Cosmology
A comprehensive exploration of the universe's origin, evolution, and ultimate fate—from the Big Bang through cosmic inflation, structure formation, dark matter, dark energy, to the cosmic microwave background and beyond.
Course Overview
Cosmology is the study of the universe as a whole—its origin, evolution, large-scale structure, and ultimate fate. Modern cosmology combines General Relativity with particle physics, quantum field theory, and observational astronomy to understand the cosmos from the Planck scale (10⁻³⁵ m) to the observable universe (10²⁶ m). This course covers the standard ΛCDM model, cosmic inflation, the cosmic microwave background (CMB), large-scale structure formation, dark matter, dark energy, and current observational frontiers.
What You'll Learn
- • FLRW metric and Friedmann equations
- • Big Bang nucleosynthesis and recombination
- • Cosmic inflation and flatness/horizon problems
- • Cosmic Microwave Background (CMB) physics
- • Large-scale structure and galaxy formation
- • Dark matter evidence and candidates
- • Dark energy and the accelerating universe
- • Cosmological perturbation theory
- • Observational cosmology (Planck, WMAP, surveys)
- • Quantum origin of primordial fluctuations
Prerequisites
- • General Relativity (FLRW metric, Einstein equations)
- • Special Relativity (spacetime, energy-momentum)
- • Quantum Mechanics and QFT (for inflation)
- • Statistical Mechanics and thermodynamics
- • Mathematics (differential equations, Fourier analysis)
- • Particle physics basics (standard model)
Course Structure
Comprehensive cosmology curriculum • From Big Bang to present epoch • Includes Friedmann equations derivation, inflation theory, CMB physics, structure formation • Features world-class video lectures from leading cosmologists • Suitable for graduate students and advanced undergraduates in physics and astronomy
Core Topics
FLRW Universe & Friedmann Equations
The Friedmann-Lemaître-Robertson-Walker metric describes a homogeneous, isotropic expanding universe. Friedmann equations govern the scale factor evolution, relating expansion rate to energy density and curvature.
Big Bang & Thermal History
The early universe underwent a hot, dense phase starting from the Planck epoch. Big Bang nucleosynthesis (BBN) formed light elements, followed by recombination when atoms formed, releasing the CMB at z ≈ 1100.
Cosmic Inflation
Inflation solves the horizon, flatness, and monopole problems via exponential expansion driven by a scalar field. Quantum fluctuations during inflation seeded all structure in the universe, imprinted in CMB anisotropies.
Cosmic Microwave Background
The CMB is thermal radiation from recombination at T ≈ 3000 K, redshifted to 2.725 K today. Its temperature anisotropies (ΔT/T ≈ 10⁻⁵) probe initial conditions, geometry, and cosmological parameters with exquisite precision.
Large-Scale Structure Formation
Gravitational instability amplifies density perturbations, forming galaxies, clusters, and the cosmic web. Dark matter dominates gravitational collapse, while baryonic matter follows to form stars and galaxies.
Dark Matter
Dark matter comprises ≈27% of the universe. Evidence from galaxy rotation curves, gravitational lensing, CMB, and structure formation points to non-baryonic, weakly interacting massive particles (WIMPs) or axions.
Dark Energy & Accelerating Universe
Dark energy (≈68% of universe) drives cosmic acceleration discovered via Type Ia supernovae (1998). The cosmological constant Λ (vacuum energy) is the simplest explanation, but its value remains a deep mystery.
Key Equations
Friedmann Equations
First Friedmann equation: Hubble parameter H relates expansion rate to energy density ρ, curvature k, and cosmological constant Λ.
Critical Density
Divides open, flat, and closed universes. Current observations: Ωtotal = ρ/ρc ≈ 1.00 (flat universe).
Hubble's Law
Recession velocity v is proportional to distance d. Current best value: H0 = 67.4 ± 0.5 km/s/Mpc (Planck 2018).
CMB Temperature
CMB temperature scales with redshift. At recombination (z ≈ 1100), T ≈ 3000 K, when hydrogen atoms formed.
📺 Video Lectures
Explore profound connections between Einstein's general relativity, quantum mechanics, and the origin of the universe's large-scale structure.
Einstein's Cosmos and the Quantum: Origin of Space, Time, and Structure
Comprehensive lecture on how quantum fluctuations in the early universe, amplified by cosmic inflation, seeded the large-scale structure we observe today. Bridges general relativity with quantum field theory in curved spacetime.
Key Topics:
- Einstein's field equations and spacetime geometry
- Quantum fluctuations and their amplification during inflation
- CMB anisotropies as a window into quantum origins
- Formation of large-scale structure from quantum seeds
- Interface between GR and quantum field theory
- The role of cosmological constant and dark energy
Related Courses
General Relativity
Foundation: Einstein field equations, FLRW metric, and spacetime curvature
Black Holes
Schwarzschild, Kerr solutions, Hawking radiation, and astrophysical observations
Quantum Field Theory
Essential for inflation: quantum fluctuations in curved spacetime
Quantum Gravity
Beyond classical cosmology: string theory, loop quantum gravity, and the Planck epoch
"The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff."— Carl Sagan
Learning Path & Prerequisites
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