Eminent Indian astrophysicist, science communicator, and Padma Vibhushan awardee Jayant Narlikar passed away recently at the age of 87.

About The Hoyle–Narlikar Theory of Gravity

• The Hoyle–Narlikar Theory of Gravity is an alternative theory to Einstein’s General Relativity. It combines ideas from Mach’s Principle and electromagnetism to describe gravity.
• Principle: The Hoyle–Narlikar Theory of Gravity incorporates Mach’s principle suggesting that the mass of every object in the universe is affected by its interaction with every other object.
  • The Principle suggests that the inertia of an object (that is the tendency to resist change in its state of motion) arises from its interaction with all other matter in the universe.
• Theory Components:
  • Steady State Theory of the Universe: An alternative to the Big Bang theory, it suggests that the universe had no beginning (Big Bang) and no end and is infinite in extent.
    • Expansion: The Theory acknowledged an expanding universe but proposed that the universe was able to maintain a constant density by continuously creating new hydrogen atoms to fill the void resulting from such expansion.
  • A “Creation Field” (C-field): The theory proposed a hypothetical negative-energy field responsible for the continuous creation of matter.
    • When this field becomes strong enough, at any point in space, a new hydrogen atom appears
  • No Fixed Gravitational Constant: The Hoyle–Narlikar theory proposes that gravitational constant (G) is a function of the average density of matter in the universe, unlike Einstein’s General Theory of Relativity, which assumes a fixed gravitational constant (G).
• Applications of the Theory:
  • To Study Formation of Black Holes: The theory has been applied to understand the formation of black holes and white holes from the existence of zero-mass surfaces in spacetime.
  • Anomalous Redshifts: It’s been suggested that anomalous redshifts of quasars and galaxies can be explained by local shifts in the zero-mass surfaces of this theory.
  • Modified Gravity: Some researchers have explored modifications to the geometry and matter within the Hoyle–Narlikar framework to explain dark energy and the accelerating expansion of the universe.
• Challenges to the Hoyle–Narlikar theory of Gravity
  • The discovery of the cosmic microwave background (CMB) radiation in 1965 gave more evidence in the favour of the Big Bang Theory and thus limiting the acceptance of the Hoyle–Narlikar theory of gravity
    • Cosmic Microwave Background (CMB) Radiation (considered as an echo or shockwave of the Big Bang) is the cooled remnant of the first light that could travel freely throughout the universe.

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