BACKGROUND:
The Universe is always taught with an aura of mystery.
Teachers are sometimes unsure about how to explain the formation of the
Universe. Part of the reason for this problem is that there is no scientific
answer for this question. The data on the formation of the Universe and its
evolution are inconclusive, indirect, and hard to decipher. We suggest that
you tell students scientists do not yet understand all that is going on in
the Universe. Part of this is because the physical rules of the Universe are
somewhat different than our everyday experience here on Earth. For example,
a light beam appears to travel in a straight line when we observe it on
Earth. However, using the Universe perspective , light commonly travels in
curved paths, when it is warped by the gravity of stars and galaxies.
Current cosmological theory (cosmology is the branch
of astronomy that studies the evolution and origin of the Universe and the
objects within it) suggests that the Universe began with the Big Bang, an
explosion and expansion which created matter and energy as we know them. We
cannot observe what came before the Big Bang, although sophisticated
computer and mathematical modeling is beginning to give some insight into
this question.
Here is a rough timetable of events after the Big
Bang. Note that the timing and details of these events change as more
research is done.
A TIME TABLE OF EVENTS AFTER THE BIG
BANG
-
The Big Bang Occurred
All interactions, gravity, strong nuclear, weak nuclear, and
electromagnetism are unified. The radius of the Universe is less than 10-50
centimeters - A very small area.
- 10-43 seconds later
Gravity separated from the other forces.
Inflation, the tremendous expansion of the early Universe. The observable
Universe expands to approximately the size of a grapefruit.
- 10-35 seconds after the Big Bang
The strong nuclear force separates from
electromagnetism and weak nuclear force. Inflation ends. The Universe
consists of a hot electron-quark soup. (a quark is a the main type of
subatomic particle which makes up protons).
- 1 second after the Big Bang
Electromagnetism and the weak nuclear force
separate. Quarks combine to form protons, and protons and electrons
combine to form neutrons. Helium and other light elements form through
from these through nucleosynthesis .
- 1 million years after the Big Bang
The universe becomes transparent as it
continues to expand. Matter releases radiation. Several spacecraft have
detected these emissions, which are called the cosmic microwave background
radiation.
- 1 billion years after the Big Bang
Protogalaxies begin to form.
- 3 billion years after the Big Bang
Quasars and some radio galaxies (galaxies
that emit extremely high amounts of electromagnetic radiation) begin to
form.
- 8 billion years after the Big Bang
Most galaxies, including the Milky Way have
formed. The Sun and Solar System form.
- 13 billion years after the Big Bang
The present.
Although no one was there to witness these events,
current evidence suggests that this is the best account of the origin of the
Universe. This scenario will certainly change with new discoveries. Students
should be told this directly. In other words, don't take the sequence of
Universe evolution as fact, it will change!
PROCEDURE:
- You may want to use Searching the Universe (slideshow) to
review the idea of the Universe with students. The last slide
illustrated the idea of the "Big Bang."
- View a video or DVD on the creation of the Universe. There are several
products on the market including Creation of the Universe (1985) and
Stephen Hawkin’s Universe (1997). You can purchase these on Internet
video sites or check your library to see what they may have.
Illustrating the creation of the Universe is difficult, and a well done
video helps. You may also ask your students if any of them has a video
they would like to share.
- You may want the students to make a cartoon of the early Universe.
Present the information in the Time Table to the students. Go slowly
through the different parameters and try to dramatize each of the
events. If students are unfamiliar with the terms review the material
from either the 4th or 5th grade Universe lessons.
