THE 25 GREATEST ASTRONOMICAL FINDINGS OF
ALL TIME
according to the editors of Astronomy
magazine (October 1998) are as follows:
- 1. the discovery of quasars (1963);
- 2. the cosmic microwave background (1965-66);
- 3. pulsars (1967);
- 4. Galileo's observations of the phases of Venus, Jupiter's
moons, and craters on the moon (c1609);
- 5. extrasolar planets (1992);
- 6. supermassive black holes (early1990s);
- 7. Newton's Principia, formulating the mathematics of
our heliocentric system (1687);
- 8. the discovery of Uranus (1781);
- 9. the first known asteroid (1801);
- 10. discovery of Pluto (1930);
- 11. Neptune (1846);
- 12. spectroscopic proof that nebulae are gaseous in
nature (1864);
- 13. recognition of galaxies beyond our own (1923);
- 14. the advent of radio astronomy (1931-32);
- 15. studies of globular clusters help to map the Milky
Way (1918);
- 16. cometary explosion over Siberia (1908);
- 17. an accurate measurement of the speed of light (1675);
- 18. Southern Hemisphere celestial objects cataloged (1834-38);
- 19. Cepheid-variable period-luminosity relationship worked
out (1912);
- 20. Copernicus' DeRevolutionibus sets forth the heliocentric
system (1543);
- 21. Laplace's theory on how the solar system formed (1796);
- 22. a transit of Venus suggests Venus has an atmosphere
(1761);
- 23. the Hertzsprung-Russell diagram for understanding
how stars age (1913);
- 24. scheme for classifying star types (1890);
- 25. the use of parallax for finding a star's distance
from Earth (1838).