💥Join UPSC 2027,2028 Mentorship (July Batch) + XFactor Notes & Microthemes PDF
Talk to Mentor

Civilsdaily

Login

Subject: SpaceXTheory

  • Oldest Quasars Ever Discovered by Euclid Telescope

    Why in News?

    The European Space Agency’s (ESA) Euclid Space Telescope has discovered 31 ancient quasars, including the oldest ever observed, dating back to when the Universe was about 670 million years old.

    Key Highlights

    • Quasars are the extremely bright cores of distant galaxies powered by supermassive black holes.
    • The newly discovered quasars belong to the Epoch of Reionisation, when the first stars and galaxies formed.
    • Euclid has doubled the number of known ancient quasars within two years.
    • The findings deepen the mystery of how supermassive black holes grew to billions of solar masses so soon after the Big Bang.
    • The James Webb Space Telescope (JWST) will further study these quasars to understand the early Universe.

    Significance

    • Helps trace the reionisation of the Universe.
    • Improves understanding of the formation of early galaxies and black holes.
    • Challenges existing models of cosmic evolution.

    UPSC Prelims Value Addition

    • Quasar: The highly luminous active galactic nucleus (AGN) of a distant galaxy, powered by matter falling into a supermassive black hole.
    • Epoch of Reionisation: The period (about 400 million to 1 billion years after the Big Bang) when the first stars and galaxies ionised neutral hydrogen, ending the Cosmic Dark Ages.

    [2017] The terms ‘Event Horizon’, ‘Singularity’, ‘String Theory’ and ‘Standard Model’ are sometimes seen in the news in the context of:

    (a) Observation and understanding of the Universe

    (b) Study of the solar and the lunar eclipses

    (c) Placing satellites in the orbit of the Earth

    (d) Origin and evolution of living organisms on the Earth

  • What are asteroids? How real is the threat of them causing extinction of life? What strategies have been developed to prevent such a catastrophe?

    Asteroids are rocky, airless remnants from the early formation of the solar system, primarily orbiting the Sun between Mars and Jupiter (asteroid belt). Some asteroids, known as Near-Earth Objects (NEOs), have orbits that bring them close to Earth, raising concerns about impact hazards.

    Key facts about asteroids

    Types –

    C-type (carbonaceous, most common)

    S-type (silicaceous)

    M-type (metal-rich)

    The total mass of all the asteroids combined is less than that of Earth’s Moon.

    Threat from asteroids

    Historical Evidence – The Chicxulub asteroid impact (~66 million years ago) led to the extinction of dinosaurs.

    Probability Assessment

    Extinction-level asteroids (>10 km) are extremely rare

    City or regional-scale impacts (50-300 m) are more frequent and pose serious human and economic risks.

    Current Scientific Consensus

    Low probability, high impact risk.

    No known large asteroid is on a confirmed collision course with Earth in the foreseeable future.

    No global policy framework or convention to prevent asteroid impact

    Strategies Developed to Prevent or Mitigate Asteroid Impact

    Detection and Tracking – Ground- and space-based surveys continuously monitor NEOs.

    Kinetic Impact Deflection – A spacecraft collides with the asteroid to slightly alter its trajectory. Demonstrated successfully by NASA’s DART mission (2022).

    Gravity Tractor – A spacecraft hovers near the asteroid, using mutual gravitational attraction to gradually change its path.

    Nuclear Deflection (Last Resort) – Use of a nuclear device near (not on) the asteroid to vaporise surface material.

    NASA’s Jet Propulsion Laboratory, accurately characterizes the orbits of all known near-Earth objects, predicts their close approaches with Earth

    The International Asteroid Warning Network (IAWN) – UN-endorsed, global collaboration of over 60 scientific institutions that detects, tracks, and characterizes Near-Earth Objects (NEOs).

    United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) has recognised asteroid impact hazards as a global risk transcending national boundaries.

    While extinction-level impacts are extremely rare, the consequences would be catastrophic, justifying sustained vigilance.

  • Consider the following pairs

    Consider the following pairs:
    Objects in space Description
    1. Cepheids : Giant clouds of dust and gas in sapce
    2. Nebulae : Stars which brighten and dim periodically
    3. Pulsars : Neutron stars that are formed when massive stars run out of fuel and collapse
    How many of the above pairs are correctly matched?

  • Consider the following statements

    Consider the following statements:

    Statement-I: Giant stars live much longer than dwarf stars.

    Statement-II: Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.

    Which one of the following is correct in respect of the above statements?

  • Fast X-ray Transients (FXTs)

    Why in the news?

    Astronomers from the Indian Institute of Astrophysics have traced the likely origin of a rare Fast X-ray Transient (FXT) event, EP241107a, detected by the Einstein Probe in November 2024.

    Key Findings

    • FXTs are energetic, non-repeating flashes of X-rays lasting from a few minutes to several hours.
    • They are a recently discovered class of transient cosmic events whose origin has remained uncertain.
    • Researchers identified a radio counterpart of FXT EP241107a using the Karl G. Jansky Very Large Array.
    • Follow-up observations were conducted using:
      • Himalayan Chandra Telescope
      • GROWTH India Telescope
      • Upgraded Giant Metrewave Radio Telescope

    Likely Origin

    • The event was probably caused by: Collapse of a massive star leading to a supernova and gamma-ray burst (GRB), or Merger of two neutron stars.
    • Researchers concluded that EP241107a is most likely an “orphan afterglow”:
      • A gamma-ray-burst-like explosion whose gamma rays were not directly detected.
      • Represents a lower-energy member of the GRB population.

    Fast X-ray Transients (FXTs)

    • Sudden flashes of low-energy X-rays.
    • Non-repeating and short-lived.
    • Fade rapidly after detection.
    • Associated with highly energetic cosmic explosions.

    Proposed Sources

    • Core-collapse supernovae.
    • Binary neutron star mergers.
    • Magnetars (highly magnetized neutron stars).
    • Tidal disruption events involving white dwarfs and black holes.
    • Gamma-ray bursts (GRBs).

    Gamma-Ray Bursts (GRBs)

    • Most energetic explosions known in the Universe.
    • Emit intense gamma radiation for a few milliseconds to several minutes.
    • Associated with the collapse of massive stars (Long GRBs) and Neutron star mergers (Short GRBs).
    • Followed by multi-wavelength “afterglows” in X-ray, optical, and radio bands.

    Neutron Star

    • Extremely dense remnant of a massive star after a supernova.
    • Mass ≈ 1.4-2 solar masses compressed into a sphere about 20 km across.
    • Composed mainly of neutrons.

    [2023] Consider the following pairs: Objects in space : Description
    1. Cepheids : Giant clouds of dust and gas in space
    2. Nebulae : Stars which brighten and dim periodically
    3. Pulsars : Neutron stars that are formed when massive stars run out of fuel and collapse
    How many of the above pairs are correctly matched ?

    [A] Only one

    [B] Only two

    [C] All three

    [D] None

  • Who of the following scientists proved that the stars with mass less than 1.44 times the mass of the Sun end up as White Dwarfs when they die

    Who of the following scientists proved that the stars with mass less than 1.44 times the mass of the Sun end up as White Dwarfs when they die?

  • Which one of the following planets has largest number of natural satellites or moons

    Which one of the following planets has largest number of natural satellites or moons ?

  • What is the difference between asteroids and comets

    What is the difference between asteroids and comets?
    1. Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material.
    2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and mercury.
    3. Comets show a perceptible glowing tail, while asteroids do not.
    Which of the statements given above is/are correct?

  • A person stood alone in a desert on a dark night and wanted to reach his village which was situated 5 km east of the point where he was standing. He had no instruments to find the direction, but he located the polestar. The most convenient way now to reach his village is to walk in the

    A person stood alone in a desert on a dark night and wanted to reach his village which was situated 5 km east of the point where he was standing. He had no instruments to find the direction, but he located the polestar. The most convenient way now to reach his village is to walk in the:

  • The term ‘Goldilocks Zone’ is often seen in the news in the context of

    The term ‘Goldilocks Zone’ is often seen in the news in the context of