The Solar System

Inner and Outer Planets

Along with some other stuff floating around out there

The Inner Planets

The inner planets are referred to as the Terrestrial or Rocky planets

All inner planets have a dense, rocky composition and are composed of minerals with high melting points

All have cores made of iron or nickel All have impact craters and tectonic surface features

such as volcanoes

The Inner Planets: MERCURY

Smallest Planet Closest to the Sun Many Craters Resembles our

Moon No atmosphere Extreme temp

fluctuations

The Inner Planets: VENUS

Atmosphere made of mostly carbon dioxide

Runaway Greenhouse effect

Higher temperatures than Mercury

Surface has active volcanoes

Size and mass aresimilar the Earths

The Inner Planets: EARTH

Only planet with liquid water.

Roughly 70% of the surface is water.

The only planet where temperatures allow water to exist as a solid, liquid, and gas.

Atmosphere is mostly nitrogen (78%) and oxygen (21%).

The Inner Planets: MARS

Mars is red due to the iron oxide in the rocks on the surface.

Polar ice caps are mostly frozen water and carbon dioxide.

Olympus Mons is the largest volcano in the solar system.

Thinner atmosphere than Earth’s. Mostly carbon dioxide.

Asteroid Belt

Asteroids are also called minor planets

Mostly empty space because the asteroids are spread over such a large volume.

Located in between the orbit of Mars and Jupiter

The dwarf planet Ceres is located in the asteroid belt

The Outer Planets

The outer planets are referred to as the Gas Giants or Jovian Planets. Uranus and Neptune are sometimes called the Ice Giants

All have ring systems Either made up of hydrogen & helium (Jupiter and

Saturn) or ice (Uranus and Neptune) Have many moons

The Outer Planets: JUPITER

Largest planet in our solar system

Composed mostly of hydrogen and helium

Has 63 moons The Great Red Spot

is an active storm The Galilean Moons:

Io, Ganymede, Europa, and Callisto

The Outer Planets: SATURN

Composed mostly of hydrogen

The ring system is mostly composed of ice particles

Titan is Saturn’s largest moon and is the only moon that has a substanial atmosphere

Galileo was the first to discover Saturn’s rings, but he didn’t know what they were

The Outer Planets: URANUS

Has the bluish-green color due to methane in the atmosphere

Has a higher proportion of ices such as methane, ammonia, and water than Jupiter and Saturn

The axis tilt at 98° so that one pole always faces the sun

The Outer Planets: NEPTUNE

Only planet found by mathematical prediction rather than observation

Similar composition to Uranus

Active and visible weather patterns

Like all Gas Giants, Neptune has a faint ring system

PLUTO: What is it?

Pluto is classified as a plutoid-not a planet or dwarf planet

Largest member of the Kuiper Belt

Composed primarily of rock and ice

1/5 the mass of Earth’s moon

The Kuiper Belt

Extends beyond the orbit of Neptune

Similar to the asteroid belt, except it’s much larger

The Kuiper Belt was founded in 1992

What Exactly Is A Planet?

The International Astronomical Union decided that planets and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:

(1) A "planet"1 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.

(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) shape2, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.

(3) All other objects except satellites orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

Comets A comet is composed of

dust and rock particles mixed with frozen water, methane, and ammonia.

A large proportion of comets lie in the Oort Cloud-outside the orbit of Pluto. Objects in the Oort Cloud are only loosely bound and are easily dislodged and sometimes sent into the inner solar system.

Structure Of A Comet

When a comet is away from the sun it looks very similar to an asteroid.

As a comet approaches the sun the comet begins to change. Ices of water, methane, and ammonia begin to vaporize

because of the heat from the Sun. Dust and bits of rock are also released. The vaporized gases and released dust form a bright

cloud called the coma around the nucleus. Solar wind pushes on the gases and dust in the coma

causing particles to form a tail that always points away from the Sun.

Comet Components

Comet Hale-Bopp that was at its brightest in April 1997. Notice that there are different parts to Hale-Bopp’s tail.

Meteoroids, Meteors, and Meteorites

A meteoroid is a solid body, moving in space, that is smaller than an asteroid and at least as large as a speck of dust.

A meteor is a meteoroid that has entered the Earth’s atmosphere.

A meteorite is a meteor that strikes Earth because it was too large to burn up in the atmosphere.