the harbour and the idea for its construction dates back over 100 years.

As early as 1815, Francis Greenway, an architect convicted of forgery in 1812, suggested the construction of a bridge across the harbour. In the decades that followed, the idea took many forms – a large cast iron bridge, a floating bridge, and even a tunnel. Some proposals were serious, some were even accepted, but nothing really materialised as the costs involved were prohibitive.

Father of the Sydney Harbour Bridge

This remained the case till the turn of the century as estimated costs meant that even satisfactory designs couldn’t be pursued. It was in 1900 that civil engineer John Job Crew Bradfield first became involved with the idea. Over the next three-plus decades, Bradfield became the project’s most vocal advocate and is even remembered as the father of the Sydney Harbour Bridge.

For Bradfield, the bridge was part of his vision for the suburban railway network’s electrification. He used his influence to both promote and oversee the construction of the Sydney Harbour Bridge.

 In 1912, Bradfield was appointed as the chief engineer of the Sydney Harbour Bridge and City Transit. Just when it looked like things were about to get moving, World War I put a halt to all plans.

International competition

 It was in 1922 that the Sydney Harbour Bridge Act was passed by parliament. Calling for worldwide tenders for the ‘Construction of a Cantilever or an Arch Bridge across Sydney Harbour’, Bradfield turned it into an international competition. After going through the 20 proposals from six companies, Bradfield and his team selected a two-hinged steel arch with abutment (substructure supporting superstructure) towers by English firm Dorman, Long & Co.

The turning of the first sod ceremony, which is a traditional ceremony in many cultures that celebrates the first day of construction, took place in July 1923. The four abutments served as the load-bearing foundation and from these the arch was built simultaneously from both ends. The construction of the arch began on October 26, 1928 and the two arches touched for the first time on August 19, 1930.

As the bridge became self-supporting once the span was complete, the bridge deck could be built and it was completed in June 1931. Load testing began in January 1932 and it was declared safe in the following weeks. While the official opening of the bridge took place on March 19, 1932, over 50,000 school children had already crossed the bridge by then in a series of “school days”.

Jobs during the Great Depression

Over 1,600 people worked in the construction of the bridge through its near decade-long construction. With the economy slowing down and encountering a worldwide depression during the period, the bridge provided much-needed jobs across various work categories. It wasn’t without danger, however, as at least 16 people died during the construction of the bridge.

In all, over 52,800 tonnes of steel was used, out of which 39,000 tonnes were employed in the arch alone. The cost of building the bridge alone was £4,238,839 and the total cost including other expenses was closer to £10 million – a debt that was paid off only in 1988. But then, the bridge handled over 200 trains, 1,60,000 vehicles, and 1.900 bicycles on average every single day in 2017. No wonder the Sydney Harbour Bridge is considered an engineering marvel.

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Kenya: Where history, nature, and culture meet

Often known as the cradle of humanity, Kenya has fossilised remains of hominids, is home to over 40 ethnic groups, and has the highest concentration of wild animals in the world.

Ranu Joardar

 Kenya, one of the countries in East Africa, has often been described as “the cradle of humanity”. It is an important business, financial, and transportation hub as about 80% of East Africa’s trade flows through its Mombasa Port.

History

Kenya’s history dates back to millions of years as some of the earliest fassilised remains of hominids have been discovered here. For instance, findings by anthropologist Richard Leakey in the Koobi Fora area along the shore of Lake Rudolf have included portions of ‘Australopithecus boisei’ and ‘Homo habilis’ (extinct species of human) skeletons.

 An important part of Kenyan history is slavery. During the 1600s and 1700s, most Kenyans were taken as slaves by the Arabs, Europeans, and Americans.

For several centuries, people from across regions have also settled in or travelled to Kenya. The Maasai tribe came to what is now known as central Kenya from north of Lake Rudolf (now called Lake Turkana in the Kenyan Rift Valley) in around mid 18th Century.

Geography

Kenya is surrounded by South Sudan, Ethiopia, Somalia, Indian Ocean, Tanzania, Lake Victoria, and Uganda.

The 38th meridian, the longitude that extends from the North Pole to the South Pole, divides Kenya into two halves. Kenya’s terrain rises from the low coastal plain on the Indian Ocean towards the mountains and plateaus.

The country’s capital, Nairobi, is at an altitude of 5,500 feet. From the west of Nairobi, the terrain descends to the Great Rift Valley, which has jade-green waters of famous Lake Turkana.

Kenya was the first African country to tap geothermal energy (heat energy from the Earth). The Hell’s Gate National Park’s geysers and hot springs are used to harvest geothermal energy and fuel almost half of Kenya’s electricity.

Flora and fauna

Kenya’s highlands consist of patches of evergreen forest separated by wide expanses of short grass. The forests have economically valuable trees such as cedar and varieties of podo.

Kenya’s ecosystem includes deserts, swamps, and even glaciers on Mount Kenya, Africa’s second highest peak. Each region has different plants and animals suited to the area’s particular conditions. The semi-desert regions below 3,000 feet have baobab trees.

The Masai Mara, situated in south-west Kenya, is one of Africa’s greatest wildlife reserves. It is named after the Maasai tribe, the ancestral inhabitants of the area. It has the highest concentration of wild animals in the world and over 40% of Africa’s larger mammals can be found here. During the migration, over 1.5 million wildebeest migrate from southern Serengeti (in Tanzania) to the Masai Mara. They travel 800 km clockwise in a circle through the Serengeti and Masai Mara ecosystems to search for greener mineral-rich pastures and water. The annual migration at the end of the rainy season (usually in May or June) is recognised as one of the “Seven Wonders of the Natural World”.

The country’s wildlife population is mostly found outside the country’s numerous national parks and game reserves. For instance, baboons and zebras are found along the Nairobi-Nakuru highway, near human settlements and urban centres.

The rainforests in highlands have various large mammals such as elephants and rhinoceroses. Besides, bushbuck, colobus monkeys, and galagos are also found in the region. The highlands have predators such as lions, leopards, and wildcats.

People

The land is home over 40 ethnic groups such as Kikuyu, Luhya, Kalenjin, Maasai, Luo, and Kamba. The country is divided into three language groups- Bantu, Nilo-Saharan, and Afro-Asiatic.

In the 19th Century, several Indians and Pakistanis came to the region, thus influencing the country’s language – Swahili. Swahili evolved along the coast from elements of local Bantu languages-Arabic, Persian, Portuguese, Hindi, and English. It is the lingua franca, a language used as a means of communication, between populations speaking vernaculars that are not mutually intelligible. It is also the language of local trade and is used along with English as an official language in the Kenyan legislative body, the National Assembly, and the courts.

Most Kenyans live in the highlands. Most of the population is rural and live in scattered settlements. Before European colonisation, the urban areas constituted only the fishing regions, Arab trading ports, and towns that were visited by dhows (sailing boats) from the Arabian Peninsula and Asia. People began migrating from the rural to the urban areas after the country’s independence in 1963.

Music and storytelling are important parts of the Kenyan culture. For centuries, the tribes used songs, stories, and poems to pass on their beliefs, history, and customs. Though school is free of cost, most children have to help their families by working the land, tending cattle, cooking, or fetching water.

Government

The country was a colony of the United Kingdom from 1920 till its independence on December 12, 1963 (known as the Jamhuri Day). The first President Jomo Kenyatta was an icon of the liberation struggle, who led Kenya from 1963 until his death in 1978, when Vice-President Daniel arap Moi took power in a constitutional succession.

According to the first constitution after independence, the Prime Minister was appointed as the head of a cabinet chosen by a bicameral National Assembly. Over the years, several constitutional reforms were made, and in 2010 a new constitution was promulgated. The country is now a republic, with a President, a national assembly, called the Bunge, and a legal system.

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