Posted 05 February 2010


       

In Celebration of Psalm Nineteen:
God's handiwork in Creation

CREATION OF THE COSMOS,
THE SOLAR SYSTEM AND THE EARTH.


UNDER CONSTRUCTION

Beginning with the depths of space and the regions of remotest nebula, we will gradually descend through the starry zone to which our solar system belongs, to our own terrestrial spheroid, circled by air and ocean, there to direct our attention to its form, temperature, and magnetic tension, and to consider the fullness of organic life unfolding itself upon its surface beneath the vivifying influence of light.
Alexander von Humboldt, Cosmos (1858) p. 79


Thus far we have described the Big Bang and the creation of the elements. Energy and primordial matter -- mostly hydrogen and helium -- were formed in the first few minutes after the Big Bang. All of the other elements were formed in the life and death of stars.

In this chapter we will back up a bit and contemplate the form of the cosmos as a whole, and then move ahead and focus in on our galaxy (the Milky Way), our Solar System and the Earth.

This is the last of the chapters that concentrates on the physical world of Creation. In future chapters we will turn to the creation of life, an even more remarkable display of God's glory and handiwork. This leads ultimately to the creation of humans in his image. So it is well that we contemplate a bit, the remarkable enterprise that went into creation of the physical world in which God could carry out that ultimate intention to create human life.

One theme that we develop is how well the cosmos has been designed to encourage discovery and observation. This is the theme of several books, both old and recent, and is further confirmation of the fact that God intentionally formed his Creation with a Silent Voice that proclaims his Glory and Handiwork.

It is perhaps difficult for an average person to understand the exquisite detail in God's creation of the physical universe -- after all, most of us are not trained in science. Such an understanding requires an appreciation for mathematical details that are both remarkable (to those who understand them) and inexplicable (to both those who understand and those who do not!). The physical world works with an unreasonable precision, following exact natural laws that in one sense seem to have no right to exist at all[FOOTNOTE: A startling example of this is some of the mathematical equations developed in quantum physics. In some cases there is no explanation as to why the equations work as well as they do (EXAMPLE: the ?? equations)]! Biographies of prominent physicists and astrophysicists of the 20th Century dwell at length on these extraordinary facts -- particularly in their descriptions of the struggles of these scientists to bring out the unexpected and profound details.

A full appreciation of the mathematical miracles displayed in the physical creation takes us astray from the present narrative, but some remarks are included in a special essay on The Basics of Physics.

A Cosmos Created to be Discovered.  The word "Cosmos" implies an "orderly, harmonious  whole." The use of the word to refer to the universe appears to go back to the Greeks and Romans[FOOTNOTE: cf. Humboldt, Cosmos (1858) Vol. I. pg 69, footnote.].

The remarkable discovery of modern science is this: the more that modern science illuminates the fundamental rational processes that underlay the universe, the more appropriate the term "cosmos" appears. Not only is the universe orderly and harmonious, but it appears to be designed so that its underlying orderliness and harmony can be understood. It would not have to be this way -- in fact the expectation through most of history up to the present time is in the opposing direction, which is why the discoveries are so surprising (and often resisted) when they arise. This is the essential theme of the "Silent Voice" that pervades this website.

The Extent of the Universe. As late as the early 20th Century the prevailing view among astronomers was that the Milky Way is the universe. Heber Curtis was the first to suggest around 1917 that other galaxies exist. A debate in 1920 between him and Harlow Shapely on this question has been called "The Great Debate".  The 100" Mount Wilson Observatory confirmed the position of Curtis when Edwin Hubble made detailed observations in the1920s. Hubble's observations of the red-shift of distant galaxies showed that the universe is expanding. The red-shift is proportional to the distance, a fact known as Hubble's Law, first published after about 10 years' observations on the 100" telescope.

Figure 1 is a recent image of deep space from the Hubble Space Telescope (launched in 1990). Such images show that the universe has billions of galaxies more-or-less uniformly distributed at all distances out to the limits of observation, each galaxy containing billions of stars (Our nearest galaxy, the Adromeda constellation, may contain as much as a trillion stars). A follow-on to the Hubble Space Telescope,  the James Webb Space Telescope will be operational around 2014. This telescope has about 3x the aperature of Hubble (6.5m vs. 2.4m), and so should be able to capture deep space in even greater detail.

Figure 1
Ultra Deep Space View
Hubble Space Telescope


In the early 1900s, many people pointed to the vastness of the universe as showing the insignificance of the human creation. For example ??? wrote [[[]]].

GIVE A QUOTE ON INSIGNIFICANCE

nondescript planet star insignificant




However, almost as soon as this assertion was made, other people disputed the conclusion by showing that in fact the universe is finely tuned for habitation by humans. Indeed, the vastness of space is an essential prerequisite for that creation. This is the general theme of the so-called Anthropic Principle, which is the theme and title of a remarkable book by John D. Barrow & Frank J. Tipler that first appeared in 1986. A brief quotation from the Introduction to that book should suffice:

"For there to be enough time to construct the constituents of living beings, the Universe must be at least ten billion years old and therefore, as a consequence of its expansion, at least ten billion light years in extent. We should not be surprised to observe that the Universe is so large. No astronomer could exist in one that was significantly smaller. The Universe needs to be as big as it is in order to evolve just a single carbon-based life form."
Barrow & Tipler,
Introduction, Pg. 3

[I would add, "and in fact, the Universe is remarkably young to have achieved such a project, which appears to have come about at the first possible moment." - dcb]


Formation of galaxies. As the universe expanded from the Big Bang, gravitational attraction separated the initial huge and amorphous cloud of hydrogen and helium atoms to into many individual clouds that were gravitationally bound. A characteristic of gravity is that gravitational attraction will over time amplify and exaggerate any non-uniformities in density. This process of segregation into gravitationally bound regions took many hundreds of millions of years in which the clouds gradually coallesced in the direction of its center of gravity, forming the future galaxies.  Each cloud has an overall, statistically random, angular momentum which may in turn be amplified or reduced by the  attraction  of nearby clouds.  As the cloud coalesces, it becomes more compact, and the (constant) angular momentum causes the cloud to rotate at increasing speed. This rotation results in a shear (the outer limits of the cloud lag the portions that are closer to the center of rotation) that becomes more pronounced as the condensation continues. The rotation defines a plane perpendicular to the (constant) angular momentum vector that passes through the cloud's center of gravity. As time passes, continued gravitational collapse causes the cloud to flatten towards the rotational plane.



How Galaxies and Stars Form
 
The formation of galaxy clusters, galaxies, star clusters and stars all proceeds in a similar sequence of stages.

Random centers of gravitational attraction appear.
- They may be black holes or other massive entities (most galaxies appear to have black holes at their center)
- They may be formed by intersecting shock waves or "tsunamis" travelling through the universe.
These centers combine and grow into large clouds of matter by collision and accumulation of surrounding matter.
The space between clouds gradually thins out and the clouds become physically separate with a characteristic center of gravity, (relatively) constant mass, angular momentum and velocity.
The clouds shrink towards the center of gravity. The ambient heat increases towards the centr of gravity, as gravitational potential energy converts to kinetic energy and the cloud particles increase their speed in moving towardsd the center.
Random motion of cloud particles gradually evolves to uniform rotation around the center of gravity. The cloud flattens as this occurs.
Nuclear ignition occurs if the temperature and density rise to levels that can sustain the fusion of hydrogen to helium. Subsequent evolution depends on the involved cloud mass -- ranging from long-lived stars for low mass to rapid formation of black holes when the mass is high.
The formation of black holes limits the practical size of stars: there are no stars of galactic mass! In fact, the mass of a typical galaxy is billions of times the mass of any star. On the other hand, there is no physical limit to the mass of a black hole (and in fact, it is surprising that the entire universe has escaped from becoming a black hole).

This process is duplicated at all size scales. At the highest scale, galactic clusters form; within clusters, galaxies form, and within galaxies, stars form, all from the same basic sequence of events. If the mass of a cloud is too small, it will remain as dark matter, because the mass is too small to cause nuclear ignition.
  
The frequently observed spiral arms of galaxies are due to the fact that matter far from the galactic center has a lower rotational velocity (has much farther to go!). Nonetheless, the implied mass of galaxies (including the Milky Way) is about ten times larger than can be accounted for by the observed stars and interstellar matter. Thus there is a lot of dark matter  left unaccounted for (see the comments on Dead Ends for Matter).



Within the cloud local fluctuations in density cause the cloud to further segregate into local regions of gravitational attraction. Again, as was the case with the overall univers (ree, local gravitational forces again accentuate the minor fluctuations. As a local region collapses, it heats up due to the gravitational acceleration of the cloud particles.  If a local region has sufficient mass, it forms a star when the heat rises to the ignition temperature for Hydrogen nuclear fusion (about ??? °K). The specific details depend strongly on the total mass of the gravitationally attracted region.

The Endgame for Stars.  Stars burn by nuclear fusion of light elements into heavier elements. This process was discovered and described by Fred Hoyle and others in the 1950s. First generation stars burn primordial hydrogen and helium into heavier elements. This burning process continues (if the star has enough mass) to heavier elements as long as the product of fusion is exothermic -- that is, it adds heat energy to the star. This includes all elements up to the iron-group elements (iron, cobalt and nickel). All heavier elements are endothermic -- that is, they absorb energy during fusion. Depending on the star's mass,  it ends in a number of ways: as a brown giant (insufficient mass to continue fusion to the iron group), white dwarf (???), supernova (ends life in a massive explosion) or black hole (so massive that it collapses in on itself.

Supernovas create the heavy elements and scatter the star's "ashes" into the surrounding space. These ashes can form new clouds which condense into second (and higher) generation stars. The distinction between first- amd second-generation stars is that first generation stars begin with hydrogen and helium, but second generation stars have in addition a small proportion (typically 1% or so) of heavier elements, the ashes of earlier generation stars. Our Sun is an example of a second-generation star, having about 99% of its mass in hydrogen and helium, and 1% of its mass in heavier elements.

Dead Ends for Matter -- The ordinary state for matter is that it exists as elements (made up of protons, neutrons and electrons) and energy in the form of photons. This ordinary matter remains available for chemical and nuclear interactions. However the endgame for stars can result in other states of matter that in effect "leaks" matter out of the universe in the sense that it becomes (virtually)  unavailable for further use. Such matter only exerts gravitational influence on ordinary matter. Examples are:

Black holes. Black holes consist of matter that is so highly condensed that light and matter cannot escape. Any matter that is gravitationally attracted will be absorbed into the black hole if it approaches to within the black hole's event horizon. Aside from gravity, a black hole can possess angular momentum (spin) and an electromagnetic axis which can affect charged particles that pass within its influence. One would normally expect a black hole to spin at rather high speed because all of the angular momentum is concentrated into a very small physical object.

Since there is a (theoretical) event horizon for a black hole of any mass, it is theoretically possible for black holes to exist at all sizes from ultra-microscopic to macroscopic.

Black holes are not perfect dead-ends. The gravitational energy near the event horizon of a black hole can cause the creation of matter-antimatter pairs. One of the pair may pass within the event horizen and the other may escape. In this way, there may be a slow leakage of the black hole's mass, and eventually small black holes may even "evaporate" away.

Neutrinos. Neutrinos are very small chargeless point particles (like electrons but without a charge) that are an end product of proton or neutron disintegration. Vast quantities of neutrinos are produced in supernova explosions. Neutrinos exhibit gravity but no electromagnetic forces and so interactions with ordinary matter are very rare. They can pass right through a nucleus without interacting unless they hit a neutron or proton "spot-on".  Neutrinos that pass out of a star into space will therefore typically travel forever without interacting with ordinary matter. In effect their mass and energy have been "leaked out" of the world of ordinary matter.

Other exotic matter. There may be other dead-end matter other than black holes and neutrinos. Not sure what they might be, but the possibility is there.

The motion and shape of the galaxies (angular momentum, etc.) indicates that only about 10% of it can be accounted for by the observable ordinary matter. Thus almost 90% of the matter of the universe is "missing" as interstellar dark matter, black holes, neutrinos or other still unidentified matter. An interesting question is whether dead-ends can account for this matter, or if there are other things to look for.

Second Generation Stars. The Solar System. The Sun is a second-generation star (stars other than first-generation are called second-generation, although they may actually be third- fourth- etc. generation). The solar system condensed out of a gravitationally-bound dust cloud that was the product of a supernova explosion that occurred 4.54±.01 billion years ago. This age equates to the age of the oldest meteorites which consist of matter formed at the time of the original supernova. The age is determined by radioactive dating based on the radioactive decay of elements with very long half-lives: Rubidium-87 to Strontium-87  (half-life 49 By) and Samarium-146 to Neodymium-142 (half-life 106 By), and other radioactive decay pathways. Confidence in this age estimate comes from the fact that the same maximum age comes out of many independent tests using many independent measuring methods on many different meteorites. It should be noted that radioactive dating gives the most recent time that the meteorite was last disturbed - through impact, melting, etc. So the oldest measured dates for meteorites are for meteorites that were undisturbed since their first formation -- younger ages correspond to meteorites that have been disturbed in some way.

As is the case with galaxies, as the cloud contracts, it flattens along the plane of rotation. Planets form by aggregating the solid matter, gradually sweeping out material in their orbits. Denser matter accumulates to form the inner planets and lighter matter accumulates to form the outer planets. All of the planetary orbits are within about 8° of the plane of the solar system.

The Solar System is about 100,000 light-years in diameter. It is part of a galaxy cluster called the Local Group, about 10 million light-years in diameter, and which includes about 36 galaxies. The nearest galaxy (Andromeda) is about 2 million light-years away.

One of the remarkable features of the Solar System is that the Sun is located in the Milky Way galaxy a position that affords a comprehensive view of the entire universe. The sky is dark, and not so filled with nearby objects that deep space is obscured from our view. In fact, this is a necessary condition for the existence of life, because other locations would be subject to excessive radiation and unstable orbits[FOOTNOTE: This is one of the observations of Gonzalez and Richards, The Privileged Planet. See also Brian Greene, The Elegant Universe.]. [ADD MORE] The only major portion of the universe that is blocked from our view is that portion that falls in the line of sight with the center of the Milky Way, which is obscured because of the dense radiation and compactness of the galaxy center itself.  Even the disk-like Milky Way galaxy itself does not severely block our view of deep space because we are located sufficiently far from the dense spiral arms of the galaxy that we have a good view of deep space in nearly every direction -- see Figure 2. The Solar System is somewhat off the Orion Spur about half way between the galaxy center and the outermost spiral arms (Figure 1a).  This spur is between the Sagittarius Arm and the Perseus Arm, both roughly 7,000 light-years away.

Annotated Solar System Showing Major Regions
The Solar System From Deep Space
FIGURE 2
The Milky Way Galaxy
Showing the location of the Solar System

The nearest star to the Solar System is at a distance of 4.24 light-years (Proxima Centauri, one of three stars in the Alpha Centauri group), and there are only 65 stars and 4 brown dwarfs within 16.3 light-years - 5 parsecs (See Figure 3). This local density is low enough that nearby stars have not had a significant gravitational influence on the Solar Syatem over the past ??? billion years.

Figure 3
Stars within 14 Light-years
(From Wikipedia)

Figure 4
The Local Group
Galaxies within 3 million Light-years
Principle galaxies are Andromeda and Triangulum


Formation of the Solar System and Planets[Footnote: See the slide presentation The Formation of the Sun and Planets].
The solar system began as a small part of a large nebula, the remnant of a supernova, and thus is a second generation star. All of the chemical elements produced by the supernova are represented in the cloud, which included chunks similar to the meteorites, some of which have remained unchanged since the occurrence of that supernova explosion. Original (unmodified) meteorites can be dated by long-lived radioactive elements (and their daughter products) that were formed in that supernova explosion. Thus the (minimum) date of the supernova explosion equates to the oldest meteorites, namely 4.55 billion years[Footnote: Dalrymple books].

This supernova or another massive explosion compressed a small part of the nebula that became gravitationally isolated and began to coalesce under its own gravitation.

The Sun formed from this cloud in the standard way.
Near the gravitational center of mass the nebula eventually collapsed enough to ignite and form our Sun, with the rest forming the materials that would become the solar system. Near to the Sun, the volatile matter (water, hydrogen, helium, methane, etc.) evaporated in the Solar heat, and dispersed, leaving a coarse dust of solid matter behind. The oldest meteorites give us a sampling of this coarse dust. The evaporated material from the inner planets was swept outward by radiation pressure and solar wind, to re-solidify in the cold outer regions.

ProtoplanetaryDisk.jpg NASA/JPL-CalTech
Figure 5
Protoplanetary Disk
Credit: NASA/JPL-CalTech
   
This matter orbited the Sun and gradually coalesced into rocks, planetessimals, eventually forming the inner planets: Mercury, Venus, Earth and Mars. Beyond a certain point, the solar heating did not evaporate the volatile matter, which remained in solid or liquid form, and eventually formed the outer planets: Jupiter, Neptune, Saturn, Uranus. Over time the planets swept out debris in their orbital paths.

Jupiter, composed largely of methane (CH4) became very massive. As a result, no large planetary objects formed between Mars and Jupiter because tidal action from Jupiter would break up large objects. This formed the Asteroid Belt. The largest object in this belt is ???.

As the rocky planets formed from increasingly larger chunks of space debris, the impacts melted the planets so that they were all molten at an early point in their lives. Heavier elements moved towards the cores of the planets, with lighter materials migrating to the surface.

Normally one would expect from this scenario that the Earth would have relatively little water -- indeed it is a trace material, less than ???% by mass. It is not certain where the water on Earth came from -- whether from water buried deep in rocks (hydrates, for example), or whether the water arrived from bombardments from the asteroid belt or from outside the Solar system. In any case, when Earth grew by aggregation, its own gravity was able to hold vaporized water, but not the lightest gases such as hydrogen and helium which would leak out into space unless they combined with some heavier molecules.


Formation of the Earth and Moon[FOOTOTE: See the description of this in David C. Bossard,
A Fit Place to Live (2003)]. About 5.2 billion years ago, late in the accretion stage and at a time when the Earth had formed a thin crust over a molten core, a Mars-sized object collided with the Earth, projecting crustal material into a close orbit around the Earth. These fragments again accreted over time to form the Moon, which consists of material similar to what is found in the Earth crust.

The Mars-sized object probably originated in the asteroid belt when a random collision displaced it out of the belt and gravitational thrust from Jupiter propelled its orbit into the Earth's path.

This impact melted the Earth once again. The Moon was in a close orbit which gradually increased to the present day. Tidal friction gradually slowed the Moon's rotation until it eventually became synchronized with the Earth, so that today the Moon presents the same face to the Earth at all times.

For the next 300 million years, 
the Earth and Moon were bombarded by many objects from space -- perhaps the Solar System passed through a belt of debris, or further material was ejected from the Asteroid belt. The current heavily cratered Moonscape shows the results of this bombardment, which probably hit Earth as well. During this time Earth remained molten -- partly due to the effect of impacts, and partly due to the extreme tidal effects of a nearby moon.

Eventually, at about 4.9 billion years ago, the Earth cooled to below the boiling point of water. At this point the Earth's crust was relatively smooth and the entire Earth was covered by water to a depth of about 800 feet. There were frequent and violent volcanos which wracked the Earth, and spewed out water, nitrogen and other gaseous material. Volcanic cones occasionally pierced the ocean surface, but quickly eroded because of the high tides.

[DEVELOP SHARP POINT: THE VALUE OF A MOON FOR LIFE]

The Earth was largely cloud-covered (much like Venus today) and the atmosphere consisted primarily of Nitrogen, with trace amounts of carbon dioxide. The ocean was quite salty because it had formed as the Earth cooled from a molten state, so it was filled with minerals to the saturation point.

At this point the Earth was heated by a combination of the Sun and radioactive elements, particularly Uranium, which was still aged far less than its half-life since the time of the Supernova. The radiation level of solid material in the crust was comparable to the radiation level of fuel rods used in modern Nuclear power plants -- about 3%[CHECK THIS!!!].



The Second Day
Genesis 1:6-8: And God said, "Let there be an expanse in the midst of the waters, and let it separate the waters from the waters." And God made the expanse and separated the waters that were under the expanse from the waters that were above the expanse. And it was so. And God called the expanse Heaven. And there was evening and there was morning, the second day.

   I suggested earlier that the First Day refers to the creation of radiant energy in the Big Bang. Continuing with this suggestion, I suggest that the Second Day is the creation of the Cosmos, the Solar System and Earth -- viewed as are all of the Days, from the perspective of an observer on the Earth.
It seems to be difficult for modern readers to avoid projecting modern meanings into the very general terms used in these verses. Readers are strongly cautioned to avoid this -- it is a particular affectation of academic scholars who tend to view the ancients with unwarranted condescension.

The term "waters" is a general term for the fluid "stuff" of the Cosmos. It does not refer specifically to water per se. This is a universal usage of the word in many ancient cosmological stories, and it reads too much into the word to assume that it means what we call water. Many modern narrators of ancient cosmologies make this mistake and assume that, for example, the Egyptians assumed that the original stuff of the universe was literal water. [GIVE REFERENCES ] This is silly. It is a much more general term that encompasses a meaning of undifferentiated fluidity. And again, "fluid" here doesn't mean just the liquid state of matter -- fire and air can also be viewed as fluid. The term is more of an expression of visual impression than of actual physical composition.

The term "expanse" (which some translations starting with the LXX interpret as "firmament") similarly has nothing to do with a solid dome or any specific physical construction. All uses of the term that may imply this are simply figurative or poetic, as in "the sky was brass."

The term "separate" implies assignment of identity and  differentiation. This task changes the undifferentiated "water" into specific objects with form, function and meaning. Some of this separation is into "below" and "above." In a very general sense, the "below" is the Earth, and the "above" is the Cosmos, with the atmosphere in between.  But again, the reader is cautioned not to make the meanings too concrete.

What is being described is the incomprehensible and inconceivably vast process by which God made the Cosmos and differentiated it into various parts with purpose and function. That process is what we have celebrated our discussions up to this point in the Creation Narrative.


The Silent Speech          Origin of the Solar System and Earth
The form and composition of the Solar System gives clear evidence of how it formed from the remnants of a supernova that occurred about 4.55 Ga ago. The evidence includes the following physical facts:

1. Shape. The solar system is a rotating, flattened disk, a shape that results when a loose, roughly spherical, rotating aggregation of widely dispersed matter contracts under gravitational attraction. The flattening occurs perpendicular to the axis of rotation.

2. Composition. The Sun is made up of the same elements that form its satellites. The primary source of energy is hydrogen fusion but the presence of the heavier elements indicate that the Sun formed from the remnants of earlier stars.

3. Gradient. The inner planets are smaller and consist primarily of heavier elements - rocky material - while the outer planets are larger and consist primarily of lighter elements. This gradient is consistent with the separation of matter that occurs due to centrifugal action of the rotating disk.

   ??? HOW DOES THIS SQUARE WITH "More-dense components of the mixture migrate away from the axis of the centrifuge, while less-dense components of the mixture migrate towards the axis." (WIKI on centrifugation)  OR IS IT SOLAR WIND???

4. Age.  The radiometric age of meteorites has an upper limit of about 4.55 Ga, which indicates that this is the time of a supernova explosion that produced the material of the solar system.



The Silent Speech          Speech from the Heavens

The Visibility of Deep Space.  The Solar System is located off of one of the arms of the Milky Way galaxy. As a result, the night sky is dark and deep space is accessible to our telescopes. If the Solar System had been located in a more "normal" position in the galaxy, then the deep space view would be much more obstructed by neighboring stars in our own galaxy.


The Moon and Earth Shadow During an Eclipse. During a solar eclipse, the Moon's disc almost exactly covers the Sun. Because of this, the Sun's corona and solar flares are clearly visible. The spectrum of the element Helium was first discovered by P.J.C. Janssen in 1868, a French scientist, P.J.C. Janssen, during a solar eclipse. In 1919 a solar eclipse provided the first confirmation of Einstein's prediction that light bends in a strong gravitational field. Anther element first discovered in the Sun's corona during a total eclipse: Coronium (1869). This was a mystery since the element did not appear to be in the periodic table. The mystery was solved in 1927 when I.S. Bown identified it as highly ionized iron (missing 13 electrons). See here for a chronology of discoveries about the Sun from analysis of solar eclipses.

In a total lunar eclipse the moon is not completely dark because it is illuminated with light that has refracted through the Earth's atmosphere. The refracted light is toward the red side of the light spectrum, which gives the moon a reddish hue. For this reason, ancient references to a lunar eclipse often referred to it as a "moon of blood" or a "bloody moon." An example is found in the Bible at Acts 2:20 where the Apostle Peter, one of Jesus' disciples implies that there was an eclipse at the time of Jesus' crucifixion.29

1999 Solar Eclipse2001 Lunar Eclipse




The Unique Requirements for Earth to Support Life. [WORKING - Later chapter??]


The Physics of Deep Space

Distance Measurements

    Deep Space distance measurements

    Direct Measurements -- Parallax

       The First parallax measurements
   
        Deep Parallax Measurements



fractal

NOTES


The Creation Days as God's Workdays
   
One way to view the days of creation is as God's workdays. [DEVELOP from Discovery institute seminar]. References to human labor are by analogy: "Six days shall thou labor and do all thy work." Mankind has its workdays, and God specifies one day of rest for six days of work. God's creative work is similarly expressed as six days of work and a day of rest. There is no implication as to the precise duration of these days, and to assert such a thing is to read an unwarranted meaning into the text.





The "Goldilocks" Universe
Many scientists and writers have remarked on the fact that the universe is remarkably fine-tuned for life -- it is "just right" as Goldilocks remarked about Baby Bear's porridge. This is the essence of the Anthropic Principle -- but it is more than just that the universe is "just right" for human existence, it is also "just right" for discovery. One could easily imagine a creation in which its most basic features would be impossible to discover -- in fact, that has been the default assumption of humans throughout history. Discovery of new facts always seems to come with amazement and disbelief: after all, humans have been contemplating the world for many thousands of years without knowing this fact -- perhaps it wasn't even missed!

Perhaps the most remarkable example of this default assumption came from the 19th century philosopher Auguste Comte, who gloomily observed regarding the starry heavens that

“On the subject of stars, all investigations which are not ultimately reducible to simple visual observations are … necessarily denied to us. While we can conceive of the possibility of determining their shapes, their sizes, and their motions, we shall never be able by any means to determine their chemical composition or even their density.”
Auguste Comte, 1835

Comte really stated what seems to be intuitively obvious. How is it possible that a person could analyse the chemistry in a star that is completely beyond reach? But less than twenty years after he said this, the new science of spectral analysis showed quite specifically that we can indeed learn quite a lot about the physical and chemical properties of the stars. And more recent advances, propelled in particular by the astrophysicist Fred Hoyle in the 1950s, have demonstrated that we can even determine the details of the star interiors, and of how they are the forges of the elements.

Books that specifically address the fine-tuning of our "Goldilocks" universe include the following:

Date
Author
Title
1858
Alexander von Humboldt  Cosmos: A Sketch of A Physical description of the Universe

[p. 068] The word Cosmos, which primitively, in the Homeric ages, indicated an idea of order and harmony, was subsequently adopted in scientific language, where it was gradually applied to the order observed in the movements of the heavenly bodies, to the whole universe, and then finally to the world in which this harmony was reflected to us. The word signified ornament (as an adornment for a man, a woman, o a horse). According to the testimony of all ancients, it was Pythagoras who first used the word to designate the order in the universe, and the universe itself.

[073] We shall never succeed in exhausting the immeasurable riches of nature; and no generation of men will ever have cause to boast of having comprehended the total aggregation of phenomena. ... the fruitful doctrine of evolution shows us how, in organic development, all that is formed is sketched out beforehand, and how the tissues of vegetable and animal matter uniformly arise from the multiplication and transformation of cells.


1902 Alfred Lord Russell Man's Place in the Universe.

 [p. 10] "Of late years, it is true, some few writers have ventured to point out how many difficulties there are in the way of accepting the belief [in a plurality of inhabited planets - dcb], but even these have never examined the question from the various points of view which are essential to a proper consideration of it; while, so far as it is still upheld, it is thought sufficient to show, that in the case of some of the planets, there seem to be such conditions as to render life possible. In the millions of planetary systems supposed to exist it is held to be incredible that there are not great numbers as well fitted to be inhabited by animals of all grades, including some as high as man or even higher, and that we must, therefore, believe that they are so inhabited. As in the present work I propose to show, that the probabilities and the weight of direct evidence tend to an exactly opposite conclusion."

1913 Lawrence J. Henderson The Fitness of the Environment.

[p. 292] To sum up, it appears certain that at least in a few instances, and possibly quite generally, purposeful tendencies exist in the organism which seem to be inexplicable by natural selection or any other existing mechanistic hypothesis.

[p312] There is, however, one scientific conclusion which I wish to put forward as a positive and, I trust, fruitful outcome of the present investigation. The properties of matter and the course of comic evolution are now seen to be intimately related to the structure of the
living being and to its activities; they become, therefore, far more important in biology than has been previously suspected. For the whole evolutionary process, both cosmic and organic, is one, and the biologist may now rightly regard the universe in its very essence as biocentric. [emphases added - dcb]

1965
A.E. Needham
The Uniqueness of Biological Materials

[preface] There were two main reasons for attempting this book. The first was an interest in the philosophical qustion: Is the uniqueness of life inherent in the material of living organisms? ... [second] whether, and in what ways, biological materials are unique.

1986
John D. Barrow & Frank J. Tipler
The Anthropic Cosmological Principle.

[p. 3] "For there to be enough time to construct the constituents of living beings, the Universe must be at least ten billion years old and therefore, as a consequence of its expansion, at least ten billion light years in extent. We should not be surprised to observe that the Universe is so large. No astronomer could exist in one that was significantly smaller. The Universe needs to be as big as it is in order to evolve just a single carbon-based life form."

1987
Wallace S. Broecker
How To Build a Habitable Planet
1992
Harold J. Morowitz
Beginnings of Cellular Life:Metabolism Recapitulates Biogenesis
2004
Guillermo Gonzalez & Jay W. Richards The Privileged Planet: How Our Place in the Cosmos is Designed for Discovery.
2007
Paul Davies
Cosmic Jackpot: Why Our Universe is Just Right for Life.
2008
George V. Coyne & Michael Heller
A Comprehensible Universe: The Interplay of Science and Theology






Meteorite Ages
   
Meteorite Ages

from G. Brent Dalrymple, Ancient Earth, Ancient Skies (2004). See also The Age of the Earth (1991) Table 6.3, p. 287


Accuracy of Positional Measurements recorded in Star Catalogs
  
Star Catalog
Time Period
Accuracy
Remarks
Ptolemy's Almagest (naked eye)
c. 200 AD
3-8 arc-minute
some systematic errors due in part to adjustments from Hipparches' sky catalogs. Ptolemy considered the (relative) accuracy of his tables at 10 arc-minutes.
Copernicus'  De Revolutionibus  (naked eye)
1543 AD
3-8 arc-minute
Used Ptolemy's tables, corrected and updated in the intervening years by many (mostly moslem) scientists.
Tycho Brahe
1590 AD
0.5 to 1 arc-minute (relative)
naked-eye measurements.
Circular approximation to Mercury's orbit had maximum systematic errors of up to 3 minutes.
Johannes Kepler
1609 AD
0.5 to 1 arc-minute Discovery of the Elliptical orbits of the planets removed all systematic errors. Fitting the Mars data with the Brahe/Copernican models showed errors up to 8 arc-minute.
Galileo Galilei
1610 AD
3 arc-seconds
Galileo's early telescope was able to resolve satellites of Jupiter that were separated by about 10 arc-seconds. Inherent error due to scintillation of the atmosphere is about ?? arc-seconds.
Planet diameters are: Jupiter - 20 to 40 arc-sec; Venus - 10 to 60 arc-sec; see http://www.pacifier.com/~tpope/Jupiter_Page.htm
Friedrich Bessel (First parallax msmt of 61 Cygni)
1838

First star parallax measured -- 0.3 arc-seconds for star 61 Cygni (distance 11.43 ly). Required precision timepiece(?)
Harrison's regulator clock 1790?
Atmospheric smearing


Atmospheric smearing of starlight is about 0.5 arc-second.
Twinkling (scintillation) can be 0.4 arc-second at clear, high altitude. Overall, a 1 arc-second smearing is considered good.  This affects spectral analysis of starlight as well as pointing.
Hubble Space Telescope
Hipparchus satellite


Present day accuracy 0.001 arc-second
Very Long Baseline Interferometer (VLBI) antenna arrays 2010?
10-6 arc-second Direct geometric distance measurements for certain classes of galaxies, out to 25 million light-years
(2009 Measurement of Galaxy NGC 4258 at 23.5x106 light-years ± 7%)

NOTES

1, The width of the Moon is about 29.5 to 33.5 arc-minutes. The width of the Sun is about 31.6 to 32.7 arc-minutes. During a full solar eclipse the Sun's corona is visible over the entire perimeter. It remains complete for only a few seconds.
2.
Earth's rotation will cause a star on the Ecliptic to move about 1 arc-minute in 4 seconds, so precise measurements of absolute position were exceedingly difficult and required accurate and reliable clocks, which did not exist until after Harrison's invention of the regulator clock. Tycho Brahe achieved accuracies of 0.5 arc-minutes in relative (star to star) position measurements averaged over a number of observations.
3. Parallax measurements using large baselines require very precise clocks. Cesium atomic clocks (accuracy ??) are used for ???

Direct measurement of Astronomical Distances by Parallax.  Parallax is the direct geometric measurement of changes in the direction of a stellar object when viewed at the extremes of a very long baseline. The first parallax measurements were done in the 1800s to measure the distance to the nearest stars. The accuracy and practical maximum distance that can be measured in this way depends on the length of the baseline and the precision of the angular measurement. The most accurate positioning at present is done in radio frequency astronomy using the Very Long Baseline Interferometer (VLBI) antenna arrays which receive signals from widely separated locations on the Earth. Of course the measurements depend on stellar objects that have suitable coherent radiations in these frequencies. The potential accuracy of current and planned VLBA precision is 10-6 arcseconds which equates to direct distance measurements out to 25 million lightyears. Recently, the galaxy NGC 4258 was measured at  23.5x 106 lightyears ± 7%, based on direct geometric triangulation. According to NASA, VLBI Radio Interferometry is hundreds of times more detailed than the Hubble Space Telescope and the dedicated Hipparcos parallax-measuring satellite.

The Goddard Space Flight Center  VLBI Summary says "VLBI is a geometric technique: it measures the time difference between the arrival at two Earth-based antennas of a radio wavefront emitted by a distant quasar. Using large numbers of time difference measurements from many quasars observed with a global network of antennas, VLBI determines the inertial reference frame defined by the quasars and simultaneously the precise positions of the antennas. Because the time difference measurements are precise to a few picoseconds, VLBI determines the relative positions of the antennas to a few millimeters and the quasar positions to fractions of a milliarcsecond. Since the antennas are fixed to the Earth, their locations track the instantaneous orientation of the Earth in the inertial reference frame."


Reference on various cosmological models and computer simulations.




Solar Heating:
How Did the Earth's Temperature Stay Steady?
   
The Earth cooled from a molten mass around 4 billion years BP. By about 3.9 BBP, it was cool enough that an ocean of water covered the globe to a depth of about 800 feet. From this point to the present -- about 4 billion years, the Earth has maintained a habitable temperature in which life could thrive. During this time heat from the Sun increased about 25%, but heat from radioactive decay of Uranium and other radioactive elements compensated for the lack of heat from the early Sun. This heating effect decreased logarithmically over the same period of time. In addition, exaggerated tidal friction from a nearby moon added a minor contribution to heating of the Earth environment.

Radioactive heating of the Earth's interior has been a main contributor to maintaining a habitable temperature. In the late 1800s, before the discovery of radioactive decay, the source for heat from the Earth's core was a great puzzle, since physical calculations at the time by
Lord Kelvin indicated that core heat would dissipate in a time on the order of 20-400 million years, which was far less than appeared to be the minimum time that life existed on Earth.

Solid line is solar luminosity relative to present (S/S0). SOURCE: Modified from Kasting and Catling (2003). -- Stanford News Press Release, 07 April 2010





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REFERENCES

[Dalrymple] C. Brent Dalrymple, The Age of the Earth (1991). and Ancient Earth, Ancient Skies (2004).

[Gonzalez] Guillermo Gonzalez and Jay W. Richards, The Privileged Planet: How Our Place in the Cosmos is Designed for Discovery (2004).

Biographies of prominent physicists of the Twentieth Century: Meintner, Einstein, Hoyle, Heisenberg, etc.
Ruth Lewin Sime, Lise Meitner: A Life in Physics (1996)
Simon Mitton, Conflict in the Cosmos: Fred Hoyle's Life in Sciences (2005)
Abraham Pais, Subtle is the Lord: The science and the life of Albert Einstein (1982)
Abraham Pais, Niels Bohr's Times (1991).
Of particular value are the books written by the physicist Abraham Pais because he  describes in detail the reasoning and insight that occurred at each stage in the development of modern physics, going far beyond the normal materials of a biography. His book Inward Bound: Of matter and forces in the physical world (1988) gives a marvelous synopsis of this development.

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Posted 05 February 2010