Cosmology and our View of the World
Asymmetry of Time I
Lead: Eddie LaVilla & Eric
McDonald
3/7/2011
Summary by Sam Woodward
Imperfection and the Weirdness of the Quantum World
Reading:
M. Gleiser “Tear at the Edge of Creation” Chapters 11-16
The discussion for this week was about how quantum mechanics affects our perception of time, which Eddie made clear by saying at the start that the discussion will only focus on time and not particles as it relates to quantum mechanics.
The lecture was started by Eric and Eddie handing out a bulleted sheet of paper that outlined some of the background information that helped aid some of the lesser versed people in quantum mechanics – such as myself. The bullets were split into three sections: Creation Myths up to Quantum Mechanics, Space and Time, and Light, Electromagnetism, and the Quantum World.
Eric went over the first section, Creation Myths up to Quantum Mechanics, which dealt with how people, for thousands of years, explained their views of the world without quantum mechanics, and how these views, beginning in the 1600’s, were not in sync with scientific discoveries. Eric also went over the second section, Space and Time, which briefly reviewed the fact that the discovery in 1965 that the Universe was once dense and very hot implies that there is an asymmetry of time, confirming that we are moving towards a future. This conclusion was made because, when, in the early stage of the universe, there was only radiation, the electrons could not bond with the protons, but as the Universe expanded and cooled down, the electrons and protons were able to bond, which led to atoms. We are capable of reading electromagnetic waves or radiation from this early stage of the universe, allowing us to read the history of the Universe, to a certain degree, which leads one to the original implication that we are moving forward in time.
The third and final section, Light, Electromagnetism, and the Quantum World, was also the hardest, or at least the most technical of all the sections. Eddie led this section by going over such things as how quantum mechanics deals with atoms and their smaller parts, which is essential in studying radiation and the early Universe; light is part of the spectrum of electromagnetic waves, and is visible to the unaided human eye; how light moves on its own through space, at 300,000 km/s; and how in the quantum world everything is in a state of flux, meaning that there are no certainties, only determinate probabilities.
There was also another chunk of the section that Eddie talked about, but it was also the most debated and difficult section, so I decided to focus on it more scrupulously, to the best of my science-inhibited ability. What Eddie was discussing was Einstein’s theory of relativity and also that electromagnetism is the unified theory of electricity and magnetism, and that all attempts to unify this with gravity have failed so far. The way in which Eddie described Einstein’s Theory of Relativity was that Einstein assumed that light, as an oscillating electromagnetic wave, moves itself through space at a constant speed, and that the laws of nature are the same for all observers, with respect to each other. Another concept that Einstein proposed was that light is not only a wave, but it is also composed of particles: photons.
Professor deVries was the first to interject, with his statement about Einstein’s electromagnetism (which attempted to meld electricity and magnetism) and how Einstein not only never used quantum mechanics, but hated the very idea of it. Professor Möbius entered the discussion here by explaining that Einstein tried to unify all the fields (which Einstein failed at), because physicists weren’t aware of the four fundamental forces (electromagnetism, strong interaction, weak interaction, and gravitation) yet. Professor deVries rebutted that Einstein unified Maxwell’s and Newton’s theories. Professor Möbius replied that Einstein combined space and time to space-time, then showed that energy and mass are the same things, and finally integrated gravity into space-time, but that he never combined different forces. Professor Möbius’s explanation was either satisfactory or Professor deVries yielded for the sake of time, either way the discourse ended there.
Before either Eddy or Eric could continue on with whatever they had planned, there was a question from the audience about the twin paradox that was in the reading (A Tear at the Edge of Creation by Marcelo Gleiser). The twin paradox is one of Einstein’s original paradoxes that he used to explain his relativity theory; the paradox goes as follows: traveling at or near the speed of light causes changes in time and length of time, shown in “time dilation.” Now, if you are like me, this is an unfamiliar and confusing example, but thankfully Professor Möbius went to the chalkboard to draw a picture to explain this complex idea in simple and easy to understand terms.
The way the paradox works is if there is a ship traveling at or near the speed of light, and there is a clock on such a ship, it will tick at regular intervals to someone who is on the ship reading the clock. But, for someone on the ground not moving at or near the speed of light, the tick on the spaceship would take longer than a tick on a clock on earth, due to time being stretched. This has been proven with precise measuring devices on planes and satellites vs. precise measuring devices on Earth. Attached is link to a website that contains an interactive animation that describes it better than I can.
Since the original intention of this lecture was on perceived time, Eddie brought up an example of perceived time, i.e. a party on Friday night vs. being at work on Friday night, in order to steer the conversation back in that direction. Eddie stated the main idea or thesis of the lecture by saying that, throughout the day you don’t have the same notion of time. The conversation got a little side-tracked here, because there was confusion about what this perceived time means. As Professor deVries put it, you can measure time any way you want; making a day constitute only ten hours doesn’t make a difference. Professor Möbius also added here how the French tried to make a measurement system, including time, international, which lead to a discussion on the meter.
In response to these questions, Eddie was more specific in his explanation of the question. Eddie proposed more of a biological aspect of time: do emotions have an influence on perceiving/influencing time? The class quickly came to the conclusion that emotions only affected the perception of time.
There was a gauntlet of examples that were given to demonstrate the biological aspect of time, such as
The conversation started to drift towards ideas of thermodynamics and time,
which led Professor deVries to ask Professor Möbius, if the Big Bang Theory
is a different time arrow than entropy – in relation to the Big Bang –
is the pre-Big Bang time non-entropic? Professor Möbius answered this by
explaining that the expanding universe with dark energy has mass, therefore,
it creates something that is uneven and unlike a closed system; you have a driven
system that produces energy with ordered structures. Professor Möbius continued
to say, if the universe expanded completely symmetrically and homogeneously,
nothing would have changed. Professor deVries had a follow-up question to this
explanation of whether or not the original force is anti-entropic. Professor
Möbius’s reply was that the fluctuations must be treated according
to quantum mechanics, and that the pre-Big Bang fluctuations were microscopic,
but there was still enough to cause unevenness and thus differences in energy.
The final conclusion was made by Professor deVries, who asked if fluctuations
caused the Big Bang, which Professor Möbius confirmed.
Eddie and Eric tried to corral the conversation and steer it back towards their
original intent, which led Eddie to ask the question whether time can be sped
up, could it go back, why does time only have to move forward? Eddie used the
example of Déjà vu and the power of memory and time. The conversation
stalled here for a brief moment, but an audience member raised the idea of time-travel
and different paths of time. This was quickly met with the grandfather paradox
(could you go back in time and kill your own grandfather?). The initial rebuttal
from the audience regarding this paradox was that there were an infinite number
of dimensions or worlds, which was a less than satisfactory answer.
The conversation on time-travel with regards to going back in time started to spiral off and become unfocused, which lead Professor deVries to ask the question of why can we distort/induce mistakes about judgments of distances, but we can’t do that the same way with time? A number of audience members made the point that it is a level of awareness that could cause a time distortion, such as the drive back always seems to be shorter than the drive to somewhere, or a daily commute will seem shorter the more often you do it. The examples given, though, still only prove that it is the perception of time that is altered, but not time itself, because time has a constant rhythm.
After this point in the lecture, there was a statement made about prophets and prophecies that appeared to defy the notion of time, but this was an unsuccessful argument that derailed the conversation and created an opportunity for less well thought-out ideas to percolate. What came from the hodge-podge conversation was that, as Professor deVries pointed out, if objective time didn’t work, we wouldn’t have used and wouldn’t still be using it; you can do a lot with an accurate clock. Professor Möbius also pointed out that physics has an objective need for time, further reinforcing the idea that time is necessary and objective and not merely a subjective experience.
The conversation petered out with Joe asking a question regarding time and quantum mechanics. Professor deVries was the first to reply by stating that uncertainty of movement doesn’t affect uncertainty in time, and that quantum mechanics plays the odds. Professor Möbius followed Professor deVries up by stating that radioactive elements have specific and definitive half-lives, but that being said, we do not know when a single atom will decay. Professor Möbius ended the class by saying that the Greeks had two words for time; one: cronoz, meaning numeric or chronological time; secondly: kairoz, meaning an undetermined moment in which something special happens.