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10 April 2014 11:44 am ,
Vol. 344 ,
The Pyrenean ibex, an impressive mountain goat that lived in the central Pyrenees in Spain, went extinct in 2000. But a...
Tight budgets are forcing NASA to consider turning off one or more planetary science projects that have completed their...
Ebola is not a stranger to West Africa—an outbreak in the 1990s killed chimpanzees and sickened one researcher. But the...
In an as-yet-unpublished report, an international panel of geoscientists has concluded that a pair of deadly...
Tropical disease experts tried and failed before to eradicate yaws, a rare disfiguring disease of poor countries. Now,...
Since 2002, researchers have reported that agricultural communities in the hot and humid Pacific Coast of Central...
Balkan endemic kidney disease surfaced in the 1950s and for decades defied attempts to finger the cause. It occurred...
- 10 April 2014 11:44 am , Vol. 344 , #6180
- About Us
Discoveries by Induction
26 February 1999 6:45 pm
is the birthday of Dominique François Jean Arago, a French astronomer and physicist born in 1786. Arago is best known for his discovery of the chromosphere--the sun's lower atmosphere--which is composed primarily of hydrogen gas, and for his accurate estimates of the diameters of the planets. In physics, Arago found that a rotating copper disk deflects a magnetic needle held above it, a phenomenon later explained in terms of magnetic induction. He also showed that light waves move more slowly through a dense medium than through air. Arago entered politics in 1848 as Minister of War and Marine and was responsible for abolishing slavery in the French colonies.
[Source: Trevor I. Williams, Ed., A Biographical Dictionary of Scientists (John Wiley & Sons, ed. 3, New York, 1982).]