Across
- 3. Greek philosopher who realized the Moon shines by reflecting sunlight and correctly explained the causes of lunar phases.
- 4. Polish astronomer who revived the heliocentric theory, showing that Earth and other planets orbit the Sun rather than the Earth being the center of the universe.
- 7. Greek-Egyptian astronomer whose Almagest described the geocentric model with Earth at the center, dominating astronomy for over a thousand years.
- 8. German mathematician and astronomer who used Brahe’s data to formulate the three laws of planetary motion describing elliptical orbits.
- 9. English scientist who formulated the laws of motion and universal gravitation, explaining how planetary motion confirmed the heliocentric system.
- 11. Ancient Greek observer who created the first star catalog and discovered the precession of the equinoxes, improving measurement of celestial motions.
- 12. Greek mathematician who believed the planets and stars moved in perfect circles and that numbers could explain the harmony of the universe.
- 13. Danish astronomer who made precise naked-eye observations of the planets and stars, creating data that helped disprove the geocentric model.
- 15. Chinese scientist of the Han Dynasty who mapped stars, recorded eclipses and comets, and invented an early seismoscope for studying Earth and sky.
- 18. Babylonian ruler-astronomer who established a fixed calendar era beginning in 747 BCE, allowing long-term tracking of astronomical cycles.
- 20. Arab astronomer who refined the length of the solar year, improved trigonometric astronomy, and influenced later European scientists like Copernicus.
Down
- 1. Librarian of Alexandria who used geometry and shadow measurements to accurately calculate the circumference of Earth.
- 2. Greek philosopher who predicted a solar eclipse around 585 BCE and was among the first to explain celestial events using natural causes instead of mythology.
- 5. Italian astronomer who used the telescope to observe Jupiter’s moons and Venus’s phases, providing strong evidence for the heliocentric model.
- 6. Influential Greek philosopher who argued that Earth was spherical based on lunar eclipses and promoted a geocentric view of the universe.
- 10. Greek astronomer who first proposed a heliocentric model with the Sun at the center, suggesting Earth moves around it long before Copernicus.
- 14. Andalusian Arab astronomer who improved the astrolabe and developed precise solar tables used for navigation and calendar reform.
- 16. Early Greek thinker who proposed that Earth floats freely in space without any physical support, using natural laws instead of myths to describe the cosmos.
- 17. Italian philosopher who supported the heliocentric model and proposed that stars are distant suns surrounded by their own planets.
- 19. Indian mathematician-astronomer who proposed that Earth rotates on its axis and correctly explained lunar and solar eclipses using geometry.