Our Solar System (Section 6.1 page 146)

An Inventory of the Solar System

Greek Astronomers’ Solar System

Moon Stars 5 planets: _______, ________,

_________, _______, _______ _______: long wispy strands of light that

were visible for weeks and slowly faded ________: shooting stars, bright streaks

of light that shoot across the night sky.

17th Century Solar System

Galileo used a telescope to discover: ___________________

and ______________________

19th Century Solar System

Saturn's’ Rings _________ (year)

Uranus ____________ (year)

Neptune ___________ (year)

Minor planets called ___________ The ____________ Belt between

Mars and Jupiter Ceres ________

20th Century Solar System

Kuiper Belt beyond Neptune Non-optical “seeing” using ____

and _____ waves Space flight: manned space craft

and un-manned space probes

***Most accepted theory of its formation: planets were formed from the same gas cloud that formed the sun

Hubble Telescope

Let’s Take A Stroll

It seems that half of all stars are _________________________

Our solar system is centered around a single star; the Sun.

Planets, in order of distance from the Sun:

M_______, V_____, E____, M___, J______, S______, U______, N______

My Very Exceptional Mother Just Served Us Nachos

Let’s Take A Stroll

Some of the planets have moons, totaling _____ at last count.

By the 1990’s, observed more than 6,000 large ________.

More than 1 million with diameters greater than 1 km.

They are debris from the formation of the Sun.

Overall Layout of the Solar System (Section 6.3 page 149)

It’s IMMENSE! HUGE! _________ AU across

(that’s ______________ miles)

Overall Layout of the Solar System (Section 6.3 page 149)

Orbits of all planets are ________ The Sun is at one _____ of the elliptical

orbits. They are not evenly spaced, (they

become _________ apart the farther out from the sun)

They all rotate __________wise All lie nearly on the same orbital

plane except Mercury (7°) Asteroid belt lies between

_________ and _________. Most of the solar system’s asteroids are here.

Comparative Planetology (pg. 147)

Comparing and contrasting the properties of the diverse planets and the conditions under which they evolve

Measuring the Planets (Sec. 6.2 pg. 148)

Distance:_______________ Orbital period:____________ Radius:_________________ Mass:___________________ Rotational period:__________ Density:__________________

Distances

Astronomers have agreed on the astronomical unit (Au) – the average distance between Earth and the Sun

1 AU = 92,754,170 miles Sun to Pluto = 40 AU If Earth were a golf ball……

Pluto would be a pea about 8 miles away Jupiter would be a basketball 1 mile away Sun would fill a 10 ft2 room less than ¼

mile away!

Distances

First determined by Kepler’s Laws, then radar ranging

Seems very far, but compared to the nearest star, the planets are next door neighbors.

Alpha Centauri (nearest star) is 4.3 light years away.

Golf ball scale: it would be 55,000 miles away!

Orbital (sidereal) Period

How long a ‘year’ is on the planet Measured relative to the stars Shortest: Mercury ______ earth years

Closest distance to Sun

Longest: Neptune ______ earth years Farthest distance from Sun

How long is Mars’ year? _______

Radius (or angular diameter)

Planets size or width Measured using geometry

The Mass of the Planet

Can be easily calculated if the planet has a moon

Newton’s Laws of motion and Law of Gravity

Determined by how the planets’ and moons’ gravity influence each other.

I’m pulling you!

NO, I’m pulling you!

At the Center… Sort of The Sun contains 99.9% of all matter

in the solar system. Jupiter is the largest planet, almost

300 times the mass of Earth. The Sun is more than 1,000 times

the mass of Jupiter!

Rotational Period

Time it takes to ‘spin’ How long is a ‘day’ Determined by watching the

surface features appear and alternately disappear as it rotates.

Can be difficult to determine if… ___________ (Mercury) ____________ (Venus) ____________ (Jupiter)

Density (Table 6.1)

Compactness of the matter of the planet

The planets Mass / Volume Measured in kg/m3 or g/cm3

Earth has a density of 5.5 g/cm3

Jupiter’s density of _____g/cm3

(mmmm. Why so much smaller than Earth????)

Bell Work: Which planet has the …

1. Most mass, least mass?

2. Longest day, shortest day?

3. Most moons, least # moons?

4. Most density, least density?

5. Highest temperature, lowest temp?

Jupiter, mercury

Venus, Jupiter

Jupiter, mercury

Earth, Saturn,

Venus, Uranus

Inner planets vs Outer planetsTerrestrial Jovian

The Inner and Outer Circles Planets fall into two broad

categories Terrestrial: four planets closest to

the Sun; rocky

Jovian: farthest from the Sun; gaseous

Pluto is more of a rogue moon than anything else.

The Terrestrial PlanetsWhat they have in common:

-_____ proximity to the Sun,

-relatively _____ spaced orbits

-_____ masses

-_____ radii

-_____ density

-_____ rotations than jovian planets

-have _____ magnetic fields

-have ______ or _____ moons.

The Jovian Planets pg. 152-153)

What they have in common: -_____ from the Sun -_____ spaced orbits

-______ size -________radii (size)-_________density-predominantly _______ (make up) -no _____ surface-rotate ___________-possess ______ magnetic fields

-orbited by many __________.-all have ______

Bellwork: True/False

1. The largest planets have the largest density.

2. The jovian planets rotate faster than earth.

3. All Inner and outer planets have moons.

4. The terrestrial planets are gaseous.

5. The jovian planets are more closely spaced.

6. The jovian planets have rings.

The Asteroid Belt Review Between Mars an Jupiter Astronomers have cataloged

more than 6,000 asteroids with regular orbits.

Size of individual asteroids: comparable to a small city

All orbit in the same direction as Earth except one, which is retrograde.

The ellipses (tilt) of the asteroids tend to be more exaggerated than the planets.

Large Asteroid or Dwarf Planet?

Ceres 950 km wide

(590 miles)

In 2006, Ceres was upgraded from an asteroid a ‘dwarf planet’

Pluto 2300 km wide

(1430 miles)

At the same time, Pluto was down-graded from a planet to a dwarf planet

PBS video clip

http://www.pbs.org/newshour/indepth_coverage/science/pluto/index.html

According to the International Astronomical Union (August 2006)... A PLANET is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that

it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit. There are eight planets under this definition: Mercury, Earth, Venus, Mars, Jupiter, Saturn, Uranus and Neptune.

A DWARF PLANET is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that

it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.

What killed the dinosaurs?

Page 366 Discovery 14-1