About 268,000 results
Open links in new tab
  1. Astronomy - Ancient, Celestial, Observations | Britannica

    Nov 14, 2025 · This article focuses on this central story line. In doing so, there is regrettably little space for other fascinating branches of the history of astronomy. New World astronomy, for …

  2. Astronomy | Definition, History, Discoveries, & Facts | Britannica

    Nov 14, 2025 · Astronomy, science that encompasses the study of all extraterrestrial objects and phenomena. Since the late 19th century, astronomy has expanded to include astrophysics, the …

  3. History of astronomy and contributions of Ptolemy, Nicolaus …

    Learn about the history of astronomy and the significant contributions of Ptolemy, Nicolaus Copernicus, and Isaac Newton Written and fact-checked by The Editors of Encyclopaedia …

  4. Astronomy - Stars, Galaxies, Cosmology | Britannica

    Sep 23, 2025 · Astronomy - Stars, Galaxies, Cosmology: In 1835 the French positivist philosopher Auguste Comte cited the chemical constitution of the stars as an example of knowledge that …

  5. Astronomy - Ancient Greece, Stars, Planets | Britannica

    Nov 14, 2025 · Astronomy - Ancient Greece, Stars, Planets: Astronomy is present from the beginning of Greek literature. In Homer’s Iliad and Odyssey, stars and constellations are …

  6. Astronomy Portal | Britannica

    Astronomy, science that encompasses the study of all extraterrestrial objects and phenomena. Until the invention of the telescope and the discovery of the laws of motion and gravity in the …

  7. Astronomy - Techniques, Observations, Measurements | Britannica

    Nov 14, 2025 · Before Galileo Galilei ’s use of telescopes for astronomy in 1609, all observations were made by naked eye, with corresponding limits on the faintness and degree of detail that …

  8. astronomy - Kids | Britannica Kids | Homework Help

    The study of astronomy involves all of the objects outside Earth’s atmosphere. These include the Sun, Moon, planets, stars, galaxies, and all other matter in the universe.

  9. Astronomy - Solar System, Planets, Stars | Britannica

    Sep 23, 2025 · Astronomy - Solar System, Planets, Stars: The solar system took shape 4.57 billion years ago, when it condensed within a large cloud of gas and dust. Gravitational …

  10. Comet - Origins, Formation, & Discovery | Britannica

    Oct 18, 2025 · German mathematician and astronomer Friedrich Bessel suggested that expulsion of material from a comet near perihelion was acting like a rocket motor and propelling the …