Free Republic

Since the early 19th century, astronomers have reported observations of peculiar flashes of light that periodically emanate from near the center... 1836... Monthly Notices of the Royal Astronomical Society where he told of seeing “a light, resembling that of a star of the 9th or 10th magnitude,” “appeared by glimpses, but at times was brilliant, and visible for several seconds together.” November 1965 edition of Understanding, the author noted observations of a single bright point of light, likened in appearance to a star, that seemed to originate from the center of the crater. Aristarchus crater is host to more than...

Consider the movement of the earth's surface with respect to the planet's center. The earth rotates once every 23 hours, 56 minutes and 4.09053 seconds, called the sidereal period, and its circumference is roughly 40,075 kilometers. Thus, the surface of the earth at the equator moves at a speed of 460 meters per second-or roughly 1,000 miles per hour. As schoolchildren, we learn that the earth is moving about our sun in a very nearly circular orbit. It covers this route at a speed of nearly 30 kilometers per second, or 67,000 miles per hour. In addition, our solar system--Earth...

Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 September 13 Aristarchus Plateau Credit & Copyright: Russell Croman Explanation: Anchored in the vast lava flows of the Moon's Oceanus Procellarum lies the Aristarchus Plateau. Recorded from a backyard observatory on planet Earth, this sharp, amazingly colorful view nicely captures the geologically diverse area, including the brownish plateau, Aristarchus and Herodotus craters, and the meandering Vallis Schroteri. The bright impact crater at the corner of the plateau is...