Tag
#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.
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.
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.
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.
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.
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.
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.
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.