The nine planets

The Nine Planets
(13.14)
The Nine Planets in our
Solar System

The Inner Planets
The four planets closest to the Sun are
Mercury, Venus, Earth, and Mars.
All four of these planets are made up of a
rocky material and therefore are called
the terrestrial planets.
These planets are also known as the inner
planets.

Mercury
Mercury is the closest planet to the Sun;
therefore, it gets sunlight that is 10
times brighter than the Earth’s.
Mercury does not have an atmosphere to
help trap the heat it receives from the
Sun, so it loses all of its heat at night
dropping to -180 degrees Celsius (o
C).
Mercury’s daytime temperature is a
sweltering 400 (o
C).

Mercury is rarely
seen in our
night sky
because it is so
close to the
Sun.
When we do see
Mercury, it is
generally at
sunset and at
sunrise.

How Was Mercury Formed?
• There are two theories as to how planets
in the solar system were created.
1.The first and most widely accepted, core
accretion..
2.The second, the disk instability method,
may account for the creation of these
giant planets.

How Big is Mercury?
• Radius, diameter and circumference
Mercury's diameter is 3,030 miles (4,878
km).The planet has a mean radius of
1,516 miles (2,440 km), and its
circumference at the equator is 9,525
miles (15,329 km).

How Big is Mercury?
Density, mass and volume
Mercury has a mass of
330 x 1023
kilograms.
This mass is
contained in a volume
of 14.6 trillion cubic
miles (60.8 trillion
cubic km). The mass
and volume of
Mercury is only about
0.055 times that of
Earth.
• But because
Mercury's small mass
is enclosed inside of a
tiny body, the planet
is the second densest
in the solar system,
weighing in at 5.427
grams per cubic
centimeter, or 98
percent of the density
of our planet.

Mercury's Atmosphere
• Of all the planets in the solar system,
Mercury has the thinnest atmosphere,
thinner than even Mars. Several
components are constantly replenished by
the solar wind blowing off of the nearby
sun.

Atmospheric Components
The makeup of Mercury's negligible atmosphere
is:
– Oxygen: 42 percent
– Sodium: 29 percent
– Hydrogen: 22 percent
– Helium: 6 percent
– Potassium: 0.5 percent
• With possible traces of argon, carbon dioxide,
water, nitrogen, xenon, krypton, neon, calcium,
and magnesium

Atmospheric Components
• The hydrogen and helium atoms likely
come from the sun, streaming in on the
solar wind and spreading out through the
planet's atmosphere. Impacting comets
and meteorites likely brought in the water
vapor and other elements. Others may
come from the radioactive decay of the
planet's crust. Eventually, these gases are
caught by the solar wind and carried off of
the planet.

Climate and Weather
The lack of atmosphere also contributes to the
planet's wild temperature extremes. On other
planets, the atmosphere functions as a blanket,
helping to redistribute heat somewhat. But on
Mercury, the thin atmosphere does nothing to
stabilize the incoming solar rays—and because
the distance to Mercury from the sun is so small,
the day side of the planet feels the heat keenly,
while the night side, turned from the sun, only
registers the cold. Mercury's lack of atmosphere
means that it is not the hottest planet; Venus,
with its runaway global warming, has that honor.

Mercury Profile
Mass 330,104,000,000,000 billion kg (0.055 x Earth)
Equatoria Diameter 4, 879 km
Polar Diameter 4, 879 km
Circumference 15, 329 km
Known Moons None
Notable Moon None
Orbit Distance 57, 909, 227 km (0.39 AU)
Orbit Period 87.97 Earth days
Surface Temperature -173 to 427°C
First Record 14th
century BC
Recorded by Assyrian Astronomers

Venus
After the Sun and the Moon,
Venus is the brightest object
that we can see in the sky
because it is so close to our
planet Earth.
Also, the atmosphere on Venus is
very thick and the light it
receives from the Sun is
reflected to us.
Venus’s atmosphere is made up
from mainly carbon dioxide.
This gas acts like the glass of a
greenhouse and keeps the
surface of the planet hot
enough to melt lead.

How Was Venus Formed?
accretion..
may account for the creation of these giant
planets.

How Big is Venus?
Venus has a mean radius of 3,760 miles, or
6,052 kilometers.
• A trip around the equator of Venus would
carry you 23,627 miles (38,025 km), 95
percent the distance around Earth's center
line.

How Big is Venus?
Density, mass and volume
• Venus is a rocky, terrestrial planet like Earth,
and likely formed the same way at the same
time. It has a mass of 4.87 trillion trillion
kilograms, about 82 percent that of its sister
planet.
• Like its size, its density is comparable to Earth at
5.243 grams per cubic centimeter. The volume
of the planet is 223 billion cubic miles (928
billion cubic kilometers), about 86 percent that of
our own.

Venus' Atmosphere: Composition,
Climate and Weather
• Venus has the distinction of being the
hottest planet in the solar system, and the
fault lies solely with its atmosphere. What
is it about the air on Venus that keeps the
planet cooking?

Atmospheric Makeup
The atmosphere of Venus is made up almost
completely of carbon dioxide. Nitrogen exists in
small doses, as do clouds of sulfuric acid. The
air of Venus is so dense that the small traces of
nitrogen are four times the amount found on
Earth, although nitrogen makes up more than
three-fourths of the terrestrial atmosphere. This
composition causes a runaway greenhouse
effect that heats the planet even hotter than the
surface of Mercury, although Venus lies
farther from the sun.

Atmospheric Makeup
• Here's a breakdown of its composition:
– Carbon dioxide: 96 percent
– Nitrogen: 3.5 percent
– Carbon monoxide, argon, sulfur dioxide, and
water vapor: less than 1 percent

Climate and Weather
• Winds of about 224 mph (360 kph) keep
the clouds of Venus in constant motion.
Though the planet spins slowly, only once
every 243 Earth days, the clouds zip
around the top of the planet every four
days. But wind speeds drop closer to the
surface, where they only move a few miles
per hour.

Climate and Weather
On Earth, seasons change based on the planet's
tilt; when a hemisphere is closer to the sun, it
experiences warmer regions. But on Venus,
most of the sun's heat fails to make it through
the thick atmosphere. As such, the planet not
only doesn't experience significant temperature
changes over the course of the year, it also
keeps things constant from night to day.

Venus Profile
Mass 4,867,320,000,000,000 billion kg
(0.815 x Earth)
Equatoria Diameter 12,104 km
Polar Diameter 12,104 km
Circumference 38,025 km
Known Moons None
Notable Moon None
Orbit Distance 108,209,475 km (0.73 AU)
Surface Temperature 462° C
First Record 14th
century BC
Recorded by Babylonian Astronomers

Earth
Life has grown on Earth because the
atmosphere on this planet is perfect for
beings to have changed.
Earth’s atmosphere is mainly made up of
nitrogen, oxygen, and water vapor.
There is a small amount of ozone in our
atmosphere and this is what filters
some of the damaging radiation from
the Sun.

Water from lakes, oceans,
and rivers covers
approximately 70% of
planet Earth.
The rest of the Earth’s
surface is covered by
soil, which allows for
the growth of
vegetations and habitat
for land creatures.
Earth is changing every
day because of several
environmental factors
such as volcanoes,
earthquakes, and
pollution.

How Was Earth Formed?
accretion..
planets.

Crust
• Earth's crust is made up of several
elements: iron, 32 percent; oxygen, 30
percent; silicon, 15 percent; magnesium,
14 percent; sulfur, 3 percent; nickel, 2
percent; and trace amounts of calcium,
aluminum and other elements.

Mantle
The mantle under the crust is about 1,800
miles deep (2,890 km). It is composed
mostly of silicate rocks rich in magnesium
and iron. Intense heat causes the rocks to
rise. They then cool and sink back down to
the core. This convection — like a lava
lamp — is believed to be what causes the
tectonic plates to move. When the mantle
pushes through the crust, volcanoes
erupt.
um and iron. Intense heat causes the rocks to rise. They then cool and sink back down to the core. This convection — like a lava lamp —

Core
At the center of the Earth is the core, which
has two parts. The solid, inner core of iron
has a radius of about 760 miles (about
1,220 km). It is surrounded by a liquid,
outer core composed of a nickel-iron alloy.
It is about 1,355 miles (2,180 km) thick.

Earth's Atmosphere: Composition,
Climate & Weather
Earth is the only planet in the solar system with an
atmosphere that can sustain life. The blanket of
gases not only contains the air that we breathe
but also protects us from the blasts of heat and
radiation emanating from the sun. It warms the
planet by day and cools it at night.
• Earth's atmosphere is about 300 miles (480
kilometers) thick, but most of it is within 10 miles
(16 km) the surface. Air pressure decreases with
altitude.

Composition of Air
• The gases in Earth's atmosphere include:
– Nitrogen – 78 percent
– Oxygen – 21 percent
– Argon – 0.93 percent
– Carbon dioxide – 0.038 percent
• Water vapor and other gases exist in small
amounts as well.

Atmosphere Layers
Earth's atmosphere is divided into five main
layers:
1.the exosphere,
2.the thermosphere,
3.the mesosphere,
4.the stratosphere and
5.the troposphere.

Atmosphere Layers
(The Troposphere)
The troposphere is the layer closest to
Earth's surface. It is 4 to 12 miles (7 to 20
km) thick and contains half of Earth's
atmosphere. Air is warmer near the
ground and gets colder higher up. Nearly
all of the water vapor and dust in the
atmosphere are in this layer and that is
why clouds are found here.

Atmosphere Layers
(The Stratosphere)
The stratosphere is the second layer. It
starts above the troposphere and ends
about 31 miles (50 km) above ground.
Ozone is abundant here and it heats the
atmosphere while also absorbing harmful
radiation from the sun. The air here is very
dry, and it is about a thousand times
thinner here than it is at sea level.
Because of that, this is where jet aircraft
and weather balloons fly.

Atmosphere Layers
(The Mesosphere)
The mesosphere starts at 31 miles (50 km) and
extends to 53 miles (85 km) high. The top of the
mesosphere, called the mesopause, is the
coldest part of Earth's atmosphere with
temperatures averaging about minus 130
degrees F (minus 90 C). This layer is hard to
study. Jets and balloons don't go high enough,
and satellites and space shuttles orbit too high.
Scientists do know that meteors burn up in this
layer.

Atmosphere Layers
(The Thermosphere)
The thermosphere extends from about 56 miles
(90 km) to between 310 and 620 miles (500 and
1,000 km). Temperatures can get up to 2,700
degrees F (1,500 C) at this altitude. The
thermosphere is considered part of Earth's
atmosphere, but air density is so low that most
of this layer is what is normally thought of as
outer space. In fact, this is where the
space shuttles flew and where the
International Space Station orbits Earth.
is and Aurora Australis.

Atmosphere Layers
(The Exosphere)
The exosphere, the highest layer, is
extremely thin and is where the
atmosphere merges into outer space. It is
composed of very widely dispersed
particles of hydrogen and helium.

Climate and Weather
• Earth is able to support a wide variety of living
beings because of its diverse regional climates,
which range from extreme cold at the poles to
tropical heat at the Equator. Regional climate is
often described as the average weather in a
place over more than 30 years. A region's
climate is often described, for example, as
sunny, windy, dry, or humid. These can also
describe the weather in a certain place, but while
the weather can change in just a few hours,
climate changes over a longer span of time.

Climate and Weather
• Earth's global climate is an average of
regional climates. The global climate has
cooled and warmed throughout history.
Today, we are seeing unusually rapid
warming. The scientific consensus is that
greenhouse gases, which are increasing
because of human activities, are trapping
heat in the atmosphere.

How Big is Earth?
The mean radius of Earth is 3,959 miles (6,371
kilometers). However, Earth is not quite a
sphere. Earth's equatorial diameter is 7,926
miles (12,756 kilometers), but from pole to pole,
the diameter is 7,900 miles (12,720 km) — a
difference of only 40 miles (64 km).
• The circumference of Earth at the equator is
about 24,902 miles (40,075 km), but from pole-
to-pole — the meridional circumference — Earth
is only 24,860 miles (40,008 km) around.

How Big is Earth?
• Density, mass and volume
Earth's density is 5.52 grams per cubic centimeter.
Earth is the densest planet in the solar system
because of its metallic core and rocky mantle.
• Earth's mass is 6.6 sextillion ton (5.9722 x
1024
kilograms). It volume is 1.08321 x 1012
km.
• The total surface area of Earth is about 197
million square miles (509 million square km).
About 71 percent is covered by water and 29
percent by land.

Earth Profile
Mass 5,972,190,000,000,000 billion kg
Known Moons 1
Notable Moon The Moon
Orbit Distance 149,598,262 km (1 AU)
Surface Temperature -88 to 58° C

Mars
Mars is one of the
brightest planets in the
sky and is sometimes
referred to as the
“RED Planet” because
of the reddish tinge it
casts. This reddish
colour is caused by the
rust-coloured soil.
Mars is very dry and
barren, but there is
evidence that Mars was
once covered with
volcanoes, glaciers and
flood waters.

How Was Mars Formed?
accretion..
planets.

What is Mars Made Of?
Composition of Planet Mars
Mars is the "red planet" for a very good
reason: its surface is made of a thick layer
of oxidized iron dust and rocks of the
same color. Maybe another name for Mars
could be "Rusty." But the ruddy surface
does not tell the whole story of the
composition of this world.

What is Mars Made Of? Composition of
Planet Mars
• Dusty crust
The dust that covers the surface
of Mars is fine like talcum
powder. Beneath the layer of
dust, the Martian crust consists
mostly of volcanic basalt rock.
The soil of Mars also holds
nutrients such as sodium,
potassium, chloride and
magnesium. The crust is about
30 miles (50 kilometers) thick.

Mantle and core
The mantle that lies beneath the crust is largely dormant. It
is made up primarily of silicon, oxygen, iron, and
magnesium and probably has the consistency of soft
rocky paste. It is probably about 900 to 1,200 miles
(5,400 to 7,200 kilometers) thick, scientists say.
• The center of Mars likely has a solid core composed of
iron, nickel, and sulfur. It is estimated to be between
1,800 and 2,400 miles (3,000 and 4,000 kilometers) in
diameter. The core does not move, and therefore Mars
has no magnetic field. Without a magnetic field, radiation
bombards the planet making it relatively inhospitable
compared to Earth.

Water and Atmosphere
Mars is too cold for liquid water to exist for any length of
time, but features on the surface suggest that water once
flowed on Mars. Today, water exists in the form of ice in
the soil, and in sheets of ice in the polar ice caps. The
average temperature is about minus 80 degrees F
(minus 60 degrees C), although they can vary from
minus 195 degrees F (minus 125 degrees C) near the
poles during the winter to as much as 70 degrees F (20
degrees C) at midday near the equator.
• The atmosphere of Mars is too thin to easily support life
as we know it. It is about 95 percent carbon dioxide.

How Big is Mars?
Diameter and circumference
Mars is not a sphere. Because the planet rotates
on its axis (every 24.6 hours), it bulges at the
equator (as do Earth and other planets). At its
equator, Mars has a diameter of 4,222 miles
(6,794 km), but from pole to pole, the diameter is
4,196 miles (6,752 km). Mars’ radius is, of
course, half of planet’s diameter.
• The circumference of Mars around the equator
is about 13,300 miles (21,343 km), but from
pole-to-pole Mars is only 13,200 miles (21,244
km) around. This shape is called an oblate
spheroid.

How Big is Mars?
• Mass and gravity
Mars' mass is 6.42 x 1023
kilograms, about
10 times less than Earth. This affects the
force of gravity. Gravity on Mars is 38
percent of Earth's gravity, so a 100-pound
person on Earth would weigh 38 pounds

Mars' Atmosphere: Composition,
Climate & Weather
Mars has a thin atmosphere — too thin to
easily support life as we know it. The
extremely thin air on Mars can also
become very dusty. Giant dust storms can
blanket the entire planet and last for
months.

What is Mars' atmosphere made
of?
The atmosphere of Mars is about 100 times
thinner than Earth's, and it is 95 percent carbon
dioxide. Here's a breakdown of its composition:
– Carbon dioxide: 95.32 percent
– Nitrogen: 2.7 percent
– Argon: 1.6 percent
– Oxygen: 0.13 percent
– Carbon monoxide: 0.08 percent
• Also, minor amounts of: water, nitrogen oxide,
neon, hydrogen-deuterium-oxygen, krypton and
xenon

Climate and Weather
• Mars' thin atmosphere and its greater distance
from the sun mean that Mars is much colder
than Earth. The average temperature is about
minus 80 degrees F (minus 60 degrees C),
although it can vary from minus 195 degrees F
(minus 125 degrees C) near the poles during the
winter to as much as a comfortable 70 degrees
F (20 degrees C) at midday near the equator.
• The atmosphere of Mars is also roughly 100
times thinner than Earth's, but it is still thick
enough to support weather, clouds and winds.

Climate and Weather
• Giant dust devils routinely kick up the oxidized
iron dust that covers Mars' surface. The
dust storms of Mars are
the largest in the solar system, capable of
blanketing the entire planet and lasting for
months. One theory as to why dust storms can
grow so big on Mars starts with airborne dust
particles absorbing sunlight, warming the
Martian atmosphere in their vicinity. Warm
pockets of air flow toward colder regions,
generating winds. Strong winds lift more dust off
the ground, which in turn heats the atmosphere,
raising more wind and kicking up more dust.

Mars Profile
Mass 641,693,000,000,000 billion kg (0.107
x Earth)
Known Moons 2
Notable Moon Phobos & Deimos
Orbit Period 686.98 Earth days (1.88 Earth years)
Surface Temperature -87 to -5 °C
First Record 2nd Millennium BC
Recorded by Egyptian astronomers

The Outer Planets
The remaining 5 planets in our solar system
are known as the outer planets: Jupiter,
Saturn, Uranus, Neptune and Pluto.
The first 4 of these planets are also known
as the Gas Giants. Their atmosphere
consists mainly of hydrogen and helium.
These planets have soupy surfaces and
gets denser as you sink to the middle.
Not possible to land on.
The outermost planet, Pluto, is unique
among the outer planets.

Jupiter
Jupiter is the largest
planet of all of the
planets.
Its diameter is 11
times larger than
Earth’s diameter.
Its mass is greater
than the masses of
all the other planets
combined.

Jupiter is also a very bright object in the
night sky because of its size and the
large amount of light reflected by its
clouds.
Jupiter’s most interesting features are
its coloured bands and the Great Red
Spot.
Jupiter has approximately 16 moons, and
sometimes you can see four of these
moons by using binoculars.

What is Jupiter Made Of?

• Atmospheric composition (by volume):
89.8 percent molecular hydrogen, 10.2
percent helium, minor amounts of
methane, ammonia, hydrogen deuteride,
ethane, water, ammonia ice aerosols,
water ice aerosols, ammonia hydrosulfide
aerosols
• Magnetic field: Nearly 20,000 times
stronger than Earth's.

Chemical composition: Jupiter has a
dense core of uncertain composition,
surrounded by a helium-rich layer of fluid
metallic hydrogen, wrapped up in an
atmosphere primarily made of molecular
hydrogen.
• Internal structure: A core less than 10 times
Earth's mass surrounded by a layer of fluid
metallic hydrogen extending out to 80 to 90
percent of the diameter of the planet, enclosed
in an atmosphere mostly made of gaseous and
liquid hydrogen.

Orbit & rotation
• Average distance from the sun: 483,682,810
miles (778,412,020 km). By comparison: 5.203
times that of Earth
• Perihelion (closest approach to the sun):
460,276,100 miles (740,742,600 km). By
comparison: 5.036 times that of Earth
• Aphelion (farthest distance from the sun):
507,089,500 miles (816,081,400 km). By
comparison: 5.366 times that of Earth

Jupiter's rings
Jupiter's three rings came as a surprise when NASA's
Voyager 1 spacecraft discovered them around the
planet's equator in 1979. Each are much fainter
than Saturn's rings. The main ring is flattened. It is
about 20 miles (30 km) thick and more than 4,000
miles (6,400 km) wide.
• The inner cloud-like ring, called the halo, is roughly
12,000 miles (20,000 km) thick. The halo extends
halfway from the main ring down to the planet's
cloud tops and expands by interaction with Jupiter's
magnetic field. Both the main ring and halo are
composed of small, dark particles.

Jupiter's rings
The third ring, known as the gossamer ring
because of its transparency, is actually three rings
of microscopic debris from three of Jupiter's
moons, Amalthea, Thebe and Adrastea. It is
probably made up of dust particles less than 10
microns in diameter, about the same size of the
particles found in cigarette smoke, and extends to
an outer edge of about 80,000 miles (129,000 km)
from the center of the planet and inward to about
18,600 miles (30,000 km).
• Ripples in the rings of both Jupiter and Saturn
may be signs of impacts from comets and
asteroids.

Jupiter Profile
Mass 1,898,130,000,000,000,000 billion kg
(317.83 x Earth)
Known Moons 67
Notable Moon Io, Europa, Ganymede, & Callisto
Known Ring 4
Orbit Period 4,332.82 Earth days (11.86 Earth
years)
Surface Temperature -108°C
First Record 7th
or 8th
Century BC
Recorded by Babylonian Astronomers

Saturn
Saturn is the second-largest planet, but it is
the least dense of all the planets, with a
possibility of no core.
Saturn’s atmosphere is cloudy and windy.
Saturn’s average temperature is -180o
C.

How Was Saturn Formed?
accretion..
planets.

What is Saturn Made Of?
The gas giant Saturn contains many of the
same components as the sun. Although it
is the solar system's second largest
planet, it lacks the necessary mass to
undergo the fusion needed to power a
star. Still, its gaseous composition — and
the stunningly beautiful rings that surround
it — make it one of the more interesting
object in the solar system.

Saturn is predominantly composed of
hydrogen and helium, the two basic gases
of the universe. The planet also bears
traces of ices containing ammonia,
methane, and water. Unlike the rocky
terrestrial planets, gas giants such as
Saturn lack the layered crust-mantle-core
structure, because they formed differently
from their rocky siblings.

(Saturn's surface)

(Saturn's surface)
• Saturn is classified as a gas giant because it is almost
completely made of gas. Its atmosphere bleeds into its
"surface" with little distinction. If a spacecraft
attempted to touch down on Saturn, it would never find
solid ground. Of course, the craft would be fortunate to
survive long before the increasing pressure of the
planet crushed it.
• Because Saturn lacks a traditional ground, scientists
consider the surface of the planet to begin when the
pressure exceeds one bar, the approximate pressure
at sea level on Earth.

(Saturn's Interior)
At higher pressures, below the determined
surface, hydrogen on Saturn becomes liquid.
Traveling inward toward the center of the planet,
the increased pressure causes the liquefied gas
to become metallic hydrogen. Saturn does not
have as much metallic hydrogen as the largest
planet, Jupiter, but it does contain more ices.
Saturn is also significantly less dense than any
other planet in the solar system; in a large
enough pool of water, the ringed planet would
float.

(Saturn's Interior)
During the formation of Saturn, the core would
have been created first. Research suggests that
Saturn's rocky core is between 9 to 22 times the
mass of Earth. Only when it reached sufficient
mass would the planet have been able to
gravitationally pile on the light hydrogen and
helium gas that make up most of the its mass.

(A strong magnetic field)
As on Jupiter, the liquid metallic hydrogen
drives the magnetic field of Saturn.
Saturn's magnetosphere is smaller than its
giant sibling, but still significantly more
powerful than those found on the
terrestrial planets. With a magnetosphere
large enough to contain the entire planet
and its rings, Saturn's magnetic field is
578 times as powerful as Earth's.

(The Rings of the Saturn)
When Italian astronomer Galileo Galilei turned his
telescope toward Saturn, he observed two blobs
on either side that he identified as bodies
separate from the main planet. It wasn't until
Dutch astronomer Christiaan Huygens studied
the planet with a more powerful scope that the
rings of Saturn were first identified.

(The Rings of the Saturn)
Although most of the gas giants boast rings
of some sort, Saturn's are the largest and
arguably the most visually stunning.
Stretching as far out as 262,670 miles
(422,730 km), or eight times the radius of
the planet, the rings are made up of ice
and rock pieces that create a rainbow
effect as they refract the light from the
sun.

How Big is Saturn?
Saturn, the sixth planet in the solar system,
is the second largest. Only Jupiter is
larger, weighing in just shy of three times
its mass. Saturn's beautiful rings, visible
even with an inexpensive telescope, make
it a favorite in the night sky.

How Big is Saturn?
(Diameter, Radius and Circumference)
The mean radius of the body of Saturn is
36,184 miles (58,232 kilometers). The
polar radius (33,780 miles, or 54,364 km)
only about 90 percent that of the
equatorial radius (37,449 miles, or 60,268
km).
The circumference of Saturn is 227, 351
miles (366, 035.11 kilometers).

How Big is Saturn?
(Density, mass and volume)
The mean density of Saturn is 0.687 grams
per cubic centimeter, making it the only
planet in the solar system less dense than
water. The mass of the ringed planet is
5.68 x 1026
kilograms, 95 times the mass of
Earth. Although the planet is only a third
the mass of Jupiter, it is about 80 percent
as large, contributing to its low density.

How Big is Saturn?
(Ring around the Planet)
Although several other planets boast rings,
Saturn's are the largest and most visually
stunning. Balanced around the equator, the
rings start about 4,120 miles (6,630 km) out from
the planet and extend to a distance of 262,670
miles (422,730 km), or eight times the radius of
the planet. The five rings are composed
primarily of chunks of water-ice, mixed with
pieces of rocks. They average a thickness of 66
feet (20 meters).

Composition & Structure
• Atmospheric composition (by volume):
96.3 percent molecular hydrogen, 3.25
percent helium, minor amounts of
methane, ammonia, hydrogen deuteride,
ethane, ammonia ice aerosols, water ice
aerosols, ammonia hydrosulfide aerosols
• Magnetic field: Saturn has a magnetic
field about 578 times more powerful than
Earth's.

Composition & Structure
Chemical composition: Saturn seems to have a
hot solid inner core of iron and rocky material
surrounded by an outer core probably composed
of ammonia, methane, and water. Next is a layer
of highly compressed, liquid metallic hydrogen,
followed by a region of viscous hydrogen and
helium. This hydrogen and helium becomes
gaseous near the planet's surface and merges
with its atmosphere.
• Internal structure: Saturn seems to have a core
between about 10 to 20 times as massive as
Earth.

Orbit & Rotation
• Average distance from the sun:
885,904,700 miles (1,426,725,400 km). By
comparison: 9.53707 times that of Earth.
• Perihelion (closest approach to sun):
838,519,000 miles (1,349,467,000 km). By
• Aphelion (farthest distance from sun):
934,530,000 miles (1,503,983,000 km). By

Saturn Profile
Mass 568,319,000,000,000,000 billion kg
(95.16 x Earth)
Known Moons 62
Notable Moon Titan, Rhea & Enceladus
Known Ring 30+ (7 Groups)
Orbit Period 1,426,666,422 km (9.58 AU)
Surface Temperature -139 °C
First Record 8th
Century BC
Recorded by Assyrian Astronomers

Uranus
Uranus’s diameter is 4
times larger than
Earth.
Its atmosphere is made
up primarily of
hydrogen, with some
helium and methane.
This planet has winds
that blow up to 500
km/h. In our night sky,
Uranus looks like an
extremely faint star.

How Was Uranus Formed?
accretion..
planets.

What is Uranus Made Of?
Far, far from the sun, Uranus has a blue-
green atmosphere that hints at its
makeup. One of the two ice giants, the
planets composition differs somewhat
from Jupiter and Saturn in that it is made
up of more ice than gas.

(The surface of Uranus)
Like the other gas giants, Uranus lacks a solid,
well-defined surface. Instead, the gas, liquid,
and icy atmosphere extends to the planet's
interior. Were you to land — and hover — at the
point where the atmosphere transitions to the
interior, you would experience less of a
gravitational tug than you might feel on Earth.
Gravity on Uranus is only about 90 percent that
of Earth; if you weigh a hundred pounds at
home, you would only weight 91 pounds on
Uranus.

(The surface of Uranus)
Uranus is the second least dense planet in the
solar system, indicating that it is made up mostly
of ices. Unlike Jupiter and Saturn, which are
composed predominantly of hydrogen and
helium, Uranus contains only a small portion of
these light elements. It also houses some rocky
elements, equal to somewhere between 0.5 to
1.5 times the mass of Earth. But most of the
planet is made up of ices, mostly water,
methane, and ammonia. Ices dominate because
the vast distance to Uranus from the sun allows
the planet to maintain frigid temperatures.

(A frigid core)
While most planets have rocky molten cores, the
center of Uranus is thought to contain icy
materials. The liquid core makes up 80 percent
of the mass of the planet, mostly comprised of
water, methane, and ammonia ice, though it only
extends to about 20 percent of the radius.
• While other gas giants are powered by their
cores, Uranus radiates almost no excess heat
into space. One reason for this could be due to
an impact soon after the planet's formation.

(Rocky Rings)
Like all gas giants, Uranus carries a set of
rocky rings around its equator. The thin
strips, most only a few miles wide, are
made up of tiny bits of rock and ice
smaller than a meter. The planet has at
least 13 known rings in two systems.

How Big is Uranus?
(Radius, diameter and circumference)
The mean radius of Uranus is 15,792 miles
(25,362 kilometers), giving a diameter four times
that of Earth. At the poles, Uranus has a radius
of 15,517 miles (24,973 km), but at the equator,
it expands to 15,882 miles (25,559 km). This
bulge gives Uranus a shape known as an oblate
spheroid.
The circumference of the Uranus is 98, 978 miles
(159,354 km)

How Big is Uranus?
(Density, Mass and Volume)
• Although Uranus, discovered in 1781, is
only four times the physical size of Earth,
it is significantly more massive, weighing
in at 86 septillion kilograms (just under
one trillion trillion trillion). That makes it
more than 14.5 times as massive as our
rocky home.
• The planet has a volume of 6.83x1013
cubic
kilometers.

How Big is Uranus?
(Density, Mass and Volume)
The density of Uranus is 1.27 grams per cubic
centimeter, making it the second least dense
planet in the solar system. Its low density
indicates that it is predominantly composed of
ice rather than gas. The icy composition of
Uranus and Neptune both differ from the heavier
gas giants, Jupiter and Saturn, and have caused
them to be labeled "ice giants."

How Big is Uranus?
• Although not as famous as Saturn, Uranus does
display a set of rings around its middle. The
rings around Uranus are made up of tiny dark
particles smaller than a meter. Only two of the
13 rings are larger than six miles across.
• Although the second ring system to be
discovered, the rings around Uranus weren't
found until 1977, when astronomers attempted
to study the planet's atmosphere as it crossed in
front of a bright star.

How Big is Uranus?
The rings of Uranus encircle the equator of
the planet, but to observers on Earth, they
appear to stand almost straight up and
down. This is because the planet is tipped
almost completely on its side in relation to
the plane of the solar system. Scientists
think a collision soon after Uranus'
formation caused the intriguing
misalignment.

What is the Temperature of
Uranus?
The seventh planet from the sun, Uranus
has the coldest atmosphere of any of the
planets in the solar system, even though it
is not the most distant. Despite the fact
that its equator faces away from the sun,
the temperature distribution on Uranus is
much like other planets, with a warmer
equator and cooler poles.

What is the Temperature of Uranus?
(An icy atmosphere)
Like Neptune, Uranus, discovered in 1781, is
known as an "ice giant," in a slightly different
category from Saturn and Jupiter. Both planets
boast frigid atmospheres made up of ice rather
than gas.
Atmospheric composition by volume:
– Molecular hydrogen: 82.5%
– Helium: 15.2%
– Methane: 2.3%

Uranus? (Tipped on its side)
Unlike most planets in the solar system,
which have their equators pointed in the
direction of the sun, Uranus is tipped on its
side. The planet faces one pole at a time
toward the sun, gradually spinning over
the course of its orbit until the other pole
receives light instead of darkness. The
strange orientation of the planet was likely
caused by a collision soon after its
formation.

Uranus? (A cool interior)
Despite the fact that it powers the planet's
weather, the internal temperature of Uranus is
lower than other planets. Very little excess heat
is radiated into space.
• Unlike other gas giants, Uranus most likely
boasts a rocky core rather than a gaseous one.
Temperatures inside it may reach 8,540 F
(4,727 C), which sounds warm but is cooler than
other planets — Jupiter's core may reach 43,000
F (24,000 C).

Uranus Profile
Mass 86,810,300,000,000,000 billion kg
(14.536 x Earth)
Equatoria Diameter 51, 118 km
Polar Diameter 49, 946km
Known Moons 27
Notable Moon Oberon, Titania, Miranda, Ariel &
Umbriel
Known Ring 13
Orbit Distance 2,870,658,186 km (19.22 AU)
years)
First Record March 13th 1781
Recorded by William Herschel

Neptune
From Earth, Neptune is
barely visible with the
use of a telescope.
Neptune has bright blue
and white clouds and a
dark region – the Great
Dark Spot – that
appears to be the
centre of a storm.
Neptune has at least 8
moons and thin rings
orbiting around it.

How Was Neptune Formed?
accretion..
planets.

What is Neptune Made Of?
Neptune, like Uranus, is one of the two outer
planets known as an "ice giant." Made up
of more ices than Jupiter and Saturn, the
chilly body almost seems to be in a class
by itself.

(Beneath the Clouds)
The first layer of Neptune is its icy
atmosphere, which is mostly hydrogen
and helium. The bluish coloration comes
from traces of methane in the air, but the
planet is a more brilliant hue than the dull
blue of Uranus, which implies something
else could be affecting it. The
enormous distance to the sun keeps the
planet's temperatures low.

(Beneath the Clouds)
Neptune is the third most massive planet. Like the
rest of the gas giants, Neptune has no definite
surface layer. Instead, the gas transits into a
slushy ice and water layer. The water-ammonia
ocean serves as the planet's mantle, and
contains more than ten times the mass of
Earth. Temperaturesinside the mantle range from
3,140 degrees Fahrenheit (1,727 degrees
Celsius) to 8,540 F (4,727 F). At deep enough
depths, the methane may transform into diamond
crystals.

(Strange Rings)
Like the other gas giants, Neptune boasts a
series of rings. But the blue planet's six
rings are not as solid as its neighbors.
Instead, the clumpy rings contain
prominent arcs, likely due to the influence
of one of Neptune's moons. Made up of
ice particles and silicates, the rings are
reddish.

(Strange Rings)
Neptune's rings were first discovered when
it passed between a star while
astronomers were attempting to study the
planet. The star faded out, then returned
to view. Unlike other rings, the arc-like
nature meant that the fading did not
repeat on the other side of the planet,
which puzzled scientist. It wasn't until
Voyager imaged the planet in 1989 that
the mystery of the rings was solved.

(A tipped magnetosphere)
Neptune has an unusual magnetic field
which is tipped on its side in relation to the
axis that the planet rotates around. The
strong magnetic field, which is about 27
times more powerful than Earth's, is tipped
at a 47 degree angle and is likely powered
by the motions inside the mantle itself.
These motions also drive strong winds
and unusual weather patterns
in Neptune's atmosphere.

How Big is Neptune?
The most distant planet from the sun,
Neptune is the third most massive.
Despite its great size, it was the last planet
to be discovered, because it lies so far
away.

How Big is Neptune?
(Radius, Diameter and Circumference)
Neptune is the fourth largest planet in terms of
diameter, making it the smallest in physical size
of the gas giants. The average distance from the
center of the planet to its surface is 15,299 miles
(24,622 kilometers). The radius at the poles is
15,125 miles (24,341 km), slightly smaller than
the equatorial radius of 15,388 miles (24,764
km). The average diameter across the planet is
30,598 miles (49,244 km), almost four times the
diameter of Earth.

How Big is Neptune?
(Radius, Diameter and Circumference)
• A trip around Neptune's equator would cover
96,129 miles (154,705 km). Such a trip could not
be made on foot—the planet's surface is
covered with water and melted ice rather than
solid rock.
• The planet's surface area covers 2.9 billion
square miles (7.6 billion square km).
• Like all of the gas giants, Neptune has rings
around it. The clumpy arcs extend as far as
39,105 miles (62,933 km) from the center of the
planet.

How Big is Neptune?
(Density, mass, and volume)
The gas giant weighs in at 1.02 x 1026
kilograms, or 102 trillion trillion kilograms.
It is more than seventeen times
as massive as Earth.
• The rock, ices, and gas that make up the
icy giant fill a volume of 15 trillion cubic
miles (62 trillion cubic kilometers), almost
58 times the volume of Earth.

How Big is Neptune?
(Density, mass, and volume)
The density of Neptune is 1.638 grams per cubic
centimeter. The low density indicates that, like
Uranus, its atmosphere is made up of more ices
than Saturn and Jupiter, causing scientists to
call it an "icy giant".
Despite hosting a significantly lower mass,
Neptune's surface gravity is second only to
Jupiter.

Neptune's Atmosphere:
Composition, Climate & Weather
The eighth and last planet in the solar
system, Neptune has an atmosphere
more comparable with Uranus than with
Saturn and Jupiter. The two most distant
planets boast atmospheres dominated by
ices. But even with a chill in the air,
Neptune still manages to host some of the
most extreme and violent weather in the
solar system.

Atmospheric composition
Neptune's atmosphere is made up
predominately of hydrogen and helium,
with some methane. The methane is part
of what gives Neptune its brilliant blue tint,
as it absorbs red light and reflects bluer
colors. Uranus also has methane in
its atmosphere, but has a duller shading.
Something else must be contributing to
Neptune's hue, but scientists aren't certain
what.

Atmospheric composition
The planet has ten to a hundred times more methane,
ethane, and ethyne at its equator than it does at its
poles.
• Atmospheric composition by volume:
– Molecular hydrogen: 80 percent
– Helium: 19 percent
– Methane 1.5 percent
– Hydrogen Deuteride: 192 parts per million
– Ethane: 1.5 parts per million
• Ammonia ice, water ice, ammonia hydrosulfide, and
methane ice also compose Neptune's atmosphere.

Layering the atmosphere
• The atmosphere of Neptune is made up of
two main regions. Like the other three gas
giants, the planet has no firm surface, so
scientists have established that the
"surface" is where the pressure is equal to
the pressure found at sea level on Earth.

Layering the atmosphere
• Just above the surface lies the troposphere. As
altitude increases,temperature in the
troposphere decreases. But in the next layer, the
stratosphere, temperatures increase with
altitude. This is related to the motion inside of
the planet's core, which heats Neptune more
than the rays from the distant sun. The next
layer is the thermosphere, where pressures are
lower. The very outer edge of the atmosphere is
known as the exosphere.

Cloud patterns on Neptune
The clouds of Neptune vary with the altitude. Cold
temperatures allow methane clouds to condense
in the highest layers of the atmosphere.
Scientists think that clouds made up of ammonia
and hydrogen sulfide exist at higher pressures.
Farther down, clouds of hydrogen sulfide,
ammonium sulfide, ammonia, and water could
exist. Clouds of water-ice may be found at
pressures of 50 bars, with clouds of hydrogen
sulfide and ammonia beneath them.

Cloud patterns on Neptune
• The highest layers contain cirrus clouds
made up of frozen methane, which have
been observed casting shadows on other
clouds 35 miles (56 kilometers) beneath
them.
• Neptune also contains a haze at very high
altitudes. These smog-like clouds are
made up of hydrocarbons, much like smog
over major cities on Earth.

Neptune Profile
Mass 102,410,000,000,000,000 billion kg
(17.15x Earth)
Polar Diameter 48, 682 km
Known Moons 14
Notable Moon Triton
Known Ring 5
Orbit Distance 4,498,396,441 km (30.10 AU)
years)
First Record September 23rd 1846
Recorded by Urbain Jean Joseph Le Verrier&
Johann Galle

Pluto
Pluto is now classified as a
dwarf planet. It is unusual
because it is not a gas
giant and it does not seem
to be terrestrial.
The motion of Pluto’s orbit
suggests that Pluto may
have been one of
Neptune’s moons at one
time.
Pluto also has a moon called
Charon which is about the
same size as Pluto.

What is Pluto Made Of?
Far out in the distant reaches of the solar
system, the dwarf planet Pluto lies in a
neighborhood of ice and rock known as
the Kuiper Belt. Frigid temperatures mean
that the tiny body contains a great deal of
ice.

How Big is Pluto?
After 76 years of classification as a planet,
Pluto was demoted in 2006 to a dwarf
planet, in part because of its size but also
because of its minor gravitational effects
on the bodies around it. It remains one of
the most well-known non-planetary bodies
in the solar system.

How Big is Pluto?
(Radius, diameter and circumference)
Pluto has a mean radius of 715 miles (1,151
kilometers). The diameter of the planet is
1,430 miles (2,302 km), only about two-
thirds the diameter of the moon.
The circumference of Pluto is 4, 490.2 miles
( 7, 230 kilometers).

How Big is Pluto?
(Density, mass and volume)
• Although all of the planets beyond Mars are gas
giants, Pluto is small and rocky. The tiny body
has a mass of only 1.31 x 1022
kilograms, about
two-tenths of a percent of Earth's. It has a
volume of 1.5 billion cubic miles (6.4 billion cubic
km).
• Pluto's small size and low mass mean that it has
a density of 2.05 grams per cubic centimeter,
about 40 percent of Earth's density.

Planetary Summary
Closest to
the Sun 0.386 0
Brown crater
Chunks of rock
none
59 days
To orbit Sun
2nd
from
the Sun
3rd from
the Sun
4th from
the Sun
5th from
the Sun
6th from
the Sun
7th from
the Sun
8th from
the Sun
9th from
the Sun
0.72
0.5326
10
11
1
0.186
3.8
4
0
1
2
63
33
29
3
13
Hot enough to
melt lead
Soil and Water
Reddish
coloured soil
Coloured Bands,
Great Red Spot
Surface temp. is
About -180o
Polar hood over
South pole
It’s blue.
Cold and rocky
CO2, N2
CO2, N2
N2, O2
H2, He, CH4
H2, He, CH4
H2, He, CH4
H2, He, CH4
none
A 1.7 KM high
Volcano
Volcanoes,
hurricanes
Volcanoes,
glaciers
Winds,
hurricanes
Windy,
cloudy
500 km/h
winds
Dark spot
Rotates on
side

The nine planets

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The nine planets