Comet of the Week: Shoemaker-Levy 9 1993e
Perihelion: 1994 April 18.57, q = 5.380 AU What could perhaps be considered the most successful search program for comets and near-Earth asteroids during the photographic era, i.e., before the advent of CCD-based comprehensive survey programs in the late 1990s, was conducted by renowned planetary geologist Eugene Shoemaker from 1982 to 1994. Usually once a …
Special Topic: Pluto
The discovery of the planet Uranus by British astronomer William Herschel in 1781 essentially doubled the size of the then-known solar system. During the years after Uranus’ discovery astronomers began to notice small discrepancies in its orbital motion, and at least two individuals – a young British astronomer named John Adams, and a French mathematician, …
Another delay slips launch of Mars 2020 to July 30
NASA’s flagship $2.4 Billion Mars 2020 Perseverance rover mission – dedicated to the search for signs of life beyond Earth – has suffered another significant delay to its launch from the Florida Space Coast to the Red Planet. The delay is a significant concern because NASA only has a narrow window until mid-August to launch …
This Week in History: July 5-11
JULY 5, 1687: British physicist Isaac Newton publishes his Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), usually known as the Principia, wherein he lays out what is now known as his Law of Universal Gravitation. Part of Newton’s work in the Principia was based upon his calculations of the Great Comet of 1680 …
Comet of the Week: 9P/Tempel 1
Perihelion: 2005 July 05.31, q = 1.506 AU With the various comprehensive survey programs that are currently operational, the discovery of previously-unknown short-period comets happens all the time these days. The situation was very different during the mid-19th Century, when only a handful of such objects were known, and the discovery of each one was …
Special Topic: Past Spacecraft Missions
The majority of what we know about the various planets and many of the other objects in our solar system has come from spacecraft missions sent to those bodies. Even with the best telescopes here on Earth many of these objects are little more than points of light in the sky, and it was only …