/Notes/ PlanetsNASA

Th

e s

tory

so

far:

NASA

Protoplanetary disk

Gas and dust left-over after the formation of the

star.

NASA

http://www.maths.qmul.ac.uk/~masset/movies/flyby.png

Gravity

Begins pulling together

bits of rock and gas

Gravity

NASA

NASA/JPL-Caltech/T. Pyle (SSC)

Planetesimals

Baby planets

NASA

They’re violent

NASA

NASA/JPL-Caltech/T. Pyle (SSC)

Planets form

Planetesimals combine and grow larger until they become planets

What is a planet?

NASA

1. Orbits the Sun

The Moon (not a planet)

NASA

NASA

2. Large enough for gravity to make it round

Phobos (a moon of Mars- not a planet) NASA

Moon

Phobos

Earth

Moon

3. Has “cleared it’s neighborhood” of debris

Pluto (not a planet) NASA

Types of Planets

NASA

Gas GiantsNASA

Made mostly of hydrogen and helium

NASA

May not have any solid ground

Probably no surface like on the Earth

NASA

All have rings and many moons.

NASA

Jupiter

Saturn

Uranus

Neptune

Terrestrial Planets

NASA

Are made of rocks similar to the Earth

NASA

All have iron cores

NASA

Have craters from asteroids and comets

NASA

NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Mercury

NASA/NSSDC

Venus

NASA

Earth

NASA

Mars

http://www.kiroastro.com/writings/perspective

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

Dwarf Planets

Orbit the Sun

NASA

Are large enough for gravity to make them round

NASA

Have NOT cleared their neighborhood

NASA

A new type of planet

Only used since August, 2006

NASA

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

http://commons.wikimedia.org/wiki/File:TheTransneptunians_Size_Albedo_Color.svg

Earth

Extrasolar Planets

• Extrasolar Planet- a planet orbiting a star other than the Sun

– As of Feb. 10, 2009:• 340 planets around other stars have been

discovered– Source: http://exoplanet.eu/catalog.php

http://commons.wikimedia.org/wiki/File:Exoplanets_en.svg