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Euclid Space Telescope Discovers Ancient Quasars: Early Universe Explained

7 Jul 2026

Euclid Space Telescope Discovers Ancient Quasars: Early Universe Explained

Subject: GS 3: Science & Technology

Context: The European Space Agency’s (ESA) Euclid Space Telescope has discovered 31 ancient quasars, including the two oldest ever detected, dating to just 670 million years after the Big Bang (about 5% of the Universe’s current age). 

  • The discovery deepens the mystery of how supermassive black holes formed and grew so rapidly in the early Universe. 

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Key Findings

Euclid Space Telescope

  • Oldest Quasars Discovered: The newly identified quasars emitted their light when the Universe was about 670 million years old, surpassing the previous record (set in 2021) by nearly 20 million years.
  • Large Discovery in Short Time: In just two years of operation, the Euclid Space Telescope has discovered 31 ancient quasars, doubling the number of known quasars from the early Universe.
  • Epoch of Reionisation: The quasars belong to the Epoch of Reionisation, when the first stars and galaxies illuminated the Universe and ended the Cosmic Dark Ages.
    • Epoch of Reionisation occurred approximately 400 million to 1 billion years after the Big Bang, when radiation from the first stars, galaxies, and quasars ionised neutral hydrogen, making the Universe transparent to light.

About Quasars

Euclid Space Telescope

  • A quasar (quasi-stellar object) is the extremely luminous core of a distant active galaxy, powered by a supermassive black hole (SMBH).
  • Source of Luminosity: As gas and dust fall into the black hole through an accretion disk, immense gravitational energy is converted into electromagnetic radiation, making quasars shine brighter than an entire galaxy—up to the light of a trillion Suns.
  • Its Importance:
    • Windows to the Early Universe: Their exceptional brightness allows astronomers to observe the first billion years of cosmic history.
    • Tracing Cosmic Evolution: They help study the evolution of galaxies, supermassive black holes, and the intergalactic medium.
    • Probing Reionisation: They act as cosmic lighthouses, enabling scientists to trace how the Universe became ionised after the Cosmic Dark Ages.

Significance of the Discovery

  • Challenges Existing Models: The discovery raises fresh questions about how supermassive black holes, with masses billions of times that of the Sun, formed within a few hundred million years after the Big Bang.
  • Understanding the Early Universe: The newly discovered quasars provide crucial evidence for studying the Epoch of Reionisation and the formation of the first stars and galaxies.
  • Advanced Cosmological Research: The findings will help refine theories related to black hole growth, galaxy formation, and the evolution of the early Universe.

About the Euclid Space Telescope

  • Developed by the European Space Agency (ESA) and launched in 2023.
  • Operates around the Sun–Earth Lagrange Point (L2), nearly 1.5 million km from Earth.
  • Its primary mission is to study dark matter, dark energy, and the large-scale structure of the Universe, while also enabling discoveries of distant galaxies and ancient quasars.

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Conclusion

Further observations by the James Webb Space Telescope (JWST), combined with Euclid’s discoveries, are expected to build a detailed chronicle of the Universe’s first billion years, helping unravel the mystery of the rapid formation and evolution of supermassive black holes and the earliest galaxies

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Euclid Space Telescope Discovers Ancient Quasars: Early Universe Explained

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UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
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Designed as per recent trends of Prelims questions
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