Knowra Discovery and exploration of the Solar System Discovery and exploration of the Solar System The history of identifying and investigating the Sun, planets, moons, and smaller Solar System objects through observation, theory, and spacecraft exploration.
Babylonian astronomy : The systematic observation and mathematical recording of celestial phenomena in ancient Babylonia. Babylonian records of planetary motion supplied observations later used to refine astronomical models.
Telescope : An instrument that collects and focuses electromagnetic radiation to reveal distant objects. Telescopes exposed moons, planetary details, and faint bodies unavailable to the naked eye.
Galilean moons : The four largest moons of Jupiter, discovered by Galileo in 1610: Io, Europa, Ganymede, and Callisto. Their orbit around Jupiter showed that not every celestial body circles Earth.
Tycho Brahe : A Danish astronomer whose precise naked-eye measurements of planetary positions preceded the telescope. His exceptionally accurate observations enabled Kepler to derive the laws of planetary motion.
Planetary science : The scientific study of planets, moons, and other planetary systems and their formation and evolution. Observations and missions built this interdisciplinary field around comparative study of worlds.
Geocentric model : A model placing Earth at the center of the cosmos, with celestial bodies moving around it. It dominated ancient and medieval astronomy before the heliocentric account gained acceptance.
Transit of Venus : The passage of Venus across the Sun's disk as seen from Earth. Timed observations from widely separated locations helped estimate the astronomical unit.
Uranus : The seventh planet from the Sun, discovered by William Herschel in 1781. Its discovery extended the known planetary system beyond the classical planets visible to the naked eye.
William Herschel : A German-born British astronomer who discovered Uranus and made extensive observations of the sky. His discovery showed that new planets could be found beyond the ancient naked-eye inventory.
Astrobiology : The study of life's origins, evolution, distribution, and future in the universe. Discoveries of subsurface oceans and diverse planetary environments sharpened questions about life beyond Earth.
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