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1.What is the most interesting thing you have learned from this book?
Alan Guth s book takes you through the journey of his life, and his career in which he made many scientific discoveries. I especially liked the way that he maps out these discoveries because it was fun to discover along with him. Throughout Guth s life he has been putting together the pieces of a giant puzzle. The concept that I found to be most interesting was that of blackbody radiation.
This concept is used universally in many situations. It is common knowledge to physicists. An object at any temperature other that absolute zero emits a glow of electromagnetic radiation. (Pg. 64) An example of this that the author gives us is the glow of the sun or the coals in a barbecue.
If this light, emitted from hot objects is put onto a spectrum there is an increasing intensity at different wavelengths. This data can be used to analyze a variety of things. A reason why this is so important for astronomers is that it can be used to understand what makes up objects such as the sun and the stars. It has also been used in determining the velocities of distant galaxies.
The author gives us the idea of constructing a closed box and heating it. The inside of the box and the outside will have two different reactions. The outside will act normally along the spectrum. On the inside, the radiation will be emitted and absorbed, and in a very short time a steady-state situation, or equilibrium, will be established. (Pg. 65) This means that it is not giving off any radiation, it is all being absorbed.
An object that gives off no radiation will fallow an equilibrium spectrum with no lines. This information was useful in the idea that the universe today should have a background of electromagnetic radiation left over from the big bang. The blackbody radiation spectrum is the way in which that energy density varies.
2. Summarize the Author s view of an inflationary period in the early Universe.
The early universe had a very uniform distribution of matter. Inflation is the explanation for this. Guth has used the idea of inflation to conquer many questions about the universe. One being the original size of the universe. The inflationary theory reveals that it must have been a lot larger that originally suspected. Can nothing be created from nothing? If the universe was created from nothing, then the total energy must be zero. But the universe is clearly filled with energy: the Earth, the Sun, the Milky Way. (Pg 9)
One idea that Guth brings is the idea of the Inflationary Universe, and the idea of a false vacuum. When applying this idea to the expansion period of the early universe Guth points out that originally it was thought that this would slow down expansion. However, due to the uniform pressure it is not a slowing force. This means that it is creating a negative pressure. The false vacuum actually leads to a strong gravitational repulsion. (Pg 173)
This vacuum happened for a brief moment causing the universe to stretch to double the size it started from. This double timing happened several times causing an overall expansion of eight times its original size. This is what can be called inflation.
What Guth is actually talking about is what happened during the bang. Evidence before Guth s inflationary universe idea, only talked about what happened after the bang.
3. Discuss an important observation presented by the author that was not made at visible wavelengths.
Guth and his partner Henry Tye looked to find how many magnetic monopoles were produced during the big bang. Magnetic monopoles have never been seen so, calculating how many there were at the start of the universe is a difficult task. In territory as unfamiliar as the early universe, my natural feelings of insecurity were quadrupled. (Pg. 147)
A magnetic monopole has an isolated North or South Pole. Not like our Earth that has a strong North and South Pole. The Grand Unified Theories predict their existence.
What Guth wanted to understand was the creation of monopoles and how they were destroyed. How he went about this was to estimate the density of monopoles when the Universe started. He estimated equal to the number of photons that were present. (This information is given in the Standard Big Bang theory.) This estimation was not likely, based on the fact that if there were that many monopoles, then they would still be abundant today and we could see them.
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