NAMES: ______________________________________________________________________________________ ACTIVITY 7.6. IT’S EXPANDING! ARTICLE READING The Big Bang Astronomers estimated that Big Bang happened between 12 and 14 billion years ago. Big Bang states that the universe started from a small, hit, dense state that rapidly expanded. This theory was proposed by a Belgian Catholic priest and cosmologist, Georges Lemaitre in 1927. Since then, scientist have focused great efforts on investigating the Big Bang model. Our knowledge of the structure of the universe and of subatomic particles is able take us back to within 10-43 second of the Big Bang. Before that time, the universe also compressed and opaque that our present understanding of the laws of relativity and quantum mechanics is inadequate. When the universe was 30 minutes old, it had cold so much that nuclear reaction ceased; the matter in the universe consisted, by mass, of about 25 % helium nuclei and 75 % hydrogen nuclei. By the time the universe was about 400, 000 years old, it was cool enough for the helium and hydrogen nuclei to capture electrons and become neutral atoms. Photons were now able to move freely through space, and matter was able to be influenced by gravity and begin forming galaxies and stars. Read the questions below. Answer the questions briefly on a separate sheet of paper. Using your balloon, put six dots around before you blow it with air. 1. Sketch the balloon before it was blown and after. 2. What happened on the dots when it was blown? 3. As time goes by, the real universe behaves just like this balloon. What do you think our astronomers must have observed about the motion of our neighboring galaxies? (Answer this question individually at the back)
