Chapter 16 and some conclusions

First we have Chapter 16
This chapter serves to tie up the loose ends left by the previous chapters and to leave the reader with a vision for the future that I believe that everyone would enjoy. The future being that all we have to do to discover the secrets of the universe is to look up, after all that's how it started in the first place.
Spacetime may not be fundamental, but may be the result of even more primordial forces. This idea is called composite spacetime and can be observed by using different string theories to describe the universe, by doing so you end up with a variety of valid perspectives that shape that the universe is different shapes despite each theory describing the same universe. Going even deeper into what spacetime is you inevitably begin to discuss the work of Bekenstein and Hawking during the 1970s. They found that the entropy of a black hole is the highest possible for the region of space that it takes up, and that it is proportional to the size of the event horizon of the black hole. By using the Planck square as the fundamental unit of space area you can find the maximum amount of entropy that can exist in a given region of space. Realizing that because the area of the event horizon represents a 2 dimensional structure the hologram principle was developed. This principle states that the universe that wee know is just a projection of the actual universe. This principle was shown to work under certain circumstances by Juan Maldacena. Then we have the question of what is spacetime made of exactly, the string theory states that spacetime could be made out of stitched together strings, but this poses a problem because for string theory to work spacetime has to already exist. There is an alternate proposal, that of loop quantum gravity, which uses general relativity as its beginning and gradually works down from the big universe the the micro-universe. Greene states that he thinks that the string theory and the loop quantum gravity theory are likely  to merge and in doing so give everyone from Newton to Hawking some credit in the creation of a fundamental theory of the universe.

Overall I really enjoyed reading this book, and although it left me with quite a few headaches. I also feel compelled to add that Einstein and I face the same problem with quantum mechanics, from what I have read he never felt comfortable leaving things to probability and quite frankly neither do I, but that isn't to say that I can't accept it.

I may post a few more times, and will likely post a portion of the paper that I am writing about "The Fabric of the Cosmos."

Additionally If anyone cares...

This is what I think the Universe looks like.

Chapter 6

I know I said that I was posting the favorite parts of the book, but it just so happens that they are in the same section of the book.

Chapter 6 attempts to answer the question of whether time has a direction. There are two ways of looking at this question. First, is through observation, and if you were to do so you would find that certain events seem to only occur in one specific direction such as an egg smashing against the floor. However, the laws of classical physics do not include the concept of time, and therefore can be reversed. Thus the conclusion you would draw from observation is only partially incorrect, as you would also have to accept that it is possible for he egg to reform and return to its previous location. The second way to approach the issue of whether time has a direction is to look at the question in a different way. It is logical to look at the transition from an egg to splattered goop is one that goes from highly ordered to disordered. By looking at the question in that manner it is possible to apply Ludwig Boltzmann's equation for entropy (S=K*logW). This is because entropy is the tendency of things to enter into a more uniform state. Thus it is the second law of thermodynamics that allows for time to have a direction. Expanding upon that, by assuming that the universe started with a low entropy and applying gravity to the laws of physics, it can be calculated that not only has the amount of entropy in the universe not decreased with the formation of planets and stars, it has actually increased by a vast amount due to the loss of energy in the form of heat.

Chapter 5 and some news

Much like this book has changed my viewpoints on space and time, I too must change some things around. First, if you are still reading my posts then I congratulate you, for I know that my writings have often been separated by vast lengths of time. Second, and the important part, instead of summarizing every chapter in the book and presenting them to you in this blog, I will be showing you, the reader my favorite portions of  "The Fabric of the Cosmos." Specifically the portions that have shattered my world view (in the context of physics).

I begin with chapter 5 of the book. The main question this chapter attempts to address is that of time; does time in fact flow? I know that all of you are thinking, "Well of course it flows, I mean I feel the passage of time, that is what I'm feeling right?" Well kind of. Not really. It appears that the passage of time that you feel is actually your mind processing the travel between the light emitted or reflected from objects reaching your eyes, in effect your entire perception of time is well in the past. Why am I telling you this, well if you remember from the earlier posts about relativity, space and time are one thing that is spacetime. Now if you remember that you may also remember that we, through motion, create curves in spacetime and so when observers move relative to one another the result is two different and completely valid perspectives on the same events. In essence the totality of their observations are the same, but the shape of the slices through spacetime are different. As most people realize the local impact of these differences in perception are minuscule, but given enough distance the effects can be staggering. If you were to take into account the infinite nature of the universe and all the perspectives there in, it is found that while the totality of spacetime exists, the flow does not. This is because, by taking into account all the perspectives of the universe, every event in all of spacetime is always occurring now.

Now it is time for a video that was sent to me after I tried to explain all of this and more to my best friend.

"So what you're saying is..."

  Now while that video is decidedly not scientific, it has a point, time is made of stuff. That stuff is  refereed to as moments

Chapter 4 Entangling Space

This chapter primarily discusses the second revolution that occurred in the early 1900s, that is of the quantum theory. The point in the book that I found most interesting is the same as the one that Einstein found most difficult to accept, that is of the lack of locality of the universe. This lack of locality is refered to as entanglement. I feel that entanglement can be best pictured using light bulbs that are seperated by a great distance, but turn on at the exact same moment in time.

The lack of locality in the universe does not preclude the possibility of their being definitive properties for specific particles. Additionally concepts discussed in chapter 4 are those of probability, in that you can never same that something is exactly at a given point without affecting the particle, thus you can only state the most probable location for the particle without changing the particle though the act of measuring.

Chapter 3 Part 3

Einstein's theories of relativity do not state that everything is relative, instead they stated that only somethings are relative and even introduced a new constant. That constant being absolute spacetime. Einstein also realized that you can divide absolute spacetime into "chunks" from many equally valid perspectives. This is due to the fact that when objects move relative to one another their way that they perceive spacetime falls out of sync with one another. Thus to different people events that occurred simultaneously would appear on different chunks of spacetime.  The concept just mentioned is known as the "relativity of simultaneity." It can be further simplified to "observes in relative motion do not agree on simultaneity-- they do not agree on what things happen at what time." His theory also provided a major point that all observers can agree on, that is that so long as your are moving straight through space time, you are not accelerating.Special relativity has one major weakness, that is that it does not account for gravity. Additionally Einstein realized that special relativity was in direct conflict with Newton's theory of universal gravitation, due to that statement  of the speed of light being that fastest that any object can go. According to Newton gravity  acts instantaneously and thus would move faster than the speed of light, making things a little bit difficult for Einstein. Einstein embarked on a quest to produce a new theory of gravity that would be as accurate as Newton's while conforming with special relativity. The key to Einstein forming the theory of general relativity was the realization that acceleration and gravity are the same, and using that equivalence he was able to apply the observation that accelerating observers view spacetime through curved/warped chunks to gravity, he then concluded that gravity is a warp or curve in the fabric of spacetime.  

Chapter 3 Part 2

Despite it being accepted that it is aether that light travels through, evidence to the contrary began to mount. The primary evidence that light doesn't need a medium through which to travel, is that experiments designed to measure the change in the speed of light depending on the motion of the observer failed to find any difference in the speed of light. Meaning that no matter what point of view you observe light from it is always traveling at the same speed. That speed being 3X10^8 meters per second. (Or 670 million miles an hour for those of you who don't use international units.)

So whether you are looking at the light from the photo above or the reflected light from the moon below

it always travels at the same speed.

Some Videos

The videos below help anyone understand many of the concepts that "The Fabric of the Cosmos" covers.