Ch 23 Touring Our Solar System 23.1 The Solar System 23.2 The Terrestrial Planet 23.3 The Outer Planets 23.4 Minor Members of the Solar System

Ch 23 Touring Our Solar System 23.1 The Solar System 23.2 The Terrestrial Planet 23.3 The Outer Planets 23.4 Minor Members of the Solar System

Ch 23.1 The Solar System Terrestrial planets- Small Rocky Dense Mercury Venus Earth Mars Jovian Planets- Huge gas giants Jupiter Saturn Uranus Neptune Size is the biggest difference between Terrestrial and Jovian. Chemical make-up and also rate of rotation are other ways the two groups of planets differ

Ch 23.1 The Solar System Interiors of the planets Terrestrial-Rocky and Metallic with minimal gases Jovian- Large amounts of gas (Water, Ammonia, and methane) with minimal amounts of metals Atmospheres of the planets Terrestrial- Small, thin atmosphere from less gravity Jovian- Thick atmosphere of hydrogen, helium, methane and ammonia

Formation of the Solar System A cloud of dust and gas in space is called a nebula. These this gaseous clouds begin to rotate slowly and contract gravitationally. Nebular Theory The sun and planets formed from a rotating disk of dus and gases. As the speed of rotation increased, the disk flattened out. Planetesimals colliding matter around the center of the disk, eventually formed the planets.

Nebula Theory

23.2 The Terrestrial Planets Mercury- The innermost planet, 2 nd smallest, barely bigger than our moon Does not reflect (6%) majority of light since it has no atmosphere Has many ridges from cooling and shrinking One day on Mercury takes 59 Earth days

23.2 The Terrestrial Planets Venus- Earths twin; Similar size, mass and density Second brightest object in the night sky Hottest planet in our solar system Radar reports indicate a very active surface from volcanoes and tectonic activities Over 1500 giant volcanoes Over 475oC from greenhouse effect Atmosphere is 97% Carbon Dioxide (Holds Heat)

23.2 The Terrestrial Planets Mars- The Red planet, Easiest planet to see from Earth Atmosphere is very thin, but still extensive dust storms occur which lead to color changes on the planet ( 270 km/h) No liquid water but frozen water covered by solid carbon dioxide was sampled by probes (Rovers Opportunity & Viking) Many scientist believe evidence indicates that Mars had a water cycle similar to Earth

Jupiter-1/800 of the sun, Largest planet by far, If 10 times as big it would ignite into a star, 63 moons including the largest in the solar system (Ganymede) 23.3 The Outer Planets Jupiter has the mass that is 2.5 times greater than all other planets and moons combined Wind systems create dark and light bands, one area called the Red Spot is where a constant cyclonic storm occurs Has fine dust particles forming rings which are thought to come from meteorites hitting its moons

23.3 The Outer Planets Saturn- 1 Saturn year is 29.46 Earth years, twice as far from the sun at Jupiter but chemically very similar, 31 moons The most prominent feature of Saturn is its system of rings, broken into 4 categories rated on size of particles Has 2nd largest moon in the solar system (Titan) which is larger than Mercury

23.3 The Outer Uranus- Rotates on its side or parallel with the plane or orbit Planets Has a ring system of at least 9 belts Neptune- 13 moons, Windiest place in all of the solar system Methane atmosphere absorbs red light and reflects blue light which is why this planet looks blue

Pluto 23.3 The Outer Planets 40 times farther away from the sun than the earth Orbit is so skewed that it travels inside the orbit of Neptune in which is resided from 1979 to Feb 1999 Its moon Charon has a diameter of over half its size which is exceptional Its size, composition leads scientists to the thoughts it shouldn t be a planet, but to not dishonor astronomical history and confuse the public they have not officially changed it.

23.4 Minor Members of the Solar System Most Asteroids lie between the orbits of Mars and Jupiter. Small, rocky bodies - flying mountains. They have orbital periods of 3-6 years Comets are pieces of rocky and metallic materials held together by frozen gases, such as water, ammonia, methane, carbon dioxide, and carbon monoxide As comets approach the sun they start evaporating the frozen gases and creates a glowing head called a Coma Tails of a comet are always pointed away from the sun

23.4 Minor Members of the Solar A Meteor is a small solid particle that travels through space, enters our atmosphere and burns up Shooting star, Meteor Shower System Small solid particles that do not enter our atmosphere are called Meteoroids. A meteoroid that actually reaches Earth s surface is called a Meteorite

23.4 Minor Members of the Solar System Most meteoroids originate from any one of the following three source 1) Interplanetary debris that was not gravitationally swept up by the planets during the formation of the solar system 2) Materials from the Asteroid Belt 3) The solid remains of comets that once traveled near Earths orbit

23.4 Minor Members of the Solar System Scientists used evidence from meteorites, moon rocks, and Earth rocks to determine the age of the solar system. Radiometric dating shows that the oldest meteorites formed more than 4.5 billion years ago. Moon rocks have been dated to about 4.6 billion years. The oldest rocks found on Earth are 4 billion years old.