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:
“No one is ahead of his time, it is only that the particular variety of creating his time is the one that his contemporaries who are also creating their own time refuse to accept.... For a very long time everybody refuses and then almost without a pause almost everybody accepts. In the history of the refused in the arts and literature the rapidity of the change is always startling.”
—Gertrude Stein (1874–1946)
“The history of our era is the nauseating and repulsive history of the crucifixion of the procreative body for the glorification of the spirit.”
—D.H. (David Herbert)
“The history of the world is the record of the weakness, frailty and death of public opinion.”
—Samuel Butler (1835–1902)