PHYS 284 Lecture Notes - Lecture 9: Giant Planet, Copernican Revolution, Pioneer 11

• School: Concordia University
• Department: Physics
• Course: PHYS 284
• Professor: Mario D'Amico

Document Summary

Jupiter and saturn are easily visible in the night sky, but the naked eye cannot discern any details about their nature. Uranus and neptune were discovered in 1781 and 1846, respectively (see special topic, page 314), so they were unknown even during the copernican revolution. Astronomers first recognized the immense sizes of jupiter and saturn about 250 years ago. Recall that (cid:449)e (cid:374)eed to k(cid:374)o(cid:449) (cid:271)oth a(cid:374)gula(cid:396) size a(cid:374)d dista(cid:374)(cid:272)e to (cid:272)al(cid:272)ulate a(cid:374) o(cid:271)je(cid:272)t"s t(cid:396)ue size. Knowing the scale of the solar system also told scientists the distances of orbiting moons, and because the orbital periods of the moons were easy to measure, the orbital distances allowed scientists to use. Ne(cid:449)to(cid:374)"s (cid:448)e(cid:396)sio(cid:374) of keple(cid:396)"s thi(cid:396)d la(cid:449) to calculate the masses of the jovian planets. Together, the measurements of size and mass revealed the low densities of the jovian planets, proving that these worlds are very different in nature from earth.