2 Section 27.1 – Formation of the Solar System What exactly is a solar system anyway?Consists of the Sun, all the planets, and any other body that revolves around the SunAnd what exactly is a planet?Any primary bodies that orbit the Sun (Earth, Venus, etc.)Where did it all come from?
3 Nebular Hypothesis1976, French mathematician Pierre-Simon, marquis de Laplace came up with explanation for creation of the solar systemSun and other planets came together and condensed at the same time out of a rotating cloud of gas and dust
4 Solar NebulaSolar Nebula – the rotating cloud of gas and dust from which the sun and planets formedAlso any nebula from which stars and planets (outside our solar system) may form99% of the material inthe Sun is matter thatwas originally in thesolar nebula
5 Steps in the process1.) Start with a solar nebula (rotating cloud of gas and dust)2.) Contraction of gas and dust into rotating disk3.) Cooling causing condensing into tiny (dust sized) solid particles4.) Collisions between these form larger bodies5.) The larger bodies accrete (or build up) to form planets
6 Let’s break it down into steps… #1 Solar NebulaWhat “fuels” the nebula?Energy from collisions and pressure from gravity makes the center of the nebula HOT and DENSE99% of all the material in the nebula is in the sunThink back to our solar nebula activity! Where is most of the material located?
7 Next Step…#2 The nebula flattens as it rotates and gets warmer near the centerStarts to look like a diskTemperature begins to rise more at the centerThink ice skater doing a spin!!
8 Third Step… #3 Things begin to form Planetsimals begin to form within the swirling diskAs they grow, gravitational pull increases and they continue to grow morePlanetesimals - “mini planets” or small bodies from which a planet originated in the early stages at the beginning of the solar system)
9 Fourth Step…#4 Small planetesimals collide with larger ones and the planets begin to growAs the planetesimals get bigger, their gravity grows and they become protoplanetsProtoplanets areplanetesimals that havecollided due to gravityto form larger bodies
10 Fifth Step…#5 The extra dust and gas is gradually removed from the solar nebula by the collisionsThe removal of the other material leaves mainly just planets around the sun and creates a new solar system
11 Creation of PlanetsKEY THOUGHT: THE FEATURES OF A NEWLY FORMED PLANET DEPEND ON THE DISTANCE BETWEEN THE PROTOPLANET AND THE DEVELOPING SUNIT ALL RELATES TO GRAVITYWhat has the most gravity in a solar system?THE SUN!
12 Inner vs. Outer PlanetsInner protoplanets (which are?) contained lots of heavy elementsVenus, Earth and Mercury contain lots of nickel and ironThese elements stuck around because they couldn’t be blown away or evaporated by the Sun’s heat and wind
13 More about inner planets As the inner planets formed, dense material sank towards the middle of the planets and lighter material stayed on top, forming layersInner planets have solid surfaces (like Earth)Inner planets are smaller, rockier, and denser than outer planets
14 Inner vs. Outer PlanetsOuter protoplanets (which are?) contained lighter elementsJupiter, Saturn, Uranus, and Neptune contain hydrogen, helium, and methaneThese planets are cold, have low densities, and are HUGE
15 More on outer planets Outer planets known as “Gas Giants” because: Mostly made of gases and are low densityJupiter’s density is only 24% of Earth’s but Jupiter’s diameter is 11 times Earth’sHave liquid cores and gas outer layers
16 Pluto! Not considered an inner or outer planet Characteristics of PlutoVery small (smaller than Earth’s Moon!)Very COLD – it’s an ice ball made of frozen rock and gas
17 More on PlutoRecently, scientists found many, many objects in the universe that are similar to Pluto beyond NeptuneBecause Pluto is more like these other common objects rather than other planets, it is no longer considered a PLANET.
18 Formation of Solid Earth 3 sources of energy contributed to the original HOT temperatures on Earth:Energy produced during collisions with other planetesimalsIncreased pressure on inner layers of Earth from weight of outer layersRadioactive materials were abundant in Earth during its formation
19 Early Solid EarthDifferentiation – the process that occurred as Earth developed where denser molten materials sank to the center and less dense materials were forced to the outer layers
20 3 Layers of EarthCore – the center of Earth that is made of dense rocksNickel and Iron most commonMantle – Earth’s thick middle layerIron and Magnesium-rich rockCrust – Outermost layer of EarthLeast dense material, including silica-rich rocks
21 Present Solid EarthAs time went on, Earth’s surface cooled enough for solid rock to formWhile Earth already had distinct layers, the surface continued to change from:Heat inside the EarthImpacts and interactions with the forming atmosphere
22 Formation of Earth’s Atmosphere Like the Earth’s interior, the atmosphere formed due to differentiationHydrogen and helium (lightest gases) rose to surface of the EarthSO, the early atmosphere was mostly made of H and He
23 The Early AtmosphereHydrogen and helium gas are so light, Earth’s gravity couldn’t hold them in for longThe Sun’s heat heated them up and they blew away into spaceAlso, Earth’s magnetosphere (protects our current atmosphere) was possibly not developed fully
24 OUTGASSING (no that’s not what you think it is) The Earth’s surface continued to evolve with creation of volcanoes and other land formsVolcanoes released additional gases into atmosphere:Water vapor, carbon dioxide, nitrogen, methane, sulfur dioxide, and ammoniaWhat’s missing from this list?????
25 More on outgassingGases released from volcanoes then interacted with sun light and heatBreakdown of ammonia and water vapor into OZONE (or three oxygen)Ozone is a shield against UV rays of the Sun
26 The PRESENT Atmosphere Later, some plant life evolved that used carbon dioxide from the atmosphere to produce food (photosynthesis!)OXYGEN is the main product of photosynthesisAbout 2 billion years ago, the amount of oxygen in the atmosphere increased a lotComposition of “air” is now stable
27 Oceans – Where did they come from? Possibly from space!Some icy bodies (ex. comets) collided with Earth and added water vapor to atmosphereAs Earth cooled, water vapor condensed to liquid rainFirst ocean was probably FRESH water
28 Why are oceans salty?Although first oceans were likely fresh, as water flowed over land and rocks, it dissolved minerals and salts carried them to the oceansAfter the water cycle was in place, the concentration of salt in oceans increased
29 How did Oceans Affect Atmosphere? Scientists believe the early atmosphere was changed as oceans began to dissolve carbon dioxideCurrent atmosphere likely has more carbon dioxide than original atmosphereEarth’s early climate likely cooler than todayDoes CO2 in the atmosphere affect climate today????
30 ASSIGNMENTSOutline Section 27.1 and Key Terms 27.1Due: