Lab 1: Scope and Nature of Matter, Universe



Science and the Supernatural


Everyone wonders where everything began, regardless of outlook regarding religion, cultural history, and education. Religious people believe that God, or gods, created the universe by supernatural power. Others see no need to invoke the supernatural, and view it as just an unknown - a very large unknown - the ultimate unknown. You can find any manner of combination of those two viewpoints.


For scientists, events and phenomena that occurred during history should be explained using the methods of science. For history, the origin of matter is as far back as you can go:




The Campfire Question (the Ultimate Unknown, Nothingness into Somethingness)


The question "How could there have been nothing?" comes up around campfires, as the conversation deepens late at night, ending without resolution into the wee hours (or at sunrise!).  So, you can call this the "campfire question."


Scientists who study the structure and distribution of galaxies and other matter in the universe, and those who study the finest divisions and machinery of the atom, use the methods of science to investigate ultimate origins. Some scientists have wondered, for this broadest level, about the possibility of the supernatural, in identifying evidence of design or "fine-tuning" that might be inherent to the structure of matter. Almost touching the realm of "nothingness," it is more tempting to invoke the supernatural. Is it appropriate, within science, even for this? Perhaps not.


Science is the clear winner for explaining things within the realm of "Somethingness." Scientists happily roll along doing their investigations using solid methods that have been refined for centuries. For a recent four-part PBS Nova series that presents how scientists are doing current work, see The Fabric of the Cosmos .


Attempts by people to push the supernatural, suggesting notions of "intelligent design," for interpreting events and processes during history, miss the mark. They try to usurp the role of science in explaining things, and fail. First, such assertions are unwarranted, given what we already understand solidly -- they don't fairly and honestly address mountains of very good knowledge. Second, for suggesting supernatural influence on the evolution of Life or on physical processes, the attempts violate a basic requirement that scientific hypotheses be testable, open to modification, and open to rejection. Assertions of the supernatural block or slow our attempts at understanding things, which we are completely capable of doing. If something has been pronounced as requiring a supernatural explanation, scientists won't pay attention to the pronouncement, and eventually somebody will make a discovery or provide an explanation that works just fine, at least nibbling around the edges of a problem to make an advance. Explanations about the origin of Life, about the intricacies of evolutionary processes and genetics, about star evolution, about mysterious forces or particles, and so on, are under active pursuit. Although it can sometimes race in a frenzy, and there are missteps, there is an ultimate patience and persistence to science, correcting as it moves knowledge along.


But who can rib someone for pausing in wonder about the origin of everything? Seems fair game for campfire discussions, but you'll need to speak intelligently about the latest astronomy, chemistry, and physics, to make any real headway.


Sometimes around the campfire, if you stay up late enough, into the wee hours of the morning, somebody will come out with the idea that existence is just in our imagination -- in our very powerful, mind-blowing imagination. Or, they may suggest that existence, Somethingness, is really a fancy computer simulation in some universal overlord's lab (Please don't unplug us!). Maybe we could even tell, if we were to get lucky on how to look . Very interesting, but there is so much to learn and enjoy about science in the known universe, however it got here...


The Big Bang Hypothesis


You've heard of the Big Bang idea probably. Big Bang research encompasses the point of origin of all matter in the Universe. Just as for the origin of the Earth itself, or for the Solar System, or for the origin of Life, scientists don't balk at asking questions here - scientists ask questions about anything and everything, as far back as they can go. Scientists consider the instants after the point of the beginning of matter in our universe, down to the finest divisions of the millisecond, to be fair game for asking meaningful questions. In fact, for scientists working in cosmology , Big Bang research is a fascinating and productive area of inquiry, where there is confidence in results.


The setup for the Big Bang idea is simple. All objects that we observe, stars and galaxies and molecular clouds, are seen to move away from us and each other. How do we see this motion? By observing light shining from stars and other luminous matter. Discoveries by Albert Einstein and others like Edwin Hubble lead to an understanding that the color of star light shows a "red shift," which indicates the relative motion away from an observer. We take advantage of this phenomenon when we use Doppler radar to sense the motion of rain in storms. We may use the example of a train's horn for understanding this:


Imagine a long straight section of railroad track. You are standing at a train station along the track.


You hear a distant train, blowing its horn. You listen to the pitch of the horn.


The horn gets louder and louder, and the pitch stays high. You gather that the train is coming toward you.


As soon as the train passes the station, you notice the pitch of the horn suddenly gets lower.


As the train moves away, the horn gets fainter in volume, but the pitch stays low.


The next day you return to the station, and apply what you learned about the pitch of train horns. Without needing to see a train, you can tell if it is coming toward you or away from you, simply by listening to the pitch of the sound. A higher pitch indicates that the train is coming toward you, and vice versa for a lower pitch.


Here's what is happening with the horn's pitch. As the train approaches your position, the velocity of the train adds to the velocity of sound and serves to "compress" the sound waves toward you:


   You (((((((((((((((((((((((((( <-train


But, when the train is moving away from your position, the velocity of the train subtracts from the velocity of sound and serves to "stretch" the sound waves:


   <-train ) ) ) ) ) ) ) ) ) ) ) ) You


What we call pitch, with sound, has to do with the frequency of energy pulses. When the train is approaching, the energy pulses are more frequent (higher pitch) vs. less frequent when it is moving away (lower pitch).


For starlight and the motion of stars and galaxies, it is the same sort of thing, except that instead of sound it is light we observe. "Compressing" and "stretching" occurs with light, depending of whether the source of the light is approaching or moving away. And, instead of a difference in pitch, there is a difference in color.


Thus, the red shift of light coming from distant stars and galaxies indicates motion away from us and each other. The geometry of the expanding shape of the universe has been likened to the movement of raisins in a baking cake: the raisins move away from one another as the dough expands. For our vision of the Universe, our vantage point is our planet, within our solar system, within our galaxy. Our vantage point is akin to being on one raisin, and looking out at all the other raisins moving apart.


Observations by telescope, other viewing instruments on Earth and dedicated spacecraft have found continuing support for the Big Bang hypothesis and the expansion of the Universe.


The WMAP (Wilkinson Microwave Anisotropy Probe) project has provided jaw-dropping images of our universe, focusing on the cosmic "background" radiation in the microwave range. We are able to detect from this faint signal the distribution of matter spreading from the Big Bang. The word anisotropy in the WMAP acronym means "not-isotropic," or not-completely-even, non-homogeneous. There are dense solid bodies, and clumps, blobs, filaments, streams, jets, swirls, and regions of sparse and diffuse gases. There are even those odd matter-sucking spots called black-holes. Matter in the universe is anisotropic in spectacular fashion! This image shows seven years worth of WMAP observation data as a composite map:


NASA/WMAP full sky map


The color patterns in the map show slight differences in temperature relating to the anisotropic distribution of elemental gases that spread out from the Big Bang. These gases, mostly hydrogen, formed the basis for heavier chemical elements that were to come over time, with the formation and destruction of so many galaxies, nebulae, stars, solar systems, and planets. Individual stars, some large, some small, some hot, some not-as-hot, have individual histories, some long, some short, some involving super-strong forces associated with supernova explosions. These super-strong forces -- of fusion -- were key to the development of the heavier elements.


When you scan this map, try to imagine zooming way in to any little dot-size area, and imagining there the evolution of entire galaxies, and within those galaxies so many billions of stars. Starting from humble hydrogen beginnings, the universe now sports fusion-produced atoms in the heavier realm: oxygen, gold, uranium, nobelium, and more than 100 other elements of the chemical world. This happened over such a huge span of time that the mind boggles at the challenge of imagining it. Luckily, the NASA/WMAP team produced a nice graphic to help:


NASA/WMAP timeline


Think through this timeline diagram carefully. At left is the bright center of the Big Bang instance that formed our universe, expanding from a central point outward in all directions. At our position, shown by the satellite (our "eyes" on the past), we "peer" back to all that is between us and the beginning. There is more out beyond our position, to the right, that we cannot "see." The quotes are used here, around "peer" and "see," to relate the abstraction of this diagram. It is a timeline chart, cleverly drawn to allow an appreciation of how the WMAP image above and in the timeline image (see the color "plane"), can bee seen as the backdrop to all that we see when we view so many galaxies and other luminous areas of the night sky. Hopefully you can now appreciate why the WMAP data is described as "cosmic background radiation," and how our galaxy is one of billions that have formed during 13.7 billion years. Finally, before leaving the timeline image, make sure you don't think of the shape of the universe as some kind of tube -- our view of the universe, as this diagram shows well, is "one-sided"; we see what we can see from your vantage point of a universe expanding from that Big Bang point in all directions.


Our sun and solar system formed about 4.6 billion years ago, which we date from meteorites and moon rocks. The sun and solar system would have formed a bit earlier, but here the origin of our solar system is put at 4.6 billion years ago, or 9.1 billion years after the Big Bang. Our sun is just one star among billions in just our Milky Way galaxy. If you were to draw vertical lines in time, for several hundred stars, some with long lifetimes, some with short lifetimes, you would begin to appreciate the timing, and how some star system in our neighborhood must have blown up in a supernova to provide the elemental matter from which our solar system formed.


Finally, with so much one could learn about the big picture, and the history of expansion of the universe, formation of myriad types of galaxies and other amazing structures, we should consider the role of the small, within the subatomic milieu of quantum mechanics. If you learn more about the Big Bang hypothesis, you will delve into this micro world of matter. Scientists in this field of cosmology, individuals for whom things really make sense, marry the micro and the macro in calculations for how it all works (e.g., String Theory, M Theory). These fields, involving advanced math and study of multimensions, are not quite as accessible as, say, molecular biology, which can be daunting enough, but this is where the action is for the heady world of theoretical physics.


Web Sources


We are finding out more about the timing of the events in the Big Bang, even down to super-fine divisions of the millisecond. NASA's Wilkinson Microwave Anisotropy Probe ( WMAP ) is a satellite designed to study the evidence left behind from the Big Bang. You may be interested to see this article about WMAP's implications for dark matter and understanding the structure of the universe to see how scientists refine their explanations with new data and reconsideration of older data. Scientists involved with the WMAP project have been awarded several prizes for their discoveries. See science writer John Gribbin's article called Inflation for Beginners .