#astronomy

8 articles

The Doppler Effect

Motion crowds the waves in front of a source and stretches the ones behind. That single geometric fact explains sirens, sonic booms, weather radar, and the expanding universe.

10 min read·Jul 19, 2026

Astronomy & Cosmology

Telescopes: Gathering Light, Resolving Detail

Why a telescope's real job is gathering light and resolving detail — set by aperture area and diffraction — while magnification is cheap, swappable, and often useless.

10 min read·Jul 16, 2026

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 min read·Jul 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 min read·Jul 14, 2026

Astronomy & Cosmology

How We Find Other Worlds

Exoplanets are found not by their light but by the shadow they cast and the tug they exert — a periodic dip in starlight and a Doppler wobble in the star's spectrum.

9 min read·Jul 12, 2026

Astronomy & Cosmology

Gravitational Waves

How accelerating masses shake spacetime, why the resulting strain is only ~10⁻²¹, and how LIGO's laser interferometers detect a ripple that stretches a 4 km arm by less than a thousandth of a proton's width.

10 min read·Jul 6, 2026

Chemistry

Spectroscopy: Reading Matter with Light

Atoms absorb and emit light only at wavelengths set by their electron energy levels, so light carries a fingerprint of composition — the basis of knowing what stars, galaxies, and unknown compounds are made of, remotely.

10 min read·Jul 4, 2026

Astronomy & Cosmology

How the Solar System Formed

How a collapsing cloud of gas and dust spun itself into a flat disk 4.6 billion years ago, why the Sun holds almost all the mass, and how the frost line split the planets into small rocky worlds and distant giants.

10 min read·Jul 2, 2026