Astronomy 1021 Chapter Notes - Chapter 9: Snakebite, Ecliptic, Nuclear Winter

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Chris Racknor

Document Summary

Planets from antiquity: mercury, venus, earth, mars, jupiter & saturn. Uranus: (accidentally) discovered in 1781 by william herschel. Italian monk piazzi discovered moving object jan 1st 1801. Convinced it was missing planet, called it ceres. Soon another planet" was found near the same distance from the sun! About 15 months later, another moving object was discovered, and was called pallas. Pallas has about the same average distance to the sun as ceres. So there were now 2 planets known where there should have been 1 missing planet. Coining a name: asteroids look like moving point-like stars. Ceres and pallas resembled point-like stars even through the most powerful telescopes of that time; all known planets appeared as a full disk. Sir william herschel coined the term asteroids for these objects, and the name stuck. 1801 : 1 asteroid (ceres, 2. 77 au) 1807 : 4 asteroids (+juno 2. 67 au, vesta 2. 36 au) 1845 : 5 asteroids (+astraea, 2. 57 au)