The Planets & The Solar System CHAPTER 23 The Planets & The Solar System

The Inner Planets Inner Planets- Mercury, Venus, Earth, and Mars Called Terrestrial planets Terra means Earth so… Earthlike These planets have a rocky crust, denser mantle, and very dense core

MERCURY

                                                                                                                                                                                                               VENUS

EARTH

                                                                                                                                                                                                               MARS

The “Grand Canyon” of Mars – Valles Marineras It’s length is the distance from NY to California! It’s widest point is the distance from NY to Georgia!

Mars sure looks a lot like Arizona, eh?

The Outer Planets Outer Planets- Jupiter, Saturn, Uranus and Neptune Called Jovian planets (Jupiter-like) These planets are much larger, more gaseous, and less dense than the inner planets Pluto is not an outer planet as it 1) is not Jovian and 2) does not meet the new criteria of the definition of a planet so scientists have deleted Pluto from their list of Planets…now it’s a Dwarf Planet

JUPITER

The Galilean Moons – The Largest of the 63 Moons of Jupiter Calisto Io Europa Ganymede

                                                                                                                                                                                                               SATURN

The Largest of the 57 Moons of Saturn – NOT TO SCALE!!!!

URANUS

Uranus and 5 of its 27 moons!

Neptune has 13 Moons NEPTUNE

PLUTO – the oddball On August 24, 2006, 424 of the world’s astronomers (less than 5% ) voted on a new definition of a planet. Because of the path of Pluto’s orbit and size, it is now considered a “Dwarf Planet” The following is the International Astronomical Union’s (IAU) definition of planet, dwarf planet and other objects in the Solar System.

RESOLUTION 5A The IAU therefore resolves that planets and other bodies in our Solar System be defined into three distinct categories in the following way: (1) 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. (the planet’s orbit doesn’t cross another planet’s orbit…this is where Pluto doesn’t “make the cut”…) (2) 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. (3) All other objects orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

Data on the planets is located in your Handy Dandy ESRT’s, page 15 (Basically, everything you ever wanted to know about the Planets that NYS can ask you about is right there at your fingertips…)

Comets, Asteroids, and Meteoroids

COMETS masses of rock, dust, ice and gases that revolve around the sun in their own orbits orbits are usually very eccentric (stretched out), which means that one complete orbit of the sun may take many years Ex. Halley’s Comet is only viewable on Earth every 76 years! It will next appear to us in the year 2062!

Comet Hyakutake  Comet Hale-Bopp

Tails get longer the closer the comet gets to the Sun. Comet Tails always point away from the Sun. Gas (Ion) tails point straight away from the Sun. Dust tails curves toward the orbital path. Orbit of Comet

ION TAIL ION TAIL DUST TAIL DUST TAIL

The orbit of Haley’s Comet is highly eccentric, and therefore the comet can only be seen on Earth every 72 years!

ASTEROIDS Solid chunks of rock in space Most asteroids are found in a nearly circular orbit between Mars and Jupiter, revolving in the same direction as the planets do This orbital cluster is called the Asteroid belt A few are large, but most asteroids are less than 1 meter long!

The Inner Planets and the Sun are in the tiny circle right here…

METEOROIDS Fragments of rocks or ice traveling through space Occasionally, these fragments may get pulled into Earth’s atmosphere by its gravity As the meteoroid shoots through the atmosphere, friction causes heat to build up and the meteoroid begins to glow The object is now called a METEOR (shooting star)

METEOROIDS Sometimes many meteoroids enter our atmosphere at one time, this is called a meteor shower If the meteor survives its trip through the atmosphere and hits the Earth’s surface, it is then called a meteorite Impact craters are “potholes” in the Earth’s crust caused by meteorites hitting the ground with great speed and force Ex. the Barringer Crater in Arizona (1,300m wide, 200m deep).

Question of the Day… Why are there so many more craters on the moon than on the Earth? There’s a couple of explanations – but they are all a result of the same reason…