Page 27 - GALIET PHYSICS BLOSSOMS III

A balloon deflates just as if it were the Universe shrinking to a zero point, thus returning to the Big Bang! In this scenario:
• All the coin-galaxies would arrive at the same place at the same time, that is, at the moment when the deflating balloon or universe reached zero size!
• We could not discern any one point in the balloon to show us where that occurred.
• Just as the balloon expanded from a Big Bang point, it can also shrink to a zero point.
BIG BANG EVIDENCE – THE MICROWAVE BACKGROUND
The cosmic microwave background (“CMB”), whose current temperature is approximately 3K or kelvins, is a radiation field that is isotropic (its intensity is virtually constant from one direction on the sky to another) and a blackbody that fills the whole universe.
The CMB is yet another direct evidence for the Big Bang. It shows how the universe expanded from a dense and hot state. As the universe has expanded, the initial high-energy radiation has redshifted or “cooled” to lower and lower temperatures.
The CMB was discovered by accident in 1964 during an experiment to end satellite communications’ interference in the American telephone system. When two Bell Labs’ scientists, Arno Penzias and Robert Wilson, were studying the emissions of the Milky Way at microwave (radio) wavelengths using a horn-shaped antenna, they kept on hearing an ongoing background hiss, sounding very much like the static heard in the background of an AM radio, despite their efforts to eliminate it by changing the antenna’s direction. Despite their efforts, the weak hiss kept on persisting uniformly, neither increasing nor decreasing, appearing to fill all space. Perplexed, after some conversations with other colleagues, they discovered that this mysterious static hiss, the CMB, was the “fiery creation of the universe itself,”29 and not ground or storm or short circuit interferences, or pigeon droppings, they had originally thought. This won them the 1978 Nobel Prize.
In the 1940’s, Princeton researchers’ had predicted:
• That the proto-universe must have been super-hot and extremely dense, and that soon after the Big Bang, it must have been filled with very short wavelength gamma rays: these, the source for extremely high-energy thermal radiation.
• That cosmic expansion would have redshifted or cooled the proto-radiation’s frequency from gamma-to X-to ultraviolet rays all the way into the electromagnetic spectrum’s radio range as the universe expanded and cooled.
Princeton researchers accurately anticipated that the redshifted fossil remnant of the proto-
29 Information gathered from class lectures and from Bennet, Donahue, Schneider, Voit. The Cosmic Perspective. Volume II. Stars and Galaxies. 6th Edition. 678-680.
•27•