tag

#distance-ladder

1 reading card on “distance-ladder”, in chronological order. Part of the full archive.

  1. The Cepheid variable V1 in the Andromeda Galaxy, imaged by the Hubble Space Telescope — the same star Edwin Hubble identified in 1923 to prove that spiral nebulae lie beyond the Milky Way.
    2026-05-26

    The Cepheids

    How a pulsating star became the ruler of the universe.

    Some stars do not shine steadily. They swell and contract on a clockwork rhythm — and the rhythm itself, it turns out, tells us how far away they are.