Context:
Indian researchers have discovered “Alaknanda”, a massive spiral galaxy resembling the Milky Way, dating back to a time when the universe was only about 1.5 billion years old. Identified using the James Webb Space Telescope (JWST), this finding challenges long-held assumptions about early galaxy formation, which suggested that early galaxies were largely chaotic and irregular.
Key Highlights:
Discovery and Observational Details
- Alaknanda was observed using the James Webb Space Telescope (JWST).
- The galaxy existed when the universe was roughly 10% of its present age.
- It spans nearly 30,000 light-years, comparable in structure (though smaller) to the Milky Way.
Structural Features of Alaknanda
- Exhibits a well-defined spiral structure.
- Contains two prominent spiral arms and a central bulge.
- Such ordered morphology was previously thought to emerge much later in cosmic history.
Scientific Significance
- Challenges prevailing models that early galaxies were clumpy, turbulent, and disordered.
- Suggests that sophisticated galactic structures formed far earlier than expected.
- Points to the possibility of alternative evolutionary pathways for galaxies in the early universe.
Ongoing and Future Research
- Researchers plan to analyse kinematics of gas and stars to understand spiral arm formation.
- Further observations using JWST and the ALMA telescope (Chile) will explore whether Alaknanda is unique or part of a broader population.
Relevant Prelims Points:
- Issue & Causes:
- Reassessment of early universe conditions due to discovery of structured galaxies.
- Scientific Instruments:
- JWST (launched 2021): Infrared space telescope studying early galaxies.
- ALMA: Radio telescope array for studying cold gas and dust.
- Key Terms:
- Spiral Galaxy, Light-year, Kinematics, Big Bang.
- Impact:
- Alters understanding of cosmic evolution timelines.
Relevant Mains Points:
- Facts & Concepts:
- Early universe galaxy formation theories vs new observational evidence.
- Role of infrared astronomy in probing distant galaxies.
- Conceptual Clarity:
- Relationship between galactic structure, star formation, and cosmic age.
- Way Forward:
- Refinement of galaxy formation models, increased multi-wavelength observations, and integration of Indian researchers into global astrophysics collaborations.
UPSC Relevance (GS-wise):
- GS 3: Science & Technology – Space technology, astrophysical discoveries.
- GS 1: World Geography – Physical universe, galaxies and cosmology.