Astronomy

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Astronomy
Space the final frontier These are the voyages of
the fifth grade class. Our year-long mission is
to seek out new life and new civilizations to
boldly go were no class has gone before.
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Terms you MUST know and spell correctly

• Astronomy
• Constellation
• Axis
• Rotation
• Revolution
• Star
• Planet
• Refraction telescope
• Reflecting telescope
• asteroid
• Comet
• Meteor
• meteorite

• Solar system
• Geocentric model
• Heliocentric model
• Ptolemy
• Copernicus
• The Big Bang Theory
• Terrestrial planets
• Moon
• Satellite
• Gas giants
• Eccentric
• Circumpolar constellations
• Star Trails

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What is Astronomy?

• Astronomy is the study of objects and matter
  outside the earth's atmosphere and their
  properties.
• You can study lots of things through astronomy
  like how the earth and sun were created, and if
  there is life on other planets!

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What is a star?

• Stars are huge balls of gas , which burn brightly
  in the darkness of space.
• Just like people, stars have a life cycle. They
  grow up just like we do!

Did you know that our Sun is A STAR?
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Stars From Our Perspective

• Stars look differently from planets because STARS
  APPEAR TO BE TWINKING, since it flickers much
  like a candle.
• Some stars form constellations which look like
  patterns or designs in the sky.
• Some examples of constellations are Orion (best
  seen in Winter), Cassiopeia and Draco (not Draco
  Malfoy)!
• Stars that help people find other constellations
  are called POINTER STARS.

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Our Sun

• Our sun is the center of our Solar System, which
  is part of the MILKY WAY GALAXY.
• The surface of the sun is very, very HOT! About
  10,000 degrees Fahrenheit!
• The sun is really big! It takes the Earth about
  365 DAYS to revolve around the sun!
• Did you know that the Earth is closest to the sun
  during our WINTER? And furthest during our summer?

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Planets

• Each of the planets revolve around the sun in
  their own ORBIT. These orbits are not perfectly
  round. Instead, they are oval or ECCENTRIC.
• There are EIGHT major planets in our solar
  system Mercury, Venus, Earth, Mars, Jupiter,
  Saturn, Uranus, and Neptune and THREE dwarf
  planets Ceres, Pluto, and Xena.
• The largest planet is JUPITER, and the smallest
  is PLUTO.

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Our Earth

• The Earth is the THIRD planet
• of the solar system.
• It rotates on an axis that is tilted
• 23.5 DEGREES.
• VENUS and Earth are almost the same according to
  size.

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Moons

• Moons are satellites they revolve around the
  planets, just like the planets revolve around the
  sun!
• Almost every planet in our solar system has at
  least one moon only MERCURY and VENUS do not.
  Jupiter has 63 moons!
• Our MOON is the closest celestial object to our
  Earth

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Asteroids and Comets

• Asteroids are rocky, metallic objects that orbit
  the sun, and are too small to be considered
  planets.
• They are the leftover particles from the creation
  of the solar system.

• Comets are small (10 km across) irregular masses
  that consist of rock, gases, dust and ice. They
  also have a tail made up of dust and gases

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Constellations

• A constellation is a shape created by the stars
  when seen from Earth .
• The constellations were created as a memory aid
  for understanding the stars. (i.e. In the winter
  parts of Orions belt can help locate other stars
  around it)
• There are a total of 88 ACCEPTED CONSTELLATIONS
  in the night sky.
• Due to the fact that the stars dont move in the
  same way as the earth and moon, we see a
  different set of constellations for each season
  in our hemisphere. Some constellations we cant
  see because we dont live in the SOUTHERN
  HEMISPHERE

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Constellations

• Constellations - groupings of stars named after
  mythical heroes, gods, and mystical beasts
• - made up over at least the last 6000 years -
  maybe more
• - used to identify seasons
• - farmers know that for most crops, you plant
  in the spring and harvest in the fall.
• - in some regions, not much differentiation
  between the seasons.
• - different constellations visible at different
  times of the year - can use them to tell what
  month it is. For example, Scorpius is only
  visible in the northern hemisphere's evening
  sky in the summer.
• - many of the myths (stories) associated with
  the constellations thought to have been
  invented to help the farmers remember them.

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Star Stories

• Star stories were created to explain natural
  phenomena.
• Many cultures including the Greeks and
  Egyptians - created their own stories based on
  their interpretation of the pattern of stars.
• The stories combine the traditional culture with
  the shapes seen in the constellations.
• Other cultures that have star stories are the
  Chinese, Native American, Indian cultures and
  many, many more!

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What are the 88 Constellations?

• 14 men and women
• 9 birds
• 19 land animals
• 2 insects
• 10 water creatures
• 2 centaurs
• 1 head of hair
• 1 serpent
• 1 dragon
• 1 flying horse
• 1 river
• 29 inanimate objects, include scientific
  instruments (Microscopium, Telescopium)

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Polaris

• The Earths axis runs from the north pole to the
  south pole.
• If you continue the axis line through the north
  pole you would run into Polaris, the North Star.
• Because it is in line with the Earths axis,
  Polaris does not appear to move in the sky.

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The axis remains at the same tilt angle - pointed
at Polaris - throughout the orbit because of
conservation of angular momentum. The ecliptic
plane is the plane of the Earths orbit. Looking
from the Earth, it is the apparent path of the
Sun (and planets) in the sky.
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Northern Circumpolar Constellations

• Depending on where you live, some constellations
  are visible all year round and some
  constellations are seasonal. If you live in the
  Northern Hemisphere, the constellations that
  circle around the North Star are visible all
  year. They are called circumpolar constellation
  because they travel in circles around the North
  Star.
• The main circumpolar constellations are
• Ursa Major, the Great Bear
• Ursa Minor, the Little Bear
• Draco, the Dragon
• Cepheus, the King
• Cassiopeia, the Queen.

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Circumpolar Constellations
The circumpolar constellations travel in circles
around the North Star, Polaris. If you take long
exposure photographs of the North sky, you can
see these star swirls
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Star Trail

• Earth rotates about an axis that is pointed very
  close to the star Polaris
• Stars rise in the east and set in the west
  everyday.
• The circumpolar constellations travel in circles
  around the North Star, Polaris. If you take long
  exposure photographs of the North sky, you can
  see these star swirls

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Ursa Major

• Three important stars in Ursa Major are Mizar,
  Dubhe and Merak. Dubhe and Merak are also known
  as the pointer stars because they point to the
  North Star.
• Mizar was the first binary star that was ever
  discovered. A binary star is a star that orbits
  another star.
• In 1650, an Italian astronomer named Riccioli
  using a simple telescope discovered that there
  were indeed two stars orbiting each other, a fact
  which could not be seen by the naked eye. Since
  then many binary stars have been discovered.

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Ursa Major

• The Big Dipper is the easiest grouping of stars
  to recognize because five of the seven stars are
  very bright and can even be seen by people living
  in cities.
• However, the Big Dipper is not a true
  constellation. It is part of a larger
  constellation called Ursa Major, the Great Bear.
• Third largest constellation
• Great Bear
• Next to Orion, it is the most famous constellation

The two stars at the end of the spoon are called
the pointer stars and if you follow a straight
line through the two pointer stars upward, the
next bright star you come across will be the
North Star.
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Ursa Major

• Artemis, the moon goddess and goddess of the
  hunt, always had hunting companions with her when
  she went on the hunt. One such companion was
  Callisto, a beautiful young maiden.
• One day Zeus passed by a woodland cove and spied
  the sleeping Callisto. Zeus made Callisto his
  lover. They had a child named Arcas. Of course
  Zeus knew that both Hera, his wife, and Artemis
  would be angry with Callisto so to protect her he
  turned her into a bear to keep her hidden from
  Artemis and Hera.
• One day, Arcas was hunting and he came across a
  great bear. He was just about to shoot his arrow
  when Zeus intervened and changed him into a
  little bear so that Arcas could know who the
  great bear really was. Zeus then transported the
  two bears to the heavens so that they would be
  protected from the wrath of the angry goddesses.
• However, Hera was unhappy that Callisto and her
  son were shining so brightly in the heavens so
  she asked the ocean god to prevent them from ever
  bathing in the ocean waters. And so, according to
  this story, that is why the two bears are forced
  to circle the heavens while the other
  constellations are allowed to dip below the
  horizon and bathe in the immortal waters every
  night.

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Ursa Minor - little bear

• Ursa Minor is much harder to find than Ursa
  Major. Usually, its easier to find Ursa Major
  first and follow the pointer stars to Polaris and
  then find the other stars of Ursa Minor.

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Ursa Minor

• Ursa Minor, the Little Bear, is visible in the
  Northern Hemisphere all year long.
• Ursa Minor is mostly known for Polaris, the
  North Star which may be found at the end of the
  handle.
• Looks like a spoon whose handle has been bent
  back by a playful child
• Polaris is an important star for navigators
  because it stays relatively fixed in the heavens
  while all of the other stars move in circular
  arcs throughout the night. In the past, it has
  been called the ship star, the leading star,
  star of the sea and the steering star.

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Draco

• The titans were giants with serpentine feet. They
  were almost invincible. When they revolted
  against the gods, they caused great destruction.
  During the battle, Athena grabbed the feet of one
  of these dragon-like giants and flung it into the
  heavens where it got tangled among the stars.

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Draco

• One interesting star is Thuban. Around 2700 BC,
  at the height of the ancient Egyptian
  civilizations, Thuban, not Polaris, was at the
  celestial north pole and was therefore the pole
  star. The pole star changes slowly because the
  Earths rotational axis wobbles (spins around
  like a top).

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Cassiopeia

• Cepheus and Cassiopeia were the king and queen of
  Joppa, a city in the land of Ethiopia. They had
  many children including a daughter named
  Andromeda.
• Andromeda was very beautiful and when the sea
  nymphs overheard Cassiopeia boasting about her
  beauty, they complained to Poseidon.
• Poseidon got angry and sent a sea monster to
  destroy the city. When the monster was coming,
  Cepheus consulted an oracle. The oracle gave
  Cepheus a choice Sacrifice his daughter
  Andromeda, or face the destruction of the
  monster. Cepheus agreed to sacrifice his daughter
  to save the people of his kingdom and so he
  chained Andromeda to a cliff.

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Cepheus

• As it happened, Perseus was flying past on his
  flying horse Pegasus. Perseus agreed to save the
  daughter in return for her hand in marriage.
  Perseus and Andromeda lived a long life. When
  they died they were transformed into the stars as
  constellations along with the King and Queen,
  Cepheus and Cassiopeia. Cassiopeia is sitting in
  her throne and Cepheus has his arms stretched
  out. However, as punishment, Poseidon made sure
  that Cassiopeias throne was dumped upside down
  every night (when the constellation forms and M
  instead of a W.

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Orion

• Orion was an ancient Greek hunter and warrior
  and the constellation resembles this figure, with
  a club and a shield, and a sword dangling from
  his belt.
• The belt is usually the easiest part of Orion to
  spot, with three bright stars in a row.
• Orion has more bright stars than any other
  constellation the two brightest are Betelguese
  (shoulder) and Rigel (foot).
• Not circumpolar, only seen from Dec. to April.

Orion is the largest constellation in the sky.
This giant figure dominates the sky in the early
mornings in late summer and fall, and in the
evenings during the first part of winter.
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Orion
In Greek mythology, Orion was a great hunter.
Artemus, the goddess of the moon and of the hunt,
fell in love him and neglected her job of
lighting the night sky. Her twin brother,
Apollo, saw Orion swimming in the sea and
challenged his sister to hit what looked like a
dot among the waves. Artemus shot an arrow and
killed Orion. When she saw what she had done,
Artemus placed Orions body in the sky with his
hunting dogs. Her grief explains why the moon
looks so sad and cold.
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Andromeda - Queen of the Winter Sky

• Andromeda was the daughter of Cepheus and
  Casseopeia and was one of the most beautiful of
  all the goddesses.
• Andromeda Galaxy is located in the constellation
  Andromeda.
• Closest major galaxy to us.
• This galaxy is over 250,000 light years across,
  which makes it more than twice as large as our
  own Milky Way galaxy.