Question

Questions Chapter 17 - Set 2 1. Why was the discovery of cosmic background radiation from all over the sky heralded as strong evidence in favor of the big bang theory? 2. Big bang cosmology involves some mind-bending concepts. Imagine that you are talking to a curious and intelligent 13-year-old cousin. Try to convey the following ideas as clearly as you can. Explain how we can look back in time by observing distant objects. 3. Explain how the physical universe could be much larger than the observable universe. 4. Explain how we can possibly have information on the universe in the first few minutes of its existence.

Answer 1

According to big bang theory when the universe was born it was extremely hot and underwent a rapid inflation and expansion. As it expands the gas within it cool down. In the late 1940s Alpher and Herman reasoned that if there was a big bang, the expansion of the universe would have stretched and cooled the high-energy radiation of the very early universe into the microwave region of the electromagnetic spectrum. Thus the universe should be filled with radiation that is literally the remnant heat left over from the Big Bang, called the “cosmic background".

Therefore discovery of cosmic background radiation gives a direct evidence of for the prediction of big bang. That's why it is heralded in favour of big bang theory.