relativity

## What I do - Analyze time dilation and length contraction - Calculate relativistic momentum and energy - Model spacetime diagrams and worldlines - Study gravitational lensing and black holes - Apply equivalence principle concepts - Analyze cosmological metrics ## When to use me When studying high-speed phenomena, gravitational physics, or cosmology. ## Key Concepts - **Lorentz Factor**: γ = 1/√(1 - v²/c²) for time dilation and length contraction - **Mass-Energy Equivalence**: E = mc², relativistic momentum p = γmv - **Spacetime Interval**: ds² = -c²dt² + dx² + dy² + dz² (invariant) - **Einstein Field Equations**: G_{μν} = (8πG/c⁴) T_{μν} relates geometry to matter - **Schwarzschild Metric**: Describes spacetime outside spherical mass - **Gravitational Redshift**: z = √((1-r_s/R)/(1-r_s/r)) - 1