# Was the Universe expanding before the beginning of inflation?

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My point of view is that first there was the Big Bang singularity, and then the period of inflation which resulted in the observable Universe becoming many times bigger. But was the Universe expanding between the Big Bang singularity and the beginning of inflation?

Inflation has started with the bigbang. In fact for anything to take place you need an expansion right away. If you had a static universe just after the bigbang, it couldn't have formed subatomic particles or atoms, without any increase in size. Inflation was always happening and will always happen. The process is behaving (in terms of duration) like radioactive material, that means that inflation slowy decays wth a halflife of about 10^-32 seconds. I hope this answer suffices.

This is likely unanswerable. Inflation was in part a resolution to a fine tuning problem: without it, it seemed we needed the early universe in a very specific and precisely balanced state to get to where it is today, and there was no solid scientific way to explain why things were so perfectly arranged (other than to simply assert that they were).

With inflation, the state of the universe before the inflationary epoch is fairly irrelevant. Mostly all it needs is that the region that inflates into what we will know as the observable universe had enough time to achieve thermal equilibrium (which we need to explain why the universe looks pretty much the same in all directions, exactly as if things well outside of light speed communication had nonetheless achieved thermal equilibrium at some point). Curvature and such get "smeared out" by the inflation to give us the mostly flat and homogeneous universe we see today.

On a pedantic note, some researchers consider inflation and the big bang to be the same thing. At least in the sense that talking about "before inflation" is scientifically meaningless, so if the Big Bang is the (scientific) beginning then we might as well take it to be inflation.

## The beginning of everything: New paradigm shift for the infant universe

A new paradigm for understanding the earliest eras in the history of the universe has been developed by scientists at Penn State University. Using techniques from an area of modern physics called loop quantum cosmology, developed at Penn State, the scientists now have extended analyses that include quantum physics farther back in time than ever before -- all the way to the beginning. The new paradigm of loop quantum origins shows, for the first time, that the large-scale structures we now see in the universe evolved from fundamental fluctuations in the essential quantum nature of "space-time," which existed even at the very beginning of the universe over 14 billion years ago. The achievement also provides new opportunities for testing competing theories of modern cosmology against breakthrough observations expected from next-generation telescopes.

The research will be published on 11 December 2012 as an "Editor's Suggestion" paper in the scientific journal Physical Review Letters.

"We humans always have yearned to understand more about the origin and evolution of our universe," said Abhay Ashtekar, the senior author of the paper. "So it is an exciting time in our group right now, as we begin using our new paradigm to understand, in more detail, the dynamics that matter and geometry experienced during the earliest eras of the universe, including at the very beginning." Ashtekar is the Holder of the Eberly Family Chair in Physics at Penn State and the director of the university's Institute for Gravitation and the Cosmos. Coauthors of the paper, along with Ashtekar, are postdoctoral fellows Ivan Agullo and William Nelson.

The new paradigm provides a conceptual and mathematical framework for describing the exotic "quantum-mechanical geometry of space-time" in the very early universe. The paradigm shows that, during this early era, the universe was compressed to such unimaginable densities that its behavior was ruled not by the classical physics of Einstein's general theory of relativity, but by an even more fundamental theory that also incorporates the strange dynamics of quantum mechanics. The density of matter was huge then -- 10 94 grams per cubic centimeter, as compared with the density of an atomic nucleus today, which is only 10 14 grams.

In this bizarre quantum-mechanical environment -- where one can speak only of probabilities of events rather than certainties -- physical properties naturally would be vastly different from the way we experience them today. Among these differences, Ashtekar said, are the concept of "time," as well as the changing dynamics of various systems over time as they experience the fabric of quantum geometry itself.

No space observatories have been able to detect anything as long ago and far away as the very early eras of the universe described by the new paradigm. But a few observatories have come close. Cosmic background radiation has been detected in an era when the universe was only 380-thousand years old. By that time, after a period of rapid expansion called "inflation," the universe had burst out into a much-diluted version of its earlier super-compressed self. At the beginning of inflation, the density of the universe was a trillion times less than during its infancy, so quantum factors now are much less important in ruling the large-scale dynamics of matter and geometry.

Observations of the cosmic background radiation show that the universe had a predominantly uniform consistency after inflation, except for a light sprinkling of some regions that were more dense and others that were less dense. The standard inflationary paradigm for describing the early universe, which uses the classical-physics equations of Einstein, treats space-time as a smooth continuum. "The inflationary paradigm enjoys remarkable success in explaining the observed features of the cosmic background radiation. Yet this model is incomplete. It retains the idea that the universe burst forth from nothing in a Big Bang, which naturally results from the inability of the paradigm's general-relativity physics to describe extreme quantum-mechanical situations," Agullo said. "One needs a quantum theory of gravity, like loop quantum cosmology, to go beyond Einstein in order to capture the true physics near the origin of the universe."

Earlier work with loop quantum cosmology in Ashtekar's group had updated the concept of the Big Bang with the intriguing concept of a Big Bounce, which allows the possibility that our universe emerged not from nothing but from a super-compressed mass of matter that previously may have had a history of its own.

Even though the quantum-mechanical conditions at the beginning of the universe were vastly different from the classical-physics conditions after inflation, the new achievement by the Penn State physicists reveals a surprising connection between the two different paradigms that describe these eras. When scientists use the inflation paradigm together with Einstein's equations to model the evolution of the seed-like areas sprinkled throughout the cosmic background radiation, they find that the irregularities serve as seeds that evolve over time into the galaxy clusters and other large-scale structures that we see in the universe today. Amazingly, when the Penn State scientists used their new loop-quantum-origins paradigm with its quantum-cosmology equations, they found that fundamental fluctuations in the very nature of space at the moment of the Big Bounce evolve to become the seed-like structures seen in the cosmic microwave background.

"Our new work shows that the initial conditions at the very beginning of the universe naturally lead to the large-scale structure of the universe that we observe today," Ashtekar said. "In human terms, it is like taking a snapshot of a baby right at birth and then being able to project from it an accurate profile of how that person will be at age 100."

"This paper pushes back the genesis of the cosmic structure of our universe from the inflationary epoch all the way to the Big Bounce, covering some 11 orders of magnitude in the density of matter and the curvature of space-time," Nelson said. "We now have narrowed down the initial conditions that could exist at the Big Bounce, plus we find that the evolution of those initial conditions agrees with observations of the cosmic background radiation."

The team's results also identify a narrower range of parameters for which the new paradigm predicts novel effects, distinguishing it from standard inflation. Ashtekar said, "It is exciting that we soon may be able to test different predictions from these two theories against future discoveries with next-generation observational missions. Such experiments will help us to continue gaining a deeper understanding of the very, very early universe."

## Inflationary universe

A model universe in which this rapid, early expansion occurs is called an inflationary universe. The inflationary universe is identical to the Big Bang universe for all time after the first 10-30 second.

The Inflationary Universe. A major aspect of applying Grand Unified Theories to the early history is the recognition that the universe did not always expand at a rate that can be determined from observations of the present day universe.

New Inflationary Universe
a revised form of the Inflationary Universe model that provides a mechanism to avoid the gross inhomogeneities which result from the theory as originally proposed. [D89]
Newton (N) .

model, 53-54
Infrared Astronomical Satellite (IRAS), 30, 35, 40, 66, 67, 75, 78, 93, 96, 117, 119, 131-132, 134
Infrared astronomy, 75-80, 158 .

A modification of the standard big bang model it says that the universe went through a brief early period of unusually rapid expansion just after the big bang itself.

- By Alan Guth via The Edge
Inflation - UC Berkeley
Did Inflation Happen Before the Big Bang? - Starts With a Bang
Andrei Linde
Alan Guth
Forces of the Universe - UTK
"Big Bang Theory" Television show
Video: "I prefer my space stringy not loopy" via Physics Buzz .

: The Quest for a New Theory of Cosmic Origins. Basic Books. p. 186. ISBN 978-0201328400. OCLC 35701222.
^ Cirigliano, D. de Vega, H.J. Sanchez, N. G. (2005). "Clarifying inflation models: The precise inflationary potential from effective field theory and the WMAP data".

expanding and contracting in cycles.

Guth, Alan H., and Alan P. Lightman. The

: The Quest for a New Theory of Cosmic Origins. Reading, MA: Addison-Wesley Publishing, 1998.
Hogan, Craig J., and Martin Rees. The Little Book of the Big Bang: A Cosmic Primer. New York: Copernicus Books, 1998.

While the wormhole solution is reasonably stable, under some conditions it is subject to instabilities that can cause either explosion to an

, or collapse to a black hole. For collapse, some 70% of the wormhole mass-energy is radiated away the rest becomes the mass of the black hole.

Alan H. Guth
1947-
American
developed the theory of cosmic evolution known as the

radiation can be so uniform in all directions when it comes from different parts of the Universe that have never been in communication with each other. Attempts have been made to invoke a very rapid period of expansion in the Universe's history in order to remove this difficulty (the so-called

## Big Bang Eras after the First Minute¶

The extremely hot, dense “soup” of matter and energy that began in the first minute is often described as the “primeval fireball”. It has been likened to something akin to a thermonuclear fusion event, yielding a detonation-like release of energy on a grandiose scale that is just hinted at by a hydrogen bomb’s explosion. This is a misnomer because hydrogen atoms did not exist as such in the early Universe. The energy release would not be visible (such radiation is characteristic of much lower temperature processes) but the fireball “glow” would radiate at very short wavelengths (gamma rays among them). This so-called invisible fireball cooled as the Universe expanded. Its existence is equated with that of the Cosmic Background Radiation, the remnant of the initial (and small) ‘fireball’ consisting of the radiation and matter of the first eras.

Over the next 10 to 100 seconds after the first minute, during the first stage of the Nucleosynthesis Epoch, the predominant process was the production of stable nuclei (nucleons) of hydrogen and helium. Some of the protons (p:sup: + ) and electrons (e:sup: - ) that survived initial annihilation combined to produce new neutrons (n) by weak force interactions, which added to the supply of remaining hadronic neutrons. During this stage, at first the dominant atomic nucleus was just a single proton (hydrogen of A=1). The basic fusion processes that formed hydrogen and helium isotopes are shown in this diagram:

As temperatures dropped below 10 9 °K (at

3 minutes), some of the neutrons started combining with available protons (hydrogen nuclei) to form deuterons (heavy hydrogen or H 2 nuclei) plus gamma (γ) rays (resulting from the conservation of the binding energy released in the reaction). When a neutron is captured at lower temperatures, the assemblage is a deuterium atom (presently,

1 such atom per 30000 hydrogen atoms is the survival ratio since deuterium is not produced in most stars, the deuterium we find on Earth [isolated from heavy water molecules] is thought to be a remnant from the first seconds of the Big Bang) the amount detected provides a good theoretical control on the nuclear processes acting during the early Big Bang. A much smaller fraction of the deuterium can capture a second neutron to form the more unstable H 3 or tritium.

Reaction between a deuteron and and a proton can produce helium (He:sup: 3 ). The much more abundant He 4 (two protons two neutrons) is generated in several ways: by reactions between two deuterons, between H 3 and a proton (rare), between He 3 and a neutron, or between two He 3 nuclei plus a released proton. Two other elements are also nucleosynthesized in this early stage in very small quantities: Lithium (Li 3 protons 4 neutrons): He 4 + H 3 –> Li 7 + γ and Beryllium (Be 4 protons + 3 neutrons): He 4 + He 4 –> Be 8 + e - (under the still high temperatures during nucleosynthesis, most of this highly unstable Be decays to Li). The general time line for formation of these elements during primary nucleosynthesis appears in this next diagram which plots mass numbers of the primordial isotopes. In it, the abundance of the hydrogen proton is arbitrarily set at 1 - it is set to remain constant in the ensuing processes in which the other nucleons develop as temperatures drop in the relative abundances shown.

Elements with higher atomic numbers (Z) are not produced at all during this initial nucleosynthesis because of energy barriers at Z = 5 (boron) and Z = 8 (oxygen) also the statistical probability of two nucleons of just the right kind meeting is quite low. This stability gap is overcome in stars by the fusion of 3 He 4 nuclei into a single C 12 nucleus. The higher atomic number elements through iron are created in more massive stars as they contract and experience rising temperatures by a complexity of fusion processes such as helium nuclei capture, proton capture, and reactions between resulting higher N nuclei themselves. Elements with atomic numbers higher than iron are produced largely by neutron capture processes. (See page 20-7 for more details on these various processes.)

Thus, this brief era witnessed the synthesis of the primordial nuclear constituents –

90% hydrogen/deuterium and 10% helium by numbers of particles and 75-25% by mass – that make up the two elements subsequently dominating the Universe, along with minute amounts of lithium and boron. Most helium was produced at this early time, but younger helium is also the product of hydrogen burning in stars the ratio of He/H has remained nearly constant because about as much new He is then created in star fusion as is converted to heavier elements during stellar evolution. The hydrogen and helium nuclei generated in this critical time span of the original nucleosynthesis later became the basic building materials for stars, which in turn are the sites of the internal stellar nucleosynthesis (fusion) that eventually spawned the elements with atomic numbers (symbol = Z, whose value is the unique number of protons in the nucleus of a given element) up to 26 (Fe or iron) these account for the dominant elements, in terms of both mass and frequency, in the Universe (elements with Z > 26 are produced in other ways that require energy input rather than release [as occurs for elements of Z < 26], as described later). (More about the creation [formation] of the heavier elements is covered on page 20-7.)

(An astounding fact, worthy of prominent insertion at this point: The vast majority of the hydrogen atoms in your body and mine, present as hydrogen-bearing substances, including water and various organic compounds, throughout the Earth [and extrapolated in scale up to the full content of the Universe] is primordial, that is, consists of the same individual protons that formed in the first minute of the Big Bang and then the nucleons of H during nucleosynthesis and the H atoms [single electron] soon thereafter. The additional elements in our bodies, O, C, N, Ca, Na, Mg, K, Al, Fe and others, were generated exclusively in stars, as we shall see later. We therefore consist of truly old matter, billions of years in age, and are in a sense “immortal” or “eternal”. Although seemingly far-fetched, some of an individual’s atoms can conceivably end up in another human’s body - reincarnation of sorts - as atoms released during decay may migrate into the food chain [although actual tracing of specific atoms through the transferrence is next to impossible] or a more direct path by cannabalism is an alternative means.)

As the fireball subsided with continuing Universe expansion, the matter produced was dispersed in a still very dense “soup” of predominantly x-ray photon radiation along with neutrinos plus nucleons and other elementary particles (this mix of radiation, ionized H and He nuclei, and free electrons is called a plasma). The time that lasted from after the first few minutes to about 300,000 years (cosmic time, i.e., since the moment of the Big Bang) is known as the Radiation Era (connoting the dominance of electromagnetic radiation). As expansion proceeded, the mass-equivalent radiation density (E = mc 2 equivalency) decreased as mass density increased (today, mass density significantly exceeds radiation energy density even though the number of photons is much larger [in a ratio of

1 billion photons to every baryon]). Matter began to dominate after

10000 years but temperatures remained too hot for electrons to combine with nuclei. The Universe during this stage was opaque (in the sense that no visible light passes from one point to the next) because even with decreasing photon density detectable radiation at these wavelengths was prevented from traversing or leaving the still enlarging fireball’s confines owing to internal scattering by free electrons.

This era of first opaqueness ended roughly 300,000 years after the Big Bang (some recent estimates put this termination at closer to 500,000 years after the B.B.) with the onset of the Decoupling Era, at which stage cooling had dropped below 4,000° K, allowing protons and helium nuclei to combine with electrons forming stable hydrogen and helium atoms - a process known as Recombination). As this era began, the Universe was about 1/200th its present size. Thereafter for a time, the extreme decrease in numbers of free electrons (today there are about one free proton and electron for every 100,000 atoms) drastically reduced scattering (not by direct collision as occurs when sunlight hits dust but by close interaction between the photon and electron or proton fields).

This atomic hydrogen absorbs radiation at various wavelengths. In the visible, for example, the Universe would appear as though it consisted primarily of a dark fog. For about 500,000 years more, this hydrogen acted as a kind of atomic “fog” which still kept the Universe opaque (often referred to as a cosmic Dark Age). At this time, any radiation within the fog would have extended into the ultraviolet. A glow would be apparent at those wavelengths, since at that time the Cosmic Background Radiation would give off UV light as it continued to redshift (see page 20-9) from preceding shorter wavelengths enroute to its present-day microwave emission wavelengths brought on by continuing expansion of space.

Then, as the first stars and protogalaxies began to develop, their strong outputs of electromagnetic radiation caused a Re-ionization (removal of electrons) of the hydrogen that increased to the extent that the earlier opaque (at visible wavelengths) Universe now became rather rapidly transparent to radiation spanning those wavelengths. This allowed visible light photons to pass through interstellar space, which is an almost perfect vacuum, and by itself is black, i.e., does not give off luminous self-radiation but does contain very low densities of photons and other particles (about 3 atoms per cubic meter). This transparency facilitates free passage from external sources of visible wavelengths within any region of the Universe. (Evidence for this re-ionization has been found so far not from visible light but by using UV radiation to “see” quasars that formed in this period). Thus, as stars and galaxies began to form, their thermal and other energy outputs would ionize the interstellar hydrogen, allowing their light to appear as now detectable in the visible range, so that the Universe at this stage started to show the stars as individuals and clusters. This did not happen “all at once” but gradually as galaxies formed and made their regions transparent thus “holes” appeared intermittently in the opaque early Universe letting light from the reionizing process in galactic neighborhoods begin to spread through their surroundings as the opaqueness progressively dissipated.

The Decoupling Era is estimated to have lasted to perhaps as long as the first million years, although most of the baryon-lepton recombination took place in the beginning years. The end of the Decoupling Era was thus the end of the Dark Ages in Cosmology. As we will see in the next page, during this period conditions turned favorable for the the clustering of matter (slight increases in density) that eventually gave rise to the organization of galaxies.

Let us summarize the above ideas, plus several introduced in the next pages, with two diagrams. The first is a variant of the above Silk diagram for the development of the Universe after the Big Bang, as seen here:

The second has been produced on one of the Websites mentioned in the Preface, the 21st Century Science course developed by Dr. J. Schombert. Labeled on his site “The Birth of the Universe”, it serves to summarize much of what has been already introduced on this page, but introduces the idea that Black Holes may have form at the very moment of inception of matter. Black Holes (in this Section often abbreviated “B.H.”) are ubiquitous objects found mostly within galaxies (but some may exist in intergalactic space). They are extremely dense, so much so that their extraordinarily intense gravitational pull prevents radiation from escaping them (exception: Hawking radiation) but also causes material around them to be pulled into them, commonly generating huge amounts of energy release that can be detected over the entire spectrum. They range in size from very small (centimeters) to sizes on planetary scales (these latter are referred to as Supermassive B.H.’s. Black Holes commmonly form from ultimate collapse of very massive stars. Black Holes play an important - perhaps critical - role in getting galaxies started and are thought to lie in the central region of most (possibly all) galaxies.

Three additional comments are appropriate here, now that the above ideas have given you a background understanding within which they become relevant:

First, The terms “mass density” and “energy density” have appeared several times in the above paragraphs. In the initial moments of the Universe, radiation energy density was dominant. By the time temperatures had fallen to

10000 °K, when the Universe was about 1/10000 its present size, radiation mass density (remember the E = mc 2 equivalency) became about equal to matter density. After the first second or so, the mass density has come to exceed radiation density, despite the aforementioned preponderance of photons over hadrons and leptons.

Second, some recent hypotheses contained in the concepts of Hyperspace consider the Universe at the Planck time to have consisted of 10 dimensions [other models begin with as many as 23 dimensions but these reduce to fewer dimensions owing to symmetry and other factors] the chief advantage of this multidimensionality lies in its mathematical “elegance” which helps to simplify and unify the relevant equations of physics. As the Big Bang then commenced, this general dimensionality split into the 4 dimensions of the extant macro-Universe that underwent expansion and 6 dimensions that simultaneously collapsed into quantum space realms having dimensions of around 10 -32 centimeters in size. This rather abstruse concept is explored in depth in the book Hyperspace by Michio Kaku (Anchor Books).

The third comment considers that the physical entities that make up both matter and energy may be smaller than quarks and leptons these are known as superstrings - one dimensional subparticles that vibrate at different frequencies and combine in various ways (straight to looped in bundles) to then make up the many different fundamental particles. Each species of particle has its characteristic vibrational frequency or harmonic) that are now known to exist or can be reasonably postulated. Proof of superstrings existence has yet been to be verified but theory favors their existence and they are consistent with quantum physics. Superstrings account for the ultimate makeup of particles that are obvious to us as the inhabitants of 3-dimensional space. In addition to the 4th dimension, time, superstrings are tied to 6 more curled dimensions whose spatial arrangement around a particle is expressed by a curvature of radius R (probably very small but one recent model allows R to be up to 1 millimeter). Superstrings therefore exist in hyperspace. If superstring theory proves to be valid, it will be one of the greatest achievement ever in physics. It is currently the most promising way to reconcile quantum theory and relativity. A more recent variant accounts for the graviton and contributes to an explanation of the role of gravity, the pervasive but weak force that is critical to the development and maintenance of our Universe. This is the so-called M-theory (M stands for multidimensional “membranes” (commonly spoken of as “branes” by superstring theorists). This theory postulates an 11th dimension (the membrane) when added to the dimensional mix, the result permits gravitons to fit in the general picture. An outstanding review of what is known or surmised about superstrings, in the context of its importance to Cosmology, has been summarized in a book (which reached best seller status) by Brian Greene, The Elegant Universe, 1999, W.W. Norton & Co.)

Note to reader: These next paragraphs were added to this first page on November 1, 2002: Before proceeding to the second page (covering Galaxies), it seems advantageous to give you a broader framework at the outset that describes a General Model for the SpaceTime expansion of the Universe that has continued after the first eras of the Big Bang. This and related subjects are considered in more detail on page 20-8, 20-9, and 20-10. Because of the length of this synopsis, you are given the option of skipping it by going directly to page 20-2 (click on Next below) or if you wish to build up this background now, you can access it at page 20-1a.

:sub: <>__*A measure of cosmic distance to any object beyond our Sun is the light year [l.y.], defined as the distance [

9.46 x 10 12 or 9,460,000,000,000 km or

5.9 trillion miles] traveled by a photon moving at the speed of light [2.998.. x 10 8 m/sec, usually rounded off and expressed as 300,000 km/sec] during a journey of 1 Earth year another distance parameter is the parsec, which is the distance traversed in 3.3 l.y.) The parts of the Universe now visible are thought to be a region within a (possibly much) larger Universe of matter and energy, with light from these portions beyond the detectable limits having not yet arrived at Earth.

:sub: <>__** It is often difficult to find a clear definition of the term “space” in most textbooks (just look for the word in their index - it is almost always absent). We tend to think first of the “out there” that has been reached and explored by unmanned probes and by astronauts as the “space” of interest. One definition recently encountered describes space as ‘the dimensionality that is characterized by containing the universal gravity field’. The writer (NMS) has tried to think up a more general definition. It goes like this: Space is the totality of that entity that contains all real particles of matter/energy, both dispersed and concentrated (in star and galaxy clots), which fill and are confined to spatial dimensions that appear to be changing (enlarging) with time. Anything one can conceive that lies outside this has no meaning in terms of a geometric framework but can be conceptualized by the word “void” which in the quantum world is hypothesized as occupied by virtual particles capable of creating new matter and space if a fluctuation succeeds in making a (or perhaps many) new Universe(s).

:sub: <>__*** Symmetry in everyday experience relates to geometric or spatial distribution of points of reference on a body that repeat systematically when the body is subjected to specific regular movements. When rotated, translated, or reversed as a reflection, the points after a certain amount of movement are repeated in their same relative positions (e.g., a cube rotated 360° around an axis passing through the centers of two opposing faces will repeat the square initially facing the observer four times [90° increments> as it returns to its initial position). The concept of symmetry as applied to subatomic physics has other, although related, meanings that depend on conservation laws as well as relevance to spatial patterns. In general terms, this mode of symmetry refers to any quantity that remains unchanged (invariant) during a transformation. Implied are the possibilities of particle equivalency and interchangeability (the term “shuffled” may be used to refer such shifts). Expressed mathematically, certain fundamental equations are symmetrical if they remain unchanged after their components (terms) are shuffled or rotated. In quantum mechanics, gauge (Yang-Mills) symmetry involves invariance when the three non-gravitational forces (as a system) undergo allowable shifts in the values of the force charges. At the subatomic level in the first moments of the Big Bang, symmetry is applied to a state in which the fundamental forces and their corresponding particles are combined, interchangeable, and equivalent during this brief time, particles can “convert” into one another, e.g., hadrons in leptons or vice versa. When this symmetry is “broken”, after the GUT state, the forces and their corresponding particles become separate and distinct.

The progressive breaking of symmetry during the first minute of the Big Bang has been likened (analogous) to crystallization of a magma (igneous rock) by the process of differentiation. At some temperature (range), a crystal of a mineral with a certain composition precipitates out if it can leave the fluid magma (crystal settling), the remaining magma has changed in composition. At a lower temperature, a second mineral species crystallizes, further altering the magma composition. When the last mineral species crystallizes, at still lower temperatures, the magma is now solidified. All the minerals that crystallized remain, each with its own composition. In the Big Bang, as temperatures fall, different fundamental particles become released, altering the energy state of the initial mix, as specific temperatures are reached (and at different times) until the final result is the appearance of all these particles, which as the Universe further expands and cools become bound in specific arrangements (e.g., neutrons and protons forming H and He nuclei later picking up electrons to convert to atoms) that ultimately reorganize in stars, galaxies, and the inter- and intra-galactic medium of near empty space.

:sub: <>__**** Energy can be said to be quantized, that is, is associated with quanta (singular, quantum) which are discrete particles having different units of energy (E) whose values are given by the Planck equation E = hc/λ where h = Planck’s constant, c = speed of light (

300,000 km/sec), and λ = the wavelength of the radiation wave for the particular energy state of the quantum being considered the energy values vary with λ as positioned on the electromagnetic spectrum (a plot of continuously varying wavelengths).

:sub: <>__***** This extremely rapid enlargement reflects the earlier influence of inflation with its initially higher expansion rates. Keep in mind that many of the parametric values cited in cosmological research are current estimates or approximations that may change as new data are acquired and/or depend on the particular cosmological model being used (e.g., standard versus inflationary Big Bang models). Among these, the most sought-after parameter is H, the Hubble Constant (discussed later in this review), being one of the prime goals for observations from the Hubble Space Telescope.

Primary Author: Nicholas M. Short, Sr. email: nmshort @ nationi . net

## Ep. 58: Inflation

We interrupt this tour through the solar system to bring you a special show to deal with one of our most complicated subjects: the big bang. Specifically, how it’s possible that the universe could have expanded faster than the speed of light. The theory is called the inflationary theory, and the evidence is mounting to support it. Einstein said that nothing can move faster than the speed of light, and yet astronomers think the universe expanded from a microscopic spec to become larger than the solar system, in a fraction of a second.

### Transcript: Inflation

Einstein said nothing could move faster than the speed of light, and yet astronomers think the universe expanded from a microscopic spec to become larger than the solar system in a fraction of a second.

Pamela, can you sort all that out?
Pamela: Itâ€™s all a matter of what is doing the moving. The idea is relative to the grid of space, I cannot move faster than the speed of light. I personally canâ€™t get anywhere near the speed of light, but even the fastest, smallest particles â€“ the things that can get the closest to going the speed of light, canâ€™t ever go faster than it, relative to space.

Now, if instead space itself grows, thatâ€™s something different. One way to think about it is: imagine you have a little kid who is walking away from school on his way home. The little kidâ€™s capable of moving at, say, four sidewalk blocks every couple of seconds. He canâ€™t go any faster than that. His family might see him moving toward the house at four sidewalk blocks a second â€“ no big deal. Heâ€™s going his typical speed.

Imagine thereâ€™s some crazy sidewalk builder building a hill of sidewalk blocks between him and the school. As the school watches, they see not just his motion but also all these new sidewalk blocks getting built.

Imagine that crazy sidewalk block-building machine is building sidewalk blocks at a rate of 10 sidewalk blocks every couple of seconds. As those new blocks appear between the school and the child, you now have the expansion of the sidewalk and the rate the kid is moving, added together.

So the school might see the kid moving at 14 sidewalk blocks every couple of seconds. That kid is moving faster than heâ€™s allowed to go â€“ but heâ€™s not. Itâ€™s the sidewalk thatâ€™s growing not the kid thatâ€™s moving relative to the sidewalk. So you get these weird additive velocities coming in that cause things to be perceived as moving faster than theyâ€™re allowed to move. Theyâ€™re not â€“ itâ€™s space moving instead.
Fraser: Isnâ€™t that the kind of argument that people have with relativity? Letâ€™s say Iâ€™m moving at close to the speed of light, and then I shine a light, and youâ€™re moving at close to the speed of light and you shine a light. Weâ€™re moving toward each other, but even though weâ€™re both moving at close to the speed of light, your light is moving at the speed of light, and my light is moving at the speed of light, so itâ€™s all relative.

So wouldnâ€™t the light appear to be moving at the speed of light? Itâ€™s just the underlying object that can be moving further.
Pamela: The weird things are happening to light during inflation. If you let a light wave go and itâ€™s trying to cover one meter of space â€“ but that one meter of space grows, the wavelength of the light will grow. So as the universe expanded, it stretched out the light and made it redder. The light we see redshifted â€“ in general when weâ€™re dealing with fairly nearby galaxies, that redshift is due to the movement of the galaxy. The same way you hear the pitch of the sirens of fire trucks/police cars change because of the motion of the vehicle.

With the expansion of the universe, as the light travels through space itâ€™s getting stretched out by the expansion of the universe.
Fraser: Okay, okay, weâ€™re getting ahead of ourselves here. Letâ€™s go back to the beginning here,
Pamela: Okay.
Fraser: Right to the beginning.
Pamela: Okay.
Fraser: and start with the big bang and re-describe the big bang. Last time I think we oversimplified it. Letâ€™s go into very nitty-gritty detail at least for the first few seconds,
Pamela: Okay.
Fraser: and explain what physicists now think happened.
Pamela: Okay. As we understand it â€“ and we canâ€™t actually observe this no matter how big a telescope we ever build, because the cosmic microwave background is at time equalling roughly 300 thousand years, and we can never see beyond that.

Based on the evidence left in the universe from the big bang, we believe thereâ€™s a moment in time from basically time equals roughly zero, to time equals 10^-33 seconds, during which the universe had these particles called inflatons that pushed everything apart. They pushed things apart so much that the universe expanded by a factor of 10^26 in that little, tiny instance, that little, tiny, bazillionth of a tiny second.
Fraser: So it started as a 10^-33. How much bigger did it get then? Is it still microscopic at this point?
Pamela: The universe started off at moment zero, as something so small we donâ€™t have a way to describe it. Then it doubled and doubled and doubled. It wasnâ€™t necessarily doing this at a linear rate â€“ it was doing it at an exponential rate. We canâ€™t tell you exactly what the curve was, exactly if it stayed the same function the entire time â€“ we donâ€™t have a way to get at that information observationally. From the estimates of what we can see in the universe around us, the scale size of the universe was roughly solar-system-like at the end of that 10^-33 of a second.
Fraser: Thatâ€™s a fraction of a second. Wow.
Pamela: At the end of this period, what happened was these inflatons, these particles that were driving the expansion, decayed. They gave off their energy to re-heat the universe.

During this frantic expansion, the universe cooled off.
Fraser: I wonder what percentage of the universe wouldâ€™ve been â€“ now we say X% of the universe is matter, X% is dark matter â€“ what percentage of the early universe wouldâ€™ve been inflatons and what wouldâ€™ve been regular matter?
Pamela: I canâ€™t tell you how much of the universe was tied up in inflatons, how much was tied up in energy. A lot of the universe was just energy at that point because matter hadnâ€™t started to freeze out of the energy yet.

The energy stored in those inflatons we think was on the order of about 10^15 giga-electron-volts. Thatâ€™s a lot of energy, which then went into re-heating the universe. It was the heat from all of those decaying inflatons that went on to drive the formation of matter, the culmination of the first protons that formed into helium and trace amounts of lithium. All the energy that went into heating the universe up and making things exciting again came out of the decay of the inflatons.
Fraser: I guess I wonder if we get a particle smasher big enough, could we make inflatons?
Pamela: I think it would sort of require the energy reserves of the entire planet â€“ so probably not. We struggle to make a lot of particles that are heavier than the quarks that make up your standard protons and neutrons in particle accelerators. They just donâ€™t like to fall out. They decay quickly. The speed that we have to accelerate protons up to during the collisions is very hard to achieve. The inflatons are a high-energy particle, so trying to get there from hereâ€¦ I donâ€™t think weâ€™re going to get there. Hopefully in the next year or so weâ€™ll find things like the Higgs-Boson that carries mass.
Fraser: Thatâ€™s another show.
Pamela: Thatâ€™s another show, but every time we find one of these theorized particles it starts to tell us the entire puzzle is correctly put together.
Fraser: Hereâ€™s where youâ€™re going to have to back this up. This theory just sounds crazy.
Pamela: (laughter)
Fraser: Why on Earth would physicists come up with this in the first place?
Pamela: The main reason is when we go outside and look left and right, the universe, on average, looks the same in both directions. The light thatâ€™s coming from the eastern horizon and the light coming from the western horizon, that are just reaching the planet Earth â€“ thatâ€™s light that hasnâ€™t had a chance to reach each other. While I can see an object thatâ€™s 13 billion light years away to the east, and I can see an object thatâ€™s 13 billion light years away to the west, those two objects canâ€™t see each other.

This means that theyâ€™ve never seen each other. When the universe formed, weâ€™d expect that one chunk of universe might have one slight temperature after everything spreads out, another might have another temperature, theyâ€™ll have a different distribution of lumpiness and bumpinessâ€¦. but they donâ€™t. Everywhere we look, if we look at a large enough chunk of space, itâ€™s exactly the same. The only way for everything to e exactly the same is for there to have been some point in time when everything was close enough together that it could communicate. Or, if everything is spread out so much, that any differences in the original distribution have been smoothed out.
Fraser: I could understand if you take two objects at different temperatures and put them next to each other, theyâ€™re going to average out there temperatures, right?
Pamela: Mm-hmm.
Fraser: So is it the same kind of situation? At some point all of the mass in the universe (or all of the energy in the universe which later became mass) had to have been in roughly the same place to even out its temperatures?
Pamela: Or another way it couldâ€™ve happened is if you take small piece of Silly Putty and put it on your Sunday morning cartoons and pick it up, you can see Garfield (or whomever) staring back at you. If you stretch that silly putty out, the more you stretch it, the more Garfield grows until if you look at a one inch section of that silly putty, everything in that one inch section now looks about the same. You might only be looking at one small piece of what used to be Garfieldâ€™s eye. If you look at one small section, everything looks the same.

If you take a universe that originally had a mass distribution that looked like Garfield, and spread it out enough, if you look at a section the size of what weâ€™re able to see, that section mightâ€™ve just been one small piece that was too small to have had any irregularities â€“ or they got flattened out so much that the bright and faint spots are really about the same thing because itâ€™s been spread out so much that the differences go away.
Fraser: If all the differences go away, why do we have galaxies, stars and planets? Why donâ€™t we just have a spray of particles?
Pamela: They didnâ€™t go away entirely. They went away enough that the large-scale differences that couldâ€™ve been there, that wouldâ€™ve caused the eastern and western horizon to look radically different â€“ like if you only had galaxies on one side and the other was an even distribution of dead stars â€“ that level of large differences got smoothed out.

The small differences that led to galaxies, that led to stars, those were still there, just like you might see a single dot of the ink from the Sunday paper spread out â€“ it got spread out, but that dot is still there.
Fraser: So who came up with this theory then?
Pamela: The theory was developed by Alan Guth originally, to try and explain the smoothness we see.
Fraser: Thatâ€™s the smoothness youâ€™re saying â€“ look to the left, look to the right, the universe looks roughly similar.
Pamela: Right. Exactly how it worked â€“ couldnâ€™t get there originally. But Alan Guth was the first one to put forth the idea that if you take the universe and blow it up fast enough at the very beginning, all the inhomogenities, all the differences, get smoothed out.
Fraser: Sorry to be labouring on this â€“ itâ€™s already giving me a headache. If the big bang just happened as a linear expansion, then you wouldâ€™ve gotten clumping of a large scale right away, and so we wouldâ€™ve seen, say, off to the left all the matter in the universe and off to the right, nada.
Pamela: Right. Exactly.
Fraser: Okay. So Guth said there had to be some moment where somebody spread the universe out fast enough that it couldnâ€™t clump it, so weâ€™d get smoothness.
Pamela: Yes. He couldnâ€™t really come up with a good mechanism for how this happened. He was originally trying to use arguments with bubble nucleation, quantum tunnelling and a whole bunch of really scary quantum mechanical particle physics, all combined together. It didnâ€™t work.

Andrei Lind and (separately and independently) Andres Albright and Paul Steinhart (and I apologise for destroying pronunciation of names), came out with a different model that basically said the universe was coupled to some sort of a scalar field. As that field changed energies, it drove this inflation, and thatâ€™s where the inflaton comes in. the inflaton is the particle that coupled the universe to this field.

This isnâ€™t a completely strange idea. When we talk about gravity, we talk about the massive objects coming from the Higgs-Boson coupling objects, coupling atoms, coupling particles, to a scalar mass field-type thing.

With the inflaton, itâ€™s another model where we have the entire universe coupled to a field that is changing energy levels. Itâ€™s this change in energy thatâ€™s driving this amazing inflation very fast.
Fraser: So where do we stand now, then? Weâ€™ve got these revisions to it. Have the experimenters gotten their hands on it?
Pamela: Right now weâ€™re at the stage of â€œoh my god, this has really, really hard math, can this be true? Can this be right? Letâ€™s see what kind of predictions we can get out of it.â€? It predicts there will be specific distributions in certain properties of the cosmic microwave background. When you look at the polarization of the light, when you look at the distribution of irregularities in the light of the cosmic microwave background, you should see certain things.

When we got the original data back from the Wilkinson Microwave Anisotropy Probe (WMAP), it looked like inflation might not quite work out. The data didnâ€™t fit exactly, but that was the first round of data. It was sort of like only making one measurement. If you only make one measurement, you canâ€™t know if it was right.

When, at the end of three years, they looked at the WMAP data, one of the things they looked at is how the photons are aligned. This is a quality called polarization.
Fraser: Sure, I remember that. We did an experiment in school where youâ€™d have like a piece of Sunglasses and if you put it one way you could see the way â€“ and you had two of them. One of them, if you twisted it, would only let certain photons polarized come through. If you twisted the two pieces of Sunglasses it would darken. So you could tell which way the light was coming.
Pamela: Whatâ€™s really cool is, if you take a piece of plastic, like a plastic spoon, and shine light through it, and then twist it so thereâ€™s stress, the twisting causes light passing through the spoon to gain different polarizations.

There is an amazing mural at the Boston Museum of Science that if you just look up at it doesnâ€™t look like much. If you look at it through a polarizing lens, all sorts of details and features that you canâ€™t even see â€“ faces, landscapes â€“ appear in the polarized light.
Fraser: What causes different polarizations of light?
Pamela: Itâ€™s often a scattering effect. If I take light of a whole bunch of different orientations, where the waves are up and down, left and right, and I shine it at a surface, the surface as the light reflects off of it will tend to preferentially cause the light to have a specific orientation. If you think about throwing your show at the ground, depending on if it hits with the shoe going in toe first or the shoe going in side first, itâ€™s going to bounce a different way.
Fraser: Iâ€™ve got an analogy for you. We even did this experiment in physics. If two of you are holding a rope and you do a wave up and down, and the waves are coming at you one way or you can do the wave side to side and the waves are coming at you sideways.
Pamela: Thatâ€™s exactly what the waves are doing, and how they reflect off of surfaces is going to depend on their orientation as the wave hits the surface.
Fraser: So different objects can generate light where the waves are going to be coming at you at different polarizations.
Pamela: So when we look at dusty objects we see specific polarizations. Like you said, sometimes the light being created has different polarizations.
Fraser: Why would different polarizations give them what theyâ€™re looking for?
Pamela: The polarized light is a diagnostic of what the light went through. For instance, astronomers studying active galactic nuclei measure the polarization of the light coming off so they can better understand the conditions inside the galaxy.

When we look at polarization from the cosmic microwave background, weâ€™re trying to diagnose the conditions inside the early universe, what the light experienced in the moment right before the cosmic microwave background was formed because the temperature changed just enough that all of the atoms combined and the light flew free.

That polarization is one of the echoes of what the universe looked like before the cosmic microwave background formed.
Fraser: What did they find?
Pamela: They found that the universe wasnâ€™t exactly the same everywhere. Instead there were areas that were a little bit fainter, or a little bit brighter â€“ there were small inhomogeneities. The inhomogeneities exactly matched what had been predicted in Andre Lind and Albrichâ€™s theories of inflation.

So we had a universe that was the same on large scales, but it did have pockets of differences that were still allowed to be there by inflation theory.
Fraser: So where did these pockets of differences come from?
Pamela: They come from slight differences in temperature that still existed after the inflation period. You had waves that were propagating through space, and these waves would cause areas that were a little bit denser or more thinned out. These waves were echoes going through the basically closed geometry of the early universe. Sound waves propagating through space creating pockets of resonances, pockets of different temperatures, is how it ended up coming out.
Fraser: So the only reason we exist, or that we have galaxies and planets, is slight differences in energy levels from the early universe?
Pamela: Slight differences in energy levels that were created during the first fractions of a second led to everything we know today.
Fraser: So it was like the different energy levels changed the amount of mass distribution and that allowed things to start clumping together and then you got stars and galaxies and so on. If there had been no differences, then it just wouldâ€™ve been expansion of a smear of particles and that wouldâ€™ve been that.
Pamela: If the densities had been bigger, everything wouldâ€™ve clumped up into black holes. If the densities had been less, then everything wouldâ€™ve been a smooth spray of pretty much nothing. Whatâ€™s cool is when we look at the cosmic microwave background, we see a distribution that corresponds to the distribution and structure we see in todayâ€™s universe.

What we see today is directly reflected in what we see that was given off at 300 thousand years after the universe began. Today weâ€™re 13.7 billion years after the universe began.

This isnâ€™t the only evidence for inflation. We look at not just the smoothness of the universe, but the flatness of the universe. These are two very different terms, mathematically. Smoothness says that if I look east or west, it all looks the same. Flatness says that the geometry of space is Euclidean. Itâ€™s like the geometry we learned in middle school and high school: straight lines stay parallel to one another, and itâ€™s just nice and balanced.
Fraser: Right, I remember we covered this in the show what the universe is expanding into. We talked about how if I fire light in one direction, and light thatâ€™s 90 degrees to that, and they both go out to the edges of the universe, you can still measure that as a nice, square angle all the way out. Itâ€™s not like they curve at some point. People were concerned it would curve at some point.

Or if Iâ€™m sitting on the Earth and shoot a line in one direction and a line in another direction, they donâ€™t actually remain at 90 degree angles because of the curvature of the Earth.
Pamela: Exactly. One of the things we find is we expect the curvature of space would change with time. One way to think of this is if one of us went and we stood on the Moon. Itâ€™s a small planet â€“ small moon, actually. Itâ€™s a small, round object you can stand on. You can see the horizon. You can see the curvature of the moon much more readily than you can see the curvature of the planet Earth.

Even on Earth, if you have binoculars and youâ€™re watching a ship in the distance you can watch it come over the horizon sail first. You can see the curvature of the planet.

If you go to Jupiter, which is way bigger than the Earth and way bigger than the Moon, the curvature becomes much less evident. The bigger something is, the less evident you expect the curvature to be.
Fraser: Right, and the universe is the biggest.
Pamela: Yeah. So looking around today and seeing that today n the nearby universe, the geometry looks pretty flat, thatâ€™s fine: the universe is big. As we look back further and further, weâ€™d expect to see the curvature crop up. Weâ€™d expect to see evidence of the curvature in the cosmic microwave background if our universe had been happily continuing to expand at a fairly constant rate since a moment where it was the size of a spec to today.

Even by the point in time when the cosmic microwave background was given off, the universe was so big that on the scale of the cosmic microwave background that weâ€™re looking at, the slice of space weâ€™re looking at that was located close enough to us 13.7 billion minus 300 thousand light years back, that place was already so big that it appeared flat. The only way to get the universe big enough when the cosmic microwave background was emitted to appear flat, is to have inflation.
Fraser: All right, so weâ€™ve got two lines of evidence. Two hard fought lines of evidence. Is there anything else?
Pamela: Thereâ€™s one more, and itâ€™s totally esoteric (and I love getting to use that word occasionally). There are these imagined particles that come from theorists called magnetic monopoles. In a lot of theories for how the universe was formed you end up generating magnetic monopoles, but we canâ€™t find the suckers.

A magnetic monopole is where you end up with either just a north pole or just a south pole of a magnet.
Fraser: Right. If you cut a magnet in half, the new pieces both have north and south poles.
Pamela: Yeah, theyâ€™re just smaller.
Fraser: Right.
Pamela: If you ever really want to mess with a company, ask to buy only north magnets.

I donâ€™t recommend actually doing this, but I know someone who did.
Fraser: Thatâ€™d be the easy way to find magnetic monopoles â€“ just have them cut. There you go. Nobel price please!

[laughter]
Pamela: We canâ€™t find magnetic monopoles in nature, and weâ€™ve looked. One of the ideas is they werenâ€™t formed in large numbers in the first moments of the universe. If the universe is small, then weâ€™d expect thereâ€™d be a few of them within the observable universe. But if the universe is truly huge, which it can only be if there was inflation, then it might be that the universe is so big, and we can see such a small fraction of it, that the probability of one of those magnetic monopoles being in the part of the universe we can see, is so low that we might not expect to see one.

Itâ€™s sort of like the idea of there are so few panda bears in china that if you randomly drop yourself in any one park, youâ€™re probably not going to see a wild panda bear. If panda bears were as common as squirrels, you could go anywhere and see one.

Weâ€™re thinking magnetic monopoles are more like the panda bear, and we live in north America instead of in Asia, so we have no chance of seeing a panda bear.
Fraser: So what implication does this have, then, for the size of the universe? How big is the universe?
Pamela: We can see out to stuff that occurred out to 13.7 billion minus 300 thousand light years out.
Fraser: Right, so I can imagine thereâ€™s a sphere we can see 13.7 billion light years in all directions. But thatâ€™s not the size of the universe.
Pamela: We think we only see three or four percent of the total universe.
Fraser: As a matter of the universeâ€™s volume.
Pamela: Yeah.
Fraser: Wow.
Pamela: So we are just three or four percent. Itâ€™s a big universe.
Fraser: Thereâ€™s parts weâ€™ll never see any of.
Pamela: Right, itâ€™s not getting any closer.
Fraser: Every year that goes by, I guess we see another light year of the universe, but thatâ€™s not fast enough to catch up with the expansion.

What do you think the future holds for inflation specifically, on top of the big bang?
Pamela: There are some neat side-theories that come out of this. First of all, our universe is still accelerating itself apart. We have this dark energy stuff, and maybe itâ€™s a little bit related to what triggered inflation. Dark energy is causing an acceleration thatâ€™s way, way, way smaller, but itâ€™s still there. Maybe theyâ€™re somehow physically related. These are theories people are still exploring.

Andre Lind has also put forward the idea that maybe there were pockets of the universe where inflation finished earlier or later. Maybe the entire universe didnâ€™t stop inflating at the same time. This means that there could be bubbles of universe coming off of our universe. When you blow up a balloon that has a defect in it, and the defect causes a pocket that sticks out further than the rest of the balloon â€“ maybe our universe has pockets like that.

Weâ€™re trying to put the pieces together. Every time we find a new high energy particle, every time we make better observations of the cosmic microwave background, we are able to add more pieces to our puzzle.

Currently we have a puzzle that cosmology has been able to put together a lot of the pieces with observations. We have holes where we can look at it and know thereâ€™s a piece that fits inside it. We name that piece and develop theories about what that piece should look like when we can put it in there. Weâ€™re getting there, but there are still areas where thereâ€™s a giant empty segment and we know thereâ€™s a lot of physics we donâ€™t understand that fits in.

Thereâ€™s a new satellite going up, Planck. Weâ€™re hoping that Planck, which will make even higher resolution images of the polarization of the cosmic microwave background will be able to confirm our theories to even greater detail. The more details we have, the more we have to fine-tune our theories. We canâ€™t say â€œitâ€™s within a factor of 10 of thisâ€?, we end up having to say itâ€™s within a factor of 0.1 of this.

So weâ€™re looking for more data, weâ€™re looking for more particles, and weâ€™re fine-tuning our theories. Now we have this dark energy thing to try and explain as well.
Fraser: I know weâ€™re running long on this show and I think Iâ€™m going to give up trying to hold us at half an hour because itâ€™s just going to go and go, but as the last thing I want to go back to what brought this up. We got all these emails from people asking how you can move faster than the speed of light.

Itâ€™s back to that thing where if you consider the universe as a stretchy fabric, it is allowed to expand, any two pieces on it are allowed to get away from each other faster than the speed of light.
Pamela: But those pieces canâ€™t move relative to space at faster than the speed of light.
Fraser: Right, itâ€™s the space itself that can do the expanding. So if Iâ€™m on one side of the space and youâ€™re on the other and weâ€™re expanding away from each other, we actually can be moving away from each other faster than the speed of light. But if we try to travel to each other, it still all has to go at or less than the speed f light.
Pamela: Yeah.
Fraser: So space itself and objects in space can be carried faster than the speed of light, but if youâ€™re going to try and move in space, then you have that speed limit.
Pamela: Yeah. Itâ€™s hard to think about. The way I usually try and explain it is with a giant imaginary Xerox machine.

If you imagine that youâ€™re trying to move across a piece of paper that is getting stretched out by a Xerox machine that can magically blow up the piece of paper (instead of creating a second piece of paper), and youâ€™re moving along at a constant stride but the grid youâ€™re moving on keeps getting bigger and bigger and bigger, it appears youâ€™re moving faster than you actually are. Thatâ€™s only because the grid is changing, not because youâ€™re moving faster.
Fraser: So if any of you still wonder how itâ€™s possible objects can be expanding away from each other faster than the speed of light, send in your questions and weâ€™ll have another run at it.

I think that is a really good explanation of that one spot of the big bang cosmology. I know itâ€™s a pretty technical discussion, but hopefully when you hear that term youâ€™ll have a much better sense of what people are talking about.

This transcript is not an exact match to the audio file. It has been edited for clarity.

## Before the beginning

Shall we ever be able to understand what was there before the universe took birth? If the Big Bang theory has to be believed, it all started with a single point where all the matter as we know today was packed up. But then where from all that matter arrived and how? What did the empty space looked like before that big crush?

If the ending is like everything tears apart from everything else then up to what span? What's there beyond that?

Hope humanity finds the answers before extinction.

#### Hayseed

We are very limited on what questions we can answer. Our knowledge of existence is only relational. The cause and the dynamic of the relationship is still un-known.

We have no clue to the cause and dynamic of charge rotation or movement. We can only measure where it moves. We relate to that. Why and how does it rotate? No one knows. Why does it continue to rotate, without energy being supplied?

We have no clue to the dynamic of emission, only the velocity after it.

We use the distortion of space to explain some relationships. But we have no idea why and how such a thing occurs. Or. what property space has, to allow it to be distorted.

We discovered an electron over one hundred years ago. What does one look like? What in the heck powers the E and M field of this spec? Do we just say that it is intrinsic? Is that the scientific answer? So, we just put that mystery aside and theorize on the beginning of the universe?

How can we answer big questions, when we can't answer the small ones?

What is mass? E=mc2. What is m? We can only define mass, by the way it reacts. We have no clue what it is. How can one answer where and when it came, without knowing what it is?

All of our technology is done with relationship, not knowledge.

We are very limited on what questions we can answer. Our knowledge of existence is only relational. The cause and the dynamic of the relationship is still un-known.

We have no clue to the cause and dynamic of charge rotation or movement. We can only measure where it moves. We relate to that. Why and how does it rotate? No one knows. Why does it continue to rotate, without energy being supplied?

We have no clue to the dynamic of emission, only the velocity after it.

We use the distortion of space to explain some relationships. But we have no idea why and how such a thing occurs. Or. what property space has, to allow it to be distorted.

We discovered an electron over one hundred years ago. What does one look like? What in the heck powers the E and M field of this spec? Do we just say that it is intrinsic? Is that the scientific answer? So, we just put that mystery aside and theorize on the beginning of the universe?

How can we answer big questions, when we can't answer the small ones?

What is mass? E=mc2. What is m? We can only define mass, by the way it reacts. We have no clue what it is. How can one answer where and when it came, without knowing what it is?

All of our technology is done with relationship, not knowledge.

#### Sacorivergraphics

This is a great question. I firmly believe that the best answer is the Many Worlds Interpretation of Quantum Mechanics. This theory answers a lot of questions but the biggest one of all is where did we come from, what was here before our existence and it may even answer the question of consciousness. As we all know, the BBT ( Big Bang theory) explains the rapid acceleration of spacetime just after the event which likely occurred due to a quantum fluctuation. but “in” what? The Multiverse answers this question. our Universe is simply a bubble Universe that formed from said fluctuation in a higher dimensional space known as the Multiverse which is infinite in every respect, up, down, left, right and in all higher dimensional timelines. In turn it is quite likely that every bubble Universe is a parent to an infinite number of its own bubble Universes and those bubble Universes create their own bubble Universes and so on. Essentially the Multiverse is an infinitely unfolding fractalThis best explains how our Universe exists at all, a Universe that would otherwise appear to have been created via intelligent design, how else could it exist perfectly calibrated to birth life, let alone intelligent life. This removes the messy loose end of what came before our current Universe which removes the need for a creative hand. We just happen to find ourselves in this Universe because statistically it was inevitable that infinite quantum fluctuations should eventually spawn a life-sustainable Universe. And since the Multiverse is a higher dimensional, infinite construct then the odds are in our favor (obviously).

Now I do have a little bit of a problem with the idea that every time a conscious, sentient being makes a decision, a whole bubble Universe splits off on its own. I think it’s more likely that an alternate timeline is generated that continues to “run” its course parallel and unreachable. At least as far as we know.

So there are a few different types of Universe creation events:

1. Quantum Field Fluctuations
2. Creation of a “new” Universe from the collision of two or more bubble Universes
3. The creation of a new Universe form when a Universe that has just the right amount of matter and energy to create an expanding and contracting Universe

## Problems with the Standard Big Bang Model

There are a number of characteristics of the universe that can only be explained by considering further what might have happened before the emission of the CMB. One problem with the standard Big Bang model is that it does not explain why the density of the universe is equal to the critical density. The mass density could have been, after all, so low and the effects of dark energy so high that the expansion would have been too rapid to form any galaxies at all. Alternatively, there could have been so much matter that the universe would have already begun to contract long before now. Why is the universe balanced so precisely on the knife edge of the critical density?

Another puzzle is the remarkable uniformity of the universe. The temperature of the CMB is the same to about 1 part in 100,000 everywhere we look. This sameness might be expected if all the parts of the visible universe were in contact at some point in time and had the time to come to the same temperature. In the same way, if we put some ice into a glass of lukewarm water and wait a while, the ice will melt and the water will cool down until they are the same temperature.

However, if we accept the standard Big Bang model, all parts of the visible universe were not in contact at any time. The fastest that information can go from one point to another is the speed of light. There is a maximum distance that light can have traveled from any point since the time the universe began—that’s the distance light could have covered since then. This distance is called that point’s horizon distance because anything farther away is “below its horizon”—unable to make contact with it. One region of space separated by more than the horizon distance from another has been completely isolated from it through the entire history of the universe.

If we measure the CMB in two opposite directions in the sky, we are observing regions that were significantly beyond each other’s horizon distance at the time the CMB was emitted. We can see both regions, but they can never have seen each other. Why, then, are their temperatures so precisely the same? According to the standard Big Bang model, they have never been able to exchange information, and there is no reason they should have identical temperatures. (It’s a little like seeing the clothes that all the students wear at two schools in different parts of the world become identical, without the students ever having been in contact.) The only explanation we could suggest was simply that the universe somehow started out being absolutely uniform (which is like saying all students were born liking the same clothes). Scientists are always uncomfortable when they must appeal to a special set of initial conditions to account for what they see.

## Before the Beginning

Britain’s Astronomer Royal, Martin Rees , took time from his busy schedule to talk with Astrobiology Magazine’s Chief Editor and Executive Producer, Helen Matsos. His three-part interview considers a broad range of alternative planetary futures, while highlighting today’s changes in one of the oldest sciences, astronomy.

Martin Rees earned his degrees in mathematics and astronomy at the University of Cambridge , where he is currently professor of cosmology and astrophysics and Master of Trinity College. Director of the Institute of Astronomy at Cambridge, he has also been a professor at Sussex University. He has been Britain’s Astronomer Royal since 1995. He has modeled quasars and has made important contributions to the theories of galaxy formation, galaxy clustering, and the origin of the cosmic background radiation. His early study of the distribution of quasars helped discredit the steady state cosmological theory. He was one of the first to propose that enormous black holes power the quasars. He has investigated the anthropic principle, the idea that we find the universe the way it is because if it were much different we would not be here to examine it, and the question of whether ours is one of a multitude of "universes." He has written nine books . Through his public speaking and writing he has made the Universe a more familiar place for everyone.

Helen Matsos (HM): Last year the big "science event" was measuring the cosmic microwave background and dating the big bang to 13.8 billion years ago, within an 8 to 10 percent margin of error. Can you give us some idea of the boundaries of the big bang — what was it like in the first seconds, and how far will the universe expand in the future?

 Spectacular gas remnants from exploding star. Image Credit: Hubble

Martin Rees (MR): It is remarkable that in the last two years we have been able to firm up some of the basic cosmic numbers about the age of the universe, the way it’s expanding, and also what it’s made of. What it’s made of turns out to be rather surprising because atoms are only 4 percent of the total, another 25 percent is so-called dark matter — probably some particles made in the big bang that have no electric charge but just swarm around. And there’s also some energy latent in empty space itself, something we call dark energy, and that’s what’s controlling the expansion of the universe. So we’ve learned that the universe has these rather mysterious ingredients.

The long-range forecast is that the universe will go on expanding forever. Stars will eventually burn out, the atoms they’re made of will eventually decay, and the stars will erode away. Distant galaxies will not merely fade but will get further and further apart and disappear from view because of the red shift. So the long-range future is a universe that is a very cold and empty place. Nonetheless it will go on for an infinite time.

That’s the best guess, but I think we can’t have great confidence in that forecast because it depends on the nature of dark energy, which at the moment is making the expansion of the universe speed up. If it continues that way then we can forecast an infinite future, but the dark energy may be more complicated than we know, so we can’t be sure about the future.

As regards the past, we can trace things back to the initial instant of the big bang. When the universe had been expanding for one second, at a temperature of about 10 billion degrees, the density of atoms still was not very high.

 Illustration of quasar jet, inset green upper left, and illustration of the high-energy particle stream from quasar GB1508+5714. The inset image is thought to be the most distant x-ray jet, at 12 billion light years distant. The jet itself stretches a monstrous 100,000 light years alone. Credit: M. Weiss, Chandra X-Ray Facility, Harvard

But when we go back to the first microsecond, the first nanosecond, the first tiny fraction of a second, then things become slightly more uncertain because conditions were more extreme. If we go back to times earlier than of a trillionth of a second, then the conditions were so extreme that we don’t have any confidence in explaining the physics. In the first trillionth of a second, every particle in the universe was moving with more energy than can be produced in the biggest possible accelerator on Earth, and the density was far higher than the density of the atomic nucleus.

So the very early universe is a matter or conjecture rather than consensus, because we don’t understand the basic laws. Nonetheless, there are many fascinating ideas about what happened in the very early universe in that first tiny fraction of a second. Certainly the key features of the present-day universe were imprinted at that time. The fact that the universe contains matter but not antimatter, the way it is expanding, the fact that it is fairly smooth but has these fluctuations which were the seeds for galaxy formations — all those features were determined at very early stages by physics.

HM: So here it comes Professor Rees, my favorite slumber party question: What happened before the big bang?

MR: (laughs) People always ask, "What happened before the big bang?" We certainly can’t answer that question, because we have to worry about what the question might actually mean. One of the most popular ideas by physicists is that when you extrapolate back to the very beginning, we have to jettison many of our common sense ideas about space and time. Maybe it’s no longer the case that space has just three important dimensions and time just ticks away.

That makes the early universe more complicated to analyze. If you don’t have a clear idea of clocks ticking away, the idea of a direction of time – a "before" and "after" – doesn’t have any clear meaning.

There are lots of ideas of what might have happened at the very beginning, but we can’t say whether there are other big bangs apart from ours. If there are, we can’t say whether they are before or after or alongside ours, because to make such a statement implies that you can have a single coordinate system covering them all and a single clock that can be coordinated and synchronized between the different universes. So we can’t trace things right back to the beginning, we can’t say whether our universe is the only one, and we can’t even say whether there are only three dimensions of space.

HM: Are you alluding to string theory? Does this theory shed new light on multiple universes?

 Higher dimensional universe of complex topologies, loops and strings Image Credit: The ATTIK, NY

MR: One feature of string theory is it requires six extra-spatial dimensions. The debate is about whether those dimensions all are so tightly wound that they manifest themselves on a microscopic scale. Each point in our ordinary space would be like origami, tightly wound to six other dimensions.

But the more exciting possibility is that not all the extra dimensions are tightly wound together. There could be other universes that are separate three-dimensional spaces, separated from us because we are all embedded in four-dimensional space. We are unaware of them in the same way that bugs crawling around on a sheet of paper might be unaware of bugs on a different sheet of paper. Each think they are in a two-dimensional universe, and have no concept of a third. So there could be another universe just a millimeter away from us.

That’s one of the many ideas opened up by string theory. The ideas are very speculative because there’s no direct measurement we can make, but they have made people more open-minded about different possibilities. Physical reality is much more complicated than we can observe with our telescopes. Indeed, some extreme versions of this idea suggest that physical reality might be as complicated as biology, and that what we call our "observable universe" may be, in the perspective of cosmic reality, no more than one twig on one tree in some enormous forest.

HM: Almost like a fractal analogy.

MR: Yes, but on a vast scale.

HM: Do you personally believe in string theory?

MR: When it’s so uncertain, it’s best to remain agnostic and open-minded about all these new ideas. I certainly think it’s good that people are seriously exploring these ideas in the hope that there will be some way of firming them up. It’s an inspiring conception: a physical reality even grander than the part people can see. Just as we regard our Earth as a rather special oasis in our galaxy, so we might regard our whole observable universe as some friendly oasis within a huge multi-verse.

The Martin Rees interviews on cosmology and biology are serialized in three parts: Our Cosmic Patch (1), Before the Beginning (2), and Our Cosmic Self-Esteem (3.

## New cosmological theory of secondary inflation avoids excess of dark matter

An artist’s impression of a shorter, secondary inflationary period that could account for the amount of dark matter estimated to exist throughout the cosmos. Image credit: Brookhaven National Laboratory. Standard cosmology &mdash that is, the Big Bang Theory with its early period of exponential growth known as inflation &mdash is the prevailing scientific model for our universe, in which the entirety of space and time ballooned out from a very hot, very dense point into a homogeneous and ever-expanding vastness. This theory accounts for many of the physical phenomena we observe. But what if that’s not all there was to it?

A new theory from physicists at the U.S. Department of Energy’s Brookhaven National Laboratory, Fermi National Accelerator Laboratory, and Stony Brook University, which will publish online on 18 January in Physical Review Letters, suggests a shorter secondary inflationary period that could account for the amount of dark matter estimated to exist throughout the cosmos.

Brookhaven Lab. physicist Hooman Davoudiasl published a theory that suggests a shorter secondary inflationary period that could account for the amount of dark matter estimated to exist throughout the cosmos. Image credit: Brookhaven National Laboratory. “In general, a fundamental theory of nature can explain certain phenomena, but it may not always end up giving you the right amount of dark matter,” said Hooman Davoudiasl, group leader in the High-Energy Theory Group at Brookhaven National Laboratory and an author on the paper. “If you come up with too little dark matter, you can suggest another source, but having too much is a problem.”

Measuring the amount of dark matter in the universe is no easy task. It is dark after all, so it doesn’t interact in any significant way with ordinary matter. Nonetheless, gravitational effects of dark matter give scientists a good idea of how much of it is out there. The best estimates indicate that it makes up about a quarter of the mass-energy budget of the universe, while ordinary matter &mdash which makes up the stars, our planet, and us &mdash comprises just 5 percent. Dark matter is the dominant form of substance in the universe, which leads physicists to devise theories and experiments to explore its properties and understand how it originated.

Some theories that elegantly explain perplexing oddities in physics &mdash for example, the inordinate weakness of gravity compared to other fundamental interactions such as the electromagnetic, strong nuclear, and weak nuclear forces &mdash cannot be fully accepted because they predict more dark matter than empirical observations can support.

This new theory solves that problem. Davoudiasl and his colleagues add a step to the commonly accepted events at the inception of space and time.

In standard cosmology, the exponential expansion of the universe called cosmic inflation began perhaps as early as 10 -35 seconds after the beginning of time &mdash that’s a decimal point followed by 34 zeros before a 1. This explosive expansion of the entirety of space lasted mere fractions of a fraction of a second, eventually leading to a hot universe, followed by a cooling period that has continued until the present day. Then, when the universe was just seconds to minutes old &mdash that is, cool enough &mdash the formation of the lighter elements began. Between those milestones, there may have been other inflationary interludes, said Davoudiasl.

“They wouldn’t have been as grand or as violent as the initial one, but they could account for a dilution of dark matter,” he said.

In the beginning, when temperatures soared past billions of degrees in a relatively small volume of space, dark matter particles could run into each other and annihilate upon contact, transferring their energy into standard constituents of matter &mdash particles like electrons and quarks. But as the universe continued to expand and cool, dark matter particles encountered one another far less often, and the annihilation rate couldn’t keep up with the expansion rate.

“At this point, the abundance of dark matter is now baked in the cake,” said Davoudiasl. “Remember, dark matter interacts very weakly. So, a significant annihilation rate cannot persist at lower temperatures. Self-annihilation of dark matter becomes inefficient quite early, and the amount of dark matter particles is frozen.”

However, the weaker the dark matter interactions, that is, the less efficient the annihilation, the higher the final abundance of dark matter particles would be. As experiments place ever more stringent constraints on the strength of dark matter interactions, there are some current theories that end up overestimating the quantity of dark matter in the universe. To bring theory into alignment with observations, Davoudiasl and his colleagues suggest that another inflationary period took place, powered by interactions in a “hidden sector” of physics. This second, milder, period of inflation, characterised by a rapid increase in volume, would dilute primordial particle abundances, potentially leaving the universe with the density of dark matter we observe today.

“It’s definitely not the standard cosmology, but you have to accept that the universe may not be governed by things in the standard way that we thought,” he said. “But we didn’t need to construct something complicated. We show how a simple model can achieve this short amount of inflation in the early universe and account for the amount of dark matter we believe is out there.”

Proving the theory is another thing entirely. Davoudiasl said there may be a way to look for at least the very feeblest of interactions between the hidden sector and ordinary matter.

“If this secondary inflationary period happened, it could be characterized by energies within the reach of experiments at accelerators such as the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider,” he said. Only time will tell if signs of a hidden sector show up in collisions within these colliders, or in other experimental facilities.

## Was the Universe expanding before the beginning of inflation? - Astronomy

At first you might think that in order to understand the structure of something as large as the universe, which by definition contains everything there is, you would need some very powerful telescope to see to the farthest reaches of space and a complex theoretical model. Actually, there are some powerful conclusions you can draw from observations with the naked eye. You will explore that first and then move on to conclusions you can draw from extending your eyesight. You will explore the basic questions that human beings have been asking themselves ever since we have walked the Earth: where did we come from and where are we going?

### Olbers' Paradox and the Dark Night Sky

If the universe is uniformly filled with stars, then no matter which direction you look, your line of sight will eventually intersect a star (or other bright thing). Now it is known that stars are grouped into galaxies, but the paradox remains: your line of sight will eventually intersect a galaxy.

The brightnesses of stars does decrease with greater distance (remember the inverse square law) BUT there are more stars further out. The number of stars within a spherical shell around us will increase by the same amount as their brightness decreases. Therefore, each shell of stars will have the same overall luminosity and because there are a lot of ever bigger shells in an infinite universe, there is going to be a lot of light!

Any intervening material absorbing the starlight would eventually heat up and radiate as much energy as it absorbed, so the problem remains even if you try these "shields". Of course, stars are not points. They do have a definite size, so they can block light from other stars. The total brightness of the universe will not be infinite, but only as bright as the surface of a star (!). You can substitute "galaxy" for "star" in the preceding paragraphs if you want to update Olbers' Paradox for modern times. The way to resolve a paradox like this is to look at the assumptions that are used (the "if" statements) and determine whether or not they are valid.

### Universe Is Expanding

Georges Lemaître and Albert Einstein

In 1915 Albert Einstein published his Theory of General Relativity that described gravity as a curvature of spacetime (see the Relativity chapter). In 1917 Einstein applied General Relativity to the universe as a whole and showed that the universe must either expand or contract. Since there was no evidence of such large-scale motion, he added a term to the equations called the "cosmological constant" to keep the universe static. Alexander Friedman (lived 1888 - 1925) in 1922 and then the Belgian priest/astrophysicist Georges Lemaître (lived 1894 - 1966) in 1927 (independent of Friedman) used General Relativity to show that the universe must be expanding. In his 1927 paper Lemaître suggested a relation between the galaxy speeds and distances like what Edwin Hubble would later observe. Einstein disagreed with Lemaître but Lemaître persevered. Einstein would later come to agree with Lemaître on the expansion of the universe arising from General Relativity after Edwin Hubble announced his observations in 1929 that the universe is not static---it is expanding. In later papers and conferences Lemaître argued for a beginning to the universe that would later become the Big Bang Theory described more fully later in this chapter. In 1933 Einstein agreed that Lemaître was correct. [There is now evidence that Lemaître actually derived a value for the Hubble constant using some early distance measurements of Hubble and Slipher's redshifts in his 1927 paper but his work is less well-known than Hubble's because the paper was published in an obscure journal (Annales de la Societe scientifique de Bruxelles) written in French while Hubble's paper (with Milton Humason) in 1931 with better distance data laying out the case for the galaxy motions first announced in 1929 appeared in the more widely-read Astrophysical Journal and the English translation of Lemaître's paper in a 1931 issue of Monthly Notices of the Royal Academy of Sciences did not have that derivation of the Hubble constant. It was probably the more convincing observational evidence laid out in the Hubble & Humason paper that led Einstein to admit that Lemaître was correct all along.]

The expansion is enough to resolve the paradox. As the universe expands, the light waves are stretched out and the energy is reduced. Also, the time to receive the light is also lengthened over the time it took to emit the photon. Because the luminosity = the energy/time, the apparent brightness will be reduced enough by the expansion to make the sky dark.

The stretching of the light waves makes the light from galaxies appear redshifted, mimicking a redshift from the doppler effect as if the galaxies were moving through space away from us. However, the galaxies are simply being carried along with the expansion of the space between them---the whole coordinate system is expanding. The expansion of the universe means that galaxies were much closer together long ago. This implies that there is a finite age to the universe, it is not eternal. Even if the universe is infinite, the light from places very far away will not have had enough time to reach us. This will make the sky dark.

The Hubble-Lemaître law, speed = Ho × distance, says the expansion is uniform. The Hubble constant, Ho, is the slope of the line relating the speed of the galaxies away from each other and their distance apart from each other. It indicates the rate of the expansion. If the slope is steep (large Ho), then the expansion rate is large and the galaxies did not need much time to get to where they are now. If the slope is shallow (small Ho), then the galaxies need a lot of time to get to where they are now.