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The 25 Greatest Astronomical Findings of All Time

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No matter what your interests are in science or engineering, or any other area for that matter, the list below should prove of value to you and your students. I've often thought that if I could somehow be teleported back to say ancient Greece, and could bring only one "thing" in my house with me that wasn't a book or other written document, it would be my 100 year-old 6" refracting telescope.


Rick Reis

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In chronological order.

Expanded from PHYSICS NEWS UPDATE, The American Institute of

Physics, September 22, 1998. [Annotations are added by KASTN.]

The Korean-American Science and Technology News,

Issue 98-36 (No. 169), October 7, 1998.

The editors of Astronomy magazine (October 1998) picked the

25 GREATEST ASTRONOMICAL FINDINGS of all time, as follows:

01. 1543: Copernicus' De Revolutionibus sets forth the heliocentric system.

[ED. Copernicuss De Revolutionibus Orbium Coelestium

(On the revolutions of the celestial bodies) set forth

planetary motions based on the assumption that Earth and

other planets revolve around the sun. On May 24 of that

year, Nicolas Copernicus, Polish astronomer, died.]

02. 1610: Galileo's observations of the phases of Venus,

Jupiter's moons, and craters on the moon.

03. 1675: An accurate measurement of the speed of light.

[ED. Ole Roemer, Danish astronomer and a monk, made

the first meaningful measurement of the speed of light,

obtaining a value that is about 80% of its known value.]

04. 1687: Newton's Principia

05. 1761: A transit of Venus suggests Venus has an atmosphere.

[ED. Since orbits of the planets are in virtually the same

plane, Venus (and Mercury) can be seen as a dot passing in

front of the sun. Such an event is called a transit.

In the 1761 transit of Venus, it was discovered that Venus

had an atmosphere.]

06. 1780: Discovery of Uranus.

[ED. Uranus was discovered on March 13 by William Herschel.]

07. 1796: The nebular hypothesis

[ED. The nebular hypothesis, that the solar system evolved

from a condensing cloud of gas, was first put forth by

Pierre-Simon Laplace in his Explanation of the system of

the world.]

08. 1801: Discovery of the first asteroid.

[ED. By Giuseppe Piazzi.]

09. 1834-38: Southern Hemisphere celestial objects catalogued.

[ED. Begun in 1834 by John Frederick Herschel.]

10. 1838: The use of parallax for finding a star's distance

from Earth

11. 1846: Discovery of Neptune.

[ED. On September 23 of that year, Johann Galle discovered

the planet Neptune.]

12. 1864: Spectroscopic proof that nebulae are gaseous.

[ED. By Sir William Huggins.]

13. 1890: Scheme for classifying star types

14. 1908: Cometary explosion over Siberia

15. 1912: Cepheid-variable period-luminosity relationship

worked out

[ED. This turned out to be the key to unlocking the

distances to galaxies outside the Milky Way.]

16. 1913: The Hertzsprung-Russell diagram for understanding

how stars age.

17. 1918: Studies of globular clusters help to map the

Milky Way

18. 1923: Recognition of galaxies beyond our own

19: 1930: Discovery of Pluto

20. 1931-32: The advent of radio astronomy

21. 1963: Discovery of quasars

22. 1965-67: The cosmic microwave background

[ED. Arno Penzias and Robert Wison accidentally find the

remnants of the Big Bang.]

23. 1967: Discovery of pulsars

[ED. Jocelyn Bell discovered the first pulsar, CP 1919, in July;

her supervisor Anthony Hewish was given a share of the 1974

Nobel Prize for this feat, but Bell was not so recognized.]

24. Early 1990s: Supermassive black holes

25. 1992: Discovery of extrasolar planets