RESEARCH BASE
Search 3,721 documents across 34 fields — every claim tier-rated by evidence
3,633 are the core, quality-scored corpus (34 lettered sections — see How We Work); the remaining 88 are cross-corpus synthesis documents (68 InterDocs, 12 Connections, 8 Theories) also indexed here.
2,646 results for "SI second" — page 43 of 133
Q_1_02 — Big Bang & Alternative Cosmologies
The Big Bang theory — that the observable universe expanded from an extremely hot, dense state ~13.8 billion years ago — is supported by three independent pillars: cosmic microwave background radiation (CMB, discovered 1
Q_1_04 — Multiverse Theories
The multiverse hypothesis — that our observable universe is one of many — arises independently from at least four domains of physics and mathematics: quantum mechanics (Everett's Many-Worlds, 1957), inflationary cosmolog
Q_1_06 — Dark Matter and Dark Energy
Approximately 95% of the universe's total mass-energy content is invisible: ~27% dark matter and ~68% dark energy. Dark matter was first inferred by Fritz Zwicky (1933) from galaxy cluster dynamics and confirmed by Vera
Q_1_08 — Observable Universe and Cosmic Web
The observable universe has a diameter of ~93 billion light-years (comoving distance) and contains an estimated 2 trillion galaxies (Conselice et al. 2016), ~10²⁴ stars, and ~10⁸⁰ atoms. But its most striking feature is
Q_1_14 — Vacuum Energy and the Cosmological Constant Problem
The cosmological constant problem is widely regarded as the most severe fine-tuning problem in all of physics. Quantum field theory predicts that the vacuum of spacetime is not empty but seethes with zero-point fluctuati
Q_1_15 — Dark Energy Models and Quintessence
The accelerating expansion of the universe, discovered in 1998 via Type Ia supernovae, demands an explanation. The simplest model — Einstein's cosmological constant Λ with equation of state $w = p/\rho = -1$ exactly — fi
Q_1_23 — White Holes: Theory and Implications
A white hole is the time-reversed analogue of a black hole — a theoretical spacetime region from which matter and light can emerge but into which nothing can enter, as opposed to a black hole's event horizon from which n
Q_1_11 — Cosmological Redshift and the Hubble Law
The discovery that distant galaxies' light is systematically shifted toward longer (redder) wavelengths was the first observational evidence that the universe is expanding. Vesto Slipher's spectroscopic measurements (191
Q_1_13 — Cosmic Strings and Topological Defects
Cosmic strings are one-dimensional topological defects that may have formed during symmetry-breaking phase transitions in the early universe, analogous to cracks in ice or vortex lines in superfluids. Predicted by Kibble
Q_1_09 — Fate of the Universe
How will the universe end? This question has moved from philosophy and eschatology into hard physics, driven by the 1998 discovery that the universe's expansion is ACCELERATING (Riess et al. 1998; Perlmutter et al. 1999
Q_1_01 — The Anthropic Principle & Fine-Tuning of the Universe
The universe appears to be astonishingly fine-tuned for the existence of complex life. Alter the cosmological constant by 1 part in 10¹²⁰, or the strong nuclear force by 0.5%, or the ratio of electromagnetic to gravitati
Q_4_09 — Statistical Mechanics: Boltzmann, Ensembles, and Thermodynamic Emergence
Statistical mechanics is the bridge between the microscopic world of atoms and molecules (governed by classical or quantum mechanics) and the macroscopic world of thermodynamics (governed by temperature, pressure, entrop
Q_4_05 — Modified Gravity Theories
Modified gravity theories propose that the observed discrepancies between luminous matter and gravitational dynamics — traditionally attributed to dark matter — instead result from a breakdown or modification of Newtonia
Q_4_02 — Gravitational Wave Astronomy
Gravitational waves — ripples in spacetime predicted by Einstein's general relativity (1916) and first directly detected by LIGO (Laser Interferometer Gravitational-Wave Observatory) on September 14, 2015 (event GW150914
Q_4_31 — Water Memory, Anomalous Properties, and Homeopathy Critique
The "water memory" hypothesis — the claim that water retains a structural or informational imprint of substances previously dissolved in it, even after dilution past Avogadro's number — sits at the center of one of 20th-
Q_4_06 — Baryon Asymmetry and Matter-Antimatter
One of the deepest unsolved problems in physics is the baryon asymmetry of the universe — the observed predominance of matter over antimatter. For every ~10⁹ photons in the cosmic microwave background, there is approxima
Q_4_22 — Tribology: Friction, Wear, and Lubrication
Tribology — the science of interacting surfaces in relative motion, encompassing friction, wear, and lubrication — was named by H. Peter Jost in a 1966 UK Department of Education and Science report estimating that improv
Q_4_23 — Chaos Theory and Nonlinear Dynamics: Deterministic Unpredictability and Complex Systems
Chaos theory is the branch of mathematics and physics studying deterministic systems whose long-term behavior is effectively unpredictable due to sensitive dependence on initial conditions — popularly known as the "butte
Q_4_18 — Spectroscopy: Principles, Methods, and Applications
Spectroscopy — the study of the interaction between matter and electromagnetic radiation — is one of the most powerful and versatile analytical methods in all of science. From Joseph von Fraunhofer's discovery of dark ab
Q_4_03 — General Relativity Tests and Confirmations
Albert Einstein's general theory of relativity (GR, 1915) has survived over a century of increasingly precise experimental tests, ranging from Solar System measurements to strong-field astrophysical observations. The cla
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