Domain
State of the field
The hot Big Bang and ΛCDM model fit a wide range of observations, but the initial conditions, the nature of inflation, and ~95% of the energy budget remain open.
A brief epoch of exponential expansion in the first fraction of a second explains the universe's flatness, homogeneity, and the origin of structure.
Cosmic acceleration is driven by a constant vacuum energy density (Λ), the simplest addition to general relativity consistent with the data.
Planck's precise measurement of CMB temperature anisotropies matches the six-parameter ΛCDM model, fixing the universe's age, geometry, and composition (5% ordi…
Distant standard-candle supernovae are dimmer than expected in a decelerating universe, evidence that cosmic expansion is accelerating — attributed to dark ener…
The vacuum energy predicted by quantum field theory exceeds the observed dark-energy density by many tens of orders of magnitude — a profound mismatch with any…
Penrose–Hawking theorems show that, under general conditions, general relativity predicts spacetime singularities — a beginning or boundary where the classical…
Guth's inflationary epoch of rapid early expansion explains the universe's flatness, homogeneity, and the absence of relics, and seeds structure from quantum fl…
Planck's measurements of the primordial spectrum are consistent with simple inflation and disfavor many specific models, while not uniquely confirming inflation…
Local distance-ladder measurements of the expansion rate disagree with the value inferred from the CMB at high significance, hinting at unknown physics or syste…
JWST has revealed surprisingly bright, mature galaxies at very high redshift, probing the first hundreds of millions of years and testing models of structure fo…