The Universe At Your Fingertips Activity: Cosmic Calendar

 

Introduction

Activity Description

Goals and Tips

Preparation

Extending the Activity

Cosmic Spinner

Cosmic Calendar Math

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Introduction

Cosmology - the study of our universe, how it began, and how it has evolved - can seem incomprehensible to students because of the vast eons of time between today and the beginning of the universe. This activity will provide a "bridge" across time that will make the numbers more meaningful. Couple this lesson with one of the Solar System scale model activities and Your Galactic Address (both described in The Universe At Your Fingertips) to give students a staggering - and humbling - perspective of their place in space and time.

In "Cosmic Calendar", students scale the evolution of the universe to a one year calendar, with the Big Bang occuring on the first moment of January 1st. Students estimate where on this one year time line significant events (like the formation of the solar system, the appearance of dinosaurs and the emergence of humanity) should be placed. More advanced students can research the dates of significant events and calculate when in the model timeline these events occurred.

This activity was written by Therese Puyau Blanchard and the staff of Project ASTRO.
Copyright © 1995, Astronomical Society of the Pacific, 390 Ashton Ave., San Francisco, CA 94112. This activity may be reproduced for nonprofit purposes.

Activity Description

Introduction

While there is currently some controversy about the exact numbers, astronomers estimate that the universe began some 12 to 20 billion years ago in the explosion of space, time, matter and energy we call the Big Bang. Such numbers are hard to visualize. Despite the fact that the national debt is even larger, most students have difficulty grasping how large a span of time this is compared to their own lifetimes or to the events they read about in history.

One way to visualize large expanses of geological or astronomical time is to draw an analogy between the time scale since the creation of the cosmos and a more familiar stretch of time. Geology educators have used this technique for a while, but in astronomy the idea was pioneered by Cornell University astronomer, Carl Sagan.

In Chapter 1 of his Pulitzer-prize winning Book, The Dragons of Eden (1977, Random House hard cover; Ballantine paperback), Sagan proposes compressing the history of the universe into one year and then seeing where in that year various events of interest fall. Based on this model, Sagan calculates that if the Big Bang takes place at the first moment of January 1, the origin of our solar system will be in mid-September, and the first appearance of humans on Earth does not take place until late evening on the 31st of December.

Procedure

1. Present the concept of a time line by displaying the 12 month calendar hung along a wall or across the room on a clothes line.

2. Explain that January 1st of our one-year "Cosmic Calendar" represents the Big Bang, which scientists theorize is the beginning of cosmic time. Explain that "today" is represented by the last possible moment on December 31st.

3. Depending on your students' background, brainstorm about some of the important events that happened between the Big Bang and now.

4. Divide the class into groups and distribute a Cosmic Calendar handout to each group. Have groups cut and paste the calendar on to the large piece of construction paper to create one long time line.

5. Each group should then cutout the major events listed on the Cosmic Calendar hand-out and decide on the probable order of occurence. Have the groups place each event next to the month they predict the event occurred. Groups that finish first can predict the day of the month also.

6. Then, select a volunteer group to be a "living time line". Give each person in the group a larger sign or picture of one of the major events (with the Cosmic Calendar date on the back of each picture) and have the students stand under the large time line in the order decided on by the group.

7. Hold a class discussion on the order of the events portrayed. A student who disagrees with the order of a certain event may change places with the person holding that card. Continue the discussion until a majority of the students agree with each other.

8. Have each person in the "living time line" uncover the appropriate date on the back of their card and position themselves on the time line.

9. Point out significant events and discuss these questions:

• Humans arrived on the scene about 7 minutes before midnight on "New Year's Eve" according to our model. How does this change your perspective of our importance?
• Dinosaurs ruled the Earth for almost two hundred million years - from December 25 to December 30 on our time line. How does this change your thinking about dinosaurs?
• How old is the Sun compared to other stars? If there are older stars than the Sun out there (and there are many), might they have older life forms on them?
• What might we be like today if hominids on Earth had evolved a million years earlier?

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