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The Solar System
The Sun, eight planets, their moons, and the small bodies that share the same gravitational neighborhood. The nearest astronomy — and often the most rewarding in a small telescope.
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Why Orbits Work: Kepler's Three Laws in Plain Language
The three laws that describe every orbit in the solar system — stated in words, backed with real numbers for the planets, and grounded in Newton's gravity.
Dmitry Shteynbuk · April 11, 2026 · 3 min read
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3 publishedThe Solar System·
Comets, Asteroids, and Meteors: What's the Difference?
Three small-body categories that get confused constantly, with clear definitions and the real numbers on size, orbit, and composition.
Dmitry Shteynbuk · 3 min read
/articles/comets-asteroids-meteorsThe Solar System·
The Moon's Phases, Finally Explained Properly
The phases of the Moon are pure geometry: the Sun lights one hemisphere, and we see how much of that hemisphere from a different angle each night.
Dmitry Shteynbuk · 3 min read
/articles/moon-phasesTerms to know
Full glossary →- Astronomical unit (AU)
- The average Earth–Sun distance: 149,597,870.7 kilometers.
- Conjunction
- When two objects appear close together in the sky.
- Opposition
- When a planet is opposite the Sun in Earth's sky — up all night.
- Elongation
- The angular separation between a planet and the Sun.
- Ecliptic
- The apparent yearly path of the Sun through the sky.
- Meteor
- The streak of light from a small piece of interplanetary debris burning up in Earth's atmosphere.