The universe, from the solar system to cosmology. The Sun and its life cycle, the planets and why they differ, asteroids and comets, eclipses and the seasons (and the misconception that distance causes them), how telescopes and light tell us everything (spectra, redshift), stars — birth, fusion, the main sequence, and the endings (white dwarfs, neutron stars, black holes), the Milky Way and galaxies, the expanding universe and the Big Bang evidence, exoplanets and how we find them, and spaceflight — orbits (why astronauts float), rockets, and the landmark missions. Authored from NASA’s public-domain materials and standard astronomy references. Every explanation names the mechanism, corrects the popular misconception, and ends with a portable rule. Wonder with rigor — the night sky, actually understood.
• Meets you at your level — never too easy, never too hard.
• Adapts every question to how you’re doing.
• Tracks your level over time. Skill practice, not a test.
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