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However, no matter what they did or where they pointed the antenna in the sky, they continued to pick up interference. They finally concluded that what they were detecting was “cosmic background radiation.”
This, as most scientists now believe, is the radiation left over from the Big Bang expansion. As particles of gas were created in the early universe, heat was produced in the form of microwave radiation.
To further test the theory, astronomers also made predictions about the amount of light that would be left over from the Big Bang expansion. For the most part, observations and other evidence seem to support the predictions.
Additional supporting evidence
One of the strongest pieces of evidence in support of the theory today is the data gathered by the Cosmic Background Explorer (COBE) satellite, which was launched in 1989 by the National Aeronautics and Space Administration (NASA). It took a team of scientists four years to map the cosmic background radiation data collected by the satellite. Some astronomers have described this map as being like a “baby picture” of the universe, showing how it may have looked early in its development (Figure 10.7). The red areas indicate the period of slightly hotter temperatures that would have occurred during the rapid expansion immediately after the Big Bang event. The blue areas indicate the period of slightly cooler temperatures that would have occurred as the universe began to cool.
Did You Know?
When Arno Penzias and Robert Wilson first detected the strange radiation signals from space, they did not understand the importance of their findings. Initially, they blamed their unexpected data on everything from faulty material in the equipment to pigeon droppings
on the antenna.
The COBE map of cosmic background radiation in the universe. This is the radiation that scientists believe is left over from the Big Bang expansion.
Figure 10.7
Chapter 10 Scientific evidence suggests the universe formed about 13.7 billion years ago. • MHR 351
Word Connect
The word “cosmology” means
the study of the universe. It is derived from the Greek word kosmos, which means orderly arrangement. Historians think that Pythagoras, the Greek mathematician, was the first person to use the word in connection with the universe.