orbital mechanics

5 articles · All tags

• Julian vs Gregorian Calendar: Why the Change Happened
  The Gregorian calendar was adopted from 1582 because the Julian year ran about 11 minutes too long, leaving the dates about ten days out of step with the seasons.
• Why Does the Moon Have Phases? A Plain Explanation
  The Moon has phases because the Sun always lights half of it, and our view of that lit half changes as the Moon orbits Earth every 29.5 days, not Earth's shadow.
• Solar Eclipses: How They Work and Why Totality Is Rare
  A solar eclipse happens when the Moon passes between Earth and the Sun. Learn the types, why totality is rare, the Saros cycle, and how to watch one safely.
• Kepler's Laws of Planetary Motion
  The three empirical laws describing planetary orbits: ellipses, equal areas in equal times, and the relation between period and orbit size.
• Tidal Locking
  Why one side of a moon or planet permanently faces its partner: the gravitational dance that synchronizes rotation with orbit.