Planet Types Terrestrial Planet 0 Inner Four Planets

Planet Types Terrestrial Planet 0 Inner Four Planets 0 Closest to the Sun 0 Mercury, Venus, Earth, and Mars 0 Close to the size of Earth 0 Solid, Rocky Surfaces Gas Planet 0 Outer four Planets 0 Farthest from the Sun 0 Jupiter, Saturn, Uranus, Neptune 0 Larger 0 More Gaseous 0 Lack Solid Surfaces

How Do Scientists Know How Our Solar System Formed? 0 Earth Based Studies 0 Use of telescopes in all wavelengths of the electromagnetic spectrum. 0 Data From Probes 0 Scientists Examined 0 1). Why the planets are so different. 0 Especially Outer and Inner Planets 0 2). Asteroids, Meteorites, and Comets.

Formation of Our Solar System Interstellar Clouds 0 Huge Clouds of Dust and Gas in Space 0 Made of Hydrogen and Helium 0 Form Stars and Planets 0 These Interstellar Clouds usually look dark because the dust blocks light. 0 Like Smog 0 Stars behind this cloud can’t shine through it.

Formation of our Solar System Interstellar Cloud 0 But…. Sometimes the light from stars within the cloud causes these interstellar clouds to glow.

Formation of our Solar System Location 0 There are many interstellar clouds found within our Milky Way Galaxy. 0 We look for high amounts of gas and dust. 0 When enough gas and dust is present, scientist think these interstellar clouds will condense because of gravity. 0 Can form a star or planet

Formation of our Solar System Collapsing Interstellar Cloud 0 Cloud begins collapsing slowly. 0 The smaller it gets the faster it begins to collapse and spin 0 This spinning motion with eventually form a rotating disk with a very dense center (core).

Formation of our Solar System 0 Scientist believe that one huge interstellar cloud called the solar nebula formed the Sun and all the planets. 0 The Sun formed first in the center of this cloud. 0 Fits with why our Sun is the brightest most dense thing in our solar system. 0 In the center of the cloud it was the hottest 0 On the edges of the cloud it was the coldest

Formation of our Solar System So What? 0 This difference in temperature as the solar system cooled caused materials to condense and be located in very narrow regions of the solar system 0 This is why we see inner planets and outer planets have such different composition.

Development of Planets 0 Once these materials condense out they begin to collide and stick together. 0 Keep growing larger until they form planetesimals 0 Objects 100’s of km in diameter 0 To produce planets, planetesimals must collide and stick together

Development of Planets Outer Planet Formation 0 1 st planet of the gas to form was Jupiter 0 This is why Jupiter is the largest. 0 Had the most materials to build with 0 Then Saturn and the rest of the gas giants formed 0 Not as large because Jupiter hogged most of the materials; gas, dust, and ice to make itself. 0 Leftovers became Moons

Development of Planets Inner Planet Formation 0 Inner planets were forming from the collision of planetesimals. 0 Made of very different things 0 Sun took all the gas and floating debris away from the inner planets. 0 Why they are rocky and dense 0 Why Moons are rare for inner planets.

Space Rocks 101 Asteroid 0 Leftover pieces of Planetesimals 0 These were never planets 0 Asteroids can collide and break apart.

Space Rocks 101 Meteoroid 0 When an asteroid or any space material falls toward Earth and enters Earth’s atmosphere. Meteor 0 The streak of light produced when a meteoroid burns up in Earth’s atmosphere.

Space Rocks 101 Meteorite 0 When a space object impacts Earth 0 Occurs when all of the meteoroid does not burn up in Earth’s atmosphere 0 Meteor Crater: Arizona 0 Gosses Bluff, Australia

Space Rocks 101 Comets 0 Small icy and rocky bodies with a highly eccentric orbit around the Sun. 0 When Earth is in the way of a comet’s orbit we see a meteor shower