What the Chandrasekhar limit is — 1.4 solar masses, above which electron degeneracy pressure fails and a white dwarf collapses

What the Penrose-Hawking singularity theorems prove — singularities are inevitable in general relativity under certain conditions

Theorems assert black holes and singularities arise from gravitational collapse in spacetime

What type Ia supernovae revealed in 1998 — the expansion of the universe is accelerating, implying dark energy

1998 discovery: Type Ia supernovae showed universe's accelerating expansion, hinting at dark energy

What the Olbers' paradox asks — why is the night sky dark if there are infinite stars (answer: finite age of universe)

Olbers' paradox: Night sky dark due to universe's finite age limiting starlight

How Eddington's 1919 eclipse observation confirmed general relativity — starlight bent by the Sun

Eddington's eclipse observation showed starlight bending due to the Sun's gravity, confirming general relativity

What dark matter candidates include — WIMPs, axions, sterile neutrinos, primordial black holes

Dark matter candidates: WIMPs, axions, sterile neutrinos, primordial black holes

What the cosmological constant problem is — quantum field theory predicts vacuum energy 10^120 times too large

Quantum field theory overestimates vacuum energy by 10^120 times, causing the cosmological constant problem