Astrophysics & Particle Physics-APPC 2026

Gravitational Physics and Lensing explores how energy and mass affect space-time curvature as outlined by Einstein's general relativity. The space-time around massive bodies like stars, galaxies, and black holes is distorted, and effects include light bending, orbital precession, and gravitational time dilation.Gravitional lensing is one of the strong phenomena in this discipline wherein light coming from a faraway source is deformed by the foreground object's gravity. Strong lensing creates images or arcs of many background galaxies, weak lensing bends the shapes of background galaxies slightly, and microlensing enables the detection of compact objects, exoplanets, or dark matter clumps.

These phenomena are strong probes of mass distribution and cosmic structure. Gravitational lensing allows astrophysicists to trace dark matter, study galaxy clusters, and determine distances in the universe. Observations of lensed galaxies or quasars give us information on galaxy evolution, cluster dynamics, and the rate of expansion of the universe. When combined with computational modeling, studies of lensing offer accurate estimates of cosmological parameters and the large-scale structure of the universe.Gravitational physics also investigates gravitational waves, orbital motion in strong gravity, and relativistic phenomena near compact objects. Observations of binary black hole or neutron star mergers result in direct tests of general relativity and extend knowledge of extreme gravitational regimes.Applications of gravitational lensing involve high-redshift galaxy surveys, exoplanet discovery, and alternative theories of gravity testing.

Through the study of light distortions, astrophysicists can unveil hidden mass, trace the history of cosmic structures, and investigate the basics of physics in ways unattainable via traditional observation.In general, gravitational physics and lensing bridge theoretical and observational astrophysics, shedding light on the physics of gravity, dark matter, the history of the cosmos, and the fabric of the universe, and thus forming the foundation of modern cosmology and high-energy astrophysics.