* Astronomy

If bacteria are ubiquitous in the Milky Way Galaxy, then our solar system also must be contaminated. Frozen comet ice may not be conducive to life unless liquid water exists in the core. As the astrophysicist Thomas Gold said: the history of life is just "a gradual systematic development toward more efficient ways of degrading energy."


Bacterial formation of rock in comet cores:

Imagine chemosynthetic bacteria and/or archaea thriving on the reduced minerals in chondrules in the salt water of comet cores. The bacteria would swarm the chondrules, creating a mass of organic material mixed with respiratory carbon dioxide bubbles. This low-density froth would float to the top of the ice water boundary in comet cores, protected from the higher saline and temperature levels further down. As the bacteria consume the chondrules, their waste products accumulate in solution and crystallize into various types of mineral grains and crystallize where the solution becomes (super)saturated, which for most minerals would happen at the low temperature ice water boundary. When the mineral grains grow too heavy to remain in suspension, they precipitate onto the growing core. Unlike most minerals, the solubility of silicon dioxide is inversely proportional to temperature, so quartz would crystallize at the hottest temperatures on the surface of the growing comet core where quartz would fuse the loose grains together like "puzzle pieces" to form solid rock. This mechanism can explain the aqueous (hydrothermal?) formation of various mineral ores, and various rock types, such as: granite, gneiss, schist, BIF, massive quartzite (without fossils), massive chert (without fossils), massive dolomite (without fossils) and some diabase (diabase boulders often exhibit an orange-yellow rind of compacted clay and pock marks of centimeter size to manhole size, likely scoured out by the impact.  Ringing rocks of diabase boulders likely ring due to the compressive stresses imparted at impact.) (Certain supposed trace fossils such as Skolithos should be considered suspect, since inorganic gas-escape structures could alter the cementing medium giving the false appearance of a biological origin.)  The pressure, temperature and chemistry of formation of these quartz-crystals are recorded in their primary fluid inclusions; however, pure water vapor from boiling may artificially lower the saline level in some inclusions. Rock is laid down in layers like on earth, and the rock type changes over time as the chondrule fuel source becomes successively depleted in higher-energy minerals, perhaps, similar to the way supergiant stars successively deplete their hydrogen, helium, carbon, neon, oxygen and silicon. Layers formed on a smaller scale of inches and centimeters could be explained by subsidence of the overlying ice that caves in creating floating icebergs that lower the temperature of the aqueous solution that alter which types of crystals are precipitated.  In between these comet quake events, the aqueous solution may rise in temperature, causing chert and quartz bands to crystallize on the core surface.  These comet quakes might explain the banding of schist, gneiss and BIF.  The waste product minerals of the bacteria are more highly-oxidized than the chondrule minerals from which they are derived, and indeed, granite from comet cores has a lower Gibbs Free Energy than basalt from the earth's crust and mantle. Rock with euhedral minerals, moderate temperature primary fluid inclusions, and the anomalous juxtaposition of minerals with high and low melt temperatures are more readily explained by an aqueous (hydrothermal?) comet source than a molten terrestrial one. As the comet core grows in size, the surface area that cools the rocky core increases as a square function of the growing radius, whereas the volume of its radioactive heat source increases as a cubic. As the temperature of the core rises, the water boils at the rock water interface, and this peculation grows more fractal rock types such as gneiss and schist. Sand and gravel layers may form after boiling begins during intervals of aqueous warming when fewer minerals precipitate and quartz formation on the core dominates.  If rock formation slows or stops, the breakdown of rock from boiling may overtake rock formation to deposit layers of sand and gravel.  Then cataclysmic events, such as impacts or comet quakes, may restart the process of rock formation.  Gneiss and schist exhibit sharp folds with acute angles that come to a sharp point and "logs" of concentric rings that could pass for petrified wood. These fractal features can be explained more simply by stalactite-like formations (both spherical in cross section with concentric rings and curtains of elongated growths) on the surface of comet cores than by metamorphism and shear of either sedimentary or igneous rock. Additionally, violently boiling water will fracture rock, leaving clasts in newly formed rock. In the endgame, the core reaches thermal equilibrium and then begins the slow process of cooling off, as the short-lived radioactive isotopes decay into stable isotopes and the frozen, chondrule fuel source is cut off. When new rock creation ends, the fragmented clasts are tumbled in the ball mill of the boiling surface until all but the hardest and toughest pebbles and cobbles, of mostly quartz and chert, are ground into sediment, sand and gravel. The finest sediment falls to the bottom forming massive shale deposits (that fracture concoidally) and may contain bacterial spores that have gone dormant with the absence of their chondrule fuel source. This organic material may form the oil and natural gas in "oil shale." Above the shale are sand and gravel deposits that form into metaconglomerate followed by conglomerate and finally, perhaps, by loose cobbles or cobbles loosely cemented into clay or mudstone. These comet cobbles are often exposed by stream cuts, and any anomalous mass of highly polished cobbles and pebbles with a rounded cross section in tight groupings of poorly sorted sizes that seem to be "case hardened," that is, having a denser rind, should be suspected to be of comet origin.  Apparently, gold, silver, uranium and thorium rain out of solution into the conglomerates as the solution cools as is found in Athabasca Basin and Wi****ersrand Basin.


Terrestrial comet impacts:

Comet meteorites may not have time to break up in their half-second transit through the lower 90% of earth's atmosphere, but the pressure of encountering the atmosphere may change the state of comet ice to water. When this liquefied ball of water impacts the ground, the splat of the impact blasts out a shallow elongated basin devoid of a crater rim, but the incompressible liquid water surrounding the rocky core apparently prevents it from fragmenting or melting, resulting in the intact succession of layers of the comet core directly overlying the unconformity of the basin. The core may not shatter or melt, but it does fracture (sometimes with slickensides) and compress in the direction of travel as it flattens into an elongated lens shape. On initial touchdown, the comet water apparently cuts through bedrock like an ultra-high-pressure water jet and blasts the fractured rock out of the impact site creating a basin. Large comet impacts may have led to the coal deposits of the Silurian and Carboniferous Periods. The impacts would have knocked down trillions of trees and the fossilized or fossil traces of roots of these trees can be found under comet clay and volcanic ash known as "seatearth," "underclay," "fireclay," or "ganister."  The trees and other dead vegetation washed into the low areas of lakes, seas and impact basins creating anaerobic bogs that eventually lithified into coal. The energy of a comet impact may also fracture the basement rock of the impact basin, creating fault lines that follow weaknesses in the underlying bedrock, and in the case of the largest impacts, may lead to flood basalts, such as the Deccan and Siberian Traps and unconformites, such as in The Great Unconformity. Kimberlite and lamproite pipes containing diamonds and exotic high-temperature minerals may be caused by comet cores impacting the earth "head on" in the earths orbit around the sun, resulting in the highest-possible velocity impacts between comets and the earth.  The geochronological age has been reset for most impacts, but the Late Pleistocene comet from 12,900 ya that hit the Laurentide Ice Sheet creating the Nastapoka Arc basin may give a true age of 4,280 Ma.  The center of the core should be older yet by almost 300 Ma.


Comet origins:

Imagine our solar system as it may have been before the formation of comets and terrestrial planets, when only the sun, the gas giant planets and a solar companion existed. The solar companion may have orbited the sun at a distance of some 500 AU from the sun. Stars typically form in multiples because relative motion to the nebula may be the only way they can sweep up enough of the nebular soup to become star size. Now imagine that the solar companion to our sun were itself a close binary pair of super-size Jupiters, rapidly orbiting their common center of gravity. When our protosun began to shine, its solar wind would have cleared the planetary solar system of gas and dust. Then at some point, a nearby supernova contaminated our solar system with short-lived isotopes and calcium-aluminum refractory grains (Calcium Aluminum Intrusions [CAI] in chondrules). The supernova may also have dislodged an earth-size body or larger that formed in the L4 LaGrangian Position ahead of the close-binary pair of companions in their orbit around the sun. This LaGrangian body apparently assumed a co-orbital horseshoe orbit with the close-binary companions around the sun. On each closest approach of the LaGrangian body to the to the close-binary pair in its horseshoe orbit, it got a gravitational boost, or kick, from the far-higher orbital velocity of the close-binary companions. This increase in orbital velocity would have translated angular momentum from the close-binary orbits into raising the solar orbits of all three bodies. In this way, the LaGrangian body may have caused the orbits of the companion pair to decay until they collided into one another at 4,567 Ma, three million years after the supernova. This collision created a vapor cloud that condensed to form snow and type I and type II chondrules which may have attained escape velocity by flashing molten hydrogen into gas and plasma. This ice and chondritic material accreted to form the terrestrial planets and moons, Saturn's rings, the comets of the Kuiper Belt and the Hills Cloud (Inner Oort Belt). Inside the "snow line," the solar wind burned off the snow to accrete dry chondrules to form the terrestrial planets. After another three million years, the LaGrangian body itself fell into the companion in a second collision creating a second vapor cloud that condensed to form the larger-sized "Type CB chondrules" of the kind found in CB chondrites. These CB chondrules were swept up by the comets, planets and moons to form a thin veneer of slightly different elemental ratios and isotopic signatures than that of ordinary chondrites. These CB chondrules fused into a rocky crust on the surface of the comets to the thickness of 250 to 400 mm from exposure to galactic cosmic rays outside the protective heliosphere of the sun. The crust isn't permanent, however, since every impact and comet-quake that cleaves overlying low density ice into the high-density melt water beneath, will bury part of the old crust and expose new granular material to the ravages of galactic cosmic rays.  This process of compaction may have lasted for several hundreds of millions of years in larger comets.  As has recently been discovered, CB chondrites have high levels of metallic iron, aluminum oxide, calcium oxide, nitrogen-15, V, Cr and Mn, but with a low Ni/Fe ratio as compared with ordinary chondrites. The comet crust as well as CB chondrites contain metallic blebs formed from smaller metallic chondrules that accreted into millimeter to centimeter sized blebs before being incorporated into the crustal rock. CB chondrites from the asteroid belt differ from comet crust, however, in that individual chondrules are still visible. Apparently, CB chondrites are young comet crust that formed at the low orbital speed of the Hills Cloud before being injected into the asteroid belt at the time of the Late Heavy Bombardment 4,100 Ma, before galactic cosmic rays had a chance to entirely break down the chondrules into a uniform matrix. The CB chondrites must have been formed further out than the asteroid belt at the lower orbital velocity of the Hills Cloud for the metallic blebs to have accreted into subspherical blebs rather than fracturing into fragments as in the ordinary chondrites. Some of the CB chondrules have accreted into exotic-shaped chunks of solid metallic iron with masses of 100's of kg before being swept up by the comets, but the majority of the thin veneer of CB chodrules exist under the comet crust in the form of a mass of unconsolidated chunks of chondrules. The present-day comet gap between the Kuiper Belt and the Hills Cloud can be explained by the orbits of the sun and companion wobbling around their common barycenter. The most primitive CI chondrites are devoid of chondrules and have an elemental ratio of Mg/S to Al/Si in common with the photosphere of the sun but at variance with ordinary chondrites[1] The upper mantle of the earth is essentially chondritic except for the thin veneer [of CB chondrules] with elevated V, Cr and Mn[2].


Other evidence on earth:

Iron ore from comet cores in numerous small impact basins has been exploited since the beginning of the iron age. The iron ore and metallic iron in comet crust is contaminated with all the elements of the periodic table that make for brittle iron. Because of this contamination, the crust material was discarded into piles surrounding iron-ore mines and old iron furnaces or used as clean fill for roads or for railroad ballast. By the Second World War, far larger and older Superior-type, BIF iron deposits from the Archean Eon had supplanted the smaller iron ore mines, and thus, our colloquial knowledge of native iron in this form of rock (comet crust) faded away. Today, rock hounds, such as me, often find chunks of comet crust with metallic-iron blebs in stream cuts through comet-impact basins or in discarded piles in the vicinity of iron ore mines or historic iron furnaces. Meteorite labs are familiar with these rocks which they routinely dismiss as industrial-slag "meteorwrongs." (True enough, the CB chondrules in comet crust have been merged into a gray matrix surrounding the metallic blebs to create a rock that superficially resembles blast-furnace slag. The additional red herring of high calcium-oxide in the comet-crust rock, is similar to the limestone flux used in iron furnaces, and the low nickel content and the rounded size of the iron blebs are unlike ordinary chondrites. Also, the occasional voids in comet crust from former ice inclusions is unlike the non pitted asteroids formed inside the "snow line," where the solar wind sublimes ice. In addition to the consolidated comet crust is a veneer layer of CB chondrule aggregates that may be found loose from "recent" comet impacts, or be consolidated into bauxite deposits, caliche, laterite and hardpan soils, and may be the origins of the spherulites on the moon and the "blueberries" on Mars.


The Late Heavy Bombardment:

The break up of our solar nursery may have given rise to the Late Heavy Bombardment of comets into the inner solar system at 4,100 Ma that implanted the granite of the continental shields. In this violent event, the companion to our sun was apparently ripped from our solar system along with a large component of comets by the close encounter of a neighboring star that may have also pulled our sun into its present inclined orbit around the center of the galaxy. The disrupted comets that remained gravitationally attached to our sun may have settled into a spherically-shaped shell as far out as 1 light year from the sun, known as the Outer Oort Cloud. Because of the low solar gravity at this distance, the comets may have organized themselves into clusters like the globular and galactic clusters that spherically orbit the core of our Milky Way Galaxy.  The larger comets would tend to sink toward the center with every gravitational interaction, and at the core of each comet cluster, the density of comets may caused comets to collide and combine into larger "black comets," similar to the black holes that are though to exist at the center of globular clusters.  These black comets would have multiple cores, perhaps leading to the multiple kimberlite pipes if a black comet hit the earth head on in its orbit around the sun. The close encounter of passing stars may sometimes disrupt these comet clusters, robbing them of angular momentum and sending them into the inner solar system where they may have resulted in extinction events on earth. When the cluster comets impact asteroids, the asteroids may go into unstable earth-crossing orbits.  A comet cluster may go into a highly elliptical orbit that repeatedly brings the cluster through the inner solar system until the individual comets are permanently scattered by Jupiter, or another planet or moon.  The comet cluster that may have dislodged the Chicxulub-Crater asteroid prior to the comet cluster impacts on earth that led to the extinction event of 65 Ma and caused to the igneous province of the Deccan Trapps could have been caused by multiple passes of the comet cluster through the inner solar system. The most recent Extinction Event at the end of the Pleistocene Epoch, 12,900 ya, may have been initiated by the close encounter of a star from the Centauri Group.  The extinction of at least 15 megafauna species[?] at the end of the last ice age that occurred over the vast distance spanned by the North and South American continents that stretch almost from the North to the South Poles, I think, requires a comet cluster strike covering a time frame of only a few hours.  Our planet is vulnerable to comet-cluster strikes, and our world needs to develop a space defense to simultaneously deflect, potentially, many thousands of fragile comets when they suddenly sprout tails inside the orbit of Jupiter.

1. CUUK615B-Anderson, Chapter 3, The Building Blocks of the Planets, Pg. 29 Fig. 3.2
2. CUUK615B-Anderson, Chapter 3, The Building Blocks of the Planets, Pg. 31

Dave Carlson
Philadelphia, PA
dave19128@gmail.com
http://picasaweb.google.com/dave19128