Transcript Our Solar System - Palo Alto Unified School District

Our Solar System
The Sun
• Our Sun is a medium-sized
yellow star in the middle of
its life cycle.
• Its the center of our Solar
System and holds objects in
orbit by gravitational pull.
• More than 1,000,000 Earths
can fit inside the Sun.
• It’s fueled by nuclear fusion
of small atoms to form larger
ones, and it’s the only source
of energy in the solar system.
• It has features: sun spots,
solar flares, and
prominences.
Mercury
• Terrestrial planet with a
solid rocky surface
• Covered with craters
• Extreme temperatures
(from -170 ºC up to
467 ºC)
• Thin atmosphere so its
temperatures vary by
day and night
• Fastest planet to
revolve around the Sun,
thus named Mercury
• No moons … why not?
Venus
• Terrestrial planet with a
solid, rocky surface
• Earth’s “twin” in size
• Extremely hot
temperatures (470 ºC)
due to thick
atmospheric cloud cover
and green house effect.
• Retrograde motion (it
rotates clockwise)
• No moons … why not?
Earth
• Terrestrial planet with a
solid, rocky surface
• Frozen caps at North &
South Poles
• Capable of supporting
life due to [C], 70%
water, and protective
atmosphere
• Seasons due to axis tilt
• 1 Moon: Luna where we
have landed multiple
times and sent more
than 70 spacecraft
Earth’s Moon “Luna”
• The moon acts like a
mirror; it reflects
sunlight to Earth
• Phases of the moon
occur as the moon
revolves around Earth
and reflects sunlight.
• Tides -- high tide and
low tide -- are caused
by the moon’s
gravitational pull
Mars
• Terrestrial planet with a
solid, rocky surface
• Red surface due to [Fe]
• Enormous active
volcanoes and dust
storms
• Thin atmosphere
• Frozen polar caps like
Earth
• Liquid water once?
• 2 Moons: Phobos and
Deimos
Asteroids
• Made of rock, minerals,
and rare elements
• More than 100,000 orbit
in the “Asteroid Belt”
between Mars and
Jupiter
• Could collide with Earth,
but probably won’t
• The largest asteroid
named Ceres is a dwarf
planet
• Moons: a few asteroids
have moons!
Meteors or “Shooting Stars”
• Pieces of rock that are
falling toward Earth are
meteors
• They glow brightly as
they burn up due to
fluid friction
• Called “meteoroids” if
they are far away,
“meteors” if they have a
bright tail, and
“meteorites” once they
hit Earth
Jupiter
• The largest “gas giant”
with no solid surface
• Faint rings
• Made of elements [H]
and [He] with a hot,
solid core of [Fe] -almost a star!
• “Red Spot” is a massive
storm
• 60+ Moons: the four
largest are named Io,
Europa, Ganymede,
Callisto, but there are
more…
Saturn
• Second largest gas giant
without a solid surface
• Famous for bright, icy
rings that we can see from
Earth with a telescope.
The rings have large
divisions.
• Mostly made of elements
[H] and [He]
• Less dense than water!
• 60+ Moons: Titan and
Phoebe and more, some
orbit in the gaps of the
rings
Uranus
• Gas giant without a solid
surface
• Made of elements [H]
and [He] and water,
ammonia and methane
• Bluish reflection due to
methane (CH4) gas
• Faint rings, but the
brightest clouds
• Axis is turned “sideways”
so it has wild seasons
• Retrograde motion
• 27 Moons: Ariel and
more…
Neptune
• Gas giant without a
solid surface
• Bluish reflection due to
methane (CH4) gas but
more vivid than Uranus
• Six faint rings
• Farthest planet from the
Sun, usually
• 13 Moons: Triton is the
largest and 12 more…
Dwarf Planets & Plutoids
• Ceres is the largest
asteroid in the asteroid belt
• Pluto has a solid, icy
surface, 3 moons, and it
orbits in a tilted plane.
Charon is the largest moon
of Pluto.
• Makemake is smaller
than Pluto, but farther
• Haumea is similar to
Pluto in size and rotates
the fastest
• Eris is larger than Pluto,
but farther away
• More to be discovered…
Comets
• Made of rock, ice and
dust
• Comets consist of a
head, coma, and two
tails that point away
from the Sun
• “Short-period” comets
come from the “Kuiper
Belt” and orbit the Sun
every 200 years or less
• “Long-period” comets
come from the “Oort
Cloud” and take longer
to orbit the Sun
Stars like our Sun
Stars are classified in many ways: by color and
temperature, mass, age in life cycle, brightness and…
The Life Cycle of Stars
Stars age through a life cycle that includes many stages.
Galaxies
• Galaxies are groups of
billions of stars, usually
classified by their
shape: spiral, elliptical,
or irregular.
Elliptical
Spiral: like our Milky Way Galaxy
Irregular (or chaotic)