A Brief History of Time - 1

Topics: General relativity, Big Bang, Quantum mechanics Pages: 3 (1159 words) Published: March 9, 2013
In our lives we’ve all looked into the night’s sky and admired its beauty. But those stars that dot the skies are moving, most of them rapidly away from us. In Chapter 3 of A Brief History of Time, Hawking describes the beginning of our universe, otherwise known as the big bang, and how our universe is expanding. In Chapter 4, Hawking explains the dismissal of the idea that future events can be predicted because of the belief that the universe was completely deterministic. As I read chapters 3 and 4, I was gripped by the idea of a big bang singularity, and immensely perplexed by the reasoning behind the uncertainty principle and quantum mechanics.

Hawking begins the chapter with the epiphany that the “fixed stars” in the sky, aren’t really fixed at all. The stars are all constantly moving with the universe, meaning the universe is always getting bigger. He compares the always expanding universe to the Doppler Effect. The Doppler Effect takes place when an object moves towards or away from another object, like the ripples in water. Scientist Edwin Hubble discovered that the stars that are moving away from us emits a red light, this is due to the wavelength of the visible light reaching us increasing, and the frequency decreasing, which shifts the visible light towards the red end of the electromagnetic spectrum. On the other end is the blue shift, or the stars that are moving toward us. Blue shifting is the opposite process of red-shift, in which the wavelength decreases and frequency increases, shifting the light towards the blue end of the spectrum. Scientist Alexander Friedmann presented a diagram that predicted what may happen to the rate of expansion in our universe based on Hubble’s observations, which would later be joined by two others. The first Friedmann diagram goes into the theory that the universe’s rate of expansion will continue, slowing down until finally the expansion comes to a halt. The stars will then move closer together until...
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