The interactive reference to the beginning and evolution of the universe, focusing on the earliest epochs from the Big Bang to the formation of the first stars and galaxies.
Molecular hydrogen (H₂) is the essential coolant that allowed the first stars and galaxies to form from primordial gas. It shaped the galaxy formation threshold, influenced the epoch of reionization, and remains a key focus of cosmological simulations and observations.
Baryogenesis is the hypothesized process that created the observed imbalance between matter and antimatter in the early universe. This article explains the cosmic timeline, the Sakharov conditions, and how this asymmetry led to the universe we see today.
The Big Bang did not occur at a single point in space; it happened everywhere at once. This article explores the origin and evolution of the universe, from the Planck epoch to the formation of stars and galaxies, and explains the evidence that supports the standard cosmological model.
Big Bang Nucleosynthesis (BBN) is the process that forged the lightest atomic nuclei—deuterium, helium-3, helium-4, and lithium-7—during the first three minutes of cosmic history. This article explains the physics, the timeline, the observational evidence, and why BBN remains a cornerstone of the standard Big Bang model.
Explore the quark epoch—the fleeting first microsecond after the Big Bang when quarks and gluons roamed free—and trace the universe’s evolution through inflation, recombination, and the birth of stars and galaxies.
The Planck epoch is the earliest period in the history of the universe, lasting from t=0 to t=10^-43 seconds, when all four fundamental forces were unified and quantum gravity dominated. This article explores the Planck epoch and the subsequent cosmic epochs that shaped the universe we observe today.
The electroweak epoch was a brief but crucial period in the early universe when the electromagnetic and weak nuclear forces were unified, until cooling triggered symmetry breaking. This article explains its timing, physics, and place in the cosmic timeline, from the Planck epoch to structure formation.
The last scattering surface is the sphere of light emitted about 380,000 years after the Big Bang, when the universe cooled enough for electrons and protons to form neutral hydrogen. This cosmic relic, observed as the cosmic microwave background, provides a snapshot of the infant universe and anchors our understanding of cosmic evolution from the Planck epoch to the present day.
The first black holes emerged from the chaotic aftermath of the Big Bang, but their origins remain one of cosmology’s deepest puzzles. This guide explores the leading theories—light seeds from the first stars and heavy seeds from direct gas collapse—and places them in the full context of cosmic evolution, from the Planck epoch to the present day.
A cosmic horizon marks the boundary of what we can observe in an expanding universe. The particle horizon defines the edge of the observable universe, while the event horizon sets the limit of future observations. This guide explains the concept and traces the cosmic epochs from the Planck era to structure formation.
