Cosmology and our View of the World
Multiple Universes and the Anthropic Principle
Lead: Jacob Day
3/25/2008
Summary by Luke Gregory
An answer for us being here?
Tonight’s presentation, brought to us by Jacob Day, began with an audio taped interview of Paul Davies on the Anthropic-Principle. Davies proposed that the formation of conditions and natural laws that are conducive to the creation of life was not a passive, or accidental process; but rather, that the evolution of these laws and conditions was “purposeful” toward the creation of life. As an example to support his argument, Davies theorized that if gravity formed too fast, than its strength would collapse the universe before it could form; if too slow, the universe would fly apart before the matter could coalesce to form the stars and galaxies we know today.
Davies also commented on how most scientists’ side with an accidental view, adding that it is part of the scientific method, and taken as a matter of course without consideration for possible “purposeful” explanations. The element of chance is part of scientific laws, in particular when it comes to statistical physics (the basis of thermodynamics) and quantum physics. Contrary to that, Davies feels that it was not chance that kept us evolving and still existing in this universe, but more coherent reasons.
Davies made reference to three variations of the Anthropic Principle:
I. Weak (WAP): Laws and conditions of the universes with their own set of laws are consistent with the formation of life. As a possible explanatory route, the multiverse theory suggests that the variations in laws and physical constants, limits the number of likely life-supporting universes to only a few.
II. Strong (SAP): The universe exists, and life exists,
therefore the universe must exist to support life. This idea implies the existence
of a creator, super-intelligent being, or that life is built into
the laws from first principle as an explanation to why life exists on earth.
III. Participatory (PAP): Observers link back to the early universe. “The universe is formed to support life”. (Wheeler, John) The PAP links quantum physics to the universe because the universe changes as we observe it. The problem with this idea is that the way in which we influence these changes is still mystery. An example of the PAP is in observations of electrons in the Young experiment. As observers, we cannot predict the final position of an electron as it passes through the slits of the apparatus, because observing involves interfering with the electron’s trajectory.
After the audio presentation was finished, Jacob continued with a PowerPoint presentation, during which the topic of the triple Alpha Process arose as one example of fine-tuning in our universe. In this case Professor Moebius elaborated upon how the fusion of Helium into Beryllium doesn’t generate energy and to form carbon is a very step. A precise resonance for this interaction was the additional help needed to form a stable carbon atom, a principal element for life.
Jacob continued to say that in a multiverse, there are many universes with variations in their constants or physical laws. These variations can have great consequences on that universes ability to support life. As Jacob explains, most universes would be devoid of life and we are fortunate enough to exist in a habitable universe where the constants are just right.
Lastly, Symmetry Breaking was brought up in Jacobs’s presentation to the class, and Professor Moebius informed us of how symmetry breaks when energy is added to the system. Professor Moebius presented as an example of how ice has a lower energy state than liquid water. The energy state of ice is so low that the water molecules cannot move and the intermolecular forces lock the molecules in place to form a rigid lattice. At a temperature below zero degrees Celsius, water exists in a solid phase and will remain as a solid as heat energy is applied to it until it reached zero degrees Celsius. At this point any extra heat applied to the ice will break the lattice of the ice and allow water molecules to flow freely as a liquid phase. Both water and ice will remain at this temperature until all the ice has melted, requiring additional energy. Ice has less symmetry than water. Thus when water cools, ice is formed, the symmetry is broken and the heat energy will be released. The rapid cooling after the big bang may have led to the symmetry breaking in the universe to form all the matter.
The class was concluded through discussion between the Professors and Students. Some of the comments made at the end of class are as follows:
The multiverse topic lead the group discussion towards the subject of simulated universes, and the possibility of a computer processor that has the power to perform all the simulations necessary to create one. Professor deVries immediately rejected this notion, saying there is no such thing as a fake universe, it either exists or it doesn’t. Andy immediately rejected that notion by suggesting that there is no difference between a god created universe and a simulated one because the mathematics behind it would be the same regardless. Andy also suggested that there are processors that are so sophisticated that it can beat any human played in a game of chess (IBM’s Deep Blue vs. Garry Kasparov), a feat that seemed impossible 100 years ago. Austin countered that argument by suggesting that in order to effectively simulate a universe you will need to simulate all the matter in it, a feat that is impossible for any computer (the principles of the Turing machine highlights many of these limitations). Professor deVries supported that statement by suggesting that it is impossible to simulate a human without simulating that world around it, because this avoids a shortcut argument to the required processing. Abby suggested that a simulated universe is indistinguishable from a real one. How are we able to say what is real and what is fake?
Abby’s comment reminded Professor Moebius of a German TV show from 1973 called ‘World on wire’ (Welt am Draht), where the characters are living in a simulated reality where outside adjustments to their reality causes the characters to go crazy. The adjustments to a simulated reality are analogous to the unexplained phenomena found in the world – even the events described in the bible. Professor deVries highlighted the fact that since the characters of ‘World on wire’ went crazy because of the simulated realities failure to go the detail that was required for the characters to remain sane. Austin instantly suggested that we are limited to our observations of fine detail by the Planck length. Austin then to suggested that our concept of reality is only our body’s reaction to the environment, which produces stimuli to provide our sense of reality. We cannot see the Planck length so that kind of fine detail is irrelevant to our reality. Professor deVries countered in stating that complex chemical processes in the brain do not suggest thought, “clams are not concise thinking creatures!”
Professor Davis guided the discussion towards the consequences of infinite regression in the multiverse theory. An example of this consequence is if the position of an object was the only distinction between one universe and a sister universe, then there will be an infinite number of sister universes, along with 1050 tons matter. Together with their own infinite possibilities in position, this illustrates the problem of infinite regression.
Abby wondered if the universes that survive will exist, while the rest just die and disappear. Abby’s comment offers a solution that avoids the issue of infinite regression. Professor deVries quickly suggested that everything in the Universe is causally connected anyway, therefore infinite regression would not be an issue since a sister universe would only exist to satisfy a specific purpose. Professor Moebius stated that sister universes will exist together in one region with local bi-laws. These bi-laws are physical laws that are unchanged with respect to other universes.
In conclusion, Professor Moebius discussed that the exploration of the String Theory, if the theory is proven to be correct, could help scientists to identify the bi-laws of other universes, thus providing evidence for the multiverse theory. An example would be to look for slight changes in some of the constants across our observable universe. In the observation of light that has passed through hydrogen gas at the largest distances in the observable universe. Hydrogen gas absorbs a specific range in the electromagnetic spectrum, so if we observe cosmic hydrogen absorbing a slightly different range on the spectrum, then we know that the bi-laws are slightly different at that point in space. Prof. Moebius also mentioned that the Large-Hadron Accelerator CERN in Switzerland offers the possibility of detecting the super-symmetrical counterparts to several subatomic particles to include the carrier particles for the electromagnetic, gravity, and nuclear strong forces. The existence of many subatomic particles has already been detected, but efforts to detect many of the force carrier particles and their super-symmetrical counterparts have not been successful. If CERN successfully detects the graviton and the symmetrical sisters for the gluon, photon, and the graviton, then String Theory will have withstood a first experimental test, and we will have first observational evidence that points to possibly living in a universe among countless others.