THE ORIGIN OF THE UNIVERSE

The origin of the universe has always been disputed. While the traditional wisdom of all cultures offers explanations, none has definitely proven how-or even if the universe began. Most religions believe that the universe was created by a supreme¹ entity. According to this view, there was a time when there was no universe, and some religions foretell an end to it.

On the other hand, thinkers like the Greek philosopher Aristotle questioned the necessity of a beginning. He believed the universe had existed and would exist forever, and was eternal and perfect. One thing that these two schools of thought originally had in common was that the universe itself was static, or unchanging. This made sense, as the technology of the time was not advanced enough to observe any major changes. We learned much about the universe and Earth's place in it in the following centuries, however. Then, in the 19th century, evidence began to challenge the idea that the universe is motionless and unchanging. At this time, several European physicists helped formulate the second law of thermodynamics. This states that the total amount of entropy, or disorder, of the universe always increases with time. Ordered structures, in other words, eventually fall apart, thereby increasing entropy.

The universe must be changing in some way in order for its entropy to increase. Also, according to Isaac Newton's law of universal gravitation², each star in the universe ought to be attracted to every other and thus start falling together and collapsing³ at a central point. If the universe were motionless, then the result would be an unavoidable collapse. Physicists soon concluded the universe could be contracting or expanding-but could not be standing still.

In the 1920s, the US astronomer Edwin Hubble observed a crucial phenomenon that increased our understanding of the question. Using a powerful new telescope, he identified a group of celestial objects outside our own galaxy⁴. By observing the Doppler shift of these stars-the way the wavelengths and colors of their light changed due to their motion—he realized that they were receding⁵ from our own position in the universe. In fact, all the observable galaxies were moving away from each other, too. Furthermore, the more distant the galaxy, the faster it was moving away. This observed acceleration implied the universe was expanding.

Hubble's observation led to the assumption that at some point, all matter in the universe was close together. The event that started its expansion is referred to as the big bang. According to the big bang theory, time and space did not exist prior to the beginning of the expansion. Thus, the age of the universe can be calculated using the distance and the velocities⁶ of the stars traveling away from us and working backward to find when they were all together at one point. The age of the universe is estimated to be between twelve and fourteen billion years.

The big bang theory has led to many other theories and predictions in science. In the 1940s, physicist George Gamow realized the early universe must have been extremely hot and dense. As the universe expanded, it would cool down, and the initial hot radiation should eventually be observable as uniform⁷ radio waves throughout space. In the 1960s, Robert Wilson and Arno Penzias discovered cosmic⁸ uniform radio waves that implied a temperature of about three degrees above absolute zero (Kelvin). Later, technology enabled scientists to take very detailed wavelength and thermal measurements of this radiation. They confirmed that it is extremely uniform, is of the shape predicted by the theory, and has a temperature of 2.7 degrees Kelvin. This observation provides strong evidence that the big bang theory is valid.

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Before the Big Bang

The big bang theory raises profound philosophical questions. For centuries, scientists believed that the universe was eternal, while religious believers held otherwise. The Old Testament is central to Judaism, Christianity, and Islam. It begins with the line, "In the beginning, God created ... the universe and everything in it." After explicitly identifying God as the creator, these religions stress the idea that God is a conscious entity who has remained in control.

The British biologist Richard Dawkins argues in his book, The God Delusion, that this idea is a fantasy. Though Dawkins stops short of saying it can be proven God does not exist, he writes that the existence of a divine creator is highly improbable. God would have to be unimaginably complex, Dawkins notes, and the more complex something is, the less probable it is.

Dawkins claims that the theory of evolution and descent by natural selection can explain how everything in the world was made and why many things are so complex that they appear to have been consciously designed. Dawkins also argues in the latter half of his book that science can even explain human morality.

Some critics answer that most of Dawkins's arguments are philosophical rather than scientific and go on to accuse Dawkins of being a poor philosopher. Others say that attributing the world's complexity to random chance is much more improbable than the existence of God. Also, some note that nothing in Dawkins's book proves God could not have simply guided the process of evolution. The philosopher Alvin Plantinga claims that Dawkins contradicts himself. "By Dawkins's own definition of complexity," writes Plantinga, "God is simple and not complex. Therefore, God's existence is more probable than Dawkins supposes."