THE SOLAR SYSTEM
By Denise Kerrigan
for the Explorers Co-op
This image of Mercury’s southern hemisphere was taken by Mariner 10, on March 29, 1974.
Image courtesy of NASA
Due to its lack of atmosphere, Mercury is the most heavily cratered planet in the solar system.
Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
o Mercury has very little gravity. If
you weighed 100 lbs here on
Earth, you would only weigh 38
lbs on Mercury!
o Mercury is only visible from Earth
13 times every 100 years! We
won’t be able to see it again until
2016!
o Temperatures on Mercury range
from 800º F to -290º F! Because
it has such a thin atmosphere, it
cannot retain its heat, even being
that close to the Sun.
Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
With all it’s clouds, Venus is a super greenhouse, reaching temperatures of 870ºF! It’s the hottest planet!
Image Courtesy of NSSDC Photo Gallery
Taken by the Magellan spacecraft in 1991, this shows the craters and volcanic activity on Venus.
Venus is covered by thousands of volcanoes.
Image courtesy of NASA/JPL
o Sometimes referred to as the
morning or evening star,
Venus is the third brightest
object in the sky, after the Sun
and Moon. It looks more than
10 times brighter than the
brightest star, Sirius.
o Venus has a retrograde
rotation, which means it
rotates on its axis backwards.
o The clouds on Venus are
made up of sulfuric acid and
the air is made up mostly of
carbon dioxide.
o One day on Venus lasts for
243 Earth days!
Earth is the only planet we know of that supports life.
Image courtesy of NASA/NSSDC
This was taken from Apollo 11, in 1969, and shows the earthrise over the moon!
Image courtesy of NASA/JPL
o This image of a thunderstorm
was taken in 2000 from the
International Space Station.
o The Earth spins on its axis at
1,000 miles per hour!
o Earth is the only planet that
has water as a solid, liquid,
and gas.
o The Earth’s axis is tilted
23.5º, and that is what gives
us seasons.
o The air we breathe is made
up mostly of Nitrogen. In fact,
it is 77% Nitrogen and only
21% Oxygen!
Image courtesy of Science & Analysis Laboratory, NASA Johnson Space Center
o The dark areas on the moon
are called maria (mär΄-ē-ə) .
They are generally flat areas,
and were once believed to be
seas. The light areas are
called terrae (ter –ē). These
areas are generally more
rugged and with many more
craters.
o If it weren’t for the moon,
Earth’s rotation, and even the
weather, would be out of
control.
o We only ever see one side of
the moon from Earth. The
dark side of the moon always
faces away from Earth, and is
much more heavily cratered.
Image courtesy of NASA
Mars appears red because the soil is made up of large amounts of iron, which has rusted.
Image courtesy of NASA (Taken by the Hubble Space Telescope..)
Scientists have found water ice on Mars, particularly on its northern and southern poles.
Image courtesy of ESA/DLR/FU Berlin (G. Neukum)
o Mars is the home to the largest
volcano in the Solar System, Olympus
Mons. The volcano is approximately
20 miles high, and has a diameter of
374 miles. Olympus Mons is about
the size of the state of Arizona.
o Mars is also the home to the longest
and deepest canyon in the Solar
System. Valles Marineris is 2,485
miles long, 124 miles wide, and up to
4 miles deep.
o Mars has terrible dust storms that can
sometimes cover the entire planet.
o Mars’ two moons are captured
asteroids, Phobos and Deimos.
Phobos is slowly spiraling down, into
Mars.
Image courtesy of NASA/NSSDC Photo Gallery
Found between Mars and Jupiter, the Asteroid Belt contains most of the asteroids in the Solar System.
Most asteroids are very irregularly shaped and have craters on them.
The Asteroid Belt contains millions of asteroids, which are very spread out.
Image courtesy of NASA/Lunar and Planetary Institute
This image shows the gas giant Jupiter with one of its moons, Europa, passing in front of it.
Image Courtesy of NASA/JPL/University of Arizona
Jupiter’s Giant Red Spot is a huge storm that has been raging on the planet for more than 400 years!
Image courtesy of NASA Planetary Photojournal
o This image shows Jupiter with one
of its moons, Io.
o Jupiter has 64 known moons. The
four largest, called the Galilean
moons, are Io, Europa, Callisto, and
Ganymede.
o The dark stripes on the planet are
called belts and the light strips are
called zones. They are created by
winds in Jupiter’s upper
atmosphere.
o Jupiter’s rings weren’t discovered
until 1979, and are only visible with
backlight from the Sun.
o The Giant Red Spot is so big that
three Earths inside of it!
Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/GSFC
Saturn is the most distant planet that we can see with the naked eye!
Image courtesy of Space Telescope Science Institute
This shows Saturn in an edge on view, with four of its moons passing in front of it.
Image courtesy of NASA/JPL/STSI
o Saturn’s rings are only about 30 feet thick!
o The rings are made up of tiny particles of
dust and ice, ranging in size from a grain
of salt to a giant boulder!
o Saturn has 62 known moons!
o Some of Saturn’s moons orbit in opposite
directions around Saturn.
o Saturn’s moon Iapetus has one
hemisphere that is white, and one that is
black! It is called the yin and yang of
Saturn’s moons.
o Saturn’s gravity is close to Earth’s. If you
weigh 100 pounds on Earth, you would
only weigh 107 pounds on Saturn!
Image courtesy of NASA.
Uranus has a 98º tilt to its axis, and is the only planet in the Solar System tilted completely on its side.
Image courtesy of NASA/Space Telescope Science Institute
Uranus’s rings are also tilted sideways, staying aligned with the planet’s equator.
Image courtesy of Erich Karkoschka (University of Arizona) and NASA
o Uranus was discovered in 1781 by
British astronomer, William Herschel. It
was the first planet discovered in over
2000 years!
o Herschel originally wanted to name the
planet Sidus Georgium, after King
George III.
o Scientists believe that Uranus was hit by
a very heavy object early in its existence,
and that is what caused it to tip on its
side.
o This shows Uranus with one of its
moons, Ariel.
o Because of its tilt, Uranus experiences
42 years of winter followed by 42 years
of summer, as it travels around the Sun!
Image courtesy of NASA/Space Telescope Science Institute
Neptune is the farthest planet from the Sun and is the smallest of the gas giants.
Image courtesy of NASA
Neptune’s Great Dark Spot is a giant storm, much like Jupiter’s Giant Red Spot, and is about the size of
Earth.
Image courtesy of JPL/NASA Planetary Photojournal
o Neptune was predicted mathematically to exist
before it was actually found. Two people are
credited with its discovery in the 1840’s,
French mathematician Urbain Le Verrier, and
British astronomer John Couch Adams. In
September of 1846, German astronomer,
Johann Galle, found it with a telescope using
the predictions.
o Neptune has the wildest weather of any planet
in the Solar System. Temperatures can reach
as low as -350ºF, even though its core is
hotter than the Sun’s! Neptune also has
terribly violent winds that can reach 932 mph!
Giant hurricanes are also extremely common.
o The Voyager 2 spacecraft reached Neptune in
1989, and is the only spacecraft to ever travel
to Neptune.
Image courtesy of NASA Planetary Photojournal
In August of 2006, the International
Astronomical Union defined the term
planet for the first time. When this
happened, a new planetary category was
created: dwarf planet.
Pluto’s status as the ninth planet was
suddenly changed, and it was reclassified
as a dwarf planet.
Now, Pluto, along with four other known
objects are considered dwarf planets.
Scientists believe there may be as many
as 100 other dwarf planets in our Solar
System, just waiting to be discovered.
This image is an artist’s depiction of some
of the dwarf planets compared to Earth
and the Moon.
Image courtesy of NASA
Ceres is the only known dwarf
planet that is not part of the
Kuiper Belt. Ceres is found in
the asteroid belt, and is the
only round object discovered
there.
Scientists think the area
surrounding the core of Ceres
may be made of water ice.
Ceres is named for the Roman
goddess of corn and harvests.
Image courtesy of NASA/ESA/SWRI/Cornell University/University of Maryland/STSci
Once the ninth planet of the Solar System, Pluto is now perhaps the most well known dwarf planet.
Pluto was discovered in 1930 by American astronomer Clyde Tombaugh.
Pluto was named by an 11 year old English girl and was named for the Roman god of the underworld.
This image, from the Hubble Space Telescope, shows Pluto with three of its moons.
Image courtesy of NASA/Hubble Space Telescope
The dwarf planet Makemake, discovered in 2005, is part of the Kuiper Belt.
Makemake was named after the Rapanui (people of Easter Island) god for fertility.
The methane and ethane in its atmosphere, mixed with solar ultraviolet light, produce the red-brown color
we see.
Image courtesy of Princeton University
Also part of the Kuiper Belt, Haumea was
discovered in 2003.
Haumea was named after the Hawaiian
goddess of childbirth and fertility.
Haumea is one of the fastest rotating
objects in our Solar System. It rotates on
its axis once ever 4 hours!
Image courtesy of NASA
Eris is another Kuiper Belt
object, and was
discovered in 2003.
Eris was originally labeled
the tenth planet in the
Solar System, but that
didn’t last for long. The
discovery of Eris sparked
the debate which
eventually led the IAU to
define what a planet was
and create the
classification of dwarf
planet.
This artist’s conception
shows Eris with its moon.
That bright star in the
background is the Sun!
Eris is named after the
Roman goddess of discord
and strife.
Image courtesy of CalTech
The Kuiper Belt is an area
beyond Neptune, somewhat
like the Asteroid Belt
between Mars and Jupiter,
but much larger. It’s filled
with rocky and icy objects,
some of which are dwarf
planets. It is also believed
to be where many comets,
such as Halley’s Comet,
come from.
Image courtesy of NASA
The Oort Cloud is an
area extending
trillions of miles
beyond the Kuiper
Belt and Solar
System. It contains
trillions of icy objects
that interact with
other parts of our
galaxy. Occasionally,
some of those
interactions will send
a comet into the
inner Solar System.
Those are the
comets that appear
to us only once in
thousands of years.
Image courtesy of NASA
Beyond Our Solar System
Image courtesy of NASA, ESA, STScI, J. Hester and P. Scowen (Arizona State University)
Inside our own Milky Way galaxy, there are billions of stars.
We know of over 400 with planets orbiting them.
Image courtesy of Kuiper Airborne Observatory
There are countless galaxies beyond our own, and billions of stars in each one.
Could one have an Earth-like planet orbiting?
Image courtesy of Robert Williams and the Hubble Deep Field Team (STScI) and NASA
There are many
wonders in the
heavens to behold!
Image courtesy of University of California Santa Cruz
Many new things to discover!
Image courtesy of NASA, ESA, and The Hubble Heritage Team
Glorious creations!
Image courtesy of NASA, ESA, and M. Livio
Who knows what we will find next!
Image courtesy of NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team