DotXivAstrophysics · Cosmology · Olympiad
Understand the universe.
From first principles.
Rigorous, beautifully explained notes and problem sets for curious minds — from your first orbit to the edge of the observable universe.
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pages of rigorous
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One shared sky.
questions worth
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Celestial mechanics
From Keplerian motion to perturbation theory.
Click to explore ↗Observational astronomy
Read the sky through photons, spectra, and surveys.
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The physics of stars, from birth to remnants.
Click to explore ↗Galactic astronomy
Structure, dynamics, and the cosmic web.
Click to explore ↗Cosmology notes
The origin, evolution, and ultimate fate of the universe.
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Derivations, not declarations
We show the path between the question and the equation.
Olympiad tested
Problems that reward intuition, persistence, and a little beautiful stubbornness.
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