Cosmology and our View of the World
Theory of Everything,
Lead: Dave Ducharme & Ben McBride
Summary by Sara Maltais
The discussion about the Theory of Everything was led by Dave Ducharme and Ben MacBride. They came prepared with an outline of their discussion that had a definition of the TOE, the four fundamental forces of nature, an image showing how the theories of the forces of nature have become unified, and questions for after their presentation.
Dave began the discussion by providing a definition from The Elegant Universe that describes the Theory of Everything as “the deepest possible theory of physics which underlies all others and does not require or even allow for a deeper explanatory base”. Ben followed up by giving a brief overview of the four forces of nature which were found on the handout:
Dave then took over the discussion and gave a history lesson of unification. He referenced the chart on the handout and explained that the dotted lines between the forces aren’t proven yet. Dave also explained that the Strong and Weak nuclear forces weren’t fully understood to be combined during Einstein’s time. Ben chimed in and told the class that Einstein refused to take quantum mechanics into account.
Next, Dave explained to the class what String Theory was. He explained that the smallest unit of anything is a string. The vibrations on a string are the particles and they combine. Dave also reiterated that there is no way to ever see one. Scientists believe the string’s movement through space-time distorts it. Finally, Dave pointed out that this theory should be taken with a grain of salt because there is no way to test it.
M-Theory was also explained during class. Dave explained that the M doesn’t really stand for anything but it could stand for membrane, as it did during the NOVA documentary. M-theory has 11 dimensions, much more than the 4 dimensions that we know of today. Professor Moebius then hypothetically asked if there was an experiment to test M-theory, and just like String Theory, explained that there isn’t one just yet. Professor deVries brought up an interesting question regarding our limits on technology. He asked if we have the technology to solve these issues or are we limited. In response, Professor Moebius explained that it is more on the principle level and not technology.
Dave and Ben then showed part of a NOVA video entitled “The Elegant Universe” in order to explain Unification more clearly. It helped to see physicists explaining the complex ideas of String and M-Theory. Dave also explained why String Theory is considered a Theory of Everything. He said it is because a string describes the smallest possible unit and they are the building blocks of what can be discovered in science. Ben then asked the class if a Theory of Everything could ever exist. He answered his own question and stated that the more we learn, the more we realize that we don’t understand.
During the discussion, Dave seemed to be grappling with the idea that we can never possibly know what the smallest unit is, because there always seems to be something smaller to be discovered. He asked the class if it is possible for us to find the smallest possible unit. If strings are the smallest possible units, what makes up a string? This is a question that may never be answered.
The discussion briefly moved on to the multiple universes that M-Theory allows. Professor Moebius reminded us that if this theory is true, our universe is only one possibility. He called the "multiverse" that contains our universe a “landscape of strings”.
Ben then reminded the class that gravity doesn’t seem to fit into the other forces because it is so weak and a possible explanation of this is that we’re only getting a slice of gravity in the dimensions we are familiar with.
As if this discussion couldn’t get more complicated, the class was introduced to Gödel’s Incompleteness Proof. It says that a complex mathematical theory can’t be both consistent and complete. This is strictly in reference to math itself, and not to theories in general. Professor Moebius believes that one cannot prove that the Theory of Everything is consistent and complete. Professor deVries offered his opinion and said that mathematical truth and physical truth deal with different kinds of truth. So comparing Gödel’s mathematical result with physical theories is like comparing apples and oranges.
The discussion took another turn when a classmate asked what gravity is. Ben explained that gravity is a reaction on an object and not just the warping of space-time. Professor Moebius offered his insight and explained that the theory of gravity is only a model. The reference to space-time left Professor Davis a bit confused and he asked for clarification on what it meant to warp space-time. He implied that light is massless and believed that Einstein invented curved spacetime simply to account for the fact that light is bent. Professor Moebius said that it is far off base to say that light has no mass. Light is energy and energy is (equivalent to) mass. He explained that accelerated motion is equivalent to being in a gravitational field.
Dave then opened the discussion back up to the Theory of Everything. He referenced the two questions from the handout:
A classmate asked Professor Moebius if more physicists believe there can be a theory of everything. Would it be more 50:50 or 90:10? Professor Moebius explained that physicists have never been one sided but if he had to guess it would probably be closer to 50:50. Professor Davis addressed Professor Moebius and asked his personal view on what strings are made of. He also wanted to know why we should believe that everything is made of something. Dave chimed in and said that in the history of science, everything trickles down into smaller units. So it seems inevitable that there are smaller units than strings.
Professor deVries added a bit of philosophy to the mix. He explained that Aristotle’s philosophy looked at matter as continuous stuff, not particles. Professor Moebius brought us back to physics and explained that today we look at the world in particles, especially the duality of things. Something could be an electromagnetic wave or a quantum wave.
The question always seems to arise whether there can ever be a Theory of Everything. Hannah brought it to a different level and said that there’s no way there can be a theory of EVERYTHING. She wanted to know what it really meant to say that there is a theory of everything. It seems a bit inclusive and complicated to say that there is a theory of everything in the entire universe. Professor Moebius believed that it was possible that physicists already made a grand theory and they ran out of names.
The discussion ended the same way it began, possibly with more questions than answers. The recurring theme seemed to be trying to find an explanation for the theory of everything. What does it mean to say that there is a theory of EVERYTHING? If String Theory can do this, what are strings made of? Can we ever know what the smallest possible unit is? If so, what is that unit made of? Although the discussion seemed to answer some questions about String Theory and M-Theory, it left the class wondering what the definition of everything is and if we can ever know the answer.