Astrophysics & Particle Physics-APPC 2026

Gravitational Physics is the physics and astrophysics discipline that deals with the force of gravity and its action on matter, energy, and the universe's structure. It covers Newtonian gravity and Einstein's general relativity, in which gravity is the curvature of spacetime due to mass and energy.Gravitational physics puts a special emphasis on the study of compact objects, including black holes and neutron stars, whose strong gravitational fields have a deep influence on surrounding matter, light, and spacetime.

Observations of these objects probe the predictions of general relativity in extreme regimes, such as the dynamics of binary orbits and relativistic orbital motion.Gravitational waves, ripples of spacetime generated by accelerating massive objects such as coalescing black holes or neutron stars, are an important area of study. Detectors such as LIGO, Virgo, and KAGRA enable the observation of these waves, providing insights into high-energy astrophysical events, stellar evolution, and the properties of dense matter.Gravitational physics also investigates gravitational lensing, where light from distant galaxies and stars is bent around massive objects, revealing mass distribution and dark matter in the universe. This effect aids astronomers in charting galaxy clusters and researching the large-scale structure of the universe.

Furthermore, gravitational physics investigates orbital dynamics, planetary orbits, and galaxy dynamics, connecting astrophysics, cosmology, and space exploration. Relativistic effects, including time dilation in the vicinity of heavy bodies, frame-dragging, and perihelion precession, are essential for proper modeling of celestial motion.The subject unifies theoretical modeling, numerical simulation, and observational evidence to study gravity from laboratory experiments at small scales to cosmic scales. Research in gravitational physics improves our knowledge of the laws of nature at the most basic level, the evolution of the universe, and extreme astrophysical events. By investigating gravity, researchers are able to examine the dynamics of space, time, and matter under the most extreme circumstances, and hence gravitational physics is a foundation of modern cosmology and astrophysics.