Transcript Our Solar System

Our Solar System
A Journey to Our Planetary Neighbors
Ideas about the night sky have changed
over time…
 Earth-centered model – early Greeks
thought planets, Sun, Moon and stars
rotated around the Earth
 Modern view –
 The
sun is the center of our solar system
 All other objects in the solar system
revolve around the sun in elliptical orbits at
different speeds.
How did our solar system form?
 A nebula of gas, ice, and dust slowly
formed in space, and rotated in space.
 The cloud began to contract and the
matter was squeezed into less space.
 The cloud became dense, heated up
and triggered a nuclear fusion reaction
that created the sun.
What happened next?
 All leftover matter became the planets
and asteroids
 The four inner planets – (Mercury, Venus,
Earth, and Mars) are small and rocky with
iron cores
 The four outer planets – (Jupiter, Saturn,
Uranus, and Neptune) are large,
lightweight, and composed of gases.
Inner Planets
 Mercury - closest to the Sun, smallest
planet
 Many
craters and high cliffs
 No true atmosphere so temperatures can
range from -292 to 806° F.
 It orbits the sun once every 88 days and is
an average of 36 million miles from the
sun.
Inner Planets
 Venus – second from the sun and
similar to the Earth in size and mass
 Mostly
smooth volcanic plains
 Extremely dense atmosphere of clouds
 Carbon dioxide gas traps solar energy
resulting in temperatures between 842 to
887° F.
 It is an average distance of 67 million miles
from the sun and orbits every 225 days
Inner Planets
 Earth – third planet from the Sun
 More than 70 percent of surface is covered
with water
 Atmosphere consists of several layers, is
mostly composed of nitrogen and oxygen,
and protects the surface from meteors and
Sun’s radiation
 It is an average of 93 million miles away
from the sun, and completes its orbit in
365.5 days
Inner Planets
 Mars – fourth planet from the Sun
 Called red planet because of iron oxide in rocks

Polar ice caps made of frozen carbon dioxide and
water

Surface contains gullies, mountains and canyons,
plains and the largest volcano in the solar system

The thin atmosphere mostly contains carbon
dioxide

It is an average of 141 million miles from the Sun,
and completes its orbit in 1.9 years
Asteroids and Other Objects in Our Solar
System
 Asteroids – rocks similar to that which
formed the planets
 Asteroid Belt – group of asteroids that
orbit the Sun between the planets Mars
and Jupiter
Comets
 Comet - dust and rock particles
combined with frozen water, methane,
and ammonia
 Halley’s
comet (occurs every 76 years),
Hale-Bopp (1995)
 Look similar to a dirty snowball
 The ice and dust vaporize as it
approaches the sun
 This
forms a comets tail
Meteoroid, Meteor, and Meteorite
 Meteoroid – small pieces of debris in
space
 Meteor – small meteoroid that burns up
in Earth’s atmosphere (falling or
shooting star)
 Meteorite – meteoroid that strikes Earth
Outer Planets
 Jupiter – Fifth planet from the sun and
the largest in our solar system
 Atmosphere
mainly consists of hydrogen
and helium
 Surface is suspected to be composed of
liquid hydrogen and helium, and may have
solid core at the center
 It is an average of 484 million miles from
the sun and 11.8 years to complete one
orbit
 Has 16 moons
Outer Planets
 Saturn – sixth planet from the Sun
 Thick outer atmosphere of hydrogen,
helium, ammonia, methane, and water
vapor
 Might have rocky core
 Rings that circle around planet are
composed of ice and rock particles
 It is an average of 887 million miles from
the Sun, and completes one orbit in 29.5
years
Outer Planets
 Uranus – seventh planet from the sun
 Atmosphere of hydrogen, helium, and
methane
 Rotates on its side
 Contains thin, dark rings
 It is an average of 1.8 billion miles from
the sun, and completes one orbit in 84
years
Outer Planets
 Neptune – eighth planet from the Sun
 Atmosphere is similar to that of Uranus
 Storms on Neptune reveal an active and
rapidly changing atmosphere
 It is an average of 2.8 billion miles from the
sun, and completes its orbit every 165
years