UPSC Courses

DNA banner


Monthly DNA

25 Jun, 2020

56 Min Read

Sudan warns against escalation in Nile dam dispute

GS-II : International Relations African dispute

Sudan warns against escalation in Nile dam dispute

GS-Paper-2 International issue AFRICA

Sudan has warned against escalation and urged further negotiations with Egypt and Ethiopia over the construction of a controversial dam on the Blue Nile river by Addis Ababa.

Important points

  • Tensions are running high between the three countries after recent talks failed to produce a deal on the filling and operation of the $4.6bn Grand Ethiopian Renaissance Dam.
  • Ethiopia has declared plans to start filling the dam next month, regardless of whether a deal has been reached.
  • The dam is more than 70 per cent complete and promises to generate much-needed electricity for the country.
  • Egypt, which views the massive hydroelectric barrage as an existential threat, urged the United Nations Security Council to intervene in the dispute, citing Ethiopia's "non-positive stances".
  • Cairo fears the dam could severely reduce its water supply from the Nile, which provides nearly 97 per cent of Egypt's freshwater needs.
  • Addis Ababa says the dam is indispensable for its development and insists Egypt's water share will not be affected.
  • The Nile is a lifeline supplying water and electricity to the 10 countries it traverses.
  • Egypt says the dam threatens the Nile's flow, most of which originates in the Blue Nile, with damaging implications for its food supply and economy.

Egypt and Ethiopia have once again locked horns over the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile.

On Feb. 26, Ethiopia temporarily suspended its participation in the U.S.-mediated negotiations over the filling and operation of the GERD, requesting more time to deliberate on the draft agreement.

With the dam 70 per cent complete and its reservoir expected to start being filled in July, the time for reaching an agreement is ticking away.

While the parties have sought international mediation from the U.S. and South Africa, that is no substitute for regional cooperation among the parties.

About Nile River:

  • The longest river in the world, the Nile stretches across 11 countries in its journey of 4,000 miles from the equatorial rivers that feed Lake Victoria to its final destination in the Mediterranean Sea.
  • Among the countries that share the Nile, two have the most at stake. Egypt, a desert nation of 100 million people, is literally the creation of the Nile, relying on the river for 90 per cent of its freshwater needs.
  • Ethiopia, an East African country of 112 million, contributes the lion’s share of the Nile waters, with its three tributaries—the Blue Nile, Sobat, and Atbara—carrying about 84 percent of the total runoff in the Nile.
  • With a growing but otherwise resource-poor economy, Ethiopia is keen to develop its vast potential for hydroelectricity generation
  • Disagreements over the Nile River have been the source of conflict between upper and downstream countries because life in both sides of the Nile highly depends on the waters of the Nile River.
  • Historically, there have been many treaties over the Nile River that were negotiated between different stakeholders in different places in 1902, 1906, 1925, 1929 and in 1959.
  • During the colonial era, Great Britain, France and Italy [especially Great Britain] either negotiated on behalf of their colonies, or controlled the Nile through their military presence in Africa.

About Grand Ethiopian Renaissance Dam (GERD):

  1. The GERD, a $5 billion project that will be the largest hydroelectric dam in Africa, is a part of that ambition.
  2. The dam is located on Ethiopia’s flank of the Blue Nile, just 12 miles from its border with Sudan. It will have paramount economic value to Ethiopia, doubling the country’s electricity generation capacity and earning as much as a billion dollars annually from energy exports to Sudan, South Sudan, Djibouti, Kenya, and potentially Egypt.
  3. The GERD’s massive reservoir will store 74 billion cubic meters (BCM) of water, roughly equal to a year-and-half’s worth of the Blue Nile’s flow, which will be gradually filled upon the dam’s completion.
  4. As the July deadline draws closer for the Grand Ethiopian Renaissance Dam (GERD) on the river Nile to become functional, the dispute between Ethiopia and Egypt, with Sudan caught in between, has escalated into a diplomatic stand-off.
  5. Differences were laid bare recently when Ethiopia skipped the latest round of tripartite negotiations with Egypt and Sudan in Washington, being mediated by the U.S. and the World Bank.

Uganda President calls for urgent African summit on GERD:

Uganda's President said that African presidents must hold frank discussions regarding the Nile River dilemma during this summit, and stressed the importance of ensuring equitable and sustainable usage of the river’s waters.

Kenyan president emphasized the importance of properly utilizing natural resources and sustainably addressing the needs of increasing populations.

Meanwhile, the Egyptian community in New York and New Jersey is gearing up to organize demonstrations in front of the White House, pressuring the US administration to protect Egypt’s water rights and support the negotiations.

The challenges for the fair utilisation of waters among the riparian states have only been compounded by the pressures of population growth and the effects of global warming.

Challenges Ahead that need to address:

  • Impact on regional & International Trade: An escalated tension between Ethiopia & Egypt would threaten the vital international trade route through the Suez Canal and along the Horn of Africa.
  • Ethiopia has stated that the dispute over the dam project is only a trilateral issue involving Egypt and Sudan.
  • Ethiopia asserts its rights for an equitable share of the Blue Nile flows from the Cooperative Framework Agreement (CFA) signed by some of the 10 Nile Basin Initiative nations
  • The establishment of the Nile River Basin Commission mandated by the CFA has not materialised so far.
  • Ethiopia is concerned that a long delay in filling the reservoir would jeopardise returns on its investments and hamper the prospects for overall growth.
  • The mediation role played by the US highlights the significance of the issue and the potential conflict it holds if unresolved. However, the mediation has not been able to progress substantially due to a lack of true intentions from both sides.


Ethiopia and Egypt should be ready to make significant concessions to avoid a catastrophic escalation in this seemingly intractable dispute.

An agreement involving Egypt, Ethiopia and other river basin countries for equitable sharing of water.

Sustainable use of river water given the ever-increasing problem of pollution and climate change.

Consistent with the principles set out in the declaration of principles, in particular the principles of not causing significant harm to downstream countries, final testing and filling should not take place without an agreement.

These countries can take inspiration from Indus Water Treaty signed between India and Pakistan and brokered by World Bank in 1960. The treaty has been functioning smoothly and has endured three wars over nearly six decades.

Read more about NILE RIVER: https://www.treehugger.com/nile-river-facts-4868689

Source: IE

Coal sector reforms

GS-II : Governance Governance reforms

Coal sector reforms

GS-PAPER-2 Governance and Energy PT-MAINS-I.V

India, being a developing country, coal remains one of the most important indigenous energy resources and the dominant fuel for power generation and many industrial applications.

Presently, despite being the world's fourth-largest producer, India is the second-largest importer of the dry-fuel. Therefore, in line with the vision to build an ‘Atma Nirbhar Bharat’, a slew of reforms to promote commercial mining of coal in India, has been announced.

Unlocking coal mining for private players is a step forward to attain self-reliance in the coal sector. However, for sustainable utilization of coal, there is a need to look into these reforms from a multidimensional viewpoint.

Announced Reforms In Coal Sector

  • Commercial mining of coal allowed, with 50 blocks to be offered to the private sector.
  • Entry norms will be liberalised as it has done away with the regulation requiring power plants to use “washed” coal.
  • Coal blocks to be offered to private companies on revenue sharing basis in place of fixed cost.
  • Coal gasification/liquefaction to be incentivised through rebate in revenue share.
  • Coal bed methane (CBM) extraction rights to be auctioned from Coal India’s coal mines.

Intended Benefits

Plugging Supply Gap: The nationalisation of coal in 1973 meant that domestic coal could be mined only by public sector companies.

  • In this pursuit, Coal India Limited (CIL), registered an unprecedented increase in coal production and became the world's largest coal miner.
  • However, the country’s coal demand continued to grow at a much faster rate. Due to this, the growth in coal import (2009 to 2014) stood at 23 per cent.
  • Commercial mining of coal can increase the domestic production of coal and bridge the supply gap.

Boost Economy and Employment: Allowing commercial mining may help to address India’s coal production needs, provide investment opportunities and save precious foreign exchange.

  • This will play a major role in ensuring the energy security of the country, as nearly the majority of power generation in India comes from thermal power plants.
  • The domino effect on sectors that use coal, like steel, power and aluminium, is going to be significant.

Win-Win Situation: The government has introduced a more equitable system of sharing of revenues, moving away from fixed rates to a revenue-sharing model.

  • Revenue sharing model will ensure when the prices go up, the miner shares more with the government; and if the price decreases, miner shares less. This is a win-win situation for both parties.


Dominance of Coal India: While reforms are aimed at ending the monopoly of Coal India Ltd., that’s unlikely to happen in the near future.

  • The current commercial coal mining regime will find it difficult to compete with Coal India. As the major consumer of coal in India (thermal power plants and steel sector) are in long term purchase agreements with Coal India.
  • Also, it will be a challenge for many companies to be able to match Coal India’s ability to navigate the complicated bureaucratic and political hurdles associated with opening new coal mines.

Issue with Non-washing of Coal: Doing away with the regulation requiring power plants to use “washed” coal will have huge environmental and economic costs.

  • The “washing” requirement was introduced in 1997 and promised the use of cleaner coal in power production. It was India’s only legitimate justification to extend the use of coal as a development fuel despite the climate crisis.
  • Also, a manufacturing or power-producing unit has to burn more coal and in turn generate not only ash but also noxious gases, particulate matter and carbon emissions.


  • Coal washeries are units that reduce the ash content in coal through a mix of segregation, blending and washing techniques.
  • These technologies are meant to allow the conservation and optimal use of coal reserves by improving the quality and efficiency of low grade, high ash Indian coal.
  • Washed coal also provides high grade “coking” coal that is essential for the steel sector.
  • Indian coal is known to contain 30-50% ash, meaning that for every two units of coal burned, one unit of ash could be produced.

External Challenges: In the era of intense competition from renewables, the rising NPAs of thermal power plants (TPPs) and a massive global withdrawal from fossil fuel for climate and environmental reasons poses a challenge of viability for commercialising coal.


  • For easing commercialisation of coal, there is a need to establish a single-window clearance process for coal mines. Offering projects with secured clearances will boost timely development as well as increase industry participation
  • Government support for the early resolution in land acquisition-related issues is needed to ensure timely operationalisation of coal mines. Further, commercial mining projects can be aided with investment in initial infrastructure settings which is more capital intensive than mining.
  • Technology upgradation measures to be imposed to improve the productivity of the coal mines and improve recovery from the coal mines.
  • The government may consider creating funds to support overseas acquisition to supplement domestic resources.
  • Steps need to be taken to promote research and exploration activities and modern underground mass production technologies.

Source: TH

Anti Defection Law

GS-II : Indian Polity Parliament

Anti Defection Law


Recently, some of the sitting MLAs in the Manipur government defected to the opposition creating instability in the state's polity. This politics of defection in Manipur is not unique, there have been some other recent examples of defection in Karnataka, Madhya Pradesh, Arunachal Pradesh and Uttarakhand.

For a very long time, the Indian political system was impacted by political defections by members of the legislature. This situation brought about greater instability and chaos in the political system.

Thus, in 1985, to curb the evil of political defections, the 52nd constitution amendment act on anti-defection was passed and the 10th Schedule was added in the Indian Constitution.

However, the recent examples of defection in the Indian polity show that the law needs a relook in order to plug the loopholes and achieve a balance between the rights of legislators and interests of legislative stability.


Subversion of electoral mandates: Defection is the subversion of electoral mandates by legislators who get elected on the ticket of one party but then find it convenient to shift to another, due to the lure of ministerial berths or financial gains.

  • Affects the normal functioning of government: The infamous “Aaya Ram, Gaya Ram” slogan was coined against the background of continuous defections by the legislators in the 1960s. The defection leads to instability in the government and affects the administration.
  • Promote horse-trading: Defection also promotes horse-trading of legislators which clearly go against the mandate of a democratic setup.

91st Constitution Amendment Act-2003

  • It aimed at limiting the size of the Council of Ministers to debar defectors from holding public offices, and to strengthen the anti-defection law.
  • Earlier, a defection by one-third of the elected members of a political party was considered a ‘merger’. The amendment changed it to at least two-thirds.

Kihota Hollohon vs. Zachilhu (1992)

  • In the judgment, the Supreme Court clarified that the 10th schedule is constitutionally valid. It neither impinges upon the freedom of speech and expression nor subverts the democratic rights of elected members.
  • It also upheld the sweeping discretion available to the Speaker in deciding cases of disqualification of MLAs. However, it also held that Presiding Officer’s decisions of disqualification shall be open to judicial review.


Against the true spirit of representative democracy: The anti-defection law seeks to provide a stable government by ensuring the legislators do not switch sides. However, this law also enforces a restriction on legislators from voting in line with their conscience, judgement and interests of his electorate.

  • Impedes legislative control on government: The anti-defection law impedes the oversight function of the legislature over the government, by ensuring that members vote based on the decisions taken by the party leadership.

In short, if legislators are not able to vote on laws independently, they would not act as an effective check on the government.

The Anti-Defection Law, in effect, dilutes the separation of powers between the Executive and the Legislature – and centralises power in the hands of the executives.

  • Role of presiding officer of the house: The law lays down that legislators may be disqualified on grounds of defection by the Presiding Officer of a legislature based on a petition by any other member of the House.

However, there are many instances when presiding officers play a part with the vested interests of a political party/government in power.

Also, the law does not specify a time period for the Presiding Officer to decide on a disqualification plea.

The decision thus is sometimes based on the whims and fancies of the presiding officer.

  • Affects the debate and discussion: The Anti-Defection Law has created a democracy of parties and numbers in India, rather than a democracy of debate and discussion. In this way, it does not make a differentiation between dissent and defection and weaken the Parliamentary deliberations on any law.

What to do?

  • Rational use of the anti-defection law: Several experts have suggested that the law should be valid only for those votes that determine the stability of the government. e.g. passage of the annual budget or no-confidence motions.
  • Advice of Election Commission: Various commissions including National Commission to review the working of the constitution (NCRWC) have recommended that rather than the Presiding Officer, the decision to disqualify a member should be made by the President (in case of MPs) or the Governor (in case of MLAs) on the advice of the Election Commission.
  • Independent authority to deal with disqualification: Justice Verma in Hollohan judgment said that tenure of the Speaker is dependent on the continuous support of the majority in the House and therefore, he does not satisfy the requirement of such independent adjudicatory authority. Also, his choice as the sole arbiter in the matter violates an essential attribute of the basic feature. Thus, the need for an independent authority to deal with the cases of defection.
  • Promoting the principle of intra-party democracy: 170th Law Commission report underscored the importance of intra-party democracy by arguing that a political party cannot be a dictatorship internally and democratic in its functioning outside. Thus, the parties should listen to the opinions of the members and have discussions on the same. This would give the freedom of speech and expression to its members and promote inner-party democracy.


Though due to anti-defection law, political instability caused by the frequent and unholy change of allegiance on the part of the legislators of our country has been contained to a very great extent, yet there is a need for a more rationalised version of anti-defection laws which will help establish a truly representative democracy.

Source: TH

Assam: Ambubachi Mela - Kamakhya temple

GS-I : Art and Culture Festivals

Assam: Ambubachi Mela - Kamakhya temple

The annual Ambubachi Mela at the historic Kamakhya temple in Guwahati began. This year, however, the fair is being observed without devotees as only rituals will be performed in the temple till June 25. Kamakhya temple located atop of Nilachal Hills is one of 51 Shakti Peeths in the country.

The Ambubachi Mela, an annual fair held at Kamakhya temple, is the celebration of the annual menstruation course of goddess Maa Kamakhya. The meal usually started on June 22 every year at Kamakhya temple. This year, however, the temple management authorities decided not to include devotees, and sadhus in the fair in view of the novel coronavirus pandemic. All entrances to the historic temple have been closed.

Source: TH

Asian Development Outlook (ADO)

GS-II : Important reports Important reports

Asian Development Outlook (ADO)

Asian Development Outlook (ADO) is a report released by Asian Development Bank. The ADO analyses economic and development issues in developing countries in Asia. This includes forecasting the inflation and growth rates of countries throughout the region, including China and India.

Highlights of the recent report are as follows

  • According to report the Indian economy is expected to contract by 4% during the current financial year (2020-21).
  • Earlier, in April 2020, ADB had projected India’s economy to grow at 4% in 2020-21.
  • The report also highlighted India’s GDP slowed to 3.1% in the last quarter (Jan-March) of the financial year 2019-20, it is the slowest since early 2003.
  • Developing Asia refers to a group of over 40 countries, including India that are members of the ADB.
  • Growth of Developing Asia is expected around 0.1%, this is down from the 2.2% forecast in April 2020 and would be the slowest growth for the region since 1961.
  • However, China is expected to record positive growth of 1.8% in 2020-21.

Source: IE

Krishi Vigyan Kendras

GS-III : Economic Issues Agriculture

Krishi Vigyan Kendras

  • It is an integral part of the National Agricultural Research System (NARS).
  • It consists of scientists, technical staff, administrative support staff and auxiliary staff.
  • The first KVK was established in 1974 at Puducherry.
  • KVKs also produce quality technological products (seed, planting material, bio-agents, and livestock) and make it available to farmers.
  • The KVK scheme is 100% financed by the Government of India.

Source: Web

China’s Tariff Exemption to Bangladesh

GS-III : Economic Issues Free trade agreement

China’s Tariff Exemption to Bangladesh

Recently, China has announced tariff exemption for 97% of exports from Bangladesh. Bangladesh had requested China to exempt its export items from tariffs in the background of the economic hardship triggered by the Covid-19 pandemic.

China considered Bangladesh's request and has granted the tariff exemption to Bangladesh on account of its Least Developed Countries (LDCs) status. The move will help Bangladesh to remove the economic impact of the pandemic and also emerge as a possible beneficiary alongside Vietnam and Chile of the U.S.-China trade war.

The supply chain disruption caused by the U.S.-China trade war is likely to be filled by a boost in the export of tariff-exempted goods from Bangladesh. It will also help Bangladesh to reduce its trade deficit with China. As a result of the latest announcement, a total of 8256 goods from Bangladesh will be exempted from Chinese tariffs. Earlier, Bangladesh used to receive tariff exemption for 3095 items under the Asia Pacific Trade Agreement (APTA).

Asia Pacific Trade Agreement

  • Asia Pacific Trade Agreement (APTA), previously the Bangkok Agreement, is a preferential tariff arrangement that aims at promoting intra-regional trade through the exchange of mutually agreed concessions by member countries.
  • Its current Members are Bangladesh, China, India, the Republic of Korea, Lao PDR and Sri Lanka.

Least Developed Countries

  • LDCs are low-income countries designated by the United Nations, confronting severe structural impediments to sustainable development.
  • They are highly vulnerable to economic and environmental shocks and have low levels of human assets.

Source: TH


GS-III : Economic Issues Government policies and interventions


  • Union Ministry of Mines has launched a portal "SATYABHAMA (Science and Technology Yojana for Atmanirbhar Bharat in Mining Advancement)".
  • Its aim is to promote research and development in the mining and minerals sector.
  • It has been launched to increase the efficiency and effectiveness of the Science and Technology Programme Scheme.
  • Under the Science and Technology Programme Scheme, the Ministry of Mines promotes research in applied geosciences, mineral exploration, mining and allied areas, mineral processing, optimum utilization and conservation of the mineral resources of the country.
  • The portal has been designed, developed and implemented by the National Informatics Centre (NIC).
  • The portal is also integrated with NGO Darpan Portal of NITI Aayog.


  • NGO-DARPAN is a platform that provides space for the interface between Non-Government organizations (NGOs)/Voluntary Organizations (VOs) and key Government Ministries / Departments / Government Bodies.
  • It is an e-governance application offered by NITI Aayog to electronically maintain data and transparency regarding NGOs/VOs in the country.
  • The NGO-DARPAN was earlier maintained by erstwhile Planning Commission, which has been replaced by the NITI Aayog in 2015.

Source: PIB

Asian Infrastructure Investment Bank


Asian Infrastructure Investment Bank

The Asian Infrastructure Investment Bank (AIIB) is a multilateral development bank with a mission to improve social and economic outcomes in Asia. Its HQ is in Beijing, China.

It is established by a multilateral treaty - AIIB Articles of Agreement. India joined AIIB in 2016 as a regional member of the Bank. Further, 14 of the G-20 nations are AIIB members including France, Germany, Italy and the United Kingdom.

China is the largest shareholder in AIIB with a 26.06% voting power, followed by India with a 7.62% voting power. Recently, the AIIB approved a $750 million loan to India to strengthen the country’s battle against the adverse impact of the Covid-19 pandemic on poor and vulnerable households. The loan is co-financed by the AIIB and the Asian Development Bank.

It aims to ensure economic resilience to prevent long-term damage to productive capacity, including human capital.

Source: TH

Star Formation Nebula White dwarf and Neutron Star or Black Hole

GS-III : S&T Space

Star Formation Nebula White dwarf and Neutron Star or Black Hole

GS- Paper-1 Geography / Geography Optional (PT-Mains-I.V)

Outlined below are the many steps involved in a star’s evolution, from its formation in a nebula, to its death as a white dwarf or a neutron star.

  1. Nebula: a star’s birthplace.
  2. Protostar: an early stage of a star formation where nuclear fusion is yet to begin.
  3. T Tauri Star
  4. Main Sequence Star: E.g. Sun – full of life (nuclear fusion at the core at full swing).
  5. Red Giant (in case of a small star) and Red Supergiant (in case of a large star).
  6. Planetary Nebula (in case of small star) and Supernova (in case of large star).
  7. White dwarf (in case of a small star) and Neutron Star or Black Hole (in case of a large star).


  • A nebula is a cloud of gas (mostly hydrogen and helium) and dust in space.
  • Nebulae are the birthplaces of stars.


  • A Protostar looks like a star, but its core is not yet hot enough for nuclear fusion to take place (nuclear fusion: the fusion of 2 hydrogen atoms into a helium atom with the liberation of a huge amount of energy. Nuclear fusion occurs only when the initial temperatures are very high – a few million degree Celsius. That is why it is hard to achieve and control).
  • The luminosity comes exclusively from the heating of the Protostar as it contracts (because of gravity).
  • Protostars are usually surrounded by dust, which blocks the light that they emit, so they are difficult to observe in the visible spectrum.

T- Tauri star

  • A very young, lightweight star, less than 10 million years old, that it still undergoing gravitational contraction; it represents an intermediate stage between a Protostar and a low-mass main sequence star like the Sun.

Main sequence stars

  • Main sequence stars are stars that are fusing hydrogen atoms to form helium atoms in their cores.
  • Most of the stars in the universe — about 90 per cent of them — are main sequence stars.
  • The sun is a main sequence star.
  • Towards the end of its life, a star like the Sun swells up into a red giant, before losing its outer layers as a planetary nebula and finally shrinking to become a white dwarf.

Red dwarf

  • The faintest (less than 1/1000th the brightness of the Sun) main sequence stars are called the red dwarfs.
  • Because of their low luminosity, they are not visible to the naked eye.
  • They are quite small compared to the sun and have a surface temperature of about 4000 ?C.
  • According to some estimates, red dwarfs make up three-quarters of the stars in the Milky Way.
  • Proxima Centauri, the nearest star to the Sun, is a red dwarf.

Red giant

  • Red giants have diameters between 10 and 100 times that of the Sun.
  • They are very bright, although their surface temperature is lower than that of the Sun.
  • A red giant is formed during the later stages of the evolution as it runs out of hydrogen fuel at its centre.
  • It still fuses hydrogen into helium in a shell surrounding a hot, dense degenerate helium core.
  • As the layer surrounding the core contains a bigger volume the fusion of hydrogen to helium around the core releases far more energy and pushes much harder against gravity and expands the volume of the star.
  • Red giants are hot enough to turn the helium at their core into heavy elements like carbon, this is how elements were formed one after the other.
  • But most stars are not massive enough to create the pressures and heat necessary to burn heavy elements, so fusion and heat production stops.

Degenerate matter

  • Fusion in a star’s core produces heat and outward pressure, but this pressure is kept in balance by the inward push of gravity generated by a star’s mass (gravity is a product of mass).
  • When the hydrogen used as fuel vanishes, and fusion slows, gravity causes the star to collapse in on itself. This creates a degenerate star.
  • Great densities (degenerate star) are only possible when electrons are displaced from their regular shells and pushed closer to the nucleus, allowing atoms to take up less space. The matter in this state is called ‘degenerate matter’.

Red Supergiant

  • As the red giant star condenses, it heats up even further, burning the last of its hydrogen and causing the star’s outer layers to expand outward.
  • At this stage, the star becomes a large red giant. A very large red giant is often called Red Supergiant.

Planetary Nebula

  • Planetary nebula is an outer layer of gas and dust (no planets involved!) that are lost when the star changes from a red giant to a white dwarf.
  • At the end of its lifetime, the sun will swell up into a red giant, expanding out beyond the orbit of Venus. As it burns through its fuel, it will eventually collapse under the influence of gravity.
  • The outer layers will be ejected in a shell of gas that will last a few tens of thousands of years before spreading into the vastness of space.

White dwarf

  • A white dwarf is very small, hot star, the last stage in the life cycle of a star like the Sun.
  • White dwarfs are the remains of normal stars, whose nuclear energy supplies have been used up.
  • White dwarf consists of degenerate matter with a very high density due to gravitational effects, i.e. one spoonful has a mass of several tonnes.


  • Novae occur on the surface of a white dwarf in a binary system.
  • If the two stars of the system are sufficiently near to one another, material (hydrogen) can be pulled from the companion star’s surface onto the white dwarf.
  • When enough material builds up on the surface of the white dwarf, it triggers a nuclear fusion on a white dwarf which causes a sudden brightening of the star.


  • A supernova is the explosive death of a star and often results in the star obtaining the brightness of 100 million suns for a short time.
  • The extremely luminous burst of radiation expels much or all of a star’s material at a great velocity, driving a shock wave into the surrounding interstellar medium.
  • These shock waves trigger condensation is a nebula paving the way for the birth of a new star ? if a star has to be born, a star has to die!
  • A great proportion of primary cosmic rays comes from supernovae.

Supernovae can be triggered in one of two ways:

Type I supernova or Type I-a supernova (read as one-a)

  • Occurs when there is a sudden re-ignition of nuclear fusion on the surface of a degenerate white dwarf in a binary system.
  • A degenerate white dwarf may accumulate sufficient material from a companion star to raise its core temperature, ignite carbon fusion, and trigger runaway nuclear fusion, completely disrupting the star.

The difference between Nova and Type I supernova


Type I supernova

In a nova, the system can shine

up to a million times brighter than normal.

A supernova is a violent stellar explosion

that can shine as brightly as an entire galaxy

of billions of normal stars.

As long as it continues to take gas

from its companion star, the white

dwarf can produce nova outbursts at regular intervals.

If enough gas piles up on the

surface of the white dwarf,

a runaway thermonuclear explosion blasts

the star to bits.

Type II supernova

  • Type II supernova is a supernova that occurs by the gravitational collapse of the core of a massive star (mostly made of iron). E.g. Supernova of a red supergiant.

Importance of supernova: Creating and dispersing new elements

  • When a star’s core runs out of hydrogen, the star begins to die out. The dying star expands into a red giant, and this now begins to manufacture carbon by fusing helium atoms.
  • More massive stars begin a further series of nuclear burning. The elements formed in these stages range from oxygen through to iron.
  • During a supernova, the star releases very large amounts of energy as well as neutrons, which allows elements heavier than iron, such as uranium and gold, to be produced.
  • In the supernova explosion, all of these elements are expelled out into space, and new stars are born out of this matter (recycling of matter in the universe!).

Black dwarf

  • The last stage of stellar evolution is a black dwarf.
  • A black dwarf is a white dwarf that has sufficiently cooled that it no longer emits significant heat or light.
  • Because the time required for a white dwarf to reach this state is calculated to be longer than the current age of the universe (13.8 billion years), no black dwarfs are expected to exist in the universe yet.

Brown Dwarfs

  • Brown dwarfs are objects which are too large to be called planets and too small to be stars.
  • Brown dwarfs are thought to form in the same way that stars do – from a collapsing cloud of gas and dust.
  • However, as the cloud collapses, the core is not dense enough to trigger nuclear fusion.

Neutron stars

  • These stars are composed mainly of neutrons and are produced after a supernova, forcing the protons and electrons to combine to produce a neutron star.
  • Neutron stars are very dense. (mass of three times the Sun can be fit in a sphere of just 20km in diameter).
  • If its mass is any greater, its gravity will be so strong that it will shrink further to become a black hole.

Black holes

  • Black holes are believed to form from massive stars at the end of their lifetimes.
  • The gravitational pull in a black hole is so great that nothing can escape from it, not even light.
  • The density of matter in a black hole cannot be measured (infinite!).
  • Black holes distort the space around them and can suck neighbouring matter into them including stars.
  • Gravitational lensing: Light around a massive object, such as a black hole, is bent, causing it to act as a lens for the things that lie behind it.


  • Galaxy is a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction. They are the major building blocks of the universe.
  • The smallest galaxies contain about 100,000 stars, while the largest contains up to 3000 billion stars.

From the billions of galaxies, two basic types have been identified:

  • Regular galaxies, and
  • Irregular galaxies.

Regular Galaxies

Spiral Galaxies: The Milky Way is an example of disc-shaped spiral galaxy which has a greater concentration of stars near its centre. They consist of populations of old stars in the centre, and the youngest stars located in the arms. Spiral galaxies are well supplied with the interstellar gas in which new bright, young stars form.

Elliptical Galaxies: Star distribution is nonuniform. Most of their member stars are very old and no new star formation in them. Smaller and less bright. The brightest galaxies in the universe are elliptical.

Irregular Galaxies

  • The irregular galaxies comprise about one-tenth of all galaxies.
  • The stars of the irregular galaxies are generally very old.

Our Galaxy (the Milky Way)

  • The Milky Way is the galaxy that hosts our solar system. It is shaped like a flat disc with a central bulge.
  • Its diameter is between 1,50,000 and 2,00,000 light-years.
  • In the nucleus, the thickness reaches 10,000 light years, whereas in the disc it is 500-2,000 light years thick.
  • It is estimated to contain 100-400 billion stars.
  • The inner stars travel faster than those further out.
  • The Solar System is located in the Orion Arm, 26,000 light years from the centre (about one-third from the centre) of the Milky Way galaxy.
  • The Sun completes one lap of the galaxy in about every 220 million years.
  • The solar system revolves around the Milky Way with a speed of 285 km per second.
  • The Andromeda Galaxy is the closest galaxy (spiral) to us – being 2 million light years away.

Source: Web

Other Related News

24 June,2020
Sustainable Developmental Goals Index 2019

Sustainable Developmental Goals Index 2019 GS-Paper-3 Environment SDG PT-MAINS The SDG India Index (NITI AAYOG) dashboard displays overall & detailed info on the progress made by States & UTs on Global Goals of the United Nations including their incremental progress from 2018, using in

ULV sprayer through drones

ULV sprayer through drones To overcome the limitation of importing equipment, the Department of Agriculture, Cooperation & Farmers’ Welfare (DAC&FW), under the Make in India initiative, has taken up the challenge to indigenously develop a vehicle-mounted ULV sprayer for locust contr

Minimum Support Price for Mature Dehusked Coconut

Government declares Minimum Support Price for Mature Dehusked Coconut The government of India has declared Minimum Support Price for mature dehusked coconut for the season 2020 at Rs. 2700/- per quintal, thus hiking the MSP by 5.02% from Rs. 2571/- per quintal during the season 2019. 

Information about Country of Origin by the sellers made mandatory on GeM to promote Make in India and Aatmanirbhar Bharat

Information about the Country of Origin by the sellers made mandatory on GeM to promote Make in India and Aatmanirbhar Bharat Government e-Marketplace (GeM), a Special Purpose Vehicle under the Ministry of Commerce and Industry, has made it mandatory for sellers to enter the Country of Origin


YUKTI 2.0 About YUKTI 1.0 Union Minister for HRD Shri Ramesh Pokhriyal “Nishank” has launched a web-portal YUKTI (Young India Combating COVID with Knowledge, Technology and Innovation) . It’s a unique portal and dashboard  to monitor and record the efforts and init

Compressed Bio-Gas plants to be brought under Priority Sector Lending

Financing for Compressed Bio-Gas plants to be brought under Priority Sector Lending Context The Government is in the process of including Compressed Bio-Gas under Priority Sector Lending.  Shri Pradhan, along with Tamil Nadu Chief Minister, inaugurates CBG Plant at Namakkal in Tamil

International Comparison Program,2017

International Comparison Program,2017 Purchasing Power Parities and the size of Indian Economy: Results from the 2017 International Comparison Program The World Bank has released new Purchasing Power Parities (PPPs) for the reference year 2017, under the International Comparison Progra

Downing the shutters: On H1-B visa halt

Downing the shutters: On H1-B visa halt Context # The White House has made a proclamation restricting the issuance of non-immigrant work visas (H1B) across the board, purportedly to clamp down on American jobs going to foreign workers, a consistent policy priority of the Donald Trump administr


NDRF The NDRF was set up in accordance with Section 46 of the Disaster Management Act, 2005. It is meant to “meet the expenses for emergency response, relief and rehabilitation” for any threatening disaster situation. Although Section 46 includes a clause regarding grants made by any

23 June,2020
Decarbonising Transport project by NITI Aayog

Decarbonising Transport project by NITI Aayog Decarbonising Transport: International Project to Develop Pathway to Low-CO2 Mobility for India NITI Aayog in collaboration with International Transport Forum (ITF) will launch the “Decarbonising Transport in India” project on 24 Jun

Foldscope could be a better alternative to clinical microscope

Foldscope could be a better alternative to the clinical microscope Foldscope is an affordable origami-based microscopy device composed of a series of paper clippings. (Origami is the Japanese art of folding paper into decorative shapes and figures) Upon assembly, the device can hold a spe

Scientists detect ionospheric irregularities

Scientists detect ionospheric irregularities during major space weather events that influence communication & navigation systems The Earth's magnetic field lines are nearly horizontal over magnetic equator due to which equatorial ionosphere is a bed for a variety of plasma instabilitie


Blazars  Study of optical properties of super-massive black-hole can provide a clue to emission mechanism from its close vicinity Context Through 153 nights, 17 scientists from 9 countries in Europe and Asia including researchers from Aryabhatta Research Institute of Observational Scie

A way out of undelineated borders (India and Nepal border disputes)

A way out of undelineated borders By, Mukul Sanwal is a former UN diplomat and has served as Deputy Commissioner Almora Context # The Galwan face-off should focus minds on resolving, not managing, different perceptions of the northern border, relying first on ‘samadhaan’, as Kau

The lone wolf threat: on isolated terror attack in London

The lone wolf threat: on isolated terror attack in London Context # The knife attack at a park in Reading, a town west of London, which killed three people and injured three others, is yet another reminder of the threat of lone wolf attacks the U.K. is facing. Lone wolf attacks in Britain

Transparency during a crisis (RTI amidst COVID19)

Transparency during a crisis By, Anjali Bhardwaj is associated with the National Campaign for Peoples’ Right to Information Context # Right to Information (RTI) applications seeking information pertaining to the PM CARES Fund have been stonewalled. #  No information exists on

Right to Information Act,2005

Right to Information Act,2005 Historical Background The right to information gained power when Universal Declaration of Human Rights was adopted in 1948 providing everyone the right to seek, receive, information and ideas through any media and regardless of frontiers. The I

Bum La Pass

Bum La Pass The Bum La Pass is a mountain pass located at the Indo-China border above 15,200 ft above sea level, it is about 37 km away from Tawang in Arunachal Pradesh. The road to Bum La is also a historical route, the People's Liberation Army of China invaded India during the 1962 Sino-Ind

Sharavathi Monkey Park

Sharavathi Monkey Park The Karnataka government has decided to develop a monkey park in the Shivamogga district. The monkey park will be established on the uninhabited islands in the Sharavathi backwaters region. The park will be the first such in the state and will be set up on 100 acres of land


01 Feb, 2024

Search By Date

Post Feed
Newsletter Subscription
SMS Alerts

Important Links