History
Proper motion was suspected by early astronomers (according to Macrobius, AD 400) but proof was provided in 1718 by Edmund Halley, who noticed that Sirius, Arcturus and Aldebaran were over half a degree away from the positions charted by the ancient Greek astronomer Hipparchus roughly 1850 years earlier.
The term "proper motion" derives from the historical use of "proper" to mean "belonging to" (cf, propre in French and the common English word property). There is no such thing as "improper motion" in astronomy.
Read more about this topic: Proper Motion
Famous quotes containing the word history:
“The history of all countries shows that the working class exclusively by its own effort is able to develop only trade-union consciousness.”
—Vladimir Ilyich Lenin (1870–1924)
“In every election in American history both parties have their clichés. The party that has the clichés that ring true wins.”
—Newt Gingrich (b. 1943)
“It’s not the sentiments of men which make history but their actions.”
—Norman Mailer (b. 1923)