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Solar System Fun Facts
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All of the outer planets have rings, with Saturn having the biggest and brightest. Saturn's
spectacular rings are made of billions of bits of ice and rock.
Uranus actually spins on its side. It is often nicknamed the "sideways planet."
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Beyond Neptune there is a ring of hundreds of thousands of small, icy objects orbiting the
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sun. This disk-shaped ring is called the Kuiper ("KI-per") Belt. There are also many comets in
this region—scientists estimate there are a trillion or more.
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Pluto and its moon, Charon, are part of the Kuiper Belt. Pluto was discovered in 1930, and
for 76 years it was considered the ninth planet. It was the smallest planet in the solar
system, only half the width of the United States and even smaller than Earth's moon. In
2006, astronomers agreed that Pluto should be called a dwarf planet instead because of
its size and unusual orbit. Since its discovery, Pluto has gone only about a third of the way
around the sun. It won't be until the year 2178 that one Plutonian year has gone by!
The sun is huge compared to the planets. Compared to other stars in the universe,
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however, the sun is only average in size.
The sun is the closest star to Earth. Our next closest star is in a star system called Alpha
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Centauri. The three stars in this system are so far from Earth that if you imagine our sun as
a grapefruit (as in this model), they would be about 2500 miles (4000 km) away—about the
distance across the United States from coast to coast!
The Star Dome
Here's another way to explore space: create your own planetarium! The star dome converts the
solar system model into a planetarium projector.
Take off the top half of the sun sphere. Put the star dome
1.
in its place. Make sure the tab on the edge of the star dome
fits into the notch on the lower half of the
sun sphere.
The projected image will look best in a darkened room. If
2.
you can, turn off the lights and close the curtains.
Switch on the light at the base of the tower. Stars and
3.
constellation outlines will be projected onto the walls and
ceiling of the room. The farther light travels before hitting a
surface, the bigger the image
will appear. Try moving the tower closer to and farther from
the walls or ceiling to get the
best image.
Constellations – Pictures in the Sky
On a clear, moonless night, you may be able to see thousands of stars. Since ancient times,
people have noticed patterns in the stars. A constellation is a group of stars that form a pattern
as seen from Earth. Breaking up the thousands of stars visible on a dark night into constellations
helps people easily find and remember the names and locations of stars.
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For centuries cultures around the world have divided
the night sky into different constellations and have
made up stories about the creatures and characters
they saw. The Greeks and Romans named their
constellations after the gods and heroes in their
mythology.
Other cultures, such as Chinese, Middle Eastern, and
Native American, view the evening sky differently. In
1929, the International Astronomical Union divided
the stars into 88 official constellations that are used
by astronomers today. Most of these constellations
come from the Greek and Roman view of the sky.
For example, Pegasus is a flying horse from Greek
mythology.
The chart below lists constellations that are on this
model's star dome. Note: Southern Hemisphere
constellations are not included.
Northern Hemisphere Constellations
Andromeda (Andromeda)
Corona Borealis (Northern Crown)
Aquila (Eagle)
Cygnus (Swan)
Aries (Ram)
Delphinus (Dolphin)
Auriga (Charioteer)
Draco (Dragon)
Boötes (Herdsman)
Equuleus (Little Horse)
Camelopardalis (Giraffe)
Gemini (Twins)
Cancer (Crab)
Hercules (Hercules)
Canes Venatici (Hunting Dogs)
Hydra (Female Water Snake)
Canis Minor (Little Dog)
Lacerta (Lizard)
Cassiopeia (Cassiopeia)
Leo (Lion)
Cepheus (King)
Leo Minor (Little Lion)
Cetus (Sea Monster)
Lynx (Lynx)
Coma Berenices (Bernice's Hair)
Lyra (Lyre)
*not a constellation
What Do You See?
Study the constellations projected on the wall or
ceiling. Do you think they resemble the names they've
been given? Choose a few of the constellations and
note what figure or object you see. Perhaps in Ursa
Major you see a person waving hello instead of a great
bear. Possibly Ursa Minor looks more like a wheel
barrow than a little bear. Or maybe you see a horse
instead of a lion in Leo. See what shapes and other
figures you can find among the stars!
Ophiuchus (Serpent Bearer)
Orion (Orion/hunter)
Pegasus (Winged Horse)
Perseus (Hero)
Pisces (Fish)
Polaris (North Star)*
Sagitta (Arrow)
Serpens (Serpent)
Taurus (Bull)
Triangulum (Triangle)
Ursa Major (Great Bear)
Ursa Minor (Little Bear)
Virgo (Maiden)
Ursa Minor
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