Definition
Cosmology is the branch of astronomy and physics that studies the origin, evolution, and ultimate fate of the universe. It seeks to provide a comprehensive, quantitative description of the universe as a single physical entity.
Why It Matters
It answers the most fundamental questions about our origin and fate, using the same physical laws that govern our daily lives.
Core Concepts
- The Big Bang Theory: The prevailing model for the early development of the universe, suggesting it began as a hot, dense singularity.
- Cosmic Microwave Background (CMB): The “afterglow” radiation from the early universe, providing a snapshot of the cosmos roughly 380,000 years after the Big Bang.
- Lambda-CDM Model: The current standard model of cosmology, which includes Dark Energy () and Cold Dark Matter (CDM).
- How to read: “The Lambda C D M model, Lambda, or C D M.”
- Meaning: Standard cosmological model— is the cosmological constant (dark energy), CDM is cold dark matter, combined with normal matter to fit observations.
- Expansion of the Universe: Described by Hubble’s Law, indicating that galaxies are moving away from each other.
- Inflation: A brief period of exponential expansion immediately following the Big Bang that explains the universe’s large-scale uniformity.