Gravitational Lensing, Redshift & Time Dilation: Physical Mechanisms

Strong lensing can create multiple images, arcs, and Einstein rings; weak lensing produces subtle statistical distortions; microlensing changes brightness without resolved image separation. Time and frequency effects depend on spacetime geometry rather than a material medium.

Photons follow null geodesics through curved spacetime. Different trajectories and potentials create path delays and magnification. Clocks at different gravitational potentials trace worldlines with different proper times, and photon frequencies measured by those clocks differ accordingly.

Solar-eclipse and radio observations confirm light deflection, galaxy clusters produce dramatic gravitational arcs, atomic clocks show gravitational time shifts over small height differences, and compact-star spectra can exhibit gravitational redshift.

Photons follow null geodesics through curved spacetime. Multiple paths can reach the observer around a mass, while proper time accumulated by clocks depends on the spacetime trajectory and gravitational environment.