Chapter 29 The Big Bang
Collaborative Group Activities
- This chapter deals with some pretty big questions and ideas. Some belief systems teach us that there are questions to which “we were not meant to know” the answers. Other people feel that if our minds and instruments are capable of exploring a question, then it becomes part of our birthright as thinking human beings. Have your group discuss your personal reactions to discussing questions like the beginning of time and space, and the ultimate fate of the universe. Does it make you nervous to hear about scientists discussing these issues? Or is it exciting to know that we can now gather scientific evidence about the origin and fate of the cosmos? (In discussing this, you may find that members of your group strongly disagree; try to be respectful of others’ points of view.)
- A popular model of the universe in the 1950s and 1960s was the so-called steady-state cosmology. In this model, the universe was not only the same everywhere and in all directions (homogeneous and isotropic), but also the same at all times. We know the universe is expanding and the galaxies are thinning out, and so this model hypothesized that new matter was continually coming into existence to fill in the space between galaxies as they moved farther apart. If so, the infinite universe did not have to have a sudden beginning, but could simply exist forever in a steady state. Have your group discuss your reaction to this model. Do you find it more appealing philosophically than the Big Bang model? Can you cite some evidence that indicates that the universe was not the same billions of years ago as it is now—that it is not in a steady state?
- One of the lucky accidents that characterizes our universe is the fact that the time scale for the development of intelligent life on Earth and the lifetime of the Sun are comparable. Have your group discuss what would happen if the two time scales were very different. Suppose, for example, that the time for intelligent life to evolve was 10 times greater than the main-sequence lifetime of the Sun. Would our civilization have ever developed? Now suppose the time for intelligent life to evolve is ten times shorter than the main-sequence lifetime of the Sun. Would we be around? (This latter discussion requires considerable thought, including such ideas as what the early stages in the Sun’s life were like and how much the early Earth was bombarded by asteroids and comets.)
- The grand ideas discussed in this chapter have a powerful effect on the human imagination, not just for scientists, but also for artists, composers, dramatists, and writers. Here we list just a few of these responses to cosmology. Each member of your group can select one of these, learn more about it, and then report back, either to the group or to the whole class.
- The California poet Robinson Jeffers was the brother of an astronomer who worked at the Lick Observatory. His poem “Margrave” is a meditation on cosmology and on the kidnap and murder of a child: http://www.poemhunter.com/best-poems/robinson-jeffers/margrave/.
- In the science fiction story “The Gravity Mine” by Stephen Baxter, the energy of evaporating supermassive black holes is the last hope of living beings in the far future in an ever-expanding universe. The story has poetic description of the ultimate fate of matter and life and is available online at: http://www.infinityplus.co.uk/stories/gravitymine.htm.
- The musical piece YLEM by Karlheinz Stockhausen takes its title from the ancient Greek term for primeval material revived by George Gamow. It tries to portray the oscillating universe in musical terms. Players actually expand through the concert hall, just as the universe does, and then return and expand again. See: http://www.karlheinzstockhausen.org/ylem_english.htm.
- The musical piece Supernova Sonata http://www.astro.uvic.ca/~alexhp/new/supernova_sonata.html by Alex Parker and Melissa Graham is based on the characteristics of 241 type Ia supernova explosions, the ones that have helped astronomers discover the acceleration of the expanding universe.
- Gregory Benford’s short story “The Final Now” envisions the end of an accelerating open universe, and blends religious and scientific imagery in a very poetic way. Available free online at: http://www.tor.com/stories/2010/03/the-final-now.
- When Einstein learned about Hubble’s work showing that the universe of galaxies is expanding, he called his introduction of the cosmological constant into his general theory of relativity his “biggest blunder.” Can your group think of other “big blunders” from the history of astronomy, where the thinking of astronomers was too conservative and the universe turned out to be more complicated or required more “outside-the-box” thinking?