Cosmology and our View of the World
Asymmetry of Time II
Lead: Brianna Jean & Christine Warden
Summary by Eric McDonald
Is there an Origin to the Universe?
M. Gleiser “Tear at the Edge of Creation” Chapters 17-25
Christine and Brianna began the discussion on the origin of the universe by providing a background history of previous theories of the universe. It began with humanity believing the earth was the center of everything and the stars in the sky were giant crystals. Clearly, our understanding of the universe has evolved quite a bit over the years. Now, in our contemporary era, we have a few prominent theories of the origin of the universe. Advances in technology, such as the Hubble telescope, allow us to observe the expansion of space, and the Big Bang theory arose, stating that a massive expansion of space began our universe. As consequences of this “explosion” of space-time, the leftover radiation from the early universe expands and cools (by distributing across space), and we can now observe other objects in space as if they are moving away from us. However, material objects (planets, etc.) are not actually moving, but space itself is expanding.
There are three related problems with the Big Bang theory. One is the problem of “flatness”. This is the problem of the observational curvature of the universe. Depending on the total energy density of the universe, the curvature can be positive, negative, or zero. If it is zero, then the universe is said to be flat. As time moves on, any deviation from exact flatness at the beginning should have grown, but the universe still remains flat. How has the universe been so fine-tuned? This is where the horizon problem comes in, which states that since we can observe the visible edges of the universe and their temperatures are almost exactly the same, they must have been in contact at one point. Inflation theory is an extension of the Big Bang theory that contains explanations for these three problems. With inflation, the theory is that the universe expanded extremely quickly at the beginning and matter formed after the expansion and rapid cooling. This expansion can be faster than the speed of light, but the movement of information (such as light itself) cannot move faster than the speed of light. Professor Möbius explained how this works by saying that the apparent speed that exceeds the speed of light comes from the fact that space-time is expanding so rapidly, and not from objects moving through space at a fast speed. Therefore, the stipulation on speed in Einstein’s theory of relativity does not apply.
Inflation states that the universe had much faster expansion at the beginning, then it slowed down, and now it has picked up again. Before this expansion process there must have been negative pressure to allow for the acceleration of space-time. As our technology improves, we realize galaxies are spinning faster than they should be. The only explanation is that there is more matter than we can actually observe and that there is a force which is making space expand at an increasingly accelerating rate. This is called dark matter and dark energy. So far, we are only capable of observing 4% of the matter in our universe; the other 96% is composed of 23% dark matter and 73% dark energy.
The discussion opened with questions about perception and measurement. Specifically, we cannot observe dark matter, but we can see how it affects other things. Professor Davis mentioned that the name we have assigned to it is simply a placeholder until we have a better idea of what it is. We may not know exactly what it is that is causing these effects, but we can definitely see that the effects are there. We observe the interactions of things and extract information. Professor Möbius then mentioned that we need models to test theories of what we observe. This is done scientifically by isolating what we are testing, having predictive models, and checking our results with the model.
Brianna mentioned that if we can’t test something, then we can’t just accept results and trust them, at which point Eddie said that results without tests fall in the same category as religion. Another student mentioned that predictions have come true in religion, and Professor deVries asked “Such as?” He then went on to say that the difference between science and religion is how each of them can be scrutinized. Religion is said to be from God or ancestors and is thus taken as fact, whereas everything else can be tested empirically. Religions generally rely on scripture as being the ultimate truth and override empirical observations, which may claim otherwise. Science, on the other hand, relies purely on observation and does not recognize scripture as true. Professor Möbius added that we should be careful with the word “prove” because theories can be tested and look legitimate if they have positive evidence, but something that has been proven cannot be negated in any way.
Professor Davis brought up the idea that the number of hypotheses will most likely increase because of how complex things are getting. We have to deduce 96% of what we think is there. How far can we push the math? Brianna then said hopefully at some point these hypotheses will put things into place, but will we be able to get a true idea of the origin of the universe? How do we even approach that? Professor Möbius added that there is a concerted effort to make that 96% observable, and Eddie said that our models may not be perfectly correct right now, but it is not that they are necessarily wrong, they just need more work.
Professor deVries said that there can be a dangerous ambiguity between a theory and a hypothesis. A hypothesis can be a single assertion, while a theory is more complex and can be more easily adjusted.
Brianna then brought up that it is clear that humans want to know their history and how the universe works through science. Theories are always building and technology is allowing us to discover things faster. Christine added that if everything is asymmetrical and things seem unrelated, maybe we will never find an answer since everything is getting so complex. Some other questions brought up were “how do the parts work so that the whole is sustained? What method works to understand the whole?” Professor deVries answered by saying that there are different kinds of wholes, thus different methods of examination and no universal method.
Professor Davis brought up the topic of our observation and perception by saying that consciousness is related to our body and our brain, but how does it arise? It seems to be the dark matter of biology. Maybe, we are not studying things correctly or confining ourselves. How do we know what is beyond our observational powers? The idea of God surfaces again when humans reach their limitations. Is God incompatible with our quest? Do we just want something simple, or do we look for certainty? Do we need certainty or belief to live our life? Professor deVries asked “What is it to know everything about yourself? Is what you should do next included?” The question of “ought” and “is” is very important.
It seems clear that everything is changing, even if we feel that things are stagnant. We may find that in our quest for answers to the origin of the universe, our responsibilities to each other and our universe either collapse entirely or grow stronger. Some things are studied out of pure curiosity, without the belief in a higher power. We have no responsibility at a macro level (we did not cause the Big Bang), but at the micro level science can change the opinions we have. The conception of what we ought to do changes with the answers we find. Where we are heading shapes what we ought to do. Purpose eases our pain and motivates us.
Professor Davis asked for a description of the difference between a fact and truth. Professor deVries replied by saying that truth does not have to be known, it is absolute and universal regardless of our awareness of it. The material-mode description of a true statement is a fact. Truth applies under certain conditions.
Our discussion ended by talking about laws within the scientific world. There are few laws in biology, but the laws of physics apply to biology. The laws of physics seem to be universal; they leave nothing outside of them, which the laws of biology might do.