A constellation is a group of stars that makes a pattern in the sky. The constellations do not change their shape, but as the night passes they seem to move around the sky. If you watch carefully, you will see that they appear to move in a circle around a center point. In the northern hemisphere, that center point is the North Star, also known as the Pole Star, or Polaris. The North Star is above the North Pole.
But the stars are not really moving. We are moving. The Earth is rotating, and that makes all the stars appear to rotate.
Questions:
What is a constellation?
What are two other names for the Pole Star?
and
Why do the stars seem to rotate around the sky?
For thousands of years, people have looked up at the sky and wondered about what they saw. They played a game by connecting the stars and creating pictures. They imagined people, animals, and gods in the heavens.
But for many of these people so long ago, this was not really a game. They needed to know how and when these star pictures moved around the sky. This told them when to plant and harvest their crops. (They didn't have calendars then.) Certain constellations would appear in the spring, and others would appear as the weather was about to get colder. Other ancient people used the stars to guide them at night, especially when they were out on the ocean.
Questions:
What are two reasons that ancient people imagined star pictures in the
heavens?
and
Many of the constellations were named by ancient astronomers
in Greece, Rome, and Babylonia. They honored the heroes and villains of many of
their favorite stories by placing them in the sky.
What do you think an astronomer is?
Here are a few of
the well-known constellations
that we can see in the northern hemisphere.
ORION - the
hunter
This
constellations was named after a hunter in an ancient story. It is seen in the
winter sky. Orion was the companion of the goddess of the hunt.
PEGASUS - the
winged horse
Perseus rode
this magical horse when he saved Andromeda from a sea monster.
AQUARIUS - the
water carrier
Ancient
people imagined seeing a man pouring water from a jar.
CANCER - the crab
The crab was
a monster in Greek legends who attacked Hercules.
CANIS MAJOR - the
great dog
This large
dog was the faithful companion of Orion, the hunter.
CAPRICORN - the
goat
This creature
had the head of a goat and the tail of a fish. He could travel on both
land and sea.
DRACO - the
dragon
Hercules
killed this monster in legend.
GEMINI - the
twins
The twins
were named Castor and Pollux, the names of the stars that are their heads.
They were devoted brothers.
HERCULES -
The ancient
Greeks thought Hercules was the strongest and bravest man on Earth. He killed
many monsters. Many of the monsters he killed are other constellations in
the sky.
LEO - the lion
Leo was the
fiercest lion in the world. No weapons would hurt him. So Hercules choked him!
PISCES - the fish
The fish were
imagined to be Venus and Cupid who turned themselves into fish and jumped into a
river to escape a monster.
SAGITTARIUS - the
archer
This centaur,
half man and half horse, aims his arrow at a giant scorpion.
TAURUS - the bull
Zeus,
according to legend, disguised himself as a white bull to win the love of a
princess.
URSA MAJOR - the
great bear
It seems Zeus
was hanging out with another woman. His wife did not like that, so she turned
the woman into a bear. Within this constellation is the familiar Big Dipper
constellation.
URSA MINOR - the
little bear
Zeus turned
his son into a little bear and put him in the sky. This constellation is
also know as the Little Dipper. The North Star is at the end of the handle
of the dipper.
VIRGO - the
maiden
Virgo was the
Greek goddess of justice. It is also linked with the goddess of the
harvest.
LIBRA - the
scales
To the
ancient Romans, this constellation represented the scales of justice.
Look back at the descriptions of Leo, Cancer, and Draco.
What do they have in common?
Click here to see what the sky looks like on a clear night in the northern hemisphere.