PHYS 2903 – Relativity: The Not-So-Obvious Applications of Einstein’s Magnum Opus In Everyday Life
Great question — Einstein's General Relativity (GR) is where physics and geometry get deeply intertwined, and the Einstein field equations (EFE) are the core of the theory.
At a high level:
They describe how mass and energy affect the curvature of spacetime, and in turn, how that curvature tells objects how to move.
Matter and energy tell spacetime how to curve. Curved spacetime tells matter how to move.
Gμν+Λgμν=8πGc4TμνG_{\mu\nu} + \Lambda g_{\mu\nu} = \frac{8\pi G}{c^4} T_{\mu\nu}
Let’s break it down:
| Symbol | Meaning |
|---|---|
| GμνG_{\mu\nu} | Einstein tensor — describes spacetime curvature |
| Λ\Lambda | Cosmological constant (related to dark energy) |
| gμνg_{\mu\nu} | Metric tensor — describes the geometry of spacetime |
| TμνT_{\mu\nu} | Stress-energy tensor — describes matter and energy |
| GG | Newton's gravitational constant |
| cc | Speed of light |
The left side is geometry, the right side is physics (mass, energy, momentum, pressure...).
Here’s a breakdown of the math topics you need to fully understand the field equations: