Universe Cycle - Universe (4)
Pre Lab 

  • Comparing astrology and astronomy.
  • Exploring stars.
  • astrology
  • astronomy
  • constellations
  • galaxy
  • star
  • Sun
  • zodiac

Students compares astrology and astronomy.

Orion Nebula


Stars are balls of gas that emit energy created by fusion, a nuclear reaction within the star. There are many sizes and brightness of stars, ranging from super hot, blue-white stars (over 20,000EK) to cool red stars (3,000EK). Our Sun is a medium yellow star, towards the small and cool end of the spectrum. Current theory suggests that stars are born in nebulae, which are interstellar gas clouds. This is happening today. An example is the Orion Nebula (in the sword or bow of the Orion the Hunter constellation). Stars also die. Older stars types include red giants and supergiants.

Constellations are apparent associations of stars and galaxies, as seen from Earth. In reality, these objects are very far away from each other. The stars that make up the constellations are all within our own Milky Way galaxy. The galaxies can be much further away; because of their distance, they appear as points of light to the naked eye.

Constellations were very important to early people. They allowed them to find directions during the night, which helped them navigate on land and at sea. The yearly changes in the constellations also revealed to early farmers when spring and summer were approaching. This was more accurate than watching the Sun rise and set every morning.

One special group of constellations is called the Zodiac. The Zodiac constellations occur in a band that is parallel to the Earthís orbit or called the ecliptic. The ecliptic is the band between the Sunís highest point (summer) and the lowest point (winter) in the sky. The stars in the Zodiac constellations move very slowly compared to the Sun and the rest of the Solar System. They seem to be fixed in the sky.

As the Earth moves around the Sun, the Sun comes between the Earth and each of the Zodiac constellations. Because the Earth always revolves around the Sun in the same direction, the Sun crosses in front of the Zodiac constellations in the same order every year. This means that if you can recognize the Zodiac constellations, you can tell what time of year it is. They work like a calender.

This sky calender and the Zodiac constellations we identify today were first used by Babylonian astronomers about 2500 years ago. Babylon was a Middle Eastern culture that is well-known for its discoveries in astronomy and other sciences. The Babylonians used the Zodiac constellations to tell when spring was coming. This allowed them to tell when it was time to plant crops and to prepare for changes in the weather.

Ancient people who studied the constellations were called astrologists. Today astrologists are pseudo scientists who try and predict the future using the signs of the Zodiac. Astronomy is the study of the origin, movement, and behavior of stars and all other components in the Universe. Astronomy is a science, based on repeated observations of the stars, and accurately predicts their motions and behavior. Some people confuse astronomy with astrology. There is no evidence that astrological predictions are accurate.

Today, we use the ancient constellations to help us locate different sectors of the Universe. Astronomers have divided the celestial globe into 88 constellation, which are listed on a separate sheet.


  1. Use the Celestial Globe to illustrate how we see the Universe from Earth. The Earth is in the center and you can easily show that if you live in the United State, the sky you see, is different than the sky you see if you lived in Australia. Compare this to the Inflatable Celestial Globe, which only illustrates the "clear" portion of the Celestial Globe.

  2. Discuss the components of the Universe by going over the vocabulary. Emphasize that the Universe includes galaxies, stars, planets, and anything else in space. Explain to the students that there is much that we do not know about stars. If some students are interested in the Universe, recommend that they consult the Internet, books, or magazines on the subject. New information on the Universe is updated, especially as new equipment is developed for space exploration.

  3. Give each student a Constellation Placemat and instruct them to try and find different constellations that you can find on the "88 Constellation Chart."

  4. Review the constellations of the Zodiac by using the worksheet and compare them with the 88 constellations used by astronomers. You may want students to write a story about one of them.

  5. Ask the students if they know the difference between astrology and astronomy. You may want to use the following graphs to help students determine the difference.
















  1. Make clear to the students that constellations refer to a grouping of stars that we see from Earth. Explain the Zodiacal constellations.

  2. See if students can determine the dates of the different Zodiac signs by asking all the students their birthdays and if they know their "sign." This is a fun way of finding the studentís birthday and perhaps discover the dates of each of the signs.
    Capricorn (December, 22 - January, 19)
    Aquarius (January, 20 - February, 18)
    Pisces (February, 19 - March, 20)
    Aries (March, 21 - April, 19)
    Taurus (April 20 - May, 20)
    Gemini (May, 21 - June, 20)
    Cancer (June, 21 - July, 22)
    Leo (July, 23 - August, 22)
    Virgo (August, 23 - September, 22)
    Libra (September, 23 - October, 22)
    Scorpio (October, 23 - November, 21)
    Sagittarius (November, 22 - December, 18)

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