Many entire galaxies (including our own) could have been fully colonized twice by the end of this period; Earth may be repeatedly frozen; sea levels are possibly 2000 feet higher than they will be in 2000 AD; global catastrophe on Venus; Earth life explodes in diversity; northern Mars calamity; our galaxy mixing with others; many mass extinction events The Signposts Perspectives 3,000,000,000 BC- 60,000,000 BC

This is also the case in our own Milky Way galaxy. The first civilizations to appear have likely had some 50 million years or so in which to colonize the whole galaxy by now.

At least fractional (10-20%) lightspeed propulsion for interstellar travel methods appear feasible to humanity, even at our present primitive level of technological know-how (2000 AD).
Thus, five million years would be a reasonable amount of time for a single star faring race to colonize the entire galaxy, even if equipped with only 10% lightspeed propulsion, and an average of 400 years was spent inbetween establishing a fresh colony and undertaking further colonization missions from that colony. If an interim period of 5000 years is substituted for the 400 number, then 50,000,000 years would be required to colonize the galaxy.
Possible resolutions of the Fermi Paradox due to things like aliens adhering to a Star Trek style "Prime Directive" demanding non-interference with primitives, or accidentally destroying themselves early in their history, or being disinterested in colonization altogether, might only work if the total number of emerging galactic civilizations is relatively small.
Just one star faring race with a history and motivations similar to our own, which avoided self-destruction, would be sufficient to colonize the entire galaxy no more than 50 million years after they began.

-- Scientific American: Feature Article: Where Are They?: July 2000 ["http://www.sciam.com/2000/0700issue/0700crawford.html"] by Ian Crawford

Of course, such early birds would also face a high frequency of gamma ray bursters, perhaps every million years or still more frequently. Such waves of radiation would certainly kill spacecraft crews in flight, as well as possibly overwhelm entire civilized planets with their scale of biospheric destruction.

-- Space Today and the Washington Post, on or about 12-18-96; "Recently Discovered Cosmic Blast May Be Biggest Since Big Bang" by MALCOLM W. BROWNE, 5-7-98, The New York Times;"Cataclysmic Explosions May Have Held Up Alien Visitors", Author: Robert Matthews, New Scientist magazine issue 23rd Jan 99

Thus, the 50 million year colonizing spree suggested above would be frequently punctuated by deadly galaxy-wide radiation baths, which might leave many colonies completely dead or suffering grievous injuries, as well as being suddenly isolated in the void, as supply lines are cut and waystation worlds and colonies killed off without warning. And all this is assuming that the home world(s) of the sprawling star faring civilization are themselves spared from the destruction. If they survive largely undamaged, they may still find it difficult to salvage their interrupted colonization plans; indeed, they might have their hands full simply trying to rescue and relieve what few of their widely dispersed colonies survives the periodic disasters.

Such galaxy-wide events doubtless cause great political and economic turmoil among a civilization so widely dispersed as an ambitious galaxy colonizer. It seems likely such a nation would soon splinter or collapse under such conditions. Thus, perhaps several-- or even many!-- civilizations make the attempt to colonize the galaxy over and over again at these early dates in universe history, only to be stymied time and time again by both cosmically spawned catastrophe and their own biological, political, and socio-economic frailties.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

2,700,000,000 BC- 2,600,000,000 BC: Living "microbial mats" are populating substantial land areas of Earth; this is perhaps an indication that Earth now has a functioning ozone layer, and the atmosphere is increasingly oxygen enriched

-- Ancient South African soils point to early terrestrial life, 29 NOVEMBER 2000, EurekAlert!, US Contact: A'ndrea Elyse Messer, aem1@psu.edu, 814-865-9481, Penn State University Park, Pa, EDITOR: Dr. Ohmoto, ohmoto@geosc.psu.edu

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

2,500,000,000 + BC: Some micro-organisms on Earth are producing oxygen

They have been doing so for quite some time already. But it'll take a long time to add enough oxygen to the atmosphere to make it comparable to what 20th century humanity will breathe.

-- Scientists Take New Step In Search For Life's Start, Reuters/Yahoo! News Top Stories Headlines, August 4 1999

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 2,500,000,000 BC to 2,300,000,000 BC: The entire Earth may be a deep frozen wasteland for millions of years

-- Oxygen may be cause of first snowball earth, , 27 OCTOBER 1999, Contact: A'ndrea Elyse Messer aem1@psu.edu 814-865-9481 Penn State
Oxygen and the first instances of photosynthesis seem to appear on Earth now.

-- Snowball earth by Gabrielle Walker, New Scientist ["http://www.newscientist.com"], 6 November 1999, http://www.newscientist.com

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 2,100,000,000 BC: An enormous asteroid or comet strikes Earth in the vicinity of Free State province, South Africa

The Vredefort crater is larger than the one someday to be left by the Chicxulub impact (Chicxulub is famous as the one which killed the dinosaurs). The Vredefort object may be as large as six miles in diameter.

The evolution of life on Earth may be set back by several million years due to this event.

-- World's Largest Impact Found In South Africa, SpaceDaily/AFP, October 5, 1999, http://www.spacedaily.com

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 2,000,000,000 BC: Seventeen naturally created nuclear fission reactors are operating in the area of Gabon in Africa

Such natural accumulations of critical mass of fissionable elements is easier now than it will be later, due to the youth of the mineral fuels involved (their half-lives will make them less of a threat as time goes by).

-- PRECAMBRIAN NUCLEAR REACTORS!From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #94, JUL-AUG 1994 by William R. Corliss, citing Bartholomew Nagy in "Precambrian Nuclear Reactors at Oklo," Geotimes, 38: 18, May 1993, and Bartholomew Nagy and others in "Role of Organic Matter in the Proterozoic Oklo Natural Fission Reactors, Gabon, Africa," Geology, 21:655, 1993

There may have been natural nuclear reactors in operation elsewhere on Earth too around this time or during other periods; and these radiation sources may have spawned some of the mutations which sped evolution.

-- THE OKLO PHENOMENON AND EVOLUTION From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #32, MAR-APR 1984 by William R. Corliss, citing "Natural Reactors Helped Evolution," New Scientist, 100:737, 1983
Oklo, Gabon is sporting several natural critical masses of uranium undergoing fission by two billion BC. These natural reactors even produce some plutonium as well, similar to later man-made breeder reactors. This find hints that natural fission reactors (including breeders) might be the source of some worlds' (perhaps even stars') internal heat. Could sporadic bursts of energy from such means spur geomagnetic reversals in planets like Earth?

-- OKLO: AN UNAPPRECIATED COSMIC PHENOMENON From Science Frontiers #121, JAN-FEB 1999 by William R. Corliss, citing J. Marvin Herndon; "Examining the Overlooked Implications of Natural Nuclear Reactors," Eos, 79:451, 1998

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 1,750,000,000 BC: The super continent Rodina (formed from a convergence of all the major continents of the Earth) may be completely assembled

-- Geologic History of the Canadian Rockies ["http://www.tgx.com/rockymountains/geology.htm"], apparently created in 1998 by Rocky Mountain Hiking, found by J.R. Mooneyham on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 1,500,000,000+ BC: The Earth's plate tectonics system has begun functioning by now, if not earlier

Evidence of plate tectonic action around 1.5 billion years ago has been found in North America.

-- Land Mass Distribution ["http://www.newton.dep.anl.gov/newton/askasci/1993/astron/AST036.HTM"], Ask A Scientist, Astronomy Archive

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 1,000,000,000+ BC: Earth's atmosphere still contains negligible amounts of oxygen; North America and Africa collide to form a single land mass

Instead of oxygen, Earth offers nitric oxide to its life forms, or NO (NO is toxic in large amounts). Oxygen will be poisonous to the earliest plants and worms.

Hemoglobin seems to be evolving in microbes as a means to rid lifeforms of NO. But later on this carrying capacity for NO will allow hemoglobin to become involved in the respiratory mechanism for more advanced life forms.

-- Common parasite overturns traditional beliefs about the evolution and role of hemoglobin, EurekAlert! ["http://www.eurekalert.org/"], 29 SEPTEMBER 1999 Contact: Richard Merritt Merri@mc.duke.edu 919-684-4148 Duke University Medical Center

North America and Africa collide to form a single land mass.

-- Lecture 14 - The Appalachian Mountains ["http://wwwcatsic.ucsc.edu/~eart3/Lectures/lecture14.html"], last reviewed by respective author(s) on 2/18/00, found by J.R. Mooneyham on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 760,000,000+ BC: The super continent Rhodinia begins splitting apart to form the beginnings of the Pacific Ocean basin

-- Popsicle Planet By Richard Monastersky, Science News Online, August 22, 1998, ScienceService ["http://www.sciserv.org"], and Snowball earth by Gabrielle Walker, New Scientist ["http://www.newscientist.com"], 6 November 1999

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 750,000,000 BC: Global sea levels are perhaps some 1,968 feet higher than they will be in 2000 AD; Australia separates from the northwestern corner of North America

The high sea levels worldwide make for a vastly shrunken mass of dry land compared to that with which circa 2000 AD humanity will be familiar. The bulk of this extra water will apparently be lost by subduction into the Earth's mantle over millions of years to come.

-- "The world's oceans seem to be draining away" by Peter Hadfield, Tokyo, New Scientist issue 11th September 99, http://www.newscientist.com, 8 SEPTEMBER 1999, EurekAlert! ["http://www.eurekalert.org/"]
The Earth also loses 1000+ gallons of water each day from the atmosphere into space, largely due to water molecules being split and ionized by interaction with charged particles from the Sun, and then thrown into space near Earth's magnetic poles. The more powerful the solar wind, the worse the loss. If not for the Earth's native magnetic field the oceans would be lost entirely millions of years before the dawn of the 21st century AD-- similar to what happened to Venus and Mars perhaps.

-- The Learning Kingdom's Cool Fact of the Day for February 1, 2000; Cool Fact: Leaky Earth, http://www.LearningKingdom.com

To better illustrate this sea height:Circa 1999 AD Jerusalem (Israel) and Johannesburg (South Africa) would still be above sea level under these circumstances-- but all the following 20th century world cities would not:

Washington DC (USA), London (UK), Paris (France), Berlin (Germany), Rome (Italy), Warsaw (Poland), Moscow (Russia), Athens (Greece), New Delhi (India), Rio de Janeiro (Brazil), Tokyo (Japan), and Sydney (Australia).

-- Latitude, Longitude, and Altitude of World Cities, page 265, The 1990 World Almanac and Book of Facts

Approximately 750,000,000 BC Australia separates from the northwestern corner of North America.

-- Geologic History of the Canadian Rockies ["http://www.tgx.com/rockymountains/geology.htm"], apparently created in 1998 by Rocky Mountain Hiking, found on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 750,000,000 BC-700,000,000 BC: The entire Earth may be a deep frozen wasteland for ten million years

During most of this period no clouds or ocean are visible on Earth from space. Only snow, ice, and rocks. Most life today is just algae and microbes. Most of it dies now, with many of the survivors likely huddling around rare hot springs and volcanic vents. Others may have survived through chemosynthesis-- processes which draw energy from chemical reactions rather than sunlight. But the Earth begins to undergo wild swings in climate after this, becoming much hotter for a while, then freezing again. These extremes may spur life to evolve to more complex forms in order to survive-- thereby eventually setting the stage for animals to arise.

The single great land continent of this time is situated in the region of Earth that'll one day be known as the tropics.

This great continent (Rhodinia) began coming apart around 760 million BC to form an embryonic Pacific Ocean basin. These changes enabled a boom in new life forms in the region, which drew carbon dioxide from the atmosphere and deposited it on the new sea bottoms as a byproduct of their biological processes. All this carbon pulled from the atmosphere weakened the Earth's ability to retain heat, leading to the oceans beginning to freeze over. One contributor to all this was the fact that the Sun was roughly seven percent weaker in those days.

However, over the course of millions of years Earth's volcanos came to the rescue, replenishing the greenhouse gases Earth needed to insulate it from the cold of space-- thereby starting the cycle all over again-- with a vengeance. Suddenly, within only a matter of centuries the Earth became hotter than it had been since its initial formation, melting glaciers at incredible speeds. The climate change was traumatic, with floods of acid rain and super hurricanes dwarfing anything human beings will have documented by the dawn of the 21st century AD, hundreds of millions of years in the future from now. After these initial changes the Earth fluctuates wildly between the two extremes of heat and cold at least four other times between 760 million BC and 550 million BC, each time culling out huge swathes of life forms and afterwards encouraging the remnants to expand to fill all the empty niches of the biosphere once more.

The ocean is frozen solid for more than a half mile in depth.

-- Oxygen may be cause of first snowball earth, 27 OCTOBER 1999, Penn State, Contact: A'ndrea Elyse Messer, aem1@psu.edu, 814-865-9481
Just how did Earth first get into the yo-yo extremes of hot and cold climates during this period anyway? Perhaps methane hydrates in the seafloor had been disturbed by some event, and begun oozing methane-- a powerful greenhouse gas-- into Earth's atmosphere. This gas served to keep Earth warmer than it otherwise would have been. This reduced the ratio of carbon dioxide in the atmosphere.
However, methane gets soaked up in various ways when oxygen is plentiful in the atmosphere, as it is here on Earth. So when the methane escaping from the seafloor diminished, the methane in the atmosphere soon dwindled as well, causing the Earth to begin cooling.

-- Scientific American: Science and The Citizen: Triggering a Snowball BY SARAH SIMPSON; September 2001

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 700,000,000 BC: Massive changes take place on the surface of Venus

Around 700 million BC much of the surface of Venus was remade. Atmospheric water and sulfur increased.

-- Math Program Cracks Cause Of Venus Climate Change; ScienceDaily Magazine; sciencedaily.com; NASA/Jet Propulsion Laboratory; 3/19/2001; http://www.sciencedaily.com/releases/2001/03/010313074923.htm; http://www.jpl.nasa.gov/releases/2001/cracks.html

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 650,000,000 BC- 500,000,000 BC: The Cambrian explosion of differentiated lifeforms is occuring

A minimum of one dozen of the animal kingdom's main categories (as will be recognized by early 21st century humanity), first emerge during this period.

-- Moon Dirt Reveals Earth Evolution By Becky Oskin, Discovery.com News, March 10, 2000, http://www.discovery.com

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 600,000,000 BC: The entire Earth may be a deep frozen wasteland for millions of years; North America and Africa begin to split apart, creating a proto-Atlantic Ocean; The strange lifeforms of Ediacarans appear on Earth

-- Oxygen may be cause of first snowball earth, , 27 OCTOBER 1999, Contact: A'ndrea Elyse Messer aem1@psu.edu 814-865-9481 Penn State
Possibly the last of as many as FIVE 'snowball Earth' cycles may have ended around 575,000,000 BC. These harsh repetitive cycles of hot and cold may have encouraged the evolution of multicellular organisms to appear after the final round. Algae and bacteria were the only life on Earth up until now. It seems most of the Earth's dry land masses are also clustered near to the equator during these cycles.

-- Snowball earth by Gabrielle Walker, New Scientist, 6 November 1999, http://www.newscientist.com

North America and Africa form a single land mass before this time. In the late Precambrian (perhaps around 600,000,000 BC) the North America and Africa begin to split apart again, creating the proto-Atlantic Ocean.

-- Geological Timescale, page 15, The Earth, The World, The Running Press Cyclopedia, 2nd Edition, 1993, 1995

The complex lifeforms Ediacarans first appear around 600 million BC. At least some Ediacarans may be neither plant or animal, but rather some sort of lichen (a combination of algae and fungi); some may be prototype animals; and still others may simply be bizarre natural experiments (one 20th century scientist will call them vendobionts, declaring that they inflated their size by drawing in water).

The Ediacarans colonize the floors of the world's oceans. Remarkably, there seems to be no overt predation among them as would be seen in animals which appeared later. The Ediacarans do not seem to be equipped with weapons for such contests. Instead, they use photosynthesis like 20th century plants, or biochemically absorb nutrition from the surrounding water or symbiotic bacteria which the Ediacarans themselve host.

Some Ediacarans attach or root themselves to terrain features, while others float about like 20th century jellyfish. A minority may develop primitive spines or fins with which to move about.

-- New Scientist Planet Science: Cast out of Eden ["http://www.newscientist.com/ns/980516/features.html"] by Bennett Daviss, From New Scientist, 16 May 1998

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 600,000,000 BC- 500,000,000 BC: The Earth and Moon may enjoy the lowest frequency of asteroid and comet impacts of their spans now

-- Meteoric wallop may have diversified life By R. Cowen: Science News Online, Mar. 11, 2000; Vol. 157, No. 11, http://www.sciserv.org

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 590,000,000 BC +: South Australia is struck by a 4 km wide asteroid; A large proportion of the Earth's continents have become roughly centered about the south pole by this time

-- One theory solves two ancient climate paradoxes, EurekAlert! ["http://www.eurekalert.org/"] 14 DECEMBER 1999, Contact: A'ndrea Elyse Messer aem1@psu.edu 814-865-9481 Penn State

Around 590 million BC a 4 km+ diameter rocky meteor impacts South Australia, creating a 40 km diameter crater and generating an earthquake leading to 100 m tall tidal waves in a shallow sea some 300 km distant. Lake Acraman will be the name of the site in the 20th century.

-- Secret strike By Tim Thwaites, From New Scientist ["http://www.newscientist.com"], 7 August 1999

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 570,000,000 BC: The Cambrian explosion in biological diversity is taking place...

...lasting perhaps only one to ten million years (incredibly fast by many later measures). Could it be the radiation from natural nuclear reactors is aiding this process?

-- THE SHORTER, THE STRANGER From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #90, NOV-DEC 1993 by William R. Corliss, citing Samuel A. Bowring,, et al; "Calibrating Rates of Early Cambrian Evolution," Science, 261:1293, 1993. Richard A. Kerr; "Evolution's Big Bang Gets Even More Explosive," Science, 261:1274, 1993. R. Monastersky; "Siberian Rocks Clock Biological Big Bang," Science News, 144:142, 1993. Carol Kaesuk Yoon; "Biology's 'Big Bang' Took a Mere Blink of the Eye," New York Times, September 7, 1993. Cr. P. Gunkel

Or might marginal effects of an otherwise deadly gamma ray burster upon lifeforms somewhat but not fully protected from the radiation have spawned this fountain of rapid evolution?

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 555,000,000 BC: The first vertebrates (animals with backbones) may be emerging now

-- Early Vertebrates Discovered By Jeff Donn The Associated Press Nov. 3, 1999, ABC News Internet Ventures, http://www.abcnews.go.com/

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 550,000,000 BC: Ediacarans may be developing sensory organs-- or even crude brains

Around 550 million BC the Ediacarans begin developing unusual new appendages. The nature of these limbs or knobs will be hotly debated by 20th century scientists. But some will see these new elements as primordial sensory organs. The configuration and location of the appendages suggest primitive brain development, if an analogy with animal development can be applied to these strange creatures.

-- New Scientist Planet Science: Cast out of Eden ["http://www.newscientist.com/ns/980516/features.html"] by Bennett Daviss, From New Scientist, 16 May 1998

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 545,000,000 BC: The Ediacarans vanish from the face of the Earth

Around 545 million BC complex lifeforms one day to be known as Ediacarans seem to disappear from the Earth. It's not entirely clear if they were driven to extinction by competition from other life (newly emerging forms one day to be called animals), or were perhaps an early stage in the evolution of those same animals. If the Ediacarans are related to 20th century humanity (that is, they are prototype animals), as of 1998 AD we will not yet have found the fossils required to prove the link.

At least some Ediacarans may have been neither plant or animal, but rather some sort of lichen (a combination of algae and fungi); some may have been prototype animals; and still others may simply have been bizarre natural experiments which proved to be dead ends in evolutionary terms (one scientist called Ediacarans vendobionts, declaring that they inflated their size by drawing in water).

The Ediacarans colonized the floors of the world's oceans. Some Ediacarans would attach or root themselves to terrain features, while others floated about like jellyfish. A minority may have developed primitive spines or fins with which to move about.

Some scientists of 2000 AD will see in the Ediacarans the possibility of a much gentler and more peaceful Earth, had they continued upon the evolutionary course they seemed to be following before their disappearance.

Why are the Ediacarans perceived as gentler and more peace-loving than the better known animal kingdom? Because there seems to be no overt predators among the Ediacarans.The Ediacarans do not seem to be equipped with weapons for such contests. Instead, they use photosynthesis like 20th century plants, or biochemically absorb nutrition from the surrounding water or symbiotic bacteria which the Ediacarans themselves host.

To top it all off, a few million years before their disappearance, some Ediacarans seem to be developing sensory organs which might lead to rudimentary brains.

Around 550 million BC the Ediacarans began developing unusual new appendages. The nature of these limbs or knobs would be hotly debated by 20th century scientists. But some would see these new elements as primordial sensory organs. The configuration and location of the appendages suggest primitive brain development, if an analogy with animal development can be applied.

Then, around 545 million BC, the Ediacarans suddenly disappeared. At least according to the fossil record to be available to humanity in 1998 AD.

Did a long lasting global geological catastrophe reduce the light entering the oceans, thereby dooming the Ediacarans? Or did our own animal ancestors appear and simply eat them out of existence? Or could it be the Ediacarans themselves evolved into our earliest animal ancestors? As of 1998 AD no one will have sufficient evidence to prove any of these scenarios.

-- New Scientist Planet Science: Cast out of Eden ["http://www.newscientist.com/ns/980516/features.html"] by Bennett Daviss, From New Scientist, 16 May 1998

[Caution: Extreme speculation ahead; the section linked to below was created mostly for "What If?" entertainment value]

To see more about what could have been about these remarkable creatures, click here.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 544,000,000 BC: Perhaps the last of three global glaciations extending even to the Earth's equator is realized

The Earth remains tilted 70 degrees from vertical. There is likely a large number of species extinctions now in many regions. However, while the equator is suffering glaciation, the poles are not. This results in at least some sea and land remaining sufficiently warm to allow life to more or less continue on in development.

The slow movement of tectonic plates may also be gathering continental masses around the southern pole, setting the stage for a righting of the axis tilt.

-- One theory solves two ancient climate paradoxes, EurekAlert! ["http://www.eurekalert.org/"] 14 DECEMBER 1999, Contact: A'ndrea Elyse Messer aem1@psu.edu 814-865-9481 Penn State

Around 544 million BC the Cambrian period began with a ten million year explosion in life diversity and size (previous to this most life consisted of microbes). It may be that the Earth's mantle shifted, imbalancing the planet and causing it to tilt on its axis.

North America began the period near to the South Pole but ended up (540 million BC- 515 million BC) on the equator. Antarctica, South America, Australia, India, and Africa were all one body called Gondwanaland, and traveled all the way across the southern half of Earth during the time (finishing the trip around 535 million BC- 500 million BC).

-- When Earth Tipped, Life Went Wild by R. Monastersky, July 26, 1997, Science News Online, http://www.sciencenews.org
One source places the Cambrian explosion in diversity at 540 million BC.

-- Meteoric wallop may have diversified life By R. Cowen: Science News Online, Mar. 11, 2000; Vol. 157, No. 11, http://www.sciserv.org

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 534,000,000 BC: A sudden mass imbalance within the Earth may set off rapid geologic changes worldwide now (with significant climatic consequences afterwards)

It may be that in the normal subduction process an unusually weak section of the sea floor breaks loose and begins sliding into the mantle. This parcel is perhaps hundreds or thousands of times larger than the typical subduction mass. Its huge size and cumbersome shape likely causes many problems for this part of the planet, such as massive and more frequent earthquakes and tsunamis, as well as perhaps gargantuan undersea volcanic eruptions and lava flows. Luckily the mass of the sea overhead may mute the effects of the eruptions on the atmosphere somewhat.

The normal tectonic processes are vastly accelerated as a result of the imbalances brought on by this event. Within 15 million years all the continents have moved by some 90 degrees from their previous positions.

-- EARTH'S SHIFTING CRUST From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #113, SEP-OCT 1997 by William R. Corliss, citing Joseph L. Kirschvink, et al; "Evidence for a Large-Scale Reorganization of Early Cambrian Continental Masses by Inertial Interchange True Polar Wander," Science, 277:541, 1997, Kathy Sawyer; "Global Shift May Have Sped Evolution," Washington Post, July 25, 1997, and Kurt P. Wise, "The Archaean Explosion," CEN Technical Journal, 10:315, 1996

The unusual size and configuration of the subducted seafloor may cause far more seawater than normal to be dragged downwards deep into the Earth as well.

It appears two enormous ancient oceans were dragged deep towards the core of the Earth (hundreds of kilometers down) by the subduction of their floors under the continents. They may host quantities of seawater comparable to the surface oceans of 20th century Earth.
One of these bizzare realms may now exist some 900 km underneath Europe. The other looks to be almost 3,000 km below Indonesia.
These regions were revealed by seismic tomography.

-- TWO REALLY DEEP OCEANS from Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #96, NOV-DEC 1994 by William R. Corliss, citing Carl Zimmer; "The Ocean Within," Discover, 15:20, October 1994, and Martin Redfern; "Lost Ocean Found Deep in the Earth," New Scientist, p. 16, September 3, 1994

Between 750 million BC and 2,000 AD the Earth's surface sea level will drop some 1,968 feet due to loss of water to subterranean regions.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 1,000,000,000 BC- 500,000,000 BC: Northern Mars suffers world-shaking catastrophe

The northern hemisphere of Mars undergoes one or more violent and geologically rapid large-scale changes involving massive, possibly explosive, lava flows over the surface.

The southern hemisphere too has its share of volcanic eruptions and lava flows both before and after this time-- but they are not as violent or rapid or massive in most cases as those of the northern half of Mars. In terms of lava flows over the long term, southern Mars resembles Earth.

These lava flow differences between northern and southern Mars may signify important internal changes to the planet before or during this time. These changes may be related to Mars' crust undergoing a thickening process, or to the ultimate fate of the planet's surface water.

-- Mars global surveyor provides a geologist's survey of Mars, Contact: James Hathaway, hathaway@asu.edu, 480-965-6375, Arizona State University College of Liberal Arts & Sciences EurekAlert! 3 MARCH 2000

It may also be that northern Mars suffers one or more cataclysmic impacts from asteroids or comets in this time frame.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 500,000,000 BC+: A significant meteor strike occurs in Lake Huron North America; Several alien galaxies may be intermingling with the Milky Way at this time

-- IMPACT CRATER BENEATH LAKE HURON from Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #72, NOV-DEC 1990 by William R. Corliss, citing W. Stolzenburg; "Impact Crater May Lie beneath Lake Huron," Science News, 138:133, 1990
"...a massive collision in the asteroid belt that took place about 500 million years ago and peppered Earth with meteorites..."

-- Scientists find intact meteors in limestone ["http://www.knoxstudio.com/shns/story.cfm?pk=FOSSILMETEORS-05-08-03&cat=AN"] By LEE BOWMAN; Scripps Howard News Service; May 08, 2003; knoxstudio.com

The possibly three separate galaxies comprising the the Large and Small Magellanic Clouds may be passing through the disk of our Milky Way galaxy now. This process may be leaving behind debris from the Magellanic galaxies in our own, such as star systems and isolated stars and rogue planets. The pass-thru may also be creating smaller galaxies in the vicinity of the Milky Way as gravitational spin offs of the passage.

-- THE NEARBY GALAXIES, CHAPTER 24: The Local Galaxies ["http://beast.as.arizona.edu/textbook/text/CH24.html"], found on or about January 15, 2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 500,000,000 BC: Emerging lifeforms of this time include starfish, corals, and clam-like shellfish

-- Geologic Time Scale, page 564, Earth Science, Science and Technology, The Universal Almanac 1996, Andrews and McMeel, 1995

Signposts 59,999,999 BC-51,000 BC Contents

Approximately 490,000,000 BC: The Earth may have slowly reduced its previous tilt of 70 degrees from the vertical to some 20 or 30 degrees now

It's taken many millions of years for the planet to reverse the extreme tilt of its axis possibly incurred by the Moon-generating collision.

-- One theory solves two ancient climate paradoxes, EurekAlert! ["http://www.eurekalert.org/"] 14 DECEMBER 1999, Contact: A'ndrea Elyse Messer aem1@psu.edu 814-865-9481 Penn State

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 450,000,000+ BC: After many false starts (species which failed to make the transition) finally one form of plant life manages to survive the change from water to dry land. I.e., the very first successful species of land plant now makes its debut

All other land plants on Earth will eventually evolve from this primordial survivor. The first land plant evolves from what was originally a fresh water plant. Eventually some of this plant's descendents will return to the water, while others go on to populate the continents.

By the end of the 20th century there will be four different lineages of plants-- including fungi, which is more like a hybrid of plant and animal.

Three of the plant lines are basically categorized according to color: green, brown, and red. Fungi is in a class of its own.

A summary of the evolution of life by this point would be: Life begins in the ocean. Some life moves into freshwater, of which a portion will eventually move back to the sea. Some of the plant life which stays in freshwater eventually colonizes dry land.

-- XVI International Botanical Congress Team of 200 scientists presents new research that reveals full 'tree of life' for plants, EurekAlert!, 4 AUGUST 1999, Contact: Ellen Wilson, Dennis Kelly, or Eileen Kugler ewilson@burnessc.com 301-652-1558 Contact the IBC press office at 314-611-3961 or 314-621-4827

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 439,000,000 BC: The Ordovician mass extinction occurs, wherein...

...about 85% of all marine animal species are killed off (there were no land animals at this time)

-- 2150 biodiversity ["http://www.enviroweb.org/coe/e-sermons/weedplan.html"]

It's possible that a gamma burster may be at least partially responsible for these events.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 425,000,000 BC: Portions of the continents are growing closer again; The Appalachian mountain range is being born

Various volcanic islands are colliding with North America, forming the Piedmont and Blue Ridge provinces of the Appalachian mountain range (the Great Smoky Mountain and Shenandoah National Parks will one day exist in the Blue Ridge provinces).

-- Lecture 14 - The Appalachian Mountains ["http://wwwcatsic.ucsc.edu/~eart3/Lectures/lecture14.html"], last reviewed by respective author(s) on 2/18/00, found on or about 7-8-2000

Emerging lifeforms of this time include land scorpions, club mosses, clams, mussels, snails, and certain types of fungi and algae which will survive into the 21st century AD.

-- Geologic Time Scale, page 564, Earth Science, Science and Technology, The Universal Almanac 1996, Andrews and McMeel, 1995

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 400,000,000 BC: The frequency of cosmic impacts suffered by both the Earth and Moon rises sharply now-- the frequency will remain fairly constant for the next 400 million years; Plants are beginning to populate the land; The four to six foot long Coelacanth fish has appeared

Impact frequency now suddenly increases back to levels not seen since 3.5 billion BC. Could it be this high rate of global and regional catastrophe actually accelerates evolution on Earth?

As of 2000 AD the mechanism behind this sudden increase will be a mystery to human scientists. Impact frequency should have gradually declined over time due to the gradual consumption of all available bodies in the solar system required to supply such events; i.e., over time the Sun and planets' gravitational fields should be sweeping the space lanes clear of such threats.

But gravitational disturbances from unknown masses in or outside our solar system could refill the impact reserves; this may be what happened around 400 million BC.

Some theorize that the Sun has a massive dark companion, often named Nemesis, which is the culprit here. Nemesis could be in an orbit far enough out to make it difficult for us to see it, but close enough so that other passing star systems might modify the orbit of Nemesis from time to time, with consequences affecting the replenishment of impact stores from the Oort cloud and elsewhere (the Oort Cloud and Kuiper belt are two regions of comets which surround the solar system).

-- Berkeley Study Of Lunar Cratering History Finds Surprising Increase at Time of Cambrian Explosion ["http://www.lbl.gov/Science-Articles/Archive/lunar-spherule.html"], March 9, 2000
-- Newz&Viewz 11-7-99: A tenth planet? And alien at that? Our solar system may have picked up an alien hitchhiker as it flew its way around the galaxy. A couple of astronomers believe they've found hints of a tenth planet in an abnormal orbit that places it far out of the system, inside the Oort Cloud itself (where most of our system comets exist).
The mystery planet may be 1.5-6 times the size of Jupiter, and offer us a tantalyzing sample of the composition of a whole different star system-- since that alien system may have been its original home. The planet's reverse orbital direction and strongly inclined orbit relative to the other worlds indicates this possibility.
The mystery planet may possess an orbit of 4-6 million years. One intriguing (and scary) thing about this discovery is the possibility that such a body could have a similar effect on us as "Nemesis"-- a black hole or distantly orbiting star some have theorized occasionally causes a slew of comets to be loosed from the Oort Cloud in our direction, causing mass extinctions in some cases from the impacts.
The alien world's existence has not yet been confirmed.
-- Then there were ten by Jeff Hecht, New Scientist, 16 October 1999
Is the unknown massive solar companion indicated by scientific research actually a distributed system? With at least a portion of the mass consisting of a collection of unseen smaller masses distributed among various Lagrangian points in our solar system?
Whatever the case, the total mystery mass involved in the gravitational effects observed within our solar system may be equivalent to as much as half the Sun's mass.
The distance the mystery mass orbits from the Sun helps determine how large it is. The further out along the edges of the system it is, the larger it must be to have the detected effect (perhaps being as much as half the mass of the Sun). The closer in it is, the less massive it would have to be. I.e., much smaller masses distributed over several inner system Lagrangian points would have a similar effect.

-- MORE ON "THE MASSIVE SOLAR COMPANION" From Science Frontiers #25, JAN-FEB 1983 by William R. Corliss, citing John P. Bagby; "Evidence for a Tenth Planet or Massive Stellar Companion Beyond Uranus," paper offered during the Tomorrow Starts Here Conference, September 1982

Another possible contribution to evolution from all these impacts could have been new and exotic organic compounds, which served as catalysts for ever more complex chemical and then biochemical processes.

-- Moon Dirt Reveals Earth Evolution By Becky Oskin, Discovery.com News, March 10, 2000, http://www.discovery.com

The first plants are appearing on land.

-- CNN.com - Nature - Plants spread secrets about climate change ["http://www.cnn.com/2000/NATURE/03/09/plants.enn/"] By Environmental News Network staff, March 9, 2000, Environmental News Network

The Coelacanth will survive at least to 2,000 AD.

-- The creatures time forgot by Lynn Dicks; New Scientist, 23 October 1999

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 395,000,000 BC: Emerging lifeforms of this time include sharks, amphibians, spiders, and ferns

-- Geologic Time Scale, page 564, Earth Science, Science and Technology, The Universal Almanac 1996, Andrews and McMeel, 1995

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 380,000,000 BC: Europe, Africa, and North America are coming together

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 367,000,000 BC: The Devonian mass extinction takes place, and is apparently near the magnitude of the Ordovician event 72 million years before...

-- 2150 biodiversity ["http://www.enviroweb.org/coe/e-sermons/weedplan.html"]

An enormous comet (as big as three miles in diameter) smashed into Nevada around 370 million BC (the Alamo Impact). This region is largely under the Pacific Ocean at this time. This impact may have been but the first of many; a series of comet showers may have begun impacting the Earth around 370 million BC, ultimately bringing about the mass extinction of 367,000,000 BC...

-- Tiny Teeth Shed Light on Ancient Comets; 3/20/98; News Release; U.S. Department of the Interior; U.S. Geological Survey, Central Region Outreach Office, P.O. Box 25046, MS 150, Denver, CO 80225-0046. Contact Heidi Koehler Phone 303-236-5900 ext. 302 Fax 303-236-5882

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 364,000,000 BC: Something of a global extinction event takes place now...

...though it is not of the catastrophic scale of some others.

-- Killer Crater Found ["http://www.discovery.com/news/briefs/20000419/geology_crater.html"] By Larry O'Hanlon, Discovery.com News, April 19, 2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 360,000,000 BC: The wide and flat plant leaves which will be familiar sights to 21st century AD humanity are evolving now

The earliest land plants of 400 million BC resembled branches of green twigs. Roots were developed next. Above-ground portions of plants gradually branched into finer and more complex twig-like structures. Thus, for millions of years plant leaves were typically spine-like. Then, around 360 million BC, so many plants were consuming the carbon dioxide from the atmosphere that a 90% depletion in the compound took place. To survive, plants grew webbing between their finest branching structures for greater respiration efficiency. This webbing became the broad, thin leaves with which we are familiar in 2001 AD.

-- Branching out by Jeff Hecht; 14 March 2001; New Scientist Online News; Nature (vol 410, p 352)

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 350,000,000 BC: Emerging lifeforms of this time include insects, reptiles, mosses, and land snails

-- Geologic Time Scale, page 564, Earth Science, Science and Technology, The Universal Almanac 1996, Andrews and McMeel, 1995

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 340,000,000 BC: A wiener-length, lizard-like creature has firmly established itself in a semi-aquatic environment...

...i.e., it alternates between water and land-based activities. It's one of the earliest vertebrates to do so. Its domain is the shallows of swamps along the coasts of large land masses. 20th century scientists will name it "Casineria".

-- "Science News Online (5/22/99): Out of the Swamps" ["http://www.sciencenews.org/sn_arc99/5_22_99/bob1.htm"] By Richard Monastersky, Science News Online,The Weekly Newsmagazine of Science, Volume 155, Number 21 (May 22, 1999), Science Service

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 360,000,000 BC- 250,000,000 BC: A cosmic impact in Australia now may be the cause of the worst extinction event(s) ever suffered by Earth

The impact of an object from space creates the 80 miles wide so-called "Woodleigh" crater, in the vicinity of Shark Bay in western coastal Australia. Could this be the doomsday rock which almost wipes out all life on Earth much bigger than a bacteria, in the combined Permian-Triassic extinctions? Altogether 96% of all sea life and close to that in land life dies in these extinctions.

-- Killer Crater Found ["http://www.discovery.com/news/briefs/20000419/geology_crater.html"] By Larry O'Hanlon, Discovery.com News, April 19, 2000

The effects of one or more gamma ray bursters may also number among the suspects here.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 300,000,000 BC: Any alien astronomers within hundreds of lightyears of Earth could by now be detecting life on the planet from afar (if they hadn't already done so earlier); The super continent Pangea takes shape; Vascular land plants like trees may have spread over the continents sufficiently by now to cause a worldwide increase in oxygen; Gigantic insects may roam the world

The high oxygen levels may enable enormous growth in insects.

Alien astronomers possessing technology comparable (or superior) to early 21st century humanity's could have become aware of Earth harboring life by sometime between one billion and 300 million BC (if such observers were within suitable viewing range). The giveaway could have been emerging signs of oxygen in the reflected light spectrum from Earth, or other markers.
-- Aliens 'know we're here'; Ananova Ltd; 19th February 2002

These high oxygen levels last for about 100 million years. Note that under such conditions forest fires would have occured more easily and devastated far greater regions in single events (oxygen aids combustion).

-- Yale researchers attribute ancient high levels of oxygen in the atmosphere to the rise of trees and large plants ["http://www.eurekalert.org/releases/yale-yra030700.html"], 7 MARCH 2000, EurekAlert! Contact: Karen Peart karen.peart@yale.edu 203-432-1326 Yale University

Approximately 300,000,000 BC the super continent Pangea takes shape. Sometime later Pangea will split into Laurasia (north) and Gondwanaland (south).

-- Geologic History of the Canadian Rockies ["http://www.tgx.com/rockymountains/geology.htm"], apparently created in 1998 by Rocky Mountain Hiking, found by J.R. Mooneyham on or about 7-8-2000

Africa and North America are colliding. Europe and South America are also colliding with North America, to form Pangea.

-- Lecture 14 - The Appalachian Mountains ["http://wwwcatsic.ucsc.edu/~eart3/Lectures/lecture14.html"], last reviewed by respective author(s) on 2/18/00, found on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 345,000,000 BC- 225,000,000 BC: The Carboniferous and Permian periods see lots of Gondwana (southern Pangea) ice-covered. Animal life is minimal in the region now

The document cited below gave 270,000,000 BC as an approximate date for an icy Gondwana, but also indicated the icy times lasted through much of the Carboniferous and Permian periods, which involve a range of as much as 120 million years (see additional info following below).

-- Common questions: Gondwana and continental drift; FAQ - Gondwana ["http://www.earth.monash.edu.au/dinodream/faq/faqgond.htm"], Monash University Earth Sciences, Monash Science Centre, Ziggurat Creative & Technical Publishing, found on or about 7-8-2000

The Universal Almanac 1996 offers 350,000,000 BC as a marker for the Carboniferous Period, and 290,000,000 BC for the Permian.

-- Geologic Time Scale, page 564, Earth Science, Science and Technology, The Universal Almanac 1996, Andrews and McMeel, 1995

The Running Press Cyclopedia offers 345,000,000 BC- 280,000,000 BC as the range for the Carboniferous Period, and 280,000,000 BC- 225,000,000 BC for the Permian.

-- Geological Timescale, page 15, The Earth, The World, The Running Press Cyclopedia, 2nd Edition, 1993, 1995

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Sometime between 295,000,000 BC and 250,000,000 BC: A foot long lizard which lives in Europe, Asia, and North America is running upright, on two legs, like a human being; it may be the fastest animal alive today

The earliest upright biped isn't a mammal, or even a dinosaur, but a still older reptile. In Germany circa 290 million BC, a foot long lizard (Eudibamus cursoris, a bolosaur) is running erect-- on two legs. This makes bipedalism something which developed at least three separate times during the evolution of life on Earth: in reptiles, dinosaurs, and mammals.
Eudibamus cursoris was a plant eater/herbivore, and likely the fastest animal on the planet at the time (when running). It had a long tail which might have helped it manuever, as well as balance while erect. Eudibamus cursoris doesn't seem to be directly related to either of the reptiles or dinosaurs which appeared later on.
Bolosaurs (and so possibly Eudibamus cursoris as well) were distributed across Asia, Europe, and North America during this time.
-- Ancient Two-Legged Lizard Intrigues Scientists By Maggie Fox, Reuters/Yahoo! Science Headlines, November 2 2000
The bolosaurid Eudibamus cursoris lived during a period between 290 million BC to 250 million BC. The group is thought to have died out around the end of the Permian, during one of the largest extinction events ever witnessed by the Earth.
-- Newly Found Bipedal Reptile Fossil Predates Dinosaurs By More Than 60 Million Years ["http://www.sciencedaily.com/releases/2000/11/001102150002.htm"], 11/3/2000, University Of Toronto (http://www.utoronto.ca); Contact: Janet Wong; (416) 978-6974; jf.wong@utoronto.ca
Eudibamus was a member of the Parareptilia group of reptiles. Its legs and feet show similarities to human limbs. For instance, the foot is unusually long for a reptile of this size, in order to enable its upright bipedalism. Its arms are also shorter than its legs, as in humans.
290 million BC to 268 million BC is given in the article cited as the relevant span of Eudibamus.
-- Ancient reptile walked on two legs ["http://news.bbc.co.uk/hi/english/sci/tech/newsid_1003000/1003886.stm"] By Dr David Whitehouse, 2 November, 2000, BBC News Online
Eudibamus may have generally ran in a posture similar to human beings. It is believed that during slow travel it may have moved quadrupedally. During its fastest sprints it may have ran on its toes.
-- Ancient running reptile was bipedal, say Science researchers ["http://www.eurekalert.org/releases/aaas-arr102700.html"] 2 NOVEMBER 2000, EurekAlert!, US Contact: Ginger Pinholster gpinhols@aaas.org 202-326-6421 American Association for the Advancement of Science
Fossils of Eudibamus cursoris so far found indicate an animal weighing about a pound or less. It sported extra long middle toes on its longer than usual feet. Eudibamus would have been awkward in quadrupedal motion. On two legs, it was very fast. Likely capable of sprinting at 15 mph, compared to only 13 mph spurts for modern (21st century) bipedal lizards.
It's a mystery as to how Eudibamus could have gone extinct, considering its significant advantages over its competitors of the time.
-- Lizard may have been first biped The Associated Press, November 2, 2000, http://www.nandotimes.com
295 million BC to 250 million BC is given by the article cited below as the likely span of the Eudibamus.
-- Newly found bipedal reptile fossil predates dinosaurs by more than 60 million years ["http://www.eurekalert.org/releases/utor-nfb103000.html"] (possibly by Diane Scott, University of Toronto at Mississauga), EurekAlert! , 2 NOVEMBER 2000 Contact: Janet Wong jf.wong@utoronto.ca 416-978-6974 University of Toronto
The closest known surviving relative to Eudibamus cursoris in the early 21st century is the turtle. The best fossil currently available seems to be of an animal drowned in a flash flood. Eudibamus cursoris is of the Bolosauridae family of reptiles.
The likely stride of Eudibamus was similar to that of the modern Jesus Christ lizard of South America, which can run bipedally across water fast enough to avoid sinking. However, Eudibamus looks to have been even faster. It survived at least 30 million years.
Some scientists dispute the idea that Eudibamus ever moved in an upright, bipedal manner, let alone run in that position.
The Jesus Christ lizard is not the only modern lizard capable of moving bipedally; there are many others.

-- Two-Legged Sprinter, Reptile With Unusually Fast Locomotion ["http://www.abcnews.go.com/sections/science/DailyNews/runningreptile001102.html"] By Amanda Onion, ABC News, 11-2-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 250,000,000 BC: A bacterium born now gets trapped in salt and goes into a form of living suspension, to eventually wake up in 2000 AD, stunning human science

This finding in 2000 AD regarding an organism named Bacillus permians will indicate that at least some bacterial spores, under certain conditions, may be effectively immortal. The process in this instance involved the bacterium in a drop of water becoming trapped within a forming salt crystal (fluid inclusion). The biggest difference so far found between this organism and typical modern bacillus is a slightly thicker cell wall.

-- Eternal life by Andy Coghlan, from New Scientist, 18 October 2000, citing Nature vol 407, p 897
Apparently entities such as Bacillus strain 2-9-3 could travel through space within meteorites or crystals. Our nearest neighboring galaxy is some 2.2 million lightyears distant from our own-- but organisms as long lived as this might still survive such a trip, even at speeds far below that of light. Independent verification of this finding is still underway.

-- Alive...after 250 million years, possibly by Christine McGourty, 18 October, 2000, BBC News Online

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 247,000,000 BC: Something of a global extinction event takes place now...

...though it is not of the catastrophic scale of some others.

-- Killer Crater Found ["http://www.discovery.com/news/briefs/20000419/geology_crater.html"] By Larry O'Hanlon, Discovery.com News, April 19, 2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 251,000,000 BC- 245,000,000 BC: The Permian mass extinction...

...apparently does away with 77-96% of all animal species on Earth.

-- 2150 biodiversity ["http://www.enviroweb.org/coe/e-sermons/weedplan.html"] and WRI Article: "A History of Extinction" ["http://www.wri.org/wri/biodiv/b03-koa.html"]

Even the insects almost don't survive this one. The actual die off may have occurred over a period of one million years or less. There may have been more than one cause for the extinctions, but one prime suspect is an enormous lava flow up to four km thick in Siberia, over a region as large as the future USA. In the 20th century the ancient hardened lava flow will be called the Siberian Traps. The volcanic gases released along with the lava may have helped plunge the world into a 'nuclear winter' type environment-- or, alternatively, they may have formed 'greenhouse gases' which effectively cooked the planet for a while. In the 'cooked' scenario much life would have had to take refuge towards the poles (higher latitudes), worldwide. Or, both circumstances could have taken place, only one after the other. First a colder period, then a hotter one. Which scenario actually transpires will remain a mystery to scientists circa 1999 AD.

Other factors could include a comet or asteroid strike during this period-- or even perhaps the killing radiation of a gamma ray burster, coming close to sterilizing the entire galaxy at this time.

Life however bounces back stronger than ever some 80 million years later.

-- Meltdown By Diana Steele, From New Scientist ["http://www.newscientist.com"], 7 August 1999

Perhaps it was a series or multitude of comet impacts over time which caused the extinctions. Or such a series may have combined with the gases emitted by the Siberian Traps above to have had the effect.

-- NOW, IT'S COMET SHOWERS THAT DID IT From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #54, NOV-DEC 1987 by William R. Corliss, citing Piet Hut, et al; "Comet Showers as a Cause of Mass Extinctions," Nature, 329:118, 1987

A fossilized forest in the central Transantarctic Mountains from the Upper Permian offers climatic evidence for its location which seems to conflict with long established ideas about the period.

-- A PERMIAN POLAR FOREST From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #84, NOV-DEC 1992 by William R. Corliss, citing Edith L. Taylor, et al; "The Present Is Not the Key to the Past: A Polar Forest from the Permian of Antarctica," Science, 257:1675, 1992
70% of land species and 85+% of ocean species went extinct by the time the Permian period ended. The extinctions appear to have occured within only one million years or less-- terribly fast, as such things go.
-- Scientific American: IN BRIEF: Fast Extinction ["http://www.sciam.com/1998/0898issue/0898inbrief.html"] (appears from the URL to be the August 1998 issue)
Around 250 million BC up to 90% of all vertebrates on land and in the sea went extinct. A massive die off of plant life also took place-- enough to drastically change the course of rivers worldwide, it appears. The clues provided by river course changes indicate the extinctions occured very quickly as such things go, more likely within only thousands of years rather than millions.
Although large tectonic/geologic movements may also cause such indications, none seem to have occured around this time.
The plant life seems to recover pretty quickly to the extinctions-- at least compared to the animal life.
-- New evidence indicates huge vegetation loss accompanied mass extinction ["http://www.eurekalert.org/releases/nsf-nei083100.html"] 7 SEPTEMBER 2000, EurekAlert!, Contact: Vince Stricherz vinces@u.washington.edu 206-543-2580 University of Washington
The 250 million BC extinctions may have occurred in a period lasting somewhere between 8000 and 100,000 years.
-- Asteroid 'destroyed life 250m years ago' By BBC News Online science editor Dr David Whitehouse; BBC News Online; 22 February, 2001
The mass extinctions of 250 million BC were likely caused by an asteroid or comet impact. The object was somewhere between four and eight miles in diameter. The impact awakened many volcanoes on Earth at the time. Centuries of perpetual darkness and cold followed, as the Earth was shrouded in dust and ash from these events.
This extinction event seemed to pave the way for the continued evolution of dinosaurs and mammals.
It appears that life on Earth comes near to being wiped out once every 100 million years or so.
-- Two Asteroids, Not One, Caused Extinctions: Study By Maggie Fox; Yahoo!/Reuters;February 22, 2001
-- Asteroid killed 90 percent of life on earth millions of years ago by Ann Kellan; February 22, 2001; CNN.com
The cosmic impact of 250 million BC might have registered 12 via the Richter scale.
-- New evidence of mass extinction 250 million years ago found By LEE BOWMAN; Nando Media/Scripps Howard News Service; February 22, 2001; http://www.nandotimes.com
-- Study shows asteroids destroyed life on Earth at least twice By Maggie Fox; Yahoo!/Reuters; February 22, 2001
The 250 million BC Permian-Triassic mass extinctions killed off 70% of land-dwelling species, and 95% of aquatic species. This die off seems to have occured abruptly, as in less than 8000 years.
By contrast, the mass extinctions of 440 million BC and 365 million BC killed off a majority of marine species; the first perhaps by substantial changes in sea levels, and the second maybe by global cooling and a reduction of available oxygen in the seas.
Mass extinctions in 200 million BC killed a majority of marine species, possibly via global warming and excessive volcanic activity.
In 65 million BC about a fifth of land vertebrates died, and a majority of marine species.

-- Scientific American: Science and The Citizen: Deeper Impact by Sarah Simpson: May 2001

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 240,000,000 BC: Much of Gondwana is freed from its previous icy conditions, and animal life repopulates the region

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 235,000,000 BC: Emerging lifeforms of this time include turtles, frogs, dinosaurs, and mammals

-- Geologic Time Scale, page 564, Earth Science, Science and Technology, The Universal Almanac 1996, Andrews and McMeel, 1995

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 230,000,000+ BC: The first dinosaurs appear on Earth

-- Dinosaurs' birth was as accidental as their death? ["http://www.exn.ca/html/templates/htmlpage.cfm?ID=19990625-54&Parent=Science"] by EXN Staff, June 25, 1999, Discovery Channel Canada

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 215,000,000 BC: Dinosaurs are rapidly becoming the dominant large life forms of planet Earth

Perhaps due to dramatic climate change and/or a cosmic impact wiping out previous, more reptilian lifeforms (terrestrial tetrapods). One hint that this is so seems to be the very slow spread of dinosaurs over the Earth prior to this time.

-- Dinosaurs' birth was as accidental as their death? ["http://www.exn.ca/html/templates/htmlpage.cfm?ID=19990625-54&Parent=Science"] by EXN Staff, June 25, 1999, Discovery Channel Canada

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 220,000,000 BC- 208,000,000 BC: The Triassic mass extinction

-- 2150 biodiversity ["http://www.enviroweb.org/coe/e-sermons/weedplan.html"] and WRI Article: "A History of Extinction" ["http://www.wri.org/wri/biodiv/b03-koa.html"]

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 213,000,000 BC- 144,000,000 BC: Global sea levels are high now

Due to the sparseness of fossils from the Jurassic period (213 million BC through 144 million BC), as of early 2001 AD humanity knows very little about mammalian species of that time.
One reason not many fossils exist is because global sea levels in the Jurassic were very high, and so dry land area limited. This meant many animal remains tended to be washed into the seas.

-- 'Jurassic Park' Unearthed in Argentina's Patagonia By Simon Gardner; Yahoo!/Reuters; February 14, 2001

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 200,000,000 BC: Now may mark the beginning of one of the lengthiest periods in galactic history so far where the galaxy is not widely sterilized of higher lifeforms by a gamma ray burster

Smaller galaxy-wide radiation baths occur, to be sure-- but for some time to come the worst events will be taking place in galaxies other than our own.

Any star faring civilization emerging now in the Milky Way will enjoy a much easier road to colonization of the entire galaxy than any who came before them.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 200,000,000 BC: An enormous line of volcanic eruptions breaks the back of the super continent Pangaea now

The eruptions continue for millions of years, with lava eventually flowing over a combined area the size of 20th century Australia.

-- "Eruptions Cleared Path for Dinosaurs" By R. Monastersky; Science News Online, Volume 155, Number 17 (April 24, 1999), ScienceService ["http://www.sciserv.org"]

Pangea begins to break apart, starting the process of widening one rift into the Atlantic Ocean with which humanity will ultimately be familiar.

-- Lecture 14 - The Appalachian Mountains ["http://wwwcatsic.ucsc.edu/~eart3/Lectures/lecture14.html"], last reviewed by respective author(s) on 2/18/00, found on or about 7-8-2000

Horseshoe crabs have appeared. They will survive at least to 2,000 AD.

-- The creatures time forgot by Lynn Dicks, From New Scientist, 23 October 1999

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 200,000,000 BC: Insect evolution seems to be winding down-- most insect designs appear to have already been perfected

Most insect species may remain virtually unchanged between now and the 21st century AD.

-- "insect", page 397, The Concise Columbia Encyclopedia, 2nd Edition, 1983, 1989, Columbia University Press

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 200,000,000 BC- 150,000,000 BC: An aquatic Pellucidar in the making may be forming from the trapped and dying Mongol-Okhotsk Ocean

The name "Pellucidar" was coined by writer Edgar Rice Burroughs (also the creator of "Tarzan") as the name of an exotic land hidden deep within the bowels of the Earth, isolated from the surface and modern human civilization.

Around 200 million BC- 150 million BC, the Mongol-Okhotsk Ocean separating present day Mongolia and Siberia was squeezed out of exsitence via tectonic processes, forcing the attendant sea bottom down into the Earth's deep mantle, at around half an inch per year in depth change. By the time of modern humans this prehistoric crust had moved to some 1550 miles below Earth's surface, roughly at or near the bottom of the Earth's mantle.
Today this slab and others exist in a region below Lake Baikal in Siberia.

-- 150 Million-Year-Old Sunken Sea Bed Found Under Siberia; Source: University Of Michigan; Utrecht University, the Netherlands Organization for Scientific Research, and the U.S. National Science Foundation all sponsered this study

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 180,000,000 BC: Laurasia and Gondwanaland themselves begin to splinter into halves, helping widen the Atlantic Ocean

-- Geologic History of the Canadian Rockies ["http://www.tgx.com/rockymountains/geology.htm"], apparently created in 1998 by Rocky Mountain Hiking, found by J.R. Mooneyham on or about 7-8-2000

Another source puts the start of the breakup of Pangea at 180,000,000 BC. Whatever the timing of that event, a certain homogenization of plant and animal species over common latitudinal regional bands of Pangea now insures many of the child continents possess a similar starting stock of species with which to begin their individual evolutionary journeys. One example of this is the Glossopteris tree, of which seeds will be found circa 20th century AD in Antarctica, Australia, South America, Asia, and Africa.

-- Pangea ["http://www.hcrhs.k12.nj.us/science/pangea.html"], found on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 175,000,000 BC: There seems to be a surprising amount of volcanic activity occuring on Mars now

-- New Clues About Martian Meteorites Baffle Scientists ["http://www.space.com/scienceastronomy/solarsystem/martian_meteorite_000830.html"] By Greg Clark, 30 August 2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 170,000,000 BC: A mass of islands collide with and become a part of North America's western edge

-- Geologic History of the Canadian Rockies ["http://www.tgx.com/rockymountains/geology.htm"], apparently created in 1998 by Rocky Mountain Hiking, found on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 170,000,000 BC- 110,000,000 BC: The Rocky Mountain range of North America is being uplifted

-- Geologic History of the Canadian Rockies ["http://www.tgx.com/rockymountains/geology.htm"], apparently created in 1998 by Rocky Mountain Hiking, found on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 150,000,000 BC: Laurasia breaks from Pangaea; The Wollemi Pine emerges during this time, and will survive (as a species) at least through 2000 AD

Laurasia consists of North America, Europe, and Asia. The rest of the child continents (Antarctica, Australia, South America, South Africa, and India) reside in Gondwana at this time

-- An Old Story -- Botanists Find 'Living Fossil' Tree By Paul Tait, Reuters/Yahoo! Science Headlines, December 15, 2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 150,000,000 BC: The first civilizations to emerge after the subsidence of gamma ray bursters in our galaxy have by now each had sufficient opportunity to colonize the entire Milky Way galaxy

The first civilizations to appear in our galaxy since the gamma bursters frequency diminished have likely had some 50 million years or so in which to colonize the whole galaxy by now.

-- Scientific American: Feature Article: Where Are They?: July 2000 ["http://www.sciam.com/2000/0700issue/0700crawford.html"] by Ian Crawford

Apparently there are more challenges and obstacles involved in the successful galaxy-wide colonization efforts of an advanced star faring civilization than we will realize, circa 2000 AD; witness the lack of evidence that Earth was colonized by advanced aliens in 150,000,000 BC or later. To see more on this subject, please refer to CONTACT! Alien Speculations: The Rise and Fall of Star Faring Civilizations in Our Own Galaxy

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 150,000,000 BC -100,000,000 BC: The super continent Pangaea is breaking apart to form all the separate continents with which 20th century humanity will be familiar

-- "Dinosaur fossils reveal evolution's big picture, says Paul Sereno", 24 JUNE 1999, American Association for the Advancement of Science, Contact: Heather Singmaster, hsingmas@aaas.org, 202-326-6414

The first ants may appear on Earth during this period.

-- Ethological Curiosities, Miscellaneous Wonders of Nature ["http://cogweb.english.ucsb.edu/EP/Ethology.html"], by Francis F. Steen, (revised 17 July 1999)

Around 150,000,000 BC there is a major asteroid impact in the Barents sea near the coast of Norway. This impact effects the entire globe via tidal waves, a climate-changing "nuclear winter", and extinctions.

-- Europe's biggest smash hit By Dr David Whitehouse; Sci/Tech; BBC News Online, February 15, 1999, http://www.bbc.co.uk/

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 145,000,000+ BC: Small Velociraptor-like dinosaurs are mutating into the earliest bird-like forms

-- Terror, Take Two By Carl Zimmer, Discover Magazine, found on or about 9-1-99
The evolution of giant flightless prehistoric birds was helped along by the existence of land bridges connecting continents. These birds appear to have competed with dinosaurs for food.
Also known as ratites, such giant flightless birds seem to have emerged before 65 million BC.
Indeed, the evidence suggests such species were spinning off from relatives as early as 145 million BC through 80 million BC-- when the southern hemisphere's super continent Gondwana existed, then began to break up into Antarctica, Africa, South America, Australia, and part of India.

-- DNA Reveals Ancient Big Birds By Jennifer Viegas, Discovery News; Feb. 13, 2001; Discovery Communications Inc./Reuters Limited

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 140,000,000 BC: Gondwana begins breaking up; 20th century-style Crocodiles have appeared

Crocodiles will survive virtually unchanged at least to 2,000 AD.

-- The creatures time forgot by Lynn Dicks, From New Scientist, 23 October 1999

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 125,000,000 BC: 20th century type Gingko trees have appeared

Gingko trees will survive at least to 2,000 AD.

-- The creatures time forgot by Lynn Dicks, From New Scientist, 23 October 1999

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 144,000,000 BC- 66,000,000 BC: The largest living creature which will ever fly Earth's skies before the 21st century does so now

The Solana Dragon is a pterosaur, with a wingspan perhaps as large as 36 feet.

-- See Largest Flying Creature By Rossella Lorenzi, Dec. 30, 1999, Discovery Online, Discovery News Brief

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 110,000,000 BC: A plateau eventually to become one third the size of 1999 AD Australia has begun to emerge in the southern hemisphere as a sequence of island continents

110 million years from now it will be known to submariners as the "Kerguelen Plateau", and lie two kilometers deep undersea. But for around 90 million years beginning now it (or portions of same) will exist as massive regions of dry land on Earth.

-- "'Lost continent' discovered" By Dr David Whitehouse, BBC News Online: Sci/Tech, 5-27-99, BBC Homepage ["http://www.bbc.co.uk/"]

NGDC/WDC A for MGG - Marine Geology & Geophysics Images ["http://www.ngdc.noaa.gov/mgg/image/images.html"] may be helpful in visualizing the size and location of this continent that Earth will eventually lose to the sea.

[To see more about this lost land, please refer to A possible history of the mysterious frozen Antarctic and sunken Kerguelen continents]

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 96,000,000 BC: Australia and Antarctica split apart

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 90,000,000 BC: The Nightcap Oak which emerges at this time or before will survive (as a species) through at least 2000 AD

The species of Nightcap Oak recently found in Australia has lived continuously on Earth since at least 90 million BC, and grew in the days when South America, Australia, New Zealand, and Antarctica were all joined together in the continent of Gondwanaland.

-- An Old Story -- Botanists Find 'Living Fossil' Tree By Paul Tait, Reuters/Yahoo! Science Headlines, December 15, 2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 84,000,000+ BC: Something rocks our world

Over about two million years the Earth rolls 16-21 degrees out of its normal position. At this time three super-volcanic eruptions and various tectonic plate changes are also taking place. The cause of the roll seems to be a change in Earth's mass distribution...

-- Study: Earth Once Wobbled, Jan. 21, 2000, Associated Press/Discovery Online News Brief/Discovery Communications Inc./http://www.discovery.com/
Around 84,000,000 BC dinosaurs worldwide suffered climatic changes brought about by a tilting of the Earth's axis by as much as 20 degrees. The tilt occured over just 2 million years-- ten times faster than normal for such movements. Tilts like this are considered to be caused by slippage between the Earth's core and the rest of the world.

-- Fast tilt, From New Scientist magazine, 29 January 2000

As of the time of the cited article above the roll had not yet been confirmed. If the roll did occur, it signifies an unusual event for which we might have insufficient clues as to the cause. A cosmic impact of sufficient magnitude to roll the planet would seem to have initiated a mass extinction as well-- especially in synch with the huge volcanic eruptions indicated too. Events which might bring about a sufficient mass shift without calamitous extinctions might include a massive earthquake rupturing the crust undersea, allowing a huge volume of seawater to be swallowed up by the mantle, in a way much more sudden than the normal subduction process. There is evidence of at least a couple of unusually large subterranean gulps of ocean water in Earth's past.

Between 750 million BC and 2,000 AD the Earth's surface sea level will drop some 1,968 feet due to loss of water to subterranean regions..

Of course, a large section of the sea floor sinking along with a vast gulp of seawater would further amplify the effects and possibly accelerate tectonic plate processes.

-- EARTH'S SHIFTING CRUST From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #113, SEP-OCT 1997 by William R. Corliss, citing Kirschvink, Joseph L., et al; "Evidence for a Large-Scale Reorganization of Early Cambrian Continental Masses by Inertial Interchange True Polar Wander," Science, 277:541, 1997. Also: Sawyer, Kathy; "Global Shift May Have Sped Evolution," Washington Post, July 25, 1997, and Wise, Kurt P., "The Archaean Explosion," CEN Technical Journal, 10:315, 1996

Another possible cause might be a large mass passing near the solar system, or even near Earth itself, thereby disturbing Earth's orbit and/or inclination. The further away from Earth such an object passed by, the more massive it would have to be to perturb things in this way. As I've seen no evidence of the other planets being significantly affected at this time, perhaps such an object only came near the Earth itself. It could have been an enormous rogue asteroid or comet not native to our system, or a moon ejected by one of the gas giants, on its way out of our system, or a small black hole passing through our system, thankfully not settling here to devour our star and planets.

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 76,000,000 BC: Australia and New Zealand split apart

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 66,500,000 BC: Emerging lifeforms of this time include rodents, primates, horses, and sycamores

-- Geologic Time Scale, page 564, Earth Science, Science and Technology, The Universal Almanac 1996, Andrews and McMeel, 1995

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Another collision of a mass of islands adds to the tectonic forces uplifting the Rocky Mountains. By 65,000,000 BC the Rockies may reach heights comparable to the Andes or even Himalayas which will be known in the 20th century

-- Geologic History of the Canadian Rockies ["http://www.tgx.com/rockymountains/geology.htm"], apparently created in 1998 by Rocky Mountain Hiking, found on or about 7-8-2000

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 65,000,000 BC: The Cretaceous mass extinction comes about, famous later for the decimation of the dinosaurs, but more importantly responsible for the end of about 76% of all life on Earth.

Although the popular notion circa 1999 AD will be that an asteroid or other large body impact from space caused the mass extinctions, the truth is that far more was also going on at this time. For instance, a developing 'nuclear winter' type effect from massive volcanic eruptions in the vicinity of 20th century India had already been present for perhaps millions of years before the meteor strike took place. And many dinosaur species were also in decline before the impact, for other reasons.

It will be becoming more widely accepted circa 1999 AD that dinosaurs did not in fact die out, but simply evolved into the birds known to 20th century humanity. As of 1999 it will also be appearing that even the popular concept of dinosaurs as large lizard-like beasts survived in the flesh for some time beyond the cosmic impact catastrophe (perhaps half a million years)-- at least in some places on Earth, like southeastern China, which maybe not coincidentally existed on the opposite side of the planet from the impact point. From the scant evidence available so far, it appears some 45% of local Chinese dinosaur species may have been among the survivors of this time. Keep in mind we're talking numbers of different species here, not total population numbers (which might still have been suffering tremendous declines).

It does appear the effects of the meteor strike and massive volcanic eruptions were poisoning the environment, perhaps adversely affecting processes like egg-laying by the dinosaurs similarly as to how the pesiticide DDT was harming egg-laying by american eagles in the mid-20th century.

One effect of the meteor strike itself appears to have been a disasterous and massive release of flammable gas (methane) from the sediments of ocean depths which filled much of the Earth's global atmosphere and was set aflame by lightning or other means, resulting in a raging firestorm racing over much of the planet. The fire consumed perhaps ten percent of all plant life on Earth's dryland surfaces.

Methane hydrates could have been the source of the gas. Shock waves from the impact could have been large enough to free gas from this undersea source all over the Earth simultaneously.

-- 2150 biodiversity ["http://www.enviroweb.org/coe/e-sermons/weedplan.html"]
-- "Did the Dark Ages begin with a bang?" by Robert Matthews Connected, Electronic Telegraph, http://www.telegraph.co.uk, 29 July 1999, Telegraph Group Limited
-- "Dino Deaths Revisited Meteor May Not Have Destroyed Them, After All" By Kenneth Chang ABCNEWS.com, Sept. 26, 1999, http://www.abcnews.go.com, ABC News Internet Ventures
-- GLOBAL FIRE AT THE K-T BOUNDARY from Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #60, NOV-DEC 1988, by William R. Corliss, citing Wendy S. Wolbach, et al; "Global Fire at the Cretaceous-Tertiary Boundary," Nature, 334:665, 1988
-- THE CRETACEOUS INCINERATION from Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #43, JAN-FEB 1986 by William R. Corliss, citing Wendy S. Wolbach, et al; "Cretaceous Extinctions: Evidence for Wildfires and Search for Meteoric Material," Science, 230:167, 1985

-- Were the last dinosaurs roasted alive? by Michael Day New Scientist issue: 20th November 99 Source: Geo-Marine Letters (vol 18, p 285), http://www.newscientist.com and EurekAlert! ["http://www.eurekalert.org/"]

Could the cosmic impacts of asteroids and comets be the dominant element of geophysics? Affecting the distribution of continents, volcanoes, and lava flows, as well the sequence of mass extinctions and generation of the geomagnetic field?

Might many cosmic impacts consist of multiple hits, or swaths of impacts, rather than individual events? If the Shoemaker-Levy 9 impacts on Jupiter in 1994 AD are any indication, the answer is yes. A possible "K-T swath" could include the Yucatan/Chicxulub impact, along with the Iowa/Manson impact, the Alaska/Avak crater, and three others in Russia---all apparently created at about the same time. Such simultaneous or near simultaneous multiple strikes might help explain the global catastrophe and effects better than a single strike.

Perhaps an uneven distribution of mass within the Earth helps funnel impacts more heavily towards some regions than others, due to gravity effects. Repeated impacts in the same regions would also have their own effect on Earth's mass distribution, thereby generating a feedback loop of sorts. Other effects serving to affect the timing and location of impacts could be the intermittant capture of comets/asteroids by the planets of the inner solar system, to feed the process for Earth impacts over time.

-- A UNIFIED THEORY OF GEOPHYSICS From Science Frontiers Digest of Scientific Anomalies ["http://www.knowledge.co.uk/frontiers/"] #98, MAR-APR 1995 by William R. Corliss, citing Richard Monastersky; "Shots from Outer Space," Science News, 147:58, 1995
A global chemical reaction in the atmosphere created by compounds thrown into the air from the asteroid impact may be what truly doomed the dinosaurs and many other lifeforms on Earth 65 million years ago.
Vaporized sulfate rocks and carbonates from the Chicxulub impact zone could have created a wealth of airborne carbon dioxide and sulfur, which in turn would have helped create major climate warming on the heels of the nuclear winter initially following the impact-- a huge see saw in climate conditions for life. The sulfur would also have remained active in the atmosphere for decades or even centuries, creating a persistent presence of sulfuric acid in rainfall. The sudden, significant change in the ratio of carbon dioxide to oxygen in the atmosphere may also have posed breathing problems for many organisms-- especially large dinosaurs.
Impacts the size of Chicxulub are thought to occur perhaps once every 350 million years on average.

-- Geophysicists ponder dinosaurs' demise Asteroid impact theory By MATTHEW FORDAHL, Nando Media/Associated Press, December 17, 2000, http://www.nandotimes.com

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

Approximately 60,000,000 BC: The platypus appears

-- The dream of the platypus by Brahm Rosensweig, brahm@exn.net, August 16, 1999, http://exn.ca/html/templates/mastertop.cfm?ID=19990816-52, EXN.CA

Signposts 3,000,000,000 BC- 60,000,000 BC Contents

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