Evidence for God from Cosmology Richard Deem Evidence for God Cosmology (the study of the cosmos and its origin) brings us to the realization that we can never know with absolute certainty where the universe came from or why anything at all should exist (rather than nothing). However, we can study the cosmos and get clues that either eliminate or strengthen various theories. Come on a journey to discover what we know about the cosmos and what it tells us about its possible origins...

The Greatest Discovery (COBE, 1992) “unbelievably important... They have found the Holy Grail of cosmology” Michael Turner (University of Chicago) “It is the discovery of the century, if not all time” Stephen Hawking (Cambridge University, UK) “What we have found is evidence for the birth of the universe. It’s like looking at God.” George Smoot (UC Berkeley - COBE project leader) COBE (Cosmic Background Explorer) was a satellite that measured the temperature of the radiation left over from the Big Bang. This background heat was expected to be present from the tremendous energy released as a result of the Big Bang explosion. The temperature had been measured many years before and was found to be ~3°K wherever anybody looked. However, in order for galaxies to have formed, it was required according to theory that there would be small variations of temperature on the order of one part in 10,000. None of our previous instruments were sensitive enough to measure this small variation, until COBE. The COBE satellite found the expected variation in temperature and mapped it, providing a startling confirmation of the Hot Big Bang model. These results have largely silenced critics of the Big Bang, who were hoping to get rid of the “problem” of an initial beginning to the universe.

Relativity vs. The Newtonian Universe Michelson and Morely (1887) Velocity of light Einstein (1905) Special Relativity (E = mc2) Einstein (1915) General Relativity Isaac Newton developed theories and equations to explain the relationships of velocity, acceleration, time, and gravity with regard to the earth. These equations were sufficient to explain the measurable universe (which was restricted almost exclusively to the earth) through the 18th century. As science progressed, scientists attempted to apply these equations to measurements of the universe. Newtonian physics suggested that the velocity of light would be constant with respect to a fixed point in space. Albert Michelson and Edward Morely (1887) thought that they could be measure the absolute velocity of the earth by measuring the speed of light from different points on the earth and from different directions. By subtracting the differences in the speed of light, they should be able to show the absolute speed of the earth in space. To their surprise, these experiments suggested that the earth was not moving at all. What they didn't realize was that the velocity of light is constant with respect to all observers, whether they are moving or not. In 1905, Albert Einstein derived the equations of special relativity that involved measurements of length, velocity and time from moving observers. These equations led to the now famous equation E = mc2, which describes how matter and energy can be converted from one form to another. In 1915, by applying relativity to Newtonian physics, Einstein derived the equations  of general relativity which describe the relationships between gravity, the speed of light, mass, and other factors in regard to the universe as a whole.

General Relativity - Einstein Discovers God In deriving the equations of general relativity and applying them to the universe, Einstein came up with the equation pictured above. The left side of the equation represents acceleration. Since p is small and c2 is very large, this value is very close to zero. If 3p/c2 is zero, what does this tell us about the value of this expression? The universe is experiencing negative acceleration, or decelerating. If you solve more equations, you also determine that the universe is expanding. What, in nature can you think of that is simultaneously expanding and decelerating? An explosion. This was the first suggestion of what has come to be called the "Big Bang." Einstein did not like the implications of the Big Bang, which he though implied the existence of a Creator. He spent many years modifying the original equations to introduce a cosmological constant "fudge factor" to attempt to eliminate the need for a Creator. This cosmological constant remained undetected until the late 1990’s, and then, it was many orders of magnitude smaller than that required to eliminate a beginning to the universe. where: =density p=pressure G=constant of gravity c=speed of light

Origins of the Big Bang Theory Vesto Slipher (1914) “Nebulae” receding from the earth Alexander Friedman (1922) Expansion of the universe Hubble (1929) Law of Red-Shifts Vesto Slipher (1914): Presented findings at an obscure astronomy meeting which showed that several "nebulae" were receding away from the earth. A graduate student named Edwin Hubble was in attendance and realized the implications of these findings. Hubble proved that these nebulae were actually galaxies, composed of billions of stars. Alexander Friedman (1922): This Russian mathematician predicted the expansion of the universe. Hubble (1929): Proposed the law of red shifts. Galaxies which are moving away from the earth demonstrate emission spectra with bands that are shifted toward the red (or longer wavelengths) end of the spectrum.

Hot Big Bang Model George Gamow (1946) First hot big bang model Bell Labs (1965) First background radiation measurement Cosmic Background Explorer (1992) Ripples in background radiation George Gamow (1946) - Proposed the "hot" model for creation of the universe. This hot explosion would have been expected to produce a background radiation temperature of 5°K (Kelvin is a metric scale of temperature, with absolute zero, the lowest possible temperature, at which no molecular motion occurs, equal to zero). At the time there was no known way to measure a temperature this low from earth, so there was no way to test this theory. Bell Labs (1965) - Scientists at Bell Labs were measuring radio emission at 7 cm wavelength (where emission from galaxies was negligible) and found a 3°K excess in antenna temperature. This 3°K background temperature was found throughout the entire universe. COBE (Cosmic Background Explorer, 1990-1992) - Demonstrated the existence of the predicted variations in background radiation (see next slide).

Cosmic Background Explorer (COBE) Universe is a perfect radiator (to 1 part in 10,000)- background temperature of 2.726°K (1990) Refined COBE measurements showed irregularities of 1 part in 100,000 (1992) COBE (Cosmic Background Explorer, 1990-1992) - Initial results were reported, which showed that the universe was a perfect radiator, with a background temperature of 2.726°K. There was no variation in measurements to the sensitivity of the instruments (1 part in 10,000). These results confirmed that at the creation of the universe, the temperature was very hot. The universe radiated this heat over the billions of years since its creation to produce such an even temperature. Theories regarding galaxy formation following the Big Bang required that there should be irregularities in the background radiation of 1 part in 100,000. In April, 1992 refined COBE measurements showed irregularities of 1 part in 100,000, exactly what was predicted by the theories. These results were confirmed by balloon-borne experiments in December, 1992, which showed identical temperature variations in the same areas of the universe. These results were the ones that led to the dramatic statements which were quoted at the beginning of this presentation. Not only was the Big Bang theory proven to be correct, but scientists now know what kind of Big Bang it was. The theological implications are inescapable. At some point in the past, the universe was created from what has been called singularity (or no volume). This event must require the existence of a creator, either natural or supernatural (God).

COBE DMR This slide shows the ripples in the background radiation, which varies up to 1 part in 100,000. The "hotter" areas are red and the "cooler" areas are blue. The differences in temperature were important in allowing the matter in the universe to condense into stars and galaxies.

Alternate Models Infinite/eternal Universe Steady State Universe Oscillating Universe The Hartle-Hawking Model Quantum Cosmology There were several models of the universe that were proposed to get around the Big Bang model. Descriptions of these models and the observational problems encountered by them in our universe follow in the next six slides.

Infinite/Eternal Universe Problems Paradox of the Dark Night Sky Light decreases 4-fold with doubling of distance Volume (or number of stars) increases 8-fold with doubling of distance Many scientists had originally thought that the universe might be infinite and eternal. However, there was a major problem with the theory. If the universe were infinite, the amount of light falling on the earth would also be infinite (assuming an approximately uniform density of galaxies throughout the universe. The reason for this is that the volume of the universe increases 8-fold with doubling of distance, while the decrease of light is only 4-fold with the doubling of the distance. The result is that the amount of light falling in the earth would double every time the size of the universe is doubled. Therefore, if the universe were infinite, we would not expect the sky to be dark at night. Since the night sky is dark, we know that the universe could not be infinite.

Steady State Universe No stars greater than 16 billion years old No newly formed galaxies (all formed at same time) The steady state universe theory claimed that the universe was eternal and that galaxies and stars were born throughout the universe over time. The theory ran up against the reality of the observations of the universe. There are no stars greater than 14-16 billion years old, even though small stars can have a lifetimes greater than 30 billion years. In addition, all the galaxies we see are fully formed. The only "young" galaxies we see are those that are at the limits of the age of the universe (very far away). In reality, because of relativity, in looking at young galaxies, we are looking at galaxies that were forming only 1 billion years after the Big Bang event (it has taken the light 12 billion years to reach the earth). Because of these problems, there are virtually no cosmologists today who believe in the steady state universe.

Oscillating universe Only 10-50% of matter needed for collapse (open universe) A collapse would lead to “Big Crunch” instead of bounce Oscillating Universe - The Big Bang implies a universe which is created, therefore the need for a creator. Scientists who didn't want to acknowledge the need for a creator developed the oscillating universe model to attempt to get around the creation of the universe. This model stated that the universe explodes, contracts, then explodes and contracts, ad infinitum. Although this theory did not completely eliminate the need for a creator, it could put his creation event into an almost infinite past. Many eastern religions (Hinduism, Buddhism, and New Age) state that everything, including the universe undergoes reincarnation. The Hindu scriptures state that the universe is successively born every 4.32 billion years. Given the age of the universe (15-18 billion years), this value is off by a factor of only 4, which looked very attractive to scientists in the 1970's. The ability of the universe to oscillate is dependent upon a certain critical mass. This critical mass is required to slow the expansion of the universe and force a contraction. If this total mass is not present, which seems likely, then the universe will continue to expand into eternity. Even if there were enough mass to cause the universe, the result of that collapse would be a "Big Crunch" as opposed to another Big Bang (see next slide for explanation).

The Universe as an Engine System or Engine Mechanical Efficiency Diesel Engine 40% Gasoline Engine 25 Steam Engine 12 Human Body 1% Universe 0.00000001% The reason that the universe would not “bounce” if it were to contract is that the universe is extremely inefficient (see table above). In fact, the universe is so inefficient that the bounce resulting from the collapse of the universe would be only 0.00000001% of the original Big Bang. Such a small “bounce” would result in an almost immediate re-collapse of the universe into one giant black hole for the rest of eternity.

The Hartle-Hawking Model Quantum physics invoked prior to 10-43 second, to eliminate the singularity Requires use of imaginary time Stephen Hawking, in an attempt to escaping the beginning of the universe, and hence the need for a Creator, has postulated that there is a point history of the universe where the equations of general relativity (on which his space-time theorem was based) might break down. In 1983 Stephen Hawking and James Hartle proposed that since we cannot determine conditions in the universe before 10-43 seconds after its origin, perhaps some unknown phenomenon would have replaced the laws of general relativity. Therefore, the universe might not have originated from a true singularity (beginning from an infinitely small volume). Appealing to quantum physics seen at the level of subatomic particles, they claimed that the universe could have just popped into existence out of absolutely nothing at the beginning of time. In his theory, Hawking employed the use of imaginary time, analogous to the use of imaginary numbers in mathematics. Neither imaginary time nor imaginary numbers exist in the real world, so their use in describing the real universe is somewhat artificial. Most likely, Hawking was trying to avoid the implications of general relativity that time had a beginning at the instant of the Big Bang. If time had a beginning, then the events that led to the Big Bang must lie outside of time - a second dimension of time. The Bible also claims that God was acting before the beginning of time and is not confined to it. It was these implications that Hawking was trying to avoid in his model.

Problems in Quantum Cosmology Observer based - who is the observer? The universe represents a very long quantum "moment" According to quantum physics virtual particles can pop into existence from nothingness through quantum tunneling. Some cosmologists have suggested that the entire universe could have emerged in this way as a giant quantum particle. However, quantum theory states that quantum systems possess dynamic properties such as position, momentum, and spin orientation only when these properties are measured by some device or observer. The physical measuring devices themselves can be given a quantum physical description. Therefore, for the universe, there is the problem that there is nothing beyond quantum physics to make the measurement that is a necessary condition of the reality of the properties of the universe. It might be argued that God is the observer. However, this is the implication that quantum cosmology attempts to avoid. It has been suggested that the collapse of the wave function associated with a quantum system might function as the observer. However, the measuring device itself, also lacks any intrinsic dynamic properties (such as precise location or velocity). So if the measuring device itself is indeterminate then it cannot collapse the wave function of the quantum system being measured. If one hypothesizes other devices that collapse the wave function, we are left with the problem of infinite regression. The second problem with quantum cosmology is that quantum mechanics states that quantum events occur according to finite probabilities within finite time intervals. The larger the time interval, the greater the probability that a quantum event will occur. Outside of time, however, no quantum event is possible. Since time originated at the moment of the creation of the universe, quantum tunneling could not be its "creator." In addition, quantum events are extremely short-lived. As a quantum event, the existence of the universe is many orders of magnitude longer than any described quantum event. Therefore, cosmologists who propose such theories must appeal to unknown laws of physics to describe the reality of the universe.

Implications of Big Bang Time, space, matter and energy all came into existence at once Time is a created dimension Stephen Hawking, George Ellis, and Roger Penrose extended the equations for general relativity to include space and time.1 Not only space, but also time has a beginning - at the moment of creation. Studies in particle physics have shown that our dimension of time is really only half a dimension, since time can only move forward2 (forget the time travel movies - this is scientifically impossible). If God existed in only one dimension of time, then He would have had to have been created at one point. The Bible says God was not created, but has existed from eternity past to eternity future. The Bible also suggests God created time and was acting before time began,3 confirming that God exists in at least two dimensions of time. In addition, the Bible states God can compress or expand our time line,4 based upon what He wants to do. For God to turn a day into 1000 years and 1000 years into a day requires that He exist in at least two dimensions of time. Later, Hawking tried to get around the concept of two dimensions of time by appealing to "imaginary time." Like imaginary numbers, imaginary time has not comparable physical reality, and so, could not explain what was happening before the creation of the universe. A real, second dimension of time would accomplish the same purpose as imaginary time, but could at least be theoretically possible. In his later book, The Nature of Space and Time, Hawking stated, "Today virtually everyone agrees that the universe and time itself had a beginning at the Big Bang."5 References Penrose, R. 1966. An analysis of the structure of space-time. Adams Prize Essay, Cambridge University. Hawking, S.W. 1966. Singularities and the Geometry of space-time. Adams Prize Essay, Cambridge University. Hawking, S.W. and G.F.R. Ellis. 1968. The cosmic black-body radiation and the existence of singularities in our universe. Astrophysical Journal 152: 25-36. Hawking, S.W. and R. Penrose. 1970. The singularities of gravitational collapse and cosmology. Proceedings of the Royal Society of London. Series A: 529-548. 1998. Particle decays reveal arrow of time. Science 282: 602-603. No, we speak of God's secret wisdom, a wisdom that has been hidden and that God destined for our glory before time began. (1 Corinthians 2:7) This grace was given us in Christ Jesus before the beginning of time (2 Timothy 1:9) The hope of eternal life, which God... promised before the beginning of time (Titus 1:2) To the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion and authority, before all time and now and forever. Amen. (Jude 1:25) But do not let this one fact escape your notice, beloved, that with the Lord one day is as a thousand years, and a thousand years as one day. (2 Peter 3:8) For a thousand years in Thy sight are like yesterday when it passes by, or as a watch in the night. (Psalms 90:4) Hawking, S.W. and Penrose, R. 1996. The Nature of Space and Time, p. 20.

Objections to the Big Bang “philosophically unacceptable” (atheist John Maddox, “Down with the Big Bang”in Nature) “smacks of divine intervention” (Stephen Hawking, A Brief History of Time ). The editor of the prestigious weekly science periodical, Nature, John Maddox, wrote an editorial entitled, "Down with the Big Bang," where he hoped for the downfall of the Big Bang model, because in it, he found it to be "philosophically unacceptable"1 and believes, theological creationists find "ample justification" for their creationist creed in it. Physicist Hubert Reeves remarked that the Big Bang "involves a certain metaphysical aspect which may be either appealing or revolting".2 Christopher Isham observes: "Perhaps the best argument in favor of the thesis that the Big Bang supports theism is the obvious unease with which it is greeted by some atheist physicists. At times this has led to scientific ideas, such as continuous creation [steady state] or an oscillating universe, being advanced with a tenacity which so exceeds their intrinsic worth that one can only suspect the operation of psychological forces lying very much deeper than the usual academic desire of a theorist to support his/her theory."3 Stephan Hawking, in his discussion of the beginning of time says that it, "smacks of divine intervention."4 It is obvious from these statements that the Big Bang does have theological implications. As alternative theories continue to fail scientific tests, even more extreme and complicated theories are proposed. Many of these new theories (such as the multiverse theory) are constructed so that they are not scientifically testable. This appeal to metaphysics (disguised religion) has even been recognized by other scientists.5 References "Apart from being philosophically unacceptable, the Big-Bang is an over-simple view of how the Universe began, and it is unlikely to survive the decade ahead." Maddox, J. 1989. Down with the Big Bang. Nature 340: 425. Reeves, H., Andouze, J., Fowler, W. A., and Schramm, D. N. 1973. On the Origin of the Light Elements. Astrophysical Journal 179: 912. Isham, C. 1988. "Creation of the Universe as a Quantum Process," in Physics, Philosophy, and Theology, A Common Quest for Understanding, eds. R. J. Russell, W. R. Stoeger, and G. V. Coyne, Vatican City State: Vatican Observatory, p. 378. Hawking, S. 1988. A Brief History of Time, New York, Bantam Books, p. 46. In a recent discussion of the origin of life, the The Origin-of-Life Foundation, Inc.® made the following admission: "Appeals to multiple or "parallel" cosmoses or to an infinite number of cosmic "Big Bang/Crunch" oscillations as essential elements of proposed mechanisms are not acceptable in submissions due to a lack of empirical correlation and testability. Such beliefs are without hard physical evidence and must therefore be considered unfalsifiable, currently outside the methodology of scientific investigation to confirm or disprove, and therefore more mathematically theoretical and metaphysical than scientific in nature. Recent cosmological evidence also suggests insufficient mass for gravity to reverse continuing cosmic expansion. The best cosmological evidence thus far suggests the cosmos is finite rather than infinite in age." (The Origin-of-Life Prize® from the The Origin-of-Life Foundation, Inc.®.)

Evidence for God’s Existence from Design Divine Watchmaker (William Paley) Refuted by: David Hume Charles Darwin Recently by: Stephen Jay Gould Richard Dawkins William Paley argued that God's existence could be inferred from the designs seen in biology. He said that if one were walking and came upon a watch, one would not assume that it was the product of nature. It must have been designed by an intelligent being. Likewise, Paley said that the designs seen in biology must be the result of an intelligent Designer.1 At the time, Paley's arguments were refuted by David Hume and Charles Darwin. The degree of knowledge in biology at the time made arguments on each side difficult to asses. Paley's argument is one of analogy. Critics have stated that it is questionable whether the complex designs of nature are a good analogy with a watchmaker. A watch is made from parts that are specifically designed and put together. The process by which animals are made seemed to be somewhat different. Little was known about embryology and nothing was known about genetic code and algorithms. Obviously, in the case of organisms, the design is passed on from parent to child. The question then becomes, "Was the mechanism designed or did it happen by accumulation of natural processes?“ Recently, biologists Stephen Jay Gould and Richard Dawkins (The Blind Watchmaker) have attempted to refute Paley's argument on the basis of "bad" design. Several of these arguments have been refuted. References: Paley, W. 1831. Natural Theology: or Evidences of the Existence and Attributes of the Deity, Collected from the Appearances of Nature.

New Watchmaker Argument Based upon measurable parameters Probabilities calculable from the observable universe Tolerance for change (fine tuning) calculable from physical laws William Paley's arguments from the complexity of living organisms is not often used as an argument for God's existence, due to potential naturalistic explanations. The apparent design of biological organisms is not fully testable at this time, since many of the genetic tests of Darwinian theory can not be completed due to incomplete databases of genetics. However, the emerging field of Intelligent Design Theory may well revive this argument in the near future. The new watchmaker argument is based upon defined, measurable parameters obtained from the observable universe. By studying the universe, scientists can determine how unique the Earth and Solar System is compared to other planetary systems in our galaxy. Probabilities can be assigned on the basis of our knowledge of the universe to determine if evidence of intelligent design exists. As our knowledge of the physics of the universe increases, scientists can ask "what if" questions, change the fundamental constants of the universe, and determine what effect these changes would have on our universe. The results of these changes are nothing less than astounding. Go to the next slide to see how tightly constrained the laws of physics must be to get a universe capable of supporting life...

A “Just Right” Universe Parameter Maximum Deviation Ground state of He, Be, C, O ± 4% Mass of neutron ± 0.1% Electron:Proton Ratio ± 1:1037 Electromagnetic force:gravity ± 1:1040 Expansion rate of universe ± 1:1055 Cosmological Constant ± 1:10120 The table above shows the maximum deviation allowable in the fundamental constants in order to get a universe capable of supporting life. In some instances, changing the constants more than the amount indicated results in a universe that doesn't even contain matter. In many other instances, only hydrogen or light elements would exist (making life impossible). Changing the last two parameters changes the longevity of the universe. Many of these perturbations would result in the universe that would have ended billions of years ago. That the universe seems to be designed specifically for human life has been called the anthropic principle. Depending upon their philosophical outlook, scientists hold to either the "weak" or "strong" anthropic principle. The weak anthropic principle states that the apparent design of the universe is an illusion, and that there must be some undiscovered underlying principle that explains why the universe seems to be designed. The strong anthropic principle states that the underlying reason that the universe appears to be designed is because it has been designed by the ultimate Intelligent Designer - God. How do we determine which version of the anthropic principle is correct? The standard way to test any theory is to gather data and see which version fits the data better. So far, the strong anthropic principle fits the data better. For example, the last physical constant mentioned in the table above was not discovered until a few years ago, and it is, by far, the most constrained constant discovered to date. Initial observations suggested that the value is the closest value to zero (within 1 part in 10120) known in the universe. Subsequent observations suggest that it may be closer to 1 part in 10240. The degree of fine tuning has led some scientists to make the statement: "This type of universe, however, seems to require a degree of fine tuning of the initial conditions that is in apparent conflict with 'common wisdom'."1 References Zehavi, I, and A. Dekel. 1999. Evidence for a positive cosmological constant from flows of galaxies and distant supernovae Nature 401: 252-254.

A “Just Right” Galaxy Parameter Probability Galaxy size 0.1 Galaxy type Galaxy location Supernovae eruptions 0.01 White dwarf binaries The table above shows the probabilities that the galaxy will match what is required for life to exist. Galaxy size is important, since galaxies that are too large tend to have a number of violent events that disturb solar orbits. Small galaxies have insufficient material to maintain star formation for long enough time periods to form rocky planets.1 The type of galaxy is also important, since elliptical and irregular galaxies (comprising most galaxies at this point) support new star formation poorly, if at all. Spiral galaxies are optimal for the formation of rocky planets.2 The galaxy location is important, since most galaxies are part of much larger galaxy clusters. We are in a very small galaxy cluster (known as the "local group"), in which we are the "big guys" among the members of the cluster. The closest galaxy to ours is Andromeda, which is 2 million light years distant. This may seem like a large distance (and it is relative to other galaxy clusters), but even so, we are scheduled for collision with Andromeda in 3 billion years. In fact, the Andromeda galaxy is closing on our galaxy at 500,000 kilometers per hour. This pace will accelerate until the two galaxies collide in 3 billion years. According to astrophysicist Chris Mihos of Case Western Reserve University in Cleveland, Ohio, "It will be a major car wreck, and we're the Yugo in this one."3 Other galaxy clusters are much more dense then ours, resulting in frequent galactic collisions. When galaxies collide, bad things happen to stellar and planetary orbits. The long term stability of our Solar System and galaxy would not be possible in most other galaxy clusters. All stars are formed in nebulae and our Sun is no exception. In order to gain enough heavy elements to form planets, our system must have formed close to a recent supernova. Heavy elements were not formed during the Big Bang. They are only formed inside the furnaces of stars and distributed through supernova events. Carl Sagan used to have a famous saying in his Cosmos series on PBS,  "We are star stuff." He had a unique way of saying it that I can still visualize today. His point was (also explained in the series) that everything that we are made of was distributed during the explosion of a large nearby star. If the solar nebula was too far from the supernova event, insufficient heavy elements would have been present for life chemistry. If the supernova event occurred too early, then the heavy elements would have been dispersed before the Solar System would have formed. If the supernova event occurred too late, then the nebula would not contain enough heavy elements for life chemistry. In addition, it is possible that the supernova event itself could destroy all life. White dwarf binaries are necessary to form the element fluorine, which is required by living organisms. Since this element is only formed in these kinds of stars, they must have been present near where the Solar System formed.4  References In a recent survey of globular cluster 47 Tucanae, scientists found zero extrasolar planets out of 37,000 stars searched (Astronomers Ponder Lack of Planets in Globular Cluster [http://oposite.stsci.edu/pubinfo/PR/2000/33/index.html] from the Space Telescope Science Institute). Cowen, R. 1992. Were spiral galaxies once more common? Science News 142: 390. Dressler, et al. 1994. New images of the distant rich cluster, CL 0939+4713 with WFPC2. Astrophysical Journal Letters 435: L23-L26. Irion, R. 2000. A Crushing End for Our Galaxy. Science 287: 62-64. Davies, R.E. and R. H. Koch. 1991. All the observed universe has contributed to life. Philosophical Transactions of the Royal Society of London, series B 334: 391-403.