Transcript What is a Planet

Terrestrial Planets
Planets,
Dwarf
Planets and
Moons of our
Solar System
Jovian Planets
TERRESTRIAL
• made of solid surfaces
• much smaller than the
jovian planets
• Atmosphere composed
mainly of carbon
dioxide and nitrogen
• Core is less dense
• Closer to the sun
• Fewer moons
JOVIAN
• made of gaseous surfaces
• much larger than the
terrestrial planets
• Atmosphere composed
mainly of helium and
hydrogen
• Core is more dense
• Farther from the sun
• More moons
Mercury: -named after the god of speed for its quick revolution
•Second smallest planet
•Diameter = 3,029 miles
•Barely any atmosphere
because low gravity and
sun’s heat burns away
•Heavily cratered due to lack
of atmosphere
•Gases of thin atmosphere=
52% Oxygen, 39% Na, 8% He
•800°F (day) / -290°F (night)
•28.6 million miles from sun
•Aphelion= 43 million miles
•Perihelion= 29 million miles
Area not
mapped by
Mariner 10
Matisse Crater
•Surface observations were made by the
Mariner10, which passed close to Mercury in
1974-1975. More WILL be learned from the
Messenger Mission in 2011 (Japan and
Europe).
Image of frozen
south pole taken
from the Mariner
10 spacecraft
• Very thick iron core
• Very dense planet
• Iron creates a magnetic field
that is only 1% the strength of
Earth’s magnetic field
• Explored by Mariner 10 in
1974, along with Venus
• Rotation Period = 59 Earth Days
• Revolution= 88 Earth days
• 0 Moons
• Gravity =.38 that of Earth
Venus- named after the Goddess of beauty for
the way that it shines in the night sky
• known as Earth’s twin because
identical in size & composition
• 67.2 million miles from sun
• Diameter = 7,521 miles
• 0 Moons
• Rotation= 243 Earth days (Only Planet
whose day is longer than its year!) Orbit is
almost a perfect circle rather than elliptical
like others
Venus is the brightest planet
in the night sky due to its
thick atmosphere. Can be
seen in early morning or
evening in the night sky.
• Revolution= 224.7 Earth days
• Gravity= .9 that of Earth
• Venus also does not have seasons
because its axis only tilts 2.6°
Venus’s Atmosphere
•Atmosphere is extremely
dangerous
•96.5% Carbon Dioxide
•3.5% nitrogen and trace gases
•The high amount of C02 causes
extreme global warming from the
Greenhouse Effect
•Surface temperature = 867°F
•The clouds(3 distinct, thick layers)
are a very thick sulfuric acid.
•pressure inside Venus’ atmosphere
is equal to being at 3,000 ft deep in
one of our oceans!
•In 1978 and 1989 US Magellan
missions used radar to map 98% if
the surface of Venus
Venus’s Surface
•interior of Venus is very similar
to Earth, except for a rocky
mantle.
•molten iron and nickel outer
core and solid iron and nickel
inner core
•formed 4.5 billion years ago
with the same materials as
Earth.
•Venus is similar but does NOT
have Plate Tectonics but its
surface is covered in mountains,
plains and very active
volcanoes.
•Over 20 probes have been sent
to Venus to explore its
atmosphere and surface!
Maat Mons, the largest
volcano on Venus
(3 miles high)
Venus’s surface is
covered in old lava
flows from about
500mya.
Earth
•93 million miles from the Sun
•Gravity = 1.0
•Rotation= 23.98 hours
•Revolution= 365.26 days (this is
why we have Leap Years)
•Diameter =7, 926 miles
•Have four distinct seasons due to
23.93° tilt
•Molten mantle which allows for
Plate Tectonics
EARTH
• Plate Tectonics not only create and change our
surface but it volcanic eruptions created water
on Earth!
• Only planet with H2O Water!
• Only planet with specialized atmosphere that
protects the surface from impacts and radiation
from sun.
• Extremely strong Magnetosphere
• Atmosphere= 78% Nitrogen, 21% Oxygen
• Only Planet with LIFE!
Mars- Named after the god of war for its red color
• 141.6 mill miles from the Sun
• Surface Temperatures -195°F to 77°F
• Diameter= 4,213 miles (About half
the size of Earth.)
• 2 Moons (Deimos and Phobos) Both
moons of Mars are captured
asteroids.
• Gravity= .38 that of Earth
• Rotation= 24.63 hours
• Revolution= 687 Earth days
The poles shift during
seasons. The seasons
are caused by tilt in axis
as well as eccentric
orbit!
MARS
• Atmosphere= 95.3% Carbon
Dioxide, 2.7% Nitrogen, 1.6%
Argon
• Atmosphere is extremely thin
with a very cold and dry
surface.
• Mars has very distinct North
and South poles which are
mainly carbon dioxide ice.
• Retrograde Motion- apparent
backward motion of a planet
Mars’s thin
atmosphere
Surface of Mars
•Iron Oxide causes the reddish-brown
appearance.
•covered in steep valleys, craters and
large volcanoes, rocks, sand dunes
•contains the solar systems’ largest
volcano- Olympus Mons (larger than
Colorado!)
•shows evidence that ancient water
flows created valleys (now the
surface is too cold for water in a
liquid state)
•poles are full of highlands and
mountains as well a CO2 ice.
•experiences dust storms that cover
the planet. (dust clouds can be 3000
ft high and last for weeks!)
•The 2001 Mars Odyssey and Global
Surveyors in 2003 explored Mars for
our most recent data.
Valles Marineris lies on the equator of Mars and is
almost 10 times longer and 3 times deeper than
the Grand Canyon! This canyon was created over
3bya by shifting of Mars’s crust.
Jupiter
•Largest planet- 2.5 x mass of all
other 8 planets combined.
•Distance from Sun-=483.6 mil. miles
•Diameter= 88,846 miles (10 times
the diameter of Earth and 318 times
more massive than Earth)
•Number of Moons= 60
•Rotation= 99.3 hours (Quicker spin
on axis than any other planet)
•Revolution= 11.86 Earth years
•Gravity= 2.64 times that of Earth
•Difference of 47.3 million miles
between Aphelion and Perihelion
The Great Red Spot- is a storm
(hurricane) larger than Earth that has
been rotating around the planet and as
been observed for the past 340 years.
JUPITER
• Atmosphere=89.8% Hydrogen, 10.2% Helium
• Temperature= -166°F
• Rings= 2 faint rings- observed by the Galileo
spacecraft during its five year mission around
the planet
• Solid core- of rock, metal and hydrogen
compounds.
• Magnetic Field- larger and stronger than any
other planet(20,000 times stronger than
Earth’s), and actually causes Aurora on the
poles of Jupiter!
Jupiter’s Interior
•Composition is mostly hydrogen,
in the form of liquid.
•Under the cloud layers, when the
pressure of the interior becomes
high enough, the hydrogen
changes to liquid hydrogen, which
gradually changes further to liquid
metallic hydrogen.
•The core of Jupiter is made out of
heavier, rocky and metal
elements.
•Electric currents exist in the
metallic layer, these create
Jupiter’s magnetic field.
Jupiter
Jupiter and its most interesting moon, Io.
Jupiter’s Moons (Galilean Satellites -after their discoverer):
1. Io- most volcanic object in solar system, orbit is only 42.5
hours around Jupiter
2. Ganymede- largest moon in solar system, made of rock
and carbon dioxide ice
3. Callisto- much brighter than our moon (ice reflects more
sunlight) darker regions are rock
4. Europa- ice-covered ball of rock, average temp around 225°F, may have liquid seas under the ice which could
have simplistic life forms!
The strength of Jupiter’s
gravity is enormous. In
1993 Jupiter ‘s gravity pulled
apart the Levy9 comet and
the pieces crashed into
Jupiter, as seen above.
Saturn
Hubble image of Saturn with an
image of shadows created by some
of Saturn’s orbiting moons.
•Distance from Sun= 888 mill
miles
•Temperature= -220 °F
•Diameter= 74, 898 miles
•Number of moons= 62
•Rotation= 10.66 hours
•Revolution= 29.46 Earth
years
•Gravity= 1.07 that of Earth
•Atmosphere= 96.3%
Hydrogen, 3.7% Helium and
trace gases with ammonia ice
near the cloud tops.
SATURN
• Saturn can be observed from
Earth with a naked eye 10
months out of the year. It
appears pale yellow due to
the thick cloud layers (3
distinct layers).
• Saturn also experiences
Auroras from the Sun’s solar
wind that can been seen on
its southern pole.
• Saturn's’ magnetic field is a
1000 X’s larger than the
Earth’s!
Five space probes have been on
missions to orbit this planet since 2004
Saturn’s Rings
Saturn’s rings,
taken by the
Voyager probe
•made up of collections of separate pieces of dirty
water and rock particles
•These pieces can range from microscopic pieces to
larger than some houses
•There are 7 major rings (each ring is made up of
smaller rings called ringlets)
•These particles reflect a lot of light creating a
beautiful color display.
•rings change as the moons move through them.
•rings are paper thin, in comparison to the size of
the planet.
•Origin of rings is most likely an object that was
shattered by an asteroid or a moon broken apart by
Saturn’s gravity.
Titan- Saturn’s largest moon
• Titan- Saturn’s largest moon
(larger than Mercury!)
• Discovered in 1655
• Only moon with substantial
atmosphere, similar to a
young Earth
• Very nitrogen and methane
rich atmosphere
• Size of Mercury
• Made of rock, ice and water
• -292°F
In 2005, the orbiter
Cassini sent a probe
to examine the
atmosphere of Triton
Uranus
*Due to a planet-size impact,
Uranus’s axis has been know onto
its side at a 98° tilt!
*Uranus also has 11 rings
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Distance from the Sun= 1.78 bill miles
Cloud Temperature= -353°F
Diameter= 31,763 miles
Numbers of moons= 27
Rotation=17.24 hours
Revolution=84 Earth years
Gravity= .89 that of Earth (at cloud
tops)
• Twice as far from the sun than Earth
• 4 times the size of the Earth
• Retrograde revolution= Uranus has
retrograde revolution which means
that it revolves the opposite direction
of the other planets
Uranus
•has many smaller moons with
five major moons
•Most of the moons follow the
retrograde revolution like
Uranus.
•Most moons are made up of
rock and ice.
• Atmosphere= 82.5% Hydrogen,
15.2% Helium, and 2.3%
Methane (small amount of
methane creates the pale blue
color)
• The surface is made up of
methane, water and ammonia
ice.
• Electrical currents in the ice
create a magnetic field on
Uranus.
• The interior is a rocky/icy core.
• Seasons last for 21 years, due
to extreme tilt.
• In 1986, Voyager 2 flew by
Uranus and provided detailed
information about the planet.
Neptune-The Blue
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Planet
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The Great Dark Spot- is a hurricane
like storm almost as big as Earth BUT
the storm disappeared in 1994.
Average distance from the
sun= 2.8 billion miles
Cloud Temperature= -320°F
Diameter= 30,760 miles
(about time s Earth)
Number of Moons= 13
Rotation= 16.11 hours
Revolution= 164.9 years
Gravity= 1.13 that of Earth
Atmosphere= 79% Hydrogen,
18% Helium 3% Methane
NEPTUNE
• Does have seasons due to 28.3% tilt
• Similar to Uranus, Neptune has a surface of
water and methane ice with a similar icy or
rocky core.
• Neptune has six thin rings, microscopic
material and difficult to see.
• Neptune was first discovered mathematically
using the Universal law of Gravitation in 1846.
• Voyager 2 flew by Neptune in 1989 to provide
the first detailed images of the blue planet.
Triton- Neptune’s only major moon
• Triton was discovered 17 days after
the planet’s own discovery
• Similar to our moon, Triton’s
synchronous, only one side of Triton
always faces Neptune.
• Triton also has a backward orbit
• The surface of Triton is most likely ice
and rock with possibly a liquid core.
• Triton also has nitrogen geysers,
caused by gas below the poles, which
expand and erupt when heated by
the sun.
Pluto- A Dwarf Planet
Why Dwarf Planets?
• There are 3 Dwarf Planets in our Solar System; Pluto,
Eris (found in the Kupier Belt) and a very large asteroid
called Ceres.
• What is a Planet?
– In 2006 the International Astronomical Union define
a planet as an object that orbits the sun with
sufficient mass and gravity.
– Dwarf Planets orbit the sun but do not clear their
“neighborhood” and they are not a moon(satellite)
Pluto now has 3 moons:
Charon, Nix, and Hydra
Pluto with its moon
Charon, which is
almost as big as
Pluto.
• Average distance from Sun- 3.8 billion
miles
• Temperature- -382°F
• Diameter- 1,432 miles
• 1 Moon- Charon (Diameter of 730
miles)
• Atmosphere- 99.97% Nitrogen
• Rotation= 6.38 days
• Revolution= 248.6 years
• Gravity- 1/8 that of Earth
• Orbit- has a more elliptical and titled
orbit, (one reason for its declassification
as a planet) This sometimes allows it to
be closer to the sun than Neptune,
making Neptune the farthest planet.
• Eccentricity: .25
Pluto
Other Dwarf Planets:
Ceres
•Ceres-located in the Asteroid Belt. It was
discovered in 1801.
•Some still consider Ceres just a very large
asteroid rather than a dwarf planet
Eris
•Eris was discovered in 2003, this
caused the controversy of Pluto
because these two objects were
the same size
•White in color and 97 AU’s away
•Has 1 moon
•Eccentricity is .43