Bellwork 10/2 What kind of “stuff” is in our Solar System? List as many items as you can.

Coming Up: Today 10/2: Formation of the Solar System This material will NOT be on your Unit 1 Test Thursday 10/4: Unit 1 Test Monday 10/8: Planet Classification & Minor Members

Coming Up: Today 10/1: Formation of the Solar System This material will NOT be on your Unit 1 Test Wednesday 10/3: Unit 1 Test Friday 10/5: Planet Classification & Minor Members

Touring Our Solar System Covered in this unit: Planets, Dwarf Planets, Exoplanets Earth’s moon & star Kepler’s Laws Asteroid Belt & Kuiper Belt Oort cloud Comets, Meteoroids, Meteorites, Asteroids Astrobiology

Nebular Hypothesis Activity Purpose: Identify physical features of our Solar System and describe why it is arranged the way it is Obtain the materials listed on your sheet Answer the questions as a group Be prepared to go over this!

Let’s review the trends…

Overview of the solar system Solar system includes Eight planets and their satellites Sun Asteroids Comets Meteoroids

Structure of the Solar System A planet's orbit lies in an orbital plane The orbital planes of the planets are inclined Planes of seven planets lie within 3 degrees of the Sun's equator Mercury's is inclined 7 degrees

How did the Solar System form? Solar Nebular hypothesis Planets formed about 4.6 billion years ago Planets formed from a rotating disk of dust and gases that surrounded the sun

What happened…? A large cloud of gas/dust formed This cloud contracts in on itself due to gravity and the “core” becomes hotter & more dense

3. The cloud collapses into an accretion disk that starts spinning with a protostar forming in the middle 4. The protostar’s temperature increases enough to begin nuclear fusion --How long did this take? From nebula to nuclear fusion took about 50 million years…

What about the planets…? Light gases were pushed to the outer regions of the system Rocky materials & metallics with high melting points were left near the Sun Through mutual gravity, particles stuck together to form rocks…and eventually planets Accretion

This created two types of planets: Terrestrial Jovian Mercury, Venus, Earth, Mars Rocky & dense Metal cores Small Jupiter, Saturn, Uranus, Neptune Gaseous & less dense Icy cores Large Thick atmospheres H, He, Methane, Ammonia Temperature LOTS of gas and dust pushed far away from the sun…HUGE planets

What kind of “stuff” was in the nebula? Gases Hydrogen Helium Rocks Silicate minerals Metallic iron Ices Ammonia (NH3) Methane (CH4) Carbon dioxide (CO2) Water (H2O) This is the “stuff” that makes up our planets.

https://www.youtube.com/watch?v=Uhy1fucSRQI

Bellwork 10/8 Why do we have two types of planets in our solar system? Describe how the process of solar system formation lead to these two types…

Meteor Shower! Draconid Meteor Shower New Moon, so the sky should be nice and dark, making for excellent viewing conditions  “The best evening to watch is likely October 8; try the evenings of October 7 and 9 also. Notice the word evening. This is one shower you don’t have to stay up late to see. Start watching first thing at nightfall.”

Quick chat about the article…

Pretend you’re back in biology class…What would you use to classify these organisms? Why is this necessary?

We sort or classify in all of the sciences. Phylogenetic trees in Biology Periodic table in Chemistry Contact vs. Action at a Distance forces in Physics What does classifying allow us to do?

We classify space objects as well.. Planets Asteroids Dwarf planet Satellites Comets Trans Neptunian Objects Let’s take a look at some of these objects and try to classify them based on physical characteristics.

Space Object Classification Activity Let’s talk through what you found

We classify space objects as well.. Planet: an object that is in orbit around the sun, has enough gravity to pull its mass into a rounded shape (hydrostatic equilibrium), and has cleared its orbit of other, smaller objects. Asteroids: small rocky irregular shaped (hence no hydro-static equilibrium) objects, most of them located in the asteroid belt, roughly between the orbits of Mars and Jupiter. 

We classify space objects as well.. Dwarf planet: planet-like object that is generally smaller than the planet Mercury. Dwarf planets tend to orbit in zones of similar objects that can cross their path around the sun. Satellites: a celestial body that orbits a planet

We classify space objects as well.. Comets: A celestial body, observed only when it is relatively close to the sun. It is made up of icy material and creates a long “tail” of vapor as it orbits the sun Trans Neptunian Objects: any object in the solar system with all or most of its orbit beyond that of Neptune.

…Elephant in the room… What about Pluto???

Why did Pluto get “demoted”? August 2006: Pluto is named a “Dwarf Planet” “The International Astronomical Union defines a planet as being in orbit around the sun, has enough gravity to pull its mass into a rounded shape (hydrostatic equilibrium), and has cleared its orbit of other, smaller objects. This last criterion is the point at which planets and dwarf planets differ. A planet's gravity either attracts or pushes away the smaller bodies that would otherwise intersect its orbit; the gravity of a dwarf planet is not sufficient to make this happen.”

Dwarf Planets in the Solar System Probably over 200 5 “Named & Confirmed” Dwarf Planets…as of now

Pluto might still have a chance… There are still lots of conversations happening about whether Pluto (and others) should be considered planets The problem: If we let Pluto in…we have to let others in as well. The definition of “Planet” is not clear

Ted Talk: Pluto’s Day of Reckoning

Now, given the definitions & criteria, let’s classify for real.