{"section":"discoveries","label":"Discoveries & History","count":10,"generatedAt":"2026-03-20","items":[{"slug":"hubble-lemaitre-cosmic-expansion-1929","path":"/discoveries/hubble-lemaitre-cosmic-expansion-1929/","title":"Hubble-Lemaître Cosmic Expansion (1927–1929)","description":"How Vesto Slipher's redshifts, Georges Lemaître's general-relativity solution, and Edwin Hubble's Cepheid distances proved the universe is expanding.","questionOrTopic":"How was the expansion of the universe discovered by Slipher, Lemaître, and Hubble?","epistemicStatus":"strong-observational-evidence","formula":"v ≈ c z = H₀ d  (for z ≪ 1)","keyMetricsCount":4,"sources":["src:shoes-2022","src:planck-2018","src:gcvs-v5"]},{"slug":"cosmic-microwave-background-discovery","path":"/discoveries/cosmic-microwave-background-discovery/","title":"Discovery of the CMB (Penzias & Wilson 1965)","description":"How Arno Penzias and Robert Wilson detected an isotropic 3 K microwave hiss at Bell Labs in 1964–1965, confirming Big Bang cosmology over Steady State.","questionOrTopic":"How did Penzias and Wilson discover the Cosmic Microwave Background and confirm the Big Bang?","epistemicStatus":"strong-observational-evidence","formula":"T_A = (c² / 2 k_B ν²) I_ν  ;  B_ν(T) = (2hν³ / c²) / [ e^(hν / k_B T) − 1 ]","keyMetricsCount":4,"sources":["src:planck-2018"]},{"slug":"jocelyn-bell-burnell-pulsars-1967","path":"/discoveries/jocelyn-bell-burnell-pulsars-1967/","title":"Jocelyn Bell Burnell & Pulsars (1967)","description":"How graduate student Jocelyn Bell Burnell discovered 1.337-second radio pulses at Cambridge in 1967, proving the existence of magnetized neutron stars.","questionOrTopic":"How did Jocelyn Bell Burnell discover pulsars and prove that neutron stars exist?","epistemicStatus":"strong-observational-evidence","formula":"P_min = 2π √(R³ / GM)  ;  P_Crab = 33.1 ms ⇒ ρ̄ > 3π / (G P²) ≈ 10¹⁴ g/cm³","keyMetricsCount":4,"sources":["src:simbad-cds"]},{"slug":"vera-rubin-galaxy-rotation-curves","path":"/discoveries/vera-rubin-galaxy-rotation-curves/","title":"Vera Rubin & Flat Galaxy Rotation Curves","description":"How Vera Rubin and Kent Ford's optical spectroscopic rotation curves of Andromeda (M31) and spiral galaxies established dark matter halos.","questionOrTopic":"How did Vera Rubin and Kent Ford's galaxy rotation curves establish the case for dark matter halos?","epistemicStatus":"strong-observational-evidence","formula":"v_Kepler(r) = √(GM_disk / r) ∝ r^(−1/2)  ;  v_flat(r) = const ⇒ M_halo(<r) = (v_flat² / G) · r ∝ r","keyMetricsCount":4,"sources":["src:simbad-cds","src:planck-2018"]},{"slug":"supernova-1987a-and-neutrino-astronomy","path":"/discoveries/supernova-1987a-and-neutrino-astronomy/","title":"Supernova 1987A & Neutrino Astronomy","description":"How the closest naked-eye supernova in 383 years produced a 24-neutrino burst three hours before optical breakout and confirmed core-collapse physics.","questionOrTopic":"Why was Supernova 1987A a watershed discovery for stellar evolution and neutrino astronomy?","epistemicStatus":"strong-observational-evidence","formula":"E_ν,total ≈ (3 / 5) G M_NS² / R_NS ≈ 3 × 10⁴⁶ J (3 × 10⁵³ erg)  ;  Φ_ν = N_ν / (4π d²)","keyMetricsCount":4,"sources":["src:jwst-archive","src:simbad-cds"]},{"slug":"51-pegasi-b-first-exoplanet-1995","path":"/discoveries/51-pegasi-b-first-exoplanet-1995/","title":"51 Pegasi b: First Sun-Like Star Exoplanet","description":"How Michel Mayor and Didier Queloz discovered a 4.23-day 'hot Jupiter' around 51 Pegasi in 1995, upending classical planet-formation theory.","questionOrTopic":"How did the 1995 discovery of 51 Pegasi b launch modern exoplanet science?","epistemicStatus":"strong-observational-evidence","formula":"a = [ G M_★ P² / (4π²) ]^(1/3) = 0.0527 AU  ;  M_p sin i = 0.46 M_Jup (K_★ = 55.9 m/s)","keyMetricsCount":4,"sources":["src:nasa-exoplanet-archive","src:simbad-cds"]},{"slug":"accelerating-universe-1998","path":"/discoveries/accelerating-universe-1998/","title":"The Accelerating Universe Discovery (1998)","description":"How two independent Type Ia supernova teams discovered in 1998 that cosmic expansion is accelerating, revealing that dark energy dominates the cosmos.","questionOrTopic":"How did astronomers discover in 1998 that the expansion of the universe is accelerating?","epistemicStatus":"strong-observational-evidence","formula":"d_L(z) ≈ (c z / H₀) · [ 1 + ½(1 − q₀) z + O(z²) ]  ;  q₀ = Ω_m / 2 − Ω_Λ ≈ −0.53","keyMetricsCount":4,"sources":["src:shoes-2022","src:planck-2018"]},{"slug":"gw150914-first-gravitational-waves","path":"/discoveries/gw150914-first-gravitational-waves/","title":"GW150914: First Gravitational-Wave Detection","description":"How Advanced LIGO detected the 0.2-second inspiral, merger, and ringdown of two ~30-solar-mass black holes on September 14, 2015.","questionOrTopic":"What did the first direct gravitational-wave detection (GW150914) prove about black holes and general relativity?","epistemicStatus":"strong-observational-evidence","formula":"𝓜_c = (m₁ m₂)^(3/5) / (m₁ + m₂)^(1/5) ≈ 28.1 M_☉  ;  ΔE_GW = (m₁ + m₂ − M_final) c² ≈ 3.0 M_☉ c²","keyMetricsCount":4,"sources":["src:gwtc-3"]},{"slug":"gw170817-multimessenger-kilonova","path":"/discoveries/gw170817-multimessenger-kilonova/","title":"GW170817: First Multimessenger Kilonova (2017)","description":"How the August 17, 2017 binary neutron star merger was observed in gravitational waves, gamma rays, and optical/infrared kilonova light across 70 observatories.","questionOrTopic":"Why is the GW170817 binary neutron star merger a landmark in multimessenger astrophysics?","epistemicStatus":"strong-observational-evidence","formula":"−3 × 10⁻¹⁵ ≤ (v_GW − c) / c ≤ +7 × 10⁻¹⁶  (from Δt = +1.74 s over d = 40 Mpc / 1.3 × 10⁸ ly)","keyMetricsCount":4,"sources":["src:gwtc-3"]},{"slug":"event-horizon-telescope-m87-and-sgra","path":"/discoveries/event-horizon-telescope-m87-and-sgra/","title":"EHT Images of M87* & Sagittarius A* (2019–2022)","description":"How the Event Horizon Telescope resolved the 42- and 52-microarcsecond photon rings of M87* and Sagittarius A*, testing Kerr spacetime across 1,500× in mass.","questionOrTopic":"What did the Event Horizon Telescope's images of M87* and Sagittarius A* prove about black holes?","epistemicStatus":"strong-observational-evidence","formula":"θ_shadow = 2√27 · (G M / c² D) ≈ 10.4 · (G M / c² D)","keyMetricsCount":4,"sources":["src:eht-m87-sgra"]}]}