Download The Gas Giants

The Gas Giants
The Planets and Other Cosmic Stuff
Chapter 20
Jovian Planets
• Are called “Jovian” which means “Jupiter-like” or
outer planets
• Are made completely of gas held together by
gravity
• Are the largest of all the planets in the solar system
• All have numerous moons and thin atmospheres
Jupiter
• Largest of all the Jovian
planets
• Composed mainly of H
and He with a partially
liquid atmosphere
• Clouds are made of
water, methane, and
ammonia
• Most noticeable feature
is the Great Red Spot
• Its mass is 318 times that
of the Earth
• As of 2004, Jupiter has 63
moons, with the largest
being Io, Europa,
Ganymede, and Callisto
Saturn
• Composition is very
similar to Jupiter, mostly
hydrogen and helium
• Most noticeable
feature are the rings
made of pieces of ice
• Has 34 moons, with the
largest being Titan
• Titan is the only moon
known to have an
atmosphere
Uranus
• Discovered by William
Herschel in 1781
• Because of the high
amounts of methane,
Uranus is a greenish-blue
• Its axis is tilted nearly parallel
to its orbital plane, rotating
like a wheel!
• Has only been visited by
Voyager 2 in 1986
• Has a few very faint rings
• Uranus has 21 moons, with
the largest being Miranda,
Ariel, Oberon, Umbriel, and
Titania
Neptune
• Atmosphere is very
similar to Uranus, in
which the methane
gives it its bluish color
• Voyager 2 took
pictures of the Great
Dark Spot, which is
similar to the Great Red
Spot on Jupiter
• Even though it is the 8th
planet, sometimes Pluto
crosses its orbit, making
it the 9th planet
• Has 13 moons, with
Triton being the largest
Pluto, Our Dwarf Planet
• The term “dwarf planet” was coined in August
2006, which means that it IS a planet, but it has not
cleared its neighborhood around its orbit like the
other 8 do
• Pluto’s orbit passes through the Kupier Belt, an area
beyond Neptune where comets are thought to be
born. The other 8 do not pass through the Kupier
Belt
• Has a moon , Charon
Charon
Pluto
Comets
Gas Tail
Coma
Dust Tail
• Sometimes referred to as “dirty snowballs” because they
are made of loosely packed ice and rock
• Orbits are VERY elliptical
• When it passes close to the Sun, the ice melts and creates
the characteristic “tail” which points away from the Sun
• Thought to originate from the Kupier Belt or Oort Cloud
found way beyond Neptune
• Most famous is Halley’s Comet, which comes closest to the
Sun every 76 years…be looking in 2061-2062!
Meteoroids, Meteors, & Meteorites
•
What’s the difference?
1.
3.
Meteoroids are small rocky bodies orbiting the Sun which
are smaller than asteroids
Meteors are meteoroids that enter our atmosphere and
burn up in spectacular meteor showers
Meteorites strike the Earth’s surface
•
Three types: stony, metallic, and stony-iron
2.
Leonid meteor
shower
Asteroids
Ida
Gaspra
• Small, rocky bodies in orbit around the Sun,
ranging in size from a few meters to more than
900 km in diameter
• Largest area of asteroids is between Mars and
Jupiter, called the Asteroid Belt
• Have a variety of compositions
• The large ones have been named