Bell Ringer _______ tides occur during New Moon and Full Moon. _______ tides occur during First Quarter and Third Quarter. YOU HAVE A VOCAB QUIZ MONDAY – UNIT TEST ON WEDNESDAY Spring Neap

The SOLAR SYSTEM

Solar Nebula Hypothesis Solar System – the collection of planets, their moons, and smaller bodies that orbit the Sun due to the Sun’s gravity

Solar Nebula Hypothesis Interstellar clouds – clouds of gases (like hydrogen and helium) and dust that lead to the formation of stars and planets Solar nebula – name of the interstellar cloud that formed OUR solar system

Solar Nebula Hypothesis Solar Nebula Hypothesis – hypothesis that the Sun, planets, and the rest of the solar system formed from an interstellar cloud (nebula)

Solar Nebula Hypothesis A strong force like the explosion of a nearby star made gases gather together and form into the solar nebula 1. Solar Nebula

Solar Nebula Hypothesis 2. The gases gathered closer together because of gravity, and the nebula began to spin 1. Solar Nebula 2. Gases gather

Solar Nebula Hypothesis The center of the cloud grew hotter and denser, eventually forming the Sun The rest of the cloud became thinner (like a disk) 1. Solar Nebula 2. Gases gather

Solar Nebula Hypothesis 3. Particles in the thin part of the cloud began to clump together, forming planetesimals The planetesimals eventually grew into ______ planets 1. Solar Nebula 3. Planetesimals form 2. Gases gather

Solar Nebula Hypothesis 4. The particles continued to form planets, while most of the remaining gases were blown away by the Sun’s solar winds 1. Solar Nebula 3. Planetesimals form 4. Solar System 2. Gases gather

Models of the Solar System Geocentric Model (Earth-centered) – early belief that everything orbited around the Earth, while the Earth remained stationary Why would the geocentric model seem to make sense to observers on Earth?

Early Ideas about the Solar System Problem with Geocentric Model: While the stars all moved across the sky at the same speed and same direction, the planets sometimes moved in the opposite direction Retrograde motion – a planet’s backward motion across the sky Tracking Mars across the night sky in 2005

Early Ideas about the Solar System Heliocentric Model (Sun-centered) – belief that the Earth and other planets orbit around a stationary Sun (correct model) Provided a simple explanation for retrograde motion, because all of the planets are moving in relation to the Sun, not the Earth

Early Ideas about the Solar System Galileo’s discovery of four of Jupiter’s moons helped the scientific community adopt the heliocentric model (if Jupiter had things orbiting it, then not all things orbited Earth) Jupiter and 4 of its moons, as seen from a telescope on Earth

Early Ideas about the Solar System Geocentric model stated that the _______ was the center of the solar system. Heliocentric model stated that the _____ was the center of the solar system. Our current model of the solar system is the ____________ model. Earth Sun Heliocentric

Kepler’s and Newton’s Laws Kepler’s First Law – each planet follows an elliptical (oval-shaped) orbit around the Sun

Kepler’s and Newton’s Laws A planet in an elliptical orbit is not a constant distance from the Sun Perihelion – part of an orbit closest to the Sun Aphelion –part of an orbit farthest from the Sun

Kepler’s and Newton’s Laws Eccentricity – a number (0-1) that describes the shape of an orbit 0 = a perfect circle orbit 1 = a very elongated oval orbit Earth’s current eccentricity = 0.0174

Kepler’s and Newton’s Laws Kepler’s Second Law – a planet covers equal area on its orbit in equal amounts of time

Kepler’s and Newton’s Laws Kepler’s Third Law – the farther away a planet is from the Sun, the longer it takes to complete its orbit Example: If Earth is 1 AU from the Sun and Saturn is 10 AU away, which one takes longer to orbit the Sun? Saturn

Kepler’s and Newton’s Laws Newton’s Law of Universal Gravitation – the force of gravity between two objects increases with the size of the objects and how close they are to each other Example: Which two bodies would attract more gravity? OR Two small bodies far away from each other? Two large bodies close together?

Kepler’s and Newton’s Laws Which two bodies would experience the MOST gravity? Question 1: Question 2: You and a classmate An ant and the Earth   You and the Earth An elephant and the Earth You and Pluto A skyscraper and the Earth

Kepler’s and Newton’s Laws Did you know that the Sun moves? Barycenter – the center of mass between two large objects that the objects orbit around

Kepler’s and Newton’s Laws The Sun is so much more massive than most planets, so the barycenter is within the Sun However, Jupiter’s mass is big enough that the barycenter is slightly outside the Sun The Sun and Jupiter orbit around that point

Kepler’s Laws Four-Square individual work! Kepler’s First Law (label) Definition Picture (with perihelion and aphelion labels) Kepler’s Second Law (label) Definition Picture Kepler’s Third Law (label) Definition Picture Universal Law of Gravitation Definition Picture (different than the one in notes)

Moon WS From yesterday’s notes (we ran out of time) Work together in groups of 1-3 (1 sheet/group) and turn in.

Astronomy Review WS Covers 6.1-6.3 – working individually Turn in when done.

Origins of the Solar System Video http://video.pbs.org/video/1790621534/