Daily Extra :
Astronomy & Space Word of The Day
sidereal: Of, relating to, or concerned with the stars. Sidereal rotation is that measured with respect to the stars rather than with respect to the Sun or the primary of a satellite.
Today in History:
1864: Robert G. Aitken, American observer who discovered and catalogued more than 3100 double and binary stars.
1958: The International Geophysical Year (IGY) ends after 18 months.
1961: NASA established a Management Council to ensure the orderly and timely progress in the manned space flight programs. The Council, composed of senior officials from NASA headquarters, Marshall Space Flight Center, and the Manned Spacecraft Center, and chaired by D. Brainerd Holmes, Director of the Office of Manned Space Flight, would meet at least once a month to identify and resolve problems as early as possible and to coordinate the interface problems.