Understand how our view of the solar system has changed over time and how discoveries made have led to our changing our view of the solar system.Learn planetary characteristics such as number of moons, size, composition, type of atmosphere, gravity, temperature and surface features.Understand the movement of planetary bodies.Understand which planetary characteristics are more important than others when it relates to our understanding of other worlds.Understand how proximity to the sun influences planets.Understand the methods and tools scientists use to learn about other planets and moons in our solar system.Understand the conditions needed for a habitable world and determine if there are habitable worlds in our solar system or outside the solar system.Understand how we look for and study solar systems other than our own.
Complex Knowledge: demonstrations of learning that goaboveandabove and beyond what was explicitly taught.Knowledge: meeting the learning goals and expectations.Foundational knowledge: simpler procedures, isolated details, vocabulary.Limited knowledge: know very little details but working toward a higher level.
Use the planet info sheets to
Find DENSITY for each planetFind a pattern in the solar system and the anomalyRecord any ideas in your notebook
Formation of the Solar System
This Week’s questions:Are all planets created equal?
What events and materials were necessary to form our solar system?How do planets differ from one another and why?
Any model of Solar System formation must explain the following facts:
All the orbits of the planets are prograde (i.e. if seen from above the North pole of the Sun they all revolve in a counter-clockwise direction).All the planets have orbital planes that are inclined by less than 6 degrees with respect to each other (i.e. all in the same plane- ecliptic).Terrestrial planets are dense, rocky and small, while Jovian planets are gaseous and large.
Any model must explain thatPlanets are relativelyisolatedin spacePlanetary orbits are nearlycircularPlanetary orbits all lie in (nearly) the sameplaneDirectionof orbital motion is the same as direction of Sun’srotationDirectionof most planets’ rotation is also the same as the Sun’s
Lets get more specific
6. Most moons’orbitsare also in the same direction7. Solar system is highlydifferentiated8.Asteroidsare very old, and not like either inner or outer planets9.Kuiper belt, asteroid-sized icy bodies beyond the orbit of Neptune10.Oortcloudis similar to Kuiper belt in composition, but farther out and with random orbits
Modeling Planet Formation (cont.)
Statistics of our Solar System
Sun contains 99.8% of the total mass of the solar system74% hydrogen24% helium2% all other elementsMetals - 0.2%Rocks - 0.4%Ices – 1.4%Light gases - 98%
Solar system is evidently not a random assemblage, but has asingle origin.Planetary condensation theory, orNebular Theoryseems to work well.Lots of room forvariation; there are alsoirregularities(Uranus’s axial tilt, Venus’s retrograde rotation, etc.) that must be allowed for by the model.
Modeling Planet Formation
Nebular Theory/Solar Nebular Disk Model
Nebular theoryis the most widely accepted model explaining the formation of the Solar System.First proposed with evidence by:Emanuel Swedenborg, Immanuel Kant, andPierre-Simon Laplace in1734Originally applied only to our own Solar System, this method of planetary system formation is now thought to be at work throughout the universe.The widely accepted modern variant of the nebular theory is Solar Nebular Disk Model (SNDM) or simply Solar Nebular Model.
Steps to a Solar System….in..1, 2, 3ish steps
Step 1 –formation of a star
stars form in massive and dense clouds of molecular hydrogen—giant molecular clouds (GMC).mattercoalescesthrough gravity to create smaller denser clumpsContinue to collapse to formproto-starsthat will eventually end up asBrand new stars!sun-like stars usually take about50 millionyears to form
Step 1 –formation of a star
star formation produces a gaseousproto-planetary diskaround the young starsWhy?As the gas cloud collapses it starts to spin and flatten outThink Figure Skaters and Pizzasformation of planetary systems is thought to be a natural result of star formation
Solar SystemFormationxxx
Why did the gas cloud suddenly collapse?
We have no clueMay have been a passing star near the gas cloudWe think it was a nearby supernova shockwave that smooshed up the gas against itself
Pinwheel Galaxy –21mlyfrom Earth
Step 1 –formation of a star
stars form in massive and dense clouds of molecular hydrogen—giant molecular clouds (GMC).gravitationally unstablematter coalesces to smaller denser clumpsCollapses to formproto-starsthat will eventually end up asBrand new stars!star formation produces a gaseousproto-planetarydisk around the young starsformation of planetary systems is thought to be a natural result of star formationsun-like stars usually take about 50 million years to form
Step 2 – form terrestrial planets
Proto-planetary disks areaccretiondisks which continue to feed the central star.But,If the disk is massive enough, accretions begin in outer areas as wellsmall dust grains and rocks are plentiful and coagulate into kilometers-wide sizedplanetesimalsrapid—100,000 to 300,000 years—formation of Moon- to Mars-sized planetary embryos.the planetesimals go through violent mergers, producing a few terrestrial planets.Planets take around 100 million to a billion years to form
PlanetesimalPlanetesimalCollisions
Pause
Please head to Google Classroom and work on the activity posted there.You need to answer 7 questions, so you have 7 minutes.Well, now less than 7 minutes…..The worksheet is posted on the assignment as a pdfYour answer sheet is a google doc with your name already on it (you have to OPEN THE ASSIGNMENT to see it)
Step 2 – form terrestrial planets
Proto-planetary disks areaccretiondisks which continue to feed the central star.But,If the disk is massive enough, accretions begin in outer areas as wellsmall dust grains and rocks are plentiful and coagulate into kilometers-wide sizedplanetesimalsrapid—100,000 to 300,000 years—formation of Moon- to Mars-sized planetary embryos.the planetesimals go through violent mergers, producing a few terrestrial planets.Planets take around 100 million to a billion years to form--Gases don’t condense into ice but instead get blown outward by the solar wind
Step 3 –form the gas giants
beyond the “snow line” planetary embryos begin to form and are mainly made of various ices.Now you can also use things like frozenmethane, water and ammoniaAlso several times more massive than the inner part of the diskIces stick together better than rocks, so they grew in size more efficientlyformation of giant planets is a more complicated processsome embryos appear to continue to grow and eventually reach 5–10 Earth masses—the threshold value, which is necessary to begin accretion of thehydrogen–heliumgas from the disk.accumulation of gas by the core is initially a slow process, which continues for several million yearsafter the forming proto-planet reaches about 30 Earth masses it accelerates and proceeds in a runaway manner.
3 –gas giants
Jupiter and Saturn–like planets are thought to accumulate the bulk of their mass during only 10,000 years. The accretion stops when the gas is exhausted.Because their gravity is so strong, the newly formed planets can migrate over long distances during or after their formation.The ice giants like Uranus and Neptune are thought to be failed cores, which formed too late when the disk had almost disappeared.
The Nebular Theory
This accounts for the other solar system stuff too…
MoonsComets/icyplanetesimalsAsteroidsDwarf planetsKuiper belt &Oortcloud objectsRings
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