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Origins & Research |
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Origins & Research |
| Philosophical Issues |
Astronomy Issues |
The anthropic principle can be stated as follows: The physical parameters of the universe and earth are consistent with conditions necessary for the existence of intelligent life. If these conditions were not met, then the existence of intelligent life on earth would not be possible. There are both a strong and weak form of the anthropic principle. The strong form states that when these conditions are met, intelligent life will come into existence. The weak form states that when these conditions are met intelligent life can form, but doesn't necessarily have to form. Regardless of your worldview there is an acknowledgment that the possibility of the existence of intelligent, carbon-based lifeforms on this planet earth requires very specific conditions.
Rare Earth: Why Complex Life Is Uncommon in the Universe
This book, written by Peter D. Ward and Donald Brownlee, evaluates the conditions necessary for the existence of life in this universe. It is a response to the work done by the SETI (Search for Extra-Terrestrial Intelligence) community, who feel the existence of intelligent life in this galaxy is common enough to warrant us looking for it. Ward and Brownlee re-examine the Drake Equation and add in additional factors that influence the possibility of intelligent life forming in this universe. The following factors are ones they consider.
- Number of stars in the Milky Way galaxy
- Fraction of stars with planets
- Fraction of metal-rich planets
- Planet's in the star's habitable zone
- Stars in the galactic habitable zone
- Fraction of habitable planets where life arises
- Fraction of planets with life where complex metazoans arise (metazoans are multi-cellular organisms with differentiated tissues)
- Percentage of a lifetime of a planet that is marked by the presence of complex metazoans
- Fraction of planets with a large moon
- Fraction of solar systems with Jupiter-sized planets
- Fraction of planets with a critically low number of mass extinction events
The Privileged Planet: How Our Place in the Cosmos Is Designed for Discovery
This book, written by Guillermo Gonzalez and Jay W. Richards, extends the Rare Earth Hypothesis by stating that the conditions that make intelligent life possible also make the universe comprehensible by intelligent beings. A number of authors have pondered why it is possible for us to understand the physical universe. This book goes one step further by saying that the universe was designed this way. The following factors are sited as support for this hypothesis and extend those expressed by the Rare Earth Hypothesis.
- Fraction of stars with early G class dwarf stars
- Fraction of stars outside the spiral arms of the galaxy
- Fraction of planets with the right mass range
- Fraction of planets with the proper concentration of sulfur in their cores
- Fraction of planets with the right amount of water in the crust
- Fraction of planets with steady plate tectonic cycling
Arguments for the existence of God based on the exacting conditions needed for the existence of intelligent life are called fine-tuning arguments. They are generally expressed in the following way: The probability of condition A being satisfied in the known universe is 1 out of 10120. Given the size and age of the universe it is extremely improbable that condition A could have happened; therefore, God must exist. The bold type is used to set off important portions of the argument. They are:
The third portion needs to be clarified because the conclusion is dependent on this step. I will illustrate it with the following example. Let's say I am required to flip a coin until I get 10 heads in a row. Now the chances of getting 10 heads by flipping a coin 10 times is 1 in 210 or 1 in 1024. This is not an extreme probability, but you would be surprised if it happened. You may even think the coin was biased if it happened. However, if I tried to get 10 heads in a row by flipping a coin 1 million times, you might come to a different conclusion. To keep the calculation simple, let's assume you do 10 flips of the coin before you evaluate whether your condition is met. With this approach you have 100,000 attempts to meet your 1 in 1024 condition. Now instead of being a rare event it has become an expected outcome.
- A condition to be satisfied
- A probability calculated
- A comparison to resources available to generate that event
- A conclusion
In the above example one person is doing the 1 million flips and this requires time. If you allow me only 1 minute to get 10 heads in a row, the event becomes improbable again since I don't have enough time to flip the coin a million times. However, if you allow 100,000 people to flip coins during one minute time period, you will again expect someone to get 10 heads in a row.
From this example, it is clear that as I make the universe larger and older, I increase the resources available to generate the improbable event. Fine-tuning arguments chose probabilities that extend beyond what could be generated by the known universe in time periods consistent with the age of the universe as predicted by the Inflationary Big Bang model.
How do we know the distance between stars? How big is our galaxy? Is there a limit to the known universe? How do we know these facts and how well established are they? These are reasonable questions and must be answered if we are going to consider our place in God's creation. The Greeks felt that the earth was the center of the universe; the sun, moon and planets revolved around the earth; and the stars were part of the celestial sphere. Our understanding of Greek astronomy and astrology come from The Almagest, which contains a description of Ptolemy's model of the universe. Copernicus proposed a sun-centered model for our solar system, which was firmly established by the work of Johannes Kepler. Our current understanding of the universe is that our solar system is one of billions that reside in the Milky Way Galaxy, which in turn is just one among billions of galaxies in the known universe.
Distance Measurements
The distance to stars is measured using several different techniques. The first is a direct measurement while the rest are inferred from statistics. Each successive measurement technique allows the astronomer to measure to greater distances. For comparison purposes, the distances determined by each method will be expressed in light years. This is the distance traveled by light in one year. In the secular astronomy community this distance is also equated to the age of the observed stars. However, in the "recent creation" community this value is used for distance purposes only; believing that age determinations of stellar phenomena are affected by assumptions on how star light reaches the earth. The main distance measurement techniques are as follows:
- Parallax - This technique is based on the fact that an object's apparent location shifts with respect to more distant objects when the observer's perspective changes. Using data from the Hipparcos satellite, stellar distances of 800 light years have been established.
- Main Sequence Fitting - The Hertzsprung-Russell diagram shows that there is a relationship between a star's spectral class and luminosity. Knowing a star's color makes it possible for one to predict its luminosity. If a star is more distant, its luminosity is spread over a larger area and, therefore, its brightness is reduced. By comparing the observed brightness to the expected luminosity, a distance can be determined. Using this technique, distances of 10,000 light years are inferred. These are distances falling within the size of our galaxy (80,000 light years in diameter).
- Cepheid Variables - Certain stars on the Hertzsprung-Russel diagram are known to be variable in their luminosity. There is a relationship between the oscillatory period of the star's luminosity and the magnitude of the luminosity. By observing the period of a variable star, its luminosity is determined and its distance is inferred. Distances to one million light years have been determined by this method. These measurements are comparable to the distances between our closest neighboring galaxies.
- Type 1a Supernovae - If a white dwarf star takes hydrogen away from a binary neighbor, it will accumulate enough hydrogen to initiate a supernovae event. It is found that this type of supernovae event follows tightly constrained conditions; therefore, giving the event a predictable luminosity. Observing such an event allows astronomers to infer distances up to one billion light years.
- Hubble's Law - Edwin Hubble observed, through the Doppler shift of light, that the more distant galaxies have a larger Doppler red shift. Therefore, by observing the amount of red shift in star light the astronomer is able to infer a distance. Using Hubble's Law, distances on the order of 10 billion light years are measured. This is comparable to the size of the known universe which is estimated to be 13.7 billion light years in size.
Historically, the universe was assumed to be eternal and infinite in extent. The scientific model that embodied this assumption was the Steady-State Theory. This model was brought into question with the development of Einstein's Theory of General Relativity and Hubble's measurement of galaxy red shifts. Einstein's theory implied that massive objects distort the fabric of space/time and will, therefore, result in a gravitational collapse of a steady-state universe. Hubble's measurement of galaxy red shifts led to the understanding that the universe is expanding. If the expansion rate is great enough, the motion will be sufficient to prevent the universe from collapsing. However, this eventually will result in a universe with a very small density of matter. Another implication of Hubble's expansion was that, when extrapolated backwards in time, the universe had a beginning. This has led to the Kalaam argument, which is a teleological argument for the existence of God. It states that if the universe had a beginning, there was a first cause of the universe. This cause was God. In Christian circles this argument is championed by William Lane Craig.
The Scientific Model
The Big Bang Cosmology is a scientific model that encompasses more than just the expansion of the universe. It is a complete cosmogony describing the origin and evolution of the universe. It begins with a highly compact object at extremely hot temperatures some 13.7 billion years ago. This object expanded outward resulting in cooling and the eventual formation of all the atoms of the universe (mostly hydrogen and helium). Local inhomogeneities in the expanding universe resulted in gravitation collapse of matter. These regions were the seeds of galaxy formation. Within the galaxy, even smaller regions collapsed to form stars. Stars achieve such high pressures and temperatures at their interior that they fuse hydrogen atoms into heavier elements. As these stars age, they generate the essential elements of life (carbon, oxygen, nitrogen) and heavier elements (silicon, iron, etc.). When massive stars run low on their nuclear fuel, they can supernovae, thus spreading heavier elements out into the galaxy. This material is available to form second and third generation stars. Since heavier elements are now available, it is possible for rocky planets to form in the collapsing material of a newly formed star system.
Evidence for the Big Bang
Evidence for the Big Bang is related to the following general categories.
- Expansion of the universe - Measured expansion rates from Hubble's Law are built into the Big Bang model. These are not predictions made by the Big Bang, but parameters used to establish possible Big Bang scenarios.
- Microwave background - The microwave background was predicted by George Gamow as an artifact of the initial fireball of the Big Bang. The expansion of the universe would stretch the wavelength of high energy photons of light into the much longer wavelengths of microwaves. These longer wavelengths correspond to the blackbody radiation of a universe that is now at a temperature of 3 K. This prediction was verified by Penzias and Wilson in 1964.
- Nucleosynthesis - The ratios of hydrogen to other elements in the universe are explained through the expansion rate of the Big Bang. If the expansion rate is too slow, a larger percentage of heavier atoms should be formed. Since heavier elements are assumed to be formed by stars, only the ratios of hydrogen to deuterium, tritium, helium-3, helium-4, and lithium are considered.
- Dark Matter - Dark matter is material in the universe that does not emit light measurable at the earth. This non-luminous material can not be observed directly, but must be inferred from gravitational effects on luminous objects.
- Large Scale Structure of the universe - It is observed that galaxies are clustered together rather than evenly distributed through space. This clustering is due to inhomogeneities in the early formation of the universe. These inhomogeneities should show a correlation between galactic clusters and inhomogeneities in the microwave background.
Metaphysics of the Big Bang
Assuming the Big Bang to be true, there are certain ontological conclusions from the current state of the model.
- Age of the Universe - The universe is 13.7 billion years old. This conclusion comes from a combination of the currently observed Hubble expansion rate and a presumed slowing of the rate due to gravitational effects.
- Existence of exotic dark matter - It is clear from current measurements that ordinary matter (atoms, molecules) interacts too well with electro-magnetic radiation. If sufficient amounts of ordinary dark matter are present to make the Big Bang model work, then we should be able to observe it directly by the effect it has on light emitted by distant stars and galaxies. Therefore, exotic forms of dark matter must be considered. In the Big Bang model 23% of the known universe must consist of dark matter. Candidates for exotic dark matter are axions, axinos, photinos, neutrinos, gravitinos, magnetic monopoles, maximons, newtorites, supersymmetric strings, quark nuggets, & primordial black holes. Larger categories for these candidates are WIMPS and MACHOS.
- Existence of dark energy - Recent measurements indicate that the expansion rate of the universe is actually accelerating. There must be a repulsive force acting on the universe on the large scale or energy must be entering the universe to fuel this acceleration. From current estimates, the known universe must be composed of 73% dark energy. Terms associated with dark energy are quintessence and the cosmological constant.
- Extent of visible and ordinary matter - Given the presence of exotic dark matter and dark energy, the type of matter that we have common experience with comprises only 4% of the universe according to the Big Bang model.
- Inflationary event - When the microwave background was measured by COBE, it was found to be very uniform. Inhomogeneities were below one part in 100,000. In order for the universe to be this uniform it must have gone through a sudden expansion. This expansion took place within the first 10-32 seconds of the history of the universe where the fabric of space went from the size of a pinhead to a sphere of one meter in radius. This expansion is also used to explain the fine tuned features of the universe, which make life possible.
Alternative models to the Big Bang have been proposed. One group hopes to modify the Steady State model so it can explain the microwave background and the expansion of space. This group would include Halton Arp and the late Fred Hoyle. Another group feel that electro-magnetic forces have a significant effect at large distances and, therefore, affect the behavior of the universe as a whole. Individuals associated with this "Plasma" universe model are Eric Lerner and Hans Alfven. Individuals supporting either of these models would not support the idea of a recent creation.
Proposed Recent Creation Explanations
Some would hold to a recent creation on earth, but hold to an old universe. One individual, Gorman Gray, proposes that on day one of creation the earth's atmosphere became translucent so that morning and evening could be observed. Over the course of the six day creation, God transforms the earth into a habitable place for life and for man. On day four when the sun, moon, and stars are made, Gray proposes that the atmosphere became transparent and these objects became visible for the first time on earth. Some discussion is made over the proper use of Hebrew terms in Genesis 1 to allow for the appearance of sun, moon, and stars versus the creation of sun, moon, and stars.
Maintaining both a recently created earth and universe requires an explanation of light observed on earth originating from distant stars and galaxies. Several explanations have been put forth and they are summarized below. In each of these cases there is a need for further investigation to explain why the universe behaves as it does. There are very few astronomers and cosmologists who approach the universe from the perspective of a recent creation. As a result, the scientific investigations and models based on a recent creation perspective are few and limited in explanatory power. It is hoped that with additional work, a model can be developed that is consistent with a literal interpretation of Genesis 1 and that explains the features of our universe. For a more complete treatment of this issue by an astronomer from a recent creation perspective see Universe by Design by Dr. Danny Faulkner.
- Mature Creation - This is a philosophical explanation rather than a scientific one. This position states that star light was created in transit in order for it to be observable from the earth. Just as Adam and Eve were placed in the Garden of Eden as mature adults, the universe was created in a mature state for functional purposes.
- Changing Speed of Light - Barry Setterfield has studied historical records of the measurement of the speed of light, which extends back to the early 1700's. He proposes that the speed of light has decreased over time and this is born out from the historical records. In the early days of creation he feels the speed of light would be nearly infinite.
- White Hole Cosmology - Russell Humphreys proposes a model of the universe that uses different boundary conditions when solving the equations of General Relativity. As a result, the universe begins as a "white hole" where matter is spread outward. Placing the earth near the middle of this shrinking "white hole" allows it to leave towards the end of the white hole's existence. Passing through the event horizon of the white hole, the earth experiences a single day while the universe as a whole undergoes billions of years of development. This model is explained in the book Starlight and Time.