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Type: Prelims Only

  • Article 143 of the Indian Constitution

    Why in the News?

    The Tamil Nadu CM has criticised the Presidential Reference under Article 143 as a “desperate attempt” to weaken State powers, following a Supreme Court ruling that set timelines for Governors and the President to act on State Bills.

    Article 143 of the Indian Constitution

    Recent Invocation:

    • The Presidential Reference asked whether the Supreme Court could impose timelines on:
      • Governors under Article 200 (assent to State Bills)
      • The President under Article 201 (Bills reserved for Presidential assent)

    What is Article 143 of the Indian Constitution?

    • Article 143 empowers the President of India to seek the advisory opinion of the Supreme Court on any question of law or fact that is-
      • of public importance
      • Likely to arise or has already arisen
    • This provision defines the Supreme Court’s advisory jurisdiction, exclusive to the President.
    • Sub-clauses and Legal Operation:
      • Article 143(1): The President may refer any matter to the Supreme Court for its opinion. In the first case, the Supreme Court may tender or may refuse to tender its opinion to the president.
      • Article 143(2): Allows the President to refer disputes arising from pre-Constitution agreements, including state-related matters, for the Supreme Court’s opinion. The Supreme Court must tender its opinion to the President.
    • Nature of the Reference: The Supreme Court’s opinion is advisory and NOT legally binding since it is NOT a judicial pronouncement.
    • President’s Response: It is NOT binding on the President; he/she may follow or may not follow the opinion. However, it facilitates the government to have an authoritative legal opinion.
    • Types of Questions Referred: Article 143(1) allows the President to refer questions of law or fact.
      1. Legal questions: Constitutional interpretation, rights, and executive powers.
      2. Factual questions: The 1993 Ram Janmabhoomi-Babri Masjid reference asked whether a temple existed at the disputed site.
    • Judicial Interpretation: The Supreme Court has clarified that Article 143 is broad in scope and not limited to questions that have arisen; potential or likely questions can also be referred.

    Executive’s Control of Presidential Reference: 

    • Although Article 143 vests the power in the President, the real decision to refer is taken by the Union Council of Ministers under Article 74(1). 
    • Article 74(2) bars the Court from inquiring whether such advice was given.

     

    [UPSC 2010] Consider the following statements:

    The Supreme Court of India tenders’ advice to the President of India on matters of law or fact

    1. on its own initiative (on any matter of larger public interest).

    2. if he seeks such an advice.

    3. only if the matters relate to the Fundamental Rights of the citizens.

    Which of the statements given above is/are correct?

    Options: (a) 1 only (b) 2 only * (c) 3 only (d) 1 and 2 only

     

  • Innovations in Sciences, IT, Computers, Robotics and Nanotechnology

    Scientists create 2D Metal Sheets using High-Pressure Technique

    Why in the News?

    A team of researchers from top Chinese scientific institutions has reported a major breakthrough in the creation of atomically thin 2D metal sheets using a novel high-pressure sandwich method.

    About the 2D Metal Created:

    • Definition: 2D metals are only one or two atoms thick, so electrons can move in just two dimensions.
    • Quantum Confinement: Electrons in 2D metals are restricted to specific energy levels, similar to how they behave in atoms.
    • Scientific Interest: Metals like bismuth, tin, and lead in 2D form are being studied for their electrical, magnetic, and quantum properties.
    • Applications: Their special properties make them useful for quantum computing, sensors, and advanced electronics.

    Technologies Involved:

    • Quantum Dots: These are tiny semiconductors where electrons are tightly confined, creating quantised energy states.
    • Quantum Confinement: In quantum dots, electrons can’t move freely in any direction, leading to discrete energy levels.
    • Link to 2D Metals: In 2D metals, electrons are confined in two dimensions, changing conductivity, magnetism, and optical behaviour.
    • Process: Chinese scientists created 2D metals by sandwiching metal powder between two MoS₂-coated sapphire layers.
    • Steps involved: The structure is heated, twisted, and pressed to form ultra-thin sheets, then cooled and peeled off.
    • Material Choice: MoS₂ and sapphire were chosen for their strength, smoothness, and low chemical reaction with metal.

    Note: 

    Quantum confinement occurs when a particle like an electron is trapped in an extremely small space, such as a nanoscale material. This restriction changes its energy levels, making them discrete instead of continuous. As a result, the material’s properties—like color and conductivity—can change with size.

     

    [UPSC 2012] Graphene is frequently in the news recently. What is its importance?

    1. It is a two-dimensional material and has good electrical conductivity.

    2. It is one of the thinnest but strongest materials tested so far.

    3. It is entirely made of silicon and has high optical transparency.

    4. It can be used as ‘conducting electrodes’ required for touch screens, LCDs and organic LEDs.

    Options: (a) 1 and 2 only (b) 3 and 4 only (c) 1, 2 and 4 only* (d) 1, 2, 3 and 4

     

  • ISRO Missions and Discoveries

    Chandrayaan-5 (LUPEX Mission) enters Preliminary Design Phase

    Why in the News?

    India and Japan have begun the preliminary design phase of the Chandrayaan-5 mission, also known as LUPEX (Lunar Polar Exploration).

    Back2Basics: Legacy of Chandrayaan Missions

    • Chandrayaan-1 (2008): First mission, focused on mineral and chemical mapping.
    • Chandrayaan-2 (2019): Orbiter mission with 98% success.
    • Chandrayaan-3 (2023): Achieved a historic soft landing on the Moon’s south pole.
    • Chandrayaan-4 (Upcoming, 2027):
      • It is a planned lunar sample return mission by ISRO, expected to launch around 2027, with the landing site near Statio Shiv Shakti at the lunar south pole.
      • The mission involves five modules launched on two LVM-3 rockets, later docked in Earth orbit to form an integrated spacecraft.
      • A robotic arm and drill will collect 2–3 kg of surface and sub-surface lunar samples for return to Earth.
      • The Re-entry Module (RM) will re-enter Earth’s atmosphere with the samples using ballistic re-entry, marking India’s first attempt at sample return.
    • Chandrayaan-5 / LUPEX: Aimed at deeper exploration with global participation.
    • Manned Lunar Mission: Prospected lunar landing by 2040.

    About Chandrayaan-5/LUPEX Mission:

    • It is a collaborative mission between ISRO and JAXA.
    • Approval: Cabinet approval for the mission was granted on March 10, 2025.
    • Launch: It will carry a 6.5-tonne payload and launch aboard Japan’s H3 rocket in 2027–28.
    • Collaboration: The lander is being developed by ISRO and the 350-kg rover by JAXA.
    • Duration: The mission is expected to last 100 days, with a possible extension of one year.
    • Mission Goals and Objectives:
      • Explore water and regolith in the lunar south pole’s Permanently Shadowed Regions (PSRs).
      • Drill into the Moon’s surface, analyse soil samples, and perform in-situ experiments.
      • Assess water content, quality, and analyse surface volatiles using advanced instrumentation.
      • Exploration of the far side of the Moon.

    Scientific Collaboration and Instruments:

    • A total of 7 scientific instruments will be onboard the mission.
    • ISRO’s Contribution: Development of the lander; creation of one sensor in a major four-sensor instrument.
    • JAXA’s Contribution: Development of the rover and three sensors in the same instrument; Rover is designed to climb 25° inclines and operate on a complex battery charging protocol.
    • ESA (European Space Agency): Developing a mass spectrometer.
    • NASA: Contributing neutron spectrometers.
    [UPSC 2009] In the context of space technology, what is Bhuvan, recently in the news?

    Options: (a) A mini satellite launched by ISRO for promoting the distance education in India (b) The name given to the next Moon Impact Probe, for Chandrayaan-II (c) A geoportal of ISRO with 3D imaging capabilities of India* (d) A space telescope developed by India

     

  • Solar Energy – JNNSM, Solar Cities, Solar Pumps, etc.

    India eases Solar Panel Efficiency Norms for Off-Grid Rural Projects

    Why in the News?

    The Ministry of New and Renewable Energy (MNRE) has lowered the efficiency requirement for off-grid solar panels to make rural electrification easier and more affordable.

    About India’s Off-Grid Solar Programme:

    • About: The programme was launched by the Ministry of New and Renewable Energy to provide solar energy access in regions without reliable grid electricity.
    • Mission Framework: Implemented under the National Solar Mission (2010), it aimed to install 2,000 megawatt-peak (MW-P) of off-grid and decentralised systems by 2022.
    • Phased Implementation:
      1. Phase I (2010–2014) targeted 200 MW-P capacity.
      2. Phase II (2014–2017) expanded to 500 MW-P with a focus on lighting, pumps, and study lamps.
      3. Phase III (2018–2021) emphasised solar streetlights, study lamps, and solar plants for public institutions.
    • Restructuring: Solar pumps were moved to the Pradhan Mantri Kisan Urja Suraksha evam Utthaan Mahabhiyan scheme (PM-KUSUM), and solar home lights were integrated into the Saubhagya Scheme.
    • Key Applications: Included solar home lighting systems, streetlights, lanterns, study lamps, power packs, and water pumps for irrigation and drinking.

    India’s Progress in Off-Grid Solar Energy:

    • Installed Capacity: As of April 2025, India’s total solar capacity reached 107.95 gigawatts, with 4.98 gigawatts from off-grid systems.
    • Capacity Growth: From 2016 to 2024, solar installations grew from 172.45 gigawatts to 216.86 gigawatts.
    • Recent Trends: In 2024, adoption rose as solar appliances became more affordable in remote and underserved regions.
    • Impact: The programme has been vital for electrification in areas where grid expansion is limited by geography, cost, or infrastructure.

    Tap to know more about India’s Solar Capacity and its Global Position.

    [UPSC 2020] With reference to solar water pumps, consider the following statements:

    1. Solar power can be used for running surface pumps and not for submersible pumps.

    2. Solar power can be used for running centrifugal pumps and not the ones with piston.

    Which of the statements given above is/are correct?

    Options: (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2*

     

  • Innovations in Sciences, IT, Computers, Robotics and Nanotechnology

    Scientists at CERN Create Gold from Lead

    Why in the News?

    In a recent breakthrough at CERN’s ALICE (A Large Ion Collider Experiment), scientists observed that near-collisions of lead ions in the Large Hadron Collider (LHC) can result in the formation of gold atoms and other novel nuclei.

    How was Lead converted into Gold?

    • In ultra-peripheral collisions at the Large Hadron Collider, lead atoms passed close without touching, creating strong electromagnetic fields.
    • These fields released photons that caused some lead atoms to lose 3 protons and 2 neutrons, transforming them into gold-203.
    • Between 2015–2018, 86 billion gold atoms were created—just 29 picograms—scientifically important but not commercially valuable.

    About the Large Hadron Collider (LHC):

    • The LHC has been working since September 2008 and is the world’s largest particle accelerator.
    • Development: Between 1998 and 2008 in collaboration with over 10,000 scientists, and hundreds of universities and laboratories across more than 100 countries.
    • Location: It lies in a 27-kilometre tunnel under the France–Switzerland border, near Geneva, and is operated by CERN.
    • Purpose: It smashes protons or lead atoms together to help scientists study the smallest building blocks of the universe.
    • Working Mechanism: About 9,600 magnets guide particles in a circle using strong magnetic fields.
    • Speed: Particles travel at 99.999999% the speed of light, creating conditions like the Big Bang.
    • Particles Studied: The LHC focuses on quarks (which come in six types) and gluons, which hold quarks together using the strong nuclear force.
    • Members: 24 countries spans across the Europe. Japan and US are Observer.
    • India and LHC: 
      • India signed a cooperation agreement with CERN in 1991 and joined its Large Hadron Collider project in 1996; it became an Associate Member in 2016 after gaining Observer status in 2002.
      • India also helped design LHC components such as superconducting magnets, cryogenic systems, and accelerator protection systems.

    About the ALICE Experiment:

    • ALICE is designed to study heavy-ion collisions, mainly using lead atoms.
    • Objective: It recreates matter similar to that formed just after the Big Bang, helping us understand the early universe.
    • Detection Range: ALICE can study both large particle blasts and rare, low-energy events with high precision.
    • Size and Setup: It weighs 10,000 tons, measures 26 × 16 × 16 metres, and sits 56 metres underground.
    • Members: As of 2024, ALICE includes over 1,900 scientists from 174 institutes across 39 countries, including India.
    • India’s Contribution: Key instruments like the Photon Multiplicity Detector for ALICE and the Hadron Outer Calorimeter for CMS.

     

    [UPSC 2009] In the year 2008, which one of the following conducted a complex scientific experiment in which sub-atomic particles were accelerated to nearly the speed of light?

    Options: (a) European Space Agency (b) European Organization for Nuclear Research* (c) International Atomic Energy Agency (d) National Aeronautics and Space administration

     

  • Judicial Appointments Conundrum Post-NJAC Verdict

    Justice B.R. Gavai takes charge as 52nd CJI

    Why in the News?

    Justice B.R. Gavai has been sworn in as the 52nd Chief Justice of India (CJI).

    About the Chief Justice of India:

    • The CJI is the head of the Supreme Court and the highest-ranking judicial officer in the country.
    • As the “Master of the Roster,” the CJI has the exclusive authority to:
      • Constitute benches
      • Allocate cases among judges
      • Decide the schedule of hearings
    • The CJI leads the judicial and administrative functions of the Supreme Court.
      • Holds administrative control as recognised in State of Rajasthan v. Prakash Chand (1997).
    • The CJI is referred to as “first among equals” among Supreme Court judges.

    Powers and functions of the CJI:

    • Judicial Functions:
      • Assigns judges to the Constitution Benches. (Article 145)
      • Handles interpretation of important legal and constitutional matters. (Article 145)
      • Exercises judicial leadership by steering jurisprudential direction. (Article 145)
      • Exercises judicial authority in matters of national significance. (Article 136)
      • Protects fundamental rights through the Supreme Court’s original and appellate jurisdiction. (Article 32)
    • Administrative Functions:
      • Maintains court roster and case listing. (Derived from judicial precedent and administrative conventions)
      • Supervises court staff and administration. (Based on administrative authority of the CJI)
      • Ensures smooth functioning of the Supreme Court. (Supreme Court Rules, 2013)
      • Holds disciplinary authority over subordinate judicial officers. (Administrative powers acknowledged in precedents)
      • Engages in administration of justice at the highest level. (Overarching responsibility under Article 145)
    • Advisory Function:
      • Provides advisory input when consulted by the President. (Article 143)

    Appointment and Terms:

    • Article 124 of the Constitution empowers the President of India to appoint the CJI.
    • Traditionally, the senior-most judge of the Supreme Court is appointed.
    • Exceptions to this practice:
      • 1973: Justice A.N. Ray appointed over 3 senior judges.
      • 1977: Justice M.H. Beg appointed over Justice H.R. Khanna.
    • Qualifications as outlined in Article 124(3):
      • Must be a citizen of India, and:
      • Served at least five years as a High Court judge, or
      • Practised at least ten years as a High Court advocate, or
      • Deemed a distinguished jurist by the President.

    Selection Procedure:

    • Governed by the Memorandum of Procedure for Appointment of Supreme Court Judges.
    • The Union Law Minister seeks the outgoing CJI’s recommendation.
    • The recommendation is processed as follows:
      • Sent to the Prime Minister by the Law Ministry.
      • Prime Minister advises the President.
      • President of India appoints the new CJI.
    • No specific timeline is defined — the recommendation must be made at the “appropriate time”.

    Tenure and Removal:

    • CJI serves until the age of 65 years.
    • Can only be removed through removal under Article 124(4):
      • Requires approval by both Houses of Parliament.
      • Must be supported by:
        • A majority of total membership, and
        • A two-thirds majority of members present and voting.
      • Grounds for removal: Proven misbehavior or incapacity.
    [UPSC 2021] With reference to the Indian judiciary, consider the following statements:

    1. Any retired judge of the Supreme Court of India can be called back to sit and act as a Supreme Court judge by the Chief Justice of India with the prior permission of the President of India.
    2. A High Court in India has the power to review its own judgment as the Supreme Court does

    Which of the statements given above is/are correct?

    Options:  (a) 1 only  (b) 2 only (c) Both 1 and 2 * (d) Neither I nor 2

     

  • Differentiated Banks – Payment Banks, Small Finance Banks, etc.

    What are Digital Banking Units (DBU)?

    Why in the News?

    In October 2022, 75 Digital Banking Units were launched across remote districts to commemorate India’s 75th Independence Day, but their momentum has declined from past 2 years.

    About Digital Banking Units (DBUs):

    • DBUs are specialized, fixed-location banking hubs designed to deliver a wide range of digital financial services using modern infrastructure.
    • They operate in both self-service and assisted modes, offering customers 24/7 access to banking in a paperless, secure, and cost-effective environment.
    • The RBI permits commercial banks with digital banking experience to establish DBUs in Tier I to Tier VI cities, without prior approval unless restricted.
      • RRBs, payment banks, and local area banks are not eligible.
    • In October 2022, as part of India’s 75th independence anniversary, 75 DBUs were launched across 75 remote districts to promote financial inclusion and bring banking services closer to citizens in semi-urban and rural areas.

    Services and Features:

    • DBUs offer digital services such as account opening, internet and mobile banking kits, debit and credit card applications, and UPI QR-based merchant solutions.
    • Customers can apply online for retail loans, MSME loans, and government-sponsored schemes, with the entire process—from application to disbursal—handled digitally.
    • Each DBU operates independently from existing branches and must follow RBI guidelines, including housing in separate premises with automated-only cash services.
    • They are equipped with interactive teller machines, cash recyclers, document upload systems, and video KYC facilities.
    • A senior bank executive is appointed as Chief Operating Officer (COO) to manage each unit.

    Benefits Offered:

    • DBUs offer a convenient, paperless banking experience, reducing the need to visit traditional branches.
    • They support inclusive banking by expanding access to financial services in underserved regions.
    • Customers in remote areas benefit from both automated and assisted service options.
    • For banks, DBUs help optimize costs while improving service delivery and outreach.
    [UPSC 2024] Consider the following statements in respect of the digital rupee:

    1. It is a sovereign currency issued by the Reserve Bank of India (RBI) in alignment with its monetary policy. 2. It appears as a liability on the RBI’s balance sheet. 3. It is insured against inflation by its very design. 4. It is freely convertible against commercial bank money and cash.

    Which of the statements given above are correct?

    Options: (a) 1 and 2 only (b) 1 and 3 only (c) 2 and 4 only (d) 1, 2 and 4*

     

  • Renewable Energy – Wind, Tidal, Geothermal, etc.

    Dirang Geothermal Project

    Why in the News?

    The Centre for Earth Sciences and Himalayan Studies (CESHS) has successfully drilled India’s first geothermal production well in Dirang, located in Arunachal Pradesh’s West Kameng district.

    This could potentially make Dirang the first geothermal-powered town in the country.

    What is Geothermal Energy?

    • Geothermal energy is derived from heat stored in the Earth’s interior, primarily from the decay of radioactive elements.
    • It can be utilised for electricity generation, heating, and industrial applications.
    • It is considered a renewable energy source as the Earth continuously generates heat.

    About Dirang Geothermal Project:

    • This project in West Kameng, Arunachal Pradesh, is the first successful geothermal drilling site in Northeast India.
    • It is led by CESHS under the Arunachal Pradesh Department of Science and Technology, with support from the Ministry of Earth Sciences.
    • It is a medium-to-high enthalpy zone (~115°C), with a fault between quartzite and schist, enabling efficient, low-impact drilling.
    • The site was selected after two years of geochemical and structural surveys, and can support applications like agricultural drying, space heating, and controlled storage.
    • International partners include the Norwegian Geotechnical Institute, Geotropy ehf (Iceland), and Guwahati Boring Service for execution.

    India’s Geothermal Landscape:

    • The Geothermal Atlas of India (2022) identifies 381 thermally anomalous sites across the country.
    • India has an estimated geothermal potential of 10,600 MW, enough to power over 10 million homes.
    • Geothermal energy offers base load power, unlike intermittent solar and wind sources.
    • The first operational plant was a 20 kW binary cycle pilot in Manuguru, Telangana, developed by SCCL.
    • A 25 MW project in Khammam remains stalled due to tariff issues with the Andhra Pradesh Electricity Regulatory Commission.
    • In Puga Valley, Ladakh, ONGC resumed work in 2024 on a 1 MW pilot plant, after a 2022 hot water leak raised safety concerns.
    • In Dholera, Gujarat, geothermal energy is used for cooking and air conditioning at a temple, showing direct-use feasibility.
    • India has signed MoUs with Iceland (2007) and Saudi Arabia (2019), and included geothermal energy in the 2023 RETAP agreement with the United States.
    [UPSC 2013] Consider the following: (1). Electromagnetic radiation (2). Geothermal energy (3). Gravitational force (4). Plate movements (5). Rotation of the earth (6). Revolution of the earth

    Which of the above are responsible for bringing dynamic changes on the surface of the earth?

    Options: (a) 1 only (b) 2 and 3 only (c) 1, 2 and 3 (d) None*

     

  • Capital Markets: Challenges and Developments

    India rolls over $50M Treasury Bill to help Maldives

    Why in the News?

    India extended critical financial assistance to the Maldives by rolling over a $50 million Treasury Bill, continuing its support under a government-to-government arrangement since 2019.

    About Treasury Bill:

    • A T-Bill is a short-term debt instrument issued by the GoI through the Reserve Bank of India (RBI).
    • They are part of Government Securities (G-Secs) and are used to raise short-term funds.
    • They are zero-coupon securities, meaning they do not carry periodic interest payments.
    • Instead, they are issued at a discount and redeemed at face value upon maturity.
    • They were first introduced in India in 1917.
    • They are ideal for investors seeking safety and liquidity over short periods.

    Features of the T-Bills:

    • Tenures Available: 91-day, 182-day, and 364-day maturity periods.
    • Issued at a Discount: T-Bills are sold at a lower price than their face value. The return (yield) is the difference between purchase price and face value.
    • Minimum Investment: Starts at ₹25,000, and in multiples of ₹25,000 thereafter.
    • Zero-Coupon Nature: No interest payments during the tenure. Investors earn via the discounted purchase price.
    • Risk-Free Investment: Backed by the Government of India, making it virtually risk-free.
    • High Liquidity: Due to short tenure, T-Bills can be easily converted to cash.
    • Auction Mechanism: Sold through competitive and non-competitive bidding at RBI auctions.
    • Taxable Gains: Returns are treated as short-term capital gains and are taxable.
    • Sensitive to Inflation: Fixed returns can be impacted by rising inflation, reducing real returns.
    [UPSC 2018] Consider the following statements:

    1.The Reserve Bank of India manages and services GoI Securities but not any State Government Securities.

    2.Treasury bills are issued by the GoI and there are no treasury bills issued by the State Governments.

    3.Treasury bills offer are issued at a discount from the par value.

    Which of the statements given above is/are correct?

    Options: (a) 1 and 2 only (b) 3 only (c) 2 and 3 only * (d) 1, 2 and 3

     

  • International Space Agencies – Missions and Discoveries

    Asteroid YR4 might miss the Earth

    Why in the News?

    Asteroid YR4, discovered in December 2024 via Chile’s ATLAS telescope, was first thought to threaten Earth but was later ruled out. Scientists now focus on its potential Moon impact in 2032.

    Asteroid YR4 might miss the Earth

    About Asteroid 2024 YR4:

    • Asteroid 2024 YR4 was discovered in December 2024 by the ATLAS telescope located in Chile.
    • It is a near-Earth asteroid (NEA) whose orbit brings it within 1.3 AU (Earth-Sun distances) of Earth.
    • It is estimated to be 65 metres wide, roughly the size of a 10-storey building.
    • Initially, it was suspected to have a 3.1% chance of impacting Earth in 2032, triggering NASA’s highest-ever asteroid impact alert.
    • Subsequent tracking ruled out an Earth impact but indicated a 3.8% chance of hitting the Moon on December 22, 2032.
    • A Moon impact would create a 500 to 2,000-metre-wide crater and release energy 340 times more powerful than the Hiroshima bomb.
    • Despite being smaller than the 140m threshold for “potentially hazardous asteroids,” its unusual trajectory drew global scientific attention.
    • Scientists continue to observe YR4, including during a close approach in 2028, to refine its orbital predictions.

    Back2Basics: ATLAS Telescope

    • ATLAS (Asteroid Terrestrial-impact Last Alert System) is a NASA-funded early warning project for detecting small near-Earth objects (NEOs).
    • It is developed and operated by the University of Hawaii’s Institute for Astronomy.
    • As of 2025, ATLAS operates five telescopes in Hawaii, South Africa, Chile, and the Canary Islands.
    • Each telescope has a 0.5-meter Wright-Schmidt design, a 1-meter focal length, and a 110 MP CCD detector with a 7.4° field of view.
    • The system scans 20,000 square degrees of sky three times per night and provides 1–3 week warnings for asteroids 45–120 meters wide.
    • In addition to asteroids, ATLAS also discovers supernovae, comets, dwarf planets, and variable stars.

     

    [UPSC 2011] Comets show a perceptible glowing tail, while asteroids do not. Which of the statements given above is/are correct?

    Options:  (a) 1 and 2 only  (b) 1 and 3 only* (c) 3 only (d) 1, 2 and 3