Astrophysics, Cosmology & Relativity
8 terms
Galaxy
Astrophysics, Cosmology & Relativity
Solar Masses (M_☉) and Kiloparsecs (kpc)
A massive, gravitationally bound system consisting of stars, stellar remnants, interstellar gas, dust, and dark matter.
M_galaxy = v² r / G (includes Dark Matter)
Galaxy Cluster
Astrophysics, Cosmology & Relativity
Megaparsecs (Mpc) & M_☉
A gravitationally bound structure containing hundreds to thousands of individual galaxies bound together by gravity.
M_total ~ 10¹⁴–10¹⁵ M_☉ (80% Dark Matter, 15% Intracluster Gas, 5% Stars)
General Relativity
Astrophysics, Cosmology & Relativity
Geometric Field Theory
Albert Einstein's 1915 geometric theory of gravitation describing gravity not as an attractive force, but as the curvature of 4D spacetime produced by mass and energy.
G_μν + Λ g_μν = (8 π G / c⁴) T_μν
Geodesic
Astrophysics, Cosmology & Relativity
Spacetime Path Trajectory
The path of shortest (or extreme) spacetime interval between two points in curved spacetime, representing the free-fall trajectory of particles under gravity.
(d²x^μ / dτ²) + Γ^μ_αβ (dx^α / dτ) (dx^β / dτ) = 0
Gravitational Lensing
Astrophysics, Cosmology & Relativity
Arcseconds (Angular Deflection)
The bending of light rays from a background astronomical source around a massive foreground object acting as a gravitational lens.
θ_deflection = (4 G M) / (c² b)
Gravitational Time Dilation
Astrophysics, Cosmology & Relativity
Seconds (Relativistic Time Difference)
The phenomenon where time passes measurably slower in regions of lower gravitational potential (stronger gravity).
t_0 = t_f √(1 - 2 G M / (r c²))
Gravitational Waves
Astrophysics, Cosmology & Relativity
Dimensionless Strain h (10⁻²¹)
Ripples in the curvature of spacetime that propagate outward as transverse waves at the speed of light, generated by accelerating asymmetric mass distributions.
h_ij = (2 G / (c⁴ r)) (d²I_ij / dt²), Strain h = ΔL / L ~ 10⁻²¹
Great Attractor
Astrophysics, Cosmology & Relativity
M_☉ (Gravitational Anomaly Mass)
A massive gravitational anomaly in intergalactic space at the center of the Laniakea Supercluster pulling galaxies across hundreds of millions of light-years.
v_peculiar ~ 600 km/s towards Laniakea Supercluster center