{"id":747,"date":"2010-01-31T01:00:10","date_gmt":"2010-01-31T06:00:10","guid":{"rendered":"http:\/\/www.dontow.com\/?p=747"},"modified":"2010-02-13T09:24:56","modified_gmt":"2010-02-13T14:24:56","slug":"review-of-martin-rees-book-just-six-numbers-the-deep-forces-that-shape-the-universe","status":"publish","type":"post","link":"http:\/\/www.dontow.com\/2010\/01\/review-of-martin-rees-book-just-six-numbers-the-deep-forces-that-shape-the-universe\/","title":{"rendered":"Review of Martin Rees’ Book “Just Six Numbers: The Deep Forces That Shape the Universe”"},"content":{"rendered":"
Synopsis<\/span>:<\/strong> How could a single “genesis event” create billions of galaxies, black holes, stars and planets? The nature of our universe is remarkably sensitive to just six numbers, constant values that describe and define everything from the way atoms are held together to the amount of matter in our universe.\u00a0 If any of these values was “untuned,” there would be no stars and life as we know it in our current universe.\u00a0 This realization offers a radically new perspective on our place in the universe, and on the deep forces that shape, quite simply, everything. <\/strong><\/p>\n <\/strong><\/p>\n Book Review<\/strong><\/span> <\/strong> We will begin this book review with an introduction providing some background information on several key astrophysical and cosmological concepts that are used by the author in this book.\u00a0 The review is presented in layman\u2019s terms.\u00a0 However, since the reader may not be familiar with some of the complex concepts discussed in the book, the reader may not be able to follow everything discussed in this review.\u00a0 That is perfectly okay, because it is not that important that the reader must understand everything that is discussed in this review.\u00a0 What is important is that the reader understands the gist of the conclusions drawn from this book, which I will try to explain clearly and plainly.<\/p>\n I want to mention that I am not an expert on astrophysics or cosmology. If someone with more expertise finds errors or unclear explanations, I would greatly appreciate receiving some comments.<\/p>\n I.\u00a0\u00a0 Some basic background concepts<\/span><\/strong><\/p>\n \n \n \n \n \n \n \n Therefore, we should be able to observe this radiation, called the Cosmic Microwave [3] Background Radiation. Various theoretical calculations before its discovery estimated that the temperature corresponding to this radiation ranged from a few degrees Kelvin to a few dozen degrees Kelvin (the lowest temperature possible is zero degree Kelvin).<\/p>\n \n This radiation was discovered in 1965 by the Bell Labs scientists Arno Penzias and Robert Wilson working at the Crawford Hill Lab in Holmdel, NJ. They found that the cosmic microwave background radiation corresponds to a temperature of 2.7 degree Kelvin, i.e., less than 3 degrees above absolute zero. Their discovery was sort of an accident, because they were not specifically looking for this remnant radiation from the Big Bang. At first they didn\u2019t realize what they had discovered; at one point they even thought that the radiation was statics from the droppings of two pigeons who nested on their 20-foot radio antenna. But the radiation remained even after they had cleaned their antenna of the droppings and got rid of the pigeons. They learned of the significance of their discovery only after another physicist (Bernard Burke of MIT) referred them to several physicists at Princeton University (Robert Dicke, Jim Peebles, P. G. Roll, and David Wilkinson) who were then also doing an experiment to detect this radiation as the remnant radiation from the Big Bang.<\/p>\n \n The discovery of this Cosmic Microwave Background Radiation provided strong support to the Big Bang Expanding Universe theory of the origin and evolution of the universe. Penzias and Wilson were awarded the Physics Nobel Prize in 1978.<\/li>\n \n II.\u00a0\u00a0 Just Six Numbers<\/span><\/strong><\/p>\n We now discuss the main contents of Martin Rees\u2019 book Just Six Numbers: The Deep Forces That Shape the Universe<\/span><\/strong>. The main thesis of this book is that the evolution (both physical and biological) of our universe is remarkably sensitive to the values of six numbers. If any of their values was \u2018untuned,\u201d there would be no stars and life as we know it in our current universe.<\/p>\n We will now discuss these six numbers, and the next section will discuss several interpretations based on the conclusions of this section.<\/p>\n \n Matter is made up of atoms and molecules which in general are neutral because they are made up of equal numbers of protons (positively charge) and electrons (negatively charge), and some neutrons (neutrally charge). Therefore, even though the electrical force is so much larger than the gravitational force, the aggregate force governing the macroscopic structure of matter is the gravitational force, and not the electrical force. This self gravitational force will pull the matter inward into smaller and smaller spheres. When they get smaller and smaller, its temperature gets hotter and hotter, because temperature is due to the collision of atoms with each other within the matter, and there will be more collisions if the spheres are smaller. When the interior temperature gets hot enough, nuclear fusion reactions can occur as in our sun. These nuclear fusion reactions release energy and therefore outward pressure which can counteract the inward pressure from gravitation. That keeps the matter from continuous collapse and allows stars like our sun to shine from the released energy.<\/p>\n \n However, If the gravitational force were larger, e.g., a million times larger, i.e., if N=1030<\/sup>, then the matter spheres would collapse much faster into smaller spheres when they reach the temperature which can generate the nuclear fusion reactions and stabilize the matter. Under these circumstances, galaxies would form much more quickly and would be much smaller in size (due to less time for the universe to expand). Instead of the stars being widely dispersed, they would be so densely packed that close encounters would be frequent, thus precluding stable planetary systems, which are a prerequisite for life. Furthermore, when gravity is so strong (relatively speaking), no animals could get much larger than very tiny insects, because gravity would cause any larger living organism to collapse.<\/p>\n \n We can conclude that instead of having 36 zeros after 1 in the value of N, if there were only 30 zeros after 1, then the universe would be very much different from the current universe, and life as we know it would not be able to exist. Note: On the other hand, if the gravitational force were even weaker, i.e., if N is even larger (having more than 36 zeros after 1), then it would take longer to form galactic structure, and galactic structures would be less densely populated, and larger and perhaps more complex life organisms, different from current life organisms, could exist.<\/li>\n \n \n The force governing nuclear fusion is called the strong force, and is one of four forces known in nature, with the other three being the electromagnetic force, the weak force (a repulsive short-range force governing radioactive decay), and the gravitational force. The strong force is the strongest of the four forces and is about 100 times stronger than the electromagnetic force. However, its force is very short range, i.e., the force falls off very rapidly with distance. The number \u20ac is a measure of the strength of the strong force; a larger \u20ac means a stronger strong force.<\/p>\n \n As explained below, if \u20ac were smaller than 0.006 or larger than 0.008, then the universe and life as we know it would not exist.<\/p>\n \n When two protons and two neutrons react to form a helium nucleus, the reaction does not go in one step. Instead, it occurs in two steps. The first step is that one proton and one neutron would react to form a deuterium nucleus, i.e., an isotope of hydrogen consisting of one proton and one neutron. Similarly, the other proton and the other neutron would react to form another deuterium nucleus. Then the two deuterium nuclei would react to form a helium nucleus consisting of two protons and two neutrons.<\/p>\n \n If \u20ac = 0.006 or smaller, the strong force is not strong enough to fuse a proton and a neutron into a stable deuterium. Without stable deuterium, helium cannot be formed. Then our universe would be composed of hydrogen only, and no heavier elements could be formed to make rocky planets and carbon-based living things. This means no chemistry and therefore no life organisms as we know it can be formed.<\/p>\n \n In our actual universe with \u20ac = 0.007, the strong force is not strong enough for two protons to overcome their electrical repulsion to fuse together. It requires one or more neutrons which provide additional strong force but no additional electrical repulsion to fuse together into a heavier element.<\/p>\n \n If \u20ac = 0.008 or greater, then the strong force is strong enough to overcome the electrical repulsion of two protons, and two protons can fuse together. This would have happened early in the life of the universe, so that all the hydrogen (i.e., protons) would have been used up very early on, and there is no hydrogen remaining to continue to provide the fuel to produce light in ordinary stars as in our sun. Furthermore, water, H2O, could never have existed, and therefore no life as we know it.<\/p>\n \n Therefore, any universe with complex chemistry and life would require \u20ac to be in the range of 0.006 \u2013 0.008.<\/li>\n \n \n When a rocket, is launched upward from the surface of a galactic object, e.g., the earth, whether it will escape from that galactic object, or whether it will be pulled back by gravity to the surface of that galactic object, depends on the velocity of the launch and the strength of gravity for that galactic object. The critical velocity that is required to cause that rocket to escape from that galactic object is known as the \u201cescape velocity\u201d. In the case of the earth with its known gravitational field, the \u201cescape velocity\u201d is 11.2 kilometers per second, or about 25,000 miles per hour.<\/p>\n \n In an expanding universe, galactic matters are moving apart from each other. Will this expansion continue forever, or will these motions eventually reverse, so that the universe will eventually re-collapse to a \u201cBig Crunch\u201d? Since we know the expansion speed of our expanding universe, the answer to the above question depends on whether there is enough matter in the universe so that gravity from all these matters is strong enough to slow down the expansion and then cause the collapse to a \u201cBig Crunch\u201d. The matter density in the universe that is necessary to cause this reversal is called the galactic \u201ccritical density\u201d. Knowing the expansion speed, we can calculate and determine this critical density to be approximately five atoms [4] per cubic meter.<\/p>\n \n If we calculate the masses of all known matter in our universe, we can determine the average mass density of all known matter in our universe, which turns out to be about 0.2 atoms per cubic meter, or about 25 times smaller than the critical density.\u03a9 = ratio of actual density in galactic matter to the galactic critical density = 0.2\/5 = 0.04. We see that the known matter in the universe is only about 4% of the critical mass (i.e., about 25 times smaller) than the amount of matter needed to keep the universe from expanding forever.<\/p>\n \n Is there any other indication for the existence of dark matter? By observing the motions of various stars and galaxies, it seems that their motions cannot be completely explained by the gravitational pulls of other stars and galaxies that are known to exist today. It seems that there are other matters in the universe, called dark matter (because we cannot see\/detect their electromagnetic radiation), that are nevertheless affecting the motions of stars and galaxies. The assumption of the existence of dark matter is actually not so ad hoc or unreasonable. Such inference is actually the same line of reasoning used to explain the unexpected motion of some stars by assuming that these stars must be orbiting around a \u201cblack hole\u201d that does not emit any radiation and therefore cannot be directly seen or detected. It is also similar to the reasoning used in the 19th century to infer the existence of the planet Neptune in order to explain the observed motion of the planet Uranus.<\/p>\n \n Even with generous account of the possibility of such dark matter, based on current information the value of \u03a9 can at most be raised to approximately 0.3, not quite the critical value of 1, but not extremely far from it. At first sight, such large abundance of dark matter may seem strange, but why most of the matter in the universe must emit radiation so that they can be seen or directly detectable? There are various theories for what constitutes dark matter, but it remains as one of the most important unsolved questions in astrophysics and cosmology.<\/p>\n \n What is the significance of the value of \u03a9 with respect to the existence of our universe and life as we know it? If \u03a9 were significantly smaller than 1, then not only that the universe would expand forever, the gravitational pull would be so small that expansion would occur so rapidly that galactic matters would be so far apart and galaxies would not be able to be formed, with a corollary that planets and life as we know it would not be able to exist. On the other hand, if \u03a9 were significantly larger than 1, then the universe would quickly collapse before there was time for any interesting evolution of galaxies, planets, and life as we know it.<\/li>\n \n \n However, in 1922, the Russian mathematician Alexander Friedman showed that Einstein\u2019s fix is unstable, like balancing a pencil on its point, and therefore really doesn\u2019t lead to a static universe.<\/p>\n \n When in 1929 Hubble discovered Hubble\u2019s Law that the universe is expanding, Einstein regretted that he ever introduced the cosmological constant term and called that action the \u201cbiggest blunder\u201d of his life. [Note: Since without the lamda term, Einstein\u2019s equation can also lead to an expanding universe, so why do we need to introduce the lamda term in an ad hoc way. That was why Einstein thought that doing that was a big blunder.]<\/p>\n \n The common belief in the 1970s and 1980s was that the expansion of the universe should slow down with time due to the continued pull of gravitation from all the matter in the universe. In the decades of the 1990s and 2000s, a series of observations of very bright stars called supernova was carried out to try to show that. [One of the leaders of this research was a physicist from the Lawrence Berkeley Laboratory of the University of California at Berkeley.] It was a great surprise that these observations found that not only that the universe is expanding, but its expansion is accelerating, i.e., the expansion speed is increasing instead of decreasing with time. The magazine Science rated this as the number-one scientific discovery of 1998 in any field of research. This led to a revival of the need for the cosmological constant term, with this term representing perhaps a new form of matter or energy that is gravitationally repulsive, unlike the dark matter of the previous section. Adding such a term could lead to an accelerating expanding universe. Such explanation is very tentative and much more work remains to elucidate this mystery!<\/p>\n \n From other astronomical observations, the current estimated value for \u03bb is around 0.7, which is also consistent with the supernova observations of an accelerating expanding universe. A much larger value for \u03bb would mean that the universe would have expanded rapidly even in its early stages. Therefore, there would not be sufficient time for stars, galaxies, planets to form, and therefore would have precluded life as we know it. On the other hand, a much smaller value for \u03bb would not lead to catastrophic consequences in terms of the formation of stars, galaxies, planets, and life; it only means that the expansion of the universe will slow down.<\/li>\n \n \n How tightly these structures are bound together is tied to the physical and biological evolution of the universe. If they were very tightly bound, i.e., it would take a lot of energy to break them up and disperse them (or Q as defined two paragraphs later is very large), then clustering would occur earlier and more likely to stay together. This would mean that it would take less time for the universe to evolve to the current structure. Stars and galaxies would be more closely packed, and they would more likely collide with each other, thus decreasing the chance to retain stable planetary systems and therefore less likely for life as we know it to exist.<\/p>\n \n On the other hand, if they were very loosely bound, i.e., it would not take a lot of energy to break them up and disperse them (or Q as defined in the next paragraph is very small), then clustering would be less likely to occur or to stay together. This would mean that it would take more time for the universe to evolve to the current structure. There would not be sufficient time for stars, galaxies, and planets to form, and then for life as we know it to develop and evolve.<\/p>\n \n The measure of the strength of these bonds among galactic matter to form clusters (stars, galaxies, and clusters of galaxies) is called Q = the amount of energy, as a proportion to their rest mass energy, needed to break up and disperse the clusters. For our universe, Q is estimated to be 10-5<\/sup>. As explained in the two previous paragraphs, if Q were much larger or smaller than 10-5<\/sup>, then life as we know it would not exist.<\/li>\n \n \n We are used to thinking that we live in a world of four dimensions, with three spatial directions and one time dimension with an arrow. But why are there only three spatial dimensions?<\/p>\n \n One consequence of a three-dimensional spatial world is that forces like gravity and electricity obey an inverse-square law, such that the force from a mass or charge is four times weaker if you go twice as far away. This can be illustrated by a graphical method (first pointed out by Michael Faraday, a pioneer in the study of electricity). If you envisage lines of (electrical or gravitational) force emanating from every charge or mass and the strength of the force is proportional to the concentration of the force lines. At a distance r, the force lines are spread over an area of (\u03c0 x r2<\/sup>). At a distance 2r, the force lines are spread over an area of [\u03c0 x (2r)2<\/sup>] = 4\u03c0r2<\/sup>. Since in both cases, the number of force lines is identical, the force at a distance of 2r is thus four times weaker than the force at a distance of r. However, in a four-dimensional spatial world, the force lines would now be spread over the volume of a sphere (instead of the area of a circle) which is proportional to r3<\/sup>, thus the force at 2r would be eight times weaker than at r, and not consistent with the physical electrical and gravitational forces we observe in nature.<\/p>\n \n The author Rees provides another reason for a three-dimensional world: \u201cAnother reason for a three-dimensional spatial world is the stability of orbits in our solar system, in the sense that a slight change in a planet\u2019s speed would only nudge its orbit slightly. But this stability would be lost if gravity followed an inverse-cube (or steeper) law rather than one based on inverse squares. An orbiting planet that was slowed down \u2013 even slightly \u2013 would then plunge ever faster into the sun, rather than merely shift into a slightly smaller orbit, because an inverse-cube force strengthens so steeply towards the center; conversely, an orbiting planet that was slightly speeded up would quickly spiral outwards into darkness.<\/p>\n \n \u201dAre there arguments against a world with fewer than three spatial dimensions? In a two-dimensional spatial world, it is impossible to have a complicated network without the wires crossing. This would make it essentially impossible to create communication networks or physiological circulatory networks. Similarly, you cannot have a channel through an organ (e.g., a digestive tract) without dividing the organ into two. The restrictions are even more severe in a one-dimensional spatial world.<\/p>\n \n Can we live in a universe where the fundamental physical laws at the time of the Big Bang have more dimensions than four, and then these physical laws \u201csimplify\u201d to our current four-dimensional world shortly after the Big Bang? To address this question, we will first discuss the grand unification of the forces of nature. Almost 150 years ago, Maxwell was able to provide a unified description of the electric force and the magnetic force into a single set of equations that describe both forces, now called the electromagnetic force. The introduction of quantum mechanics and especially the advances in the last 60 years seem to have led first to a quantum mechanical unified field theory of the electromagnetic force, called Quantum Electrodynamics. Then it led to a quantum mechanical unified field theory of the electromagnetic force and the weak force, called the Standard Electroweak Theory. Similar type of field theory may also have the potential to provide a quantum mechanical field theory of the strong force, called Quantum Chromodynamics, thus leading to the hope that such field theories may be able to provide a unified description of the electromagnetic force, the weak force, the strong force, and perhaps also the gravitational force.<\/p>\n \n Einstein\u2019s theory of relativity is a classical theory of gravitation, in the sense that it did not include quantum mechanics. To date, we still don\u2019t have a satisfactory quantum gravitational theory. Furthermore, we don\u2019t have a grand unified theory that can provide a unified description of all four forces of nature: the electromagnetic force, the weak force, the strong force, and the gravitational force (and there could be a new force associated with a new type of matter\/energy that is gravitationally repulsive that was discussed earlier with the cosmological constant \u03bb). Because the strength of the strong force and the weak force fall off rapidly with distance and because of the electrical neutrality of atoms and molecules, the gravitational force, in spite of its being so weak in comparison with the other forces, becomes the dominant force in the celestial realm of planets, stars, and galaxies where very large distances are involved. However, at the time of the Big Bang when we had very large masses concentrated in very small spaces and where we might have exotic objects like black holes where our current laws of physics might not be applicable, we really need a quantum gravitational theory and a grand unified theory of all the forces.<\/p>\n \n Many (but definitely not all) physicists are pinning their hopes on the superstring theories, sometimes called \u201cthe theory of everything.\u201d In superstring theories, the fundamental entities in our universe are not points but tiny string loops, and that the various subnuclear particles are different modes of vibration \u2013 different harmonics \u2013 of these strings. The strings are very small, about 10-19<\/sup> times smaller than the proton. Furthermore, these strings are vibrating not in our (3+1)-dimensional space, but in a space of 10 (9+1) or 11 (10+1)-dimensions, depending on the specific superstring theory. At the time of the Big Bang, the four forces of nature were unified and actually more or less equal in strength. Very shortly after the Big Bang, the four forces transformed into their current forces with tremendous differences in their strengths. Furthermore, during this short period, the six or seven extra spatial dimensions collapsed into extremely small dimensions, which become essentially invisible to us. This is analogous to a long two-dimensional sheet when rolled up into a very tight cylinder may look like a one-dimensional line from far distances. The superstring theories not only claim to provide a unified description of the strong, electromagnetic, and weak forces, it also yields quantum gravity almost as a bonus, i.e., quantum gravity is an essential ingredient of the theory, rather than an extra complication.<\/p>\n \n Superstring theories are currently one of the most actively research areas in both elementary particle\/high energy physics and astrophysics\/cosmology. Although many physicists believe that superstring theories will lead us to the ultimate theory, many other physicists are very skeptical of it, and believe that it is more of a mathematical theory, instead of a physics theory. Many superstring advocates call superstring theories or the eventual superstring theory \u201cThe Theory of Everything.\u201d Personally, I think that is more for posturing to help get research grants and to make their important research to sound even more important. I think that if we look back into history, we will find that major discoveries only showed us that there are more unknowns to be discovered or solved.<\/p>\n \n One reason for the merging of these two areas of research, high energy physics and astrophysics, is because the extremely high energies that are involved in these grand unified theories are many, many orders of magnitude larger than the energies that can be reached by the world\u2019s largest accelerators that can be built in the foreseeable future. The only way to have such high energies is to look at the initial period around the Big Bang.<\/p>\n \n Therefore, there also seems to be fine tuning of the number D. If D is not equal to 4 shortly after the Big Bang, our physical world and life as we know it would not exist. If D is not equal to 10 or 11 during the short period around the Big Bang, then we may not have a grand unified theory (assuming that superstring theories will turn out to be correct).<\/li>\n<\/ol>\n III.\u00a0\u00a0 Interpretation<\/strong><\/p>\n The above six numbers provide a recipe for a universe. They govern the outcome of the recipe, i.e., the formation and evolution of a universe, including the existence and type of life in that universe. It seems that the outcome is remarkably sensitive to the values of these six numbers. It seems that these six numbers were tuned so that our current universe and life can exist. If any of these six numbers was untuned, there would be no stars or life as we know it in our current universe.<\/p>\n There are at least three interpretations of the fine tuning of these six numbers.<\/p>\n Interpretation A:<\/strong> These numbers just so happen to take these values. They could have taken other values, then the universe and life as we know it will not exist. But another type of universe, perhaps without life, could exist.<\/p>\n Interpretation B:<\/strong> There is a Creator who purposely designed the universe in this way so that we could exist, i.e., there is intelligent design. It is important to point out that this type of intelligent design is not the same as those intelligent design advocates who claim that Darwin\u2019s evolution theory cannot be correct.<\/p>\n Interpretation C:<\/strong> There could actually be many universes, with each having a different set of values for these numbers. This is the viewpoint of the \u201cmultiverse\u201d advocates. Depending on the particular multiverse theory, the different universes may or may not interact with each other, and it is not clear how these different universes were created. The multiverse (or many-world) concept actually has existed for more than 50 years. It was first formulated in 1956 as the Many-World Interpretation of Quantum Mechanics in Hugh Everett\u2019s Ph.D. thesis at Princeton (under Professor John A. Wheeler). In quantum mechanics, we cannot predict the exact outcome of any experimental observation; but we can predict only the probability distribution of multiple outcomes. For example, in the famous double slit experiment when electrons (or photons) pass through two slits, the only way to explain the interference pattern obtained is that the waves associated with the electrons went through both slits, and not just one slit. However, when you try to experimentally detect the electrons, you will always find that the electrons end up in one spot and not two or multiple spots, or saying it in another way, you don\u2019t find part of an electron. So it seems that when you make an experimental observation to determine the location of the electron, you end up in one particular universe (out of many possible universes), i.e., you are put in the universe in which the electron ended up on the spot on the right or the spot on the left. [5] Both universes exist, but the different universes do not interact with each other. I should add that even if this could be a possible interpretation of quantum mechanics, most physicists do not accept this interpretation, including Professor Wheeler later in his life.<\/p>\n Martin Rees, the author of this book, believes in the multiverse interpretation of the fine tuning of these six numbers. Personally, I do not agree with his interpretation. I favor Interpretation B.<\/p>\n Final Comments:<\/strong> A lot of progress has been made in high energy physics, astrophysics, and cosmology during the last 50 years. Many people claim that we are on the verge of discovering a theory of everything. Personally even though I agree that we have made tremendous progress, we are far from discovering a theory of everything. Just on the topic of this article, there are still too many fundamental issues that we either do not understand or do not have an adequate explanation, e.g., what caused the Big Bang, what was before the Big Bang, what caused the universe to expand, what caused the universe to inflate, what is the dark matter, what is the potentially new unknown repulsive force that seems to be required to explain the accelerating expansion of the universe, what are the extra dimensions, why there is not a symmetry between the amount of matter and anti-matter, etc.<\/p>\n [1] The label \u201ctypical\u201d is to indicate galaxies that do not have any large peculiar motion of their own, but are simply carried along with the general cosmic flow of galaxies. Synopsis: How could a single “genesis event” create billions of galaxies, black holes, stars and planets? The nature of our universe is remarkably sensitive to just six numbers, constant values that describe and define everything from the way atoms are held together to the amount of matter in our universe.\u00a0 If any of these values […]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[6],"tags":[],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/posts\/747"}],"collection":[{"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/comments?post=747"}],"version-history":[{"count":69,"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/posts\/747\/revisions"}],"predecessor-version":[{"id":806,"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/posts\/747\/revisions\/806"}],"wp:attachment":[{"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/media?parent=747"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/categories?post=747"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.dontow.com\/wp-json\/wp\/v2\/tags?post=747"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n
\nAbout the book author<\/span>:<\/strong> Martin Rees is a famous astrophysicist and cosmologist from England.\u00a0 He is currently Professor of Cosmology and Astrophysics at Cambridge University; he is also the President of the Royal Society in England. The book is published by Basic Books in 2000.<\/p>\n
\n<\/strong>
\n<\/p>\n\n
\n
\n
\n[2] For more discussion of the Cosmological Principle, see, e.g., Figure 1 \u201cHomogeneity and the Hubble Law\u201d in the book The First Three Minutes<\/span><\/strong> by Nobel Prize physicist Steven Weinberg, Basic Books, 1988.
\n[3] It is called microwave radiation because the wavelength of this radiation is in the microwave range.
\n[4] The atoms are mostly hydrogen, with a smaller amount of helium and much smaller amounts of other heavier elements.
\n[5] This is known as the collapsing of the probabilistic wave function into a definite state.<\/p>\n","protected":false},"excerpt":{"rendered":"