SPONGE n n What objects make up our solar system ?

Solar System n n Solar System – composed of the Sun (a star) and the planets and other bodies that travel around the Sun.

Percentages n n Sun: 99.85% n n Planets: 0.135% n n Comets: 0.01% ? n n Moons: % n n Minor Planets: % n n Meteoroids: % n n Interplanetary Medium: %

Solar System Structure n n The planets revolve around the Sun in orbits that lie close to a common plane. (Mercury 7 o ; Pluto 17.2 o ) n n All planets orbit the sun in a counter- clockwise fashion as seen from above the north pole of the sun. Orbits are contained within a very narrow disk or plane. n n Most orbits are elliptical with the exception of Mercury and Pluto.

Small Rocky Worlds n n Terrestrial Planets – the small, dense, rocky planets of the inner solar system.  Mercury  Venus  Earth  Mars

Terrestrial Planets

Big Gaseous Worlds n n Gas Giants – the large, gaseous planets of the outer solar system.  Jupiter  Saturn  Uranus  Neptune – –All gas giants have rings!

Gas Giants

Pluto n n Pluto – doesn’t fit either category. Pluto is a small icy world clearly different from either the Terrestrial and Gas Giant worlds.

Acronym for Order of Planets nMnMnVnVnEnEnMnMnJnJnSnSnUnUnNnNnMnMnVnVnEnEnMnMnJnJnSnSnUnUnNnN

Age of the Solar System n n Oldest Rocks dated on Earth ~ 3.9 billion years, however the Earth’s own volcanism and plate-tectonics erase most of the evidence!! n n Lunar Rocks are dated to 4.48 billion years. n n Meteorites ~ 4.6 billion years n n Sun estimate based on all the circumstantial evidence ~ 5 billion years.

Formation of a Solar System n n Solar Nebula – the nebula that formed into the solar system.

n n OUT: Summarize the difference between terrestrial planets and gas giants.