Tag
#gravitation
3 articles
Astronomy & Cosmology
Black Holes
How escape velocity reaching the speed of light defines an event horizon, why the Sun would be 3 km across, and what a black hole would — and would not — do to Earth.
10 minJul 15, 2026
Physics
Kepler's Laws of Planetary Motion
How Kepler's stubborn refusal to ignore a tiny discrepancy in Mars's orbit produced three laws that Newton later derived from a single inverse-square force.
10 minJul 14, 2026
Astronomy & Cosmology
Galaxies and Dark Matter
Vera Rubin's flat rotation curves, gravitational lensing, and the Bullet Cluster all point to the same conclusion: galaxies are embedded in vast halos of unseen mass that gravitates but does not shine.
10 minJul 3, 2026