TIME COUNTING FORWARDS FROM THE BIG BANG to 420 Million years before the Present (A)

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Wikipedia: http://www.wikipedia.org/wiki/Timeline_of_the_Big_Bang
The universe in 18 minutes:


What did the Earth look like xxxx years ago? Interactive map.


Astronomers in 1998 reported sighting galaxies 12 billion light-years away using the Near Infrared Security Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope. Other information regarding these device types can be found here .
BeforeBigBang  In a vacuum state with no space or time, physical laws would not seem appropriate. However, the law that states matter can neither be created nor destroyed implies another state here, i.e. a state of pure energy unbound by space and time. The chance fluctuation indicated below for the beginning of the Big Bang would have occurred in this energy field. This occurrence could have been like the breaking of a dam, or a puncture that explodes a filled tire, or a bomb that violently explodes upon detonation. The resulting tiny bubble of space-time provided an outlet for the enormous energy latent in the pre-space-time state. This of course gives no account of how or where or why the initial pure-energy state came about. We may never know, but we can always speculate.
 (AR, 2/1/02)

BBB        Before the Big Bang: In a vacuum state with no space and consequently no time, physical laws would not seem appropriate. However, the law that states matter can neither be created nor destroyed implies another state of matter, i.e. a state of pure energy unbound by space and time. The chance fluctuation indicated below for the beginning of the Big Bang would have occurred in this energy field. This occurrence could have been like the breaking of a dam, or a puncture that explodes a filled tire, or a bomb that violently explodes upon detonation. The resulting tiny bubble of space-time provided an outlet for the enormous energy latent in the pre-space-time state. This of course gives no account of how or where or why the initial pure-energy state came about. We may never know, but we can always speculate.
    (AR, 2/1/02)(AR, 9/10/10)

0000        While in a vacuum state a chance fluctuation occurred in the void owing to quantum uncertainty. This yielded an infinitesimal bit of space-time that ballooned in size 10 to the 50th times in a quadrillionth of a quadrillionth of a second. Before it could revert back to nothing, a sort of negative pressure caused a runaway expansion faster than the speed of light. This is described in the 1997 book: "The Inflationary Universe" by Alan H. Guth.
    (WSJ, 6/17/97, p.A16)(WSJ, 4/11/03, p.B1)

BIG BANG    Time, space, matter and energy came into being. Matter and energy began to define space and time. In 2002 scientists said experiments confirmed that only 5% of the universe was composed of ordinary matter. 65% was said to be "dark energy" and 30% was "dark matter." In 1998 Joseph Silk authored “The Big Bang." A 3rd ed. was published in 2004. In 2004 Simon Singh authored “Big Bang: The Most Important Scientific Discovery of All Time and Why You Need to Know About It." In 2006 NASA released data backing the Big Bang theory that the universe sprang from marble size to infinity in less than a trillion-trillionth second.
    (SFC, 12/14/02, p.A2)(SSFC, 5/30/04, p.M7)(Econ, 11/6/04, p.87)(WSJ, 3/17/06, p.A1)

10-43 Second    Theorists think that before gravity separated out at this moment, that the strong and weak nuclear forces, and the electromagnetic force were unified.
    (NG, May 1985, J. Boslough, p. 652)
    Planck Epoch. On time scales shorter than this, the effects of gravity must be included in all physical processes. In this time light can travel 3 x 10-32 cm, less than a quadrillionth of the distance across a proton.
    (JST-TMC,1983, p.197,227)(http://en.wikipedia.org/wiki/Timeline_of_the_Big_Bang)
10-43 Sec - 10-35 Sec    We will call the period beginning at 10-43 second and ending at 10-35 second after the Big Bang the GUT, or grand unified theory era. This was an era of very high temperatures, with the energy of collisions ranging from 1019 GeV at the beginning to 1015 GeV at the end. During the GUT era, then, there were only two kinds of particles: fermions (leptons and quarks, now understood to be identical) and bosons (the X-particles, gluons, vector mesons, and photons). In 2006 experiments at Fermilab found that a type of B-mesons (Bs) switch between being matter and antimatter some three trillion times a second.
    (JST-TMC,1983, p.155)(Econ, 4/22/06, p.77)

10-36 Sec    Separation of the Strong Force. Although atoms do not yet exist, the force that will hold their nuclei together becomes an individual entity. In 2005 it was reported that scientific evidence from Brookhaven National Laboratory indicated the creation of a quark-gluon plasma, a form of matter that last existed moments after the big bang.
    (NG, p.12, Jan, 94)(WSJ, 4/1/05, p.B1)

10-36 Sec - 10-32 Sec    Inflation. Triggered by separation of the strong force, the universe expanded more in this instant than it has in the roughly 15 billion years since. The inflation theory was dreamed up by Alan Guth of MIT to explain the extraordinary uniformity of the universe.
    (NG, p.12, Jan, 94)(Econ, 12/4/10, p.101)

10-35 Sec    Strong force freezes. This begins the electroweak era. The interactions between particles are governed by three (rather than four) fundamental forces: the strong, electroweak, and gravitational interactions. It is suspected that the universe inflated very rapidly about this time... the curvature of the universe increased from 10-23 cm (about 10 billion times smaller than the size of a single proton) to something around 10 cm, the size of a grapefruit.
    (JST-TMC,1983, p.151,157)(http://en.wikipedia.org/wiki/Electroweak_epoch)
10-32 Sec - 10-5 Sec     Quarks and anti-quarks. As inflation ended, the still expanding universe now teemed with quarks and anti-quarks that annihilate each other upon contact. But a surplus of quarks, one per billion pairs, survives. This surplus of quarks will ultimately combine to form matter.
    (NG, p.12, Jan, 94)

10-32 Sec to 3,000 Years    Energy domination. Because of high temperatures, radiant energy generates most of the gravity in the universe during this period.
    (NG, p.12, Jan, 94)
10-12 Sec    The final two forces split off. Electromagnetism is carried by photons, the basic unit of electromagnetic energy. The weak force controls certain forms of radioactive decay.
    (NG, p.12, Jan, 94)

10-10 Sec    Weak and electromagnetic forces freeze. This was the beginning of the quark era. The universe will have cooled off to some 10 quadrillion degrees or so. Above this temperature, there is enough energy available (>100 GeV) in interparticle collisions to create vector bosons; below this temperature there is not sufficient energy to do so.
    (JST-TMC,1983, p.151,157)

10-6 Sec      The hadron epoch was the period in the evolution of the early universe during which the mass of the Universe was dominated by hadrons. It started approximately 10-6 seconds after the Big Bang, when the temperature of the universe had fallen sufficiently to allow the quarks from the preceding quark epoch to bind together into hadrons. The elimination of anti-hadrons was completed by one second after the Big Bang, when the following lepton epoch began.

10 -5 Sec    Quark confinement. As the universe cools to one trillion degrees K, trios of quarks form protons and neutrons.
    (NG, p.12, Jan, 94)

10-3 Sec    Quarks freeze into particles. (JST-TMC,1983, p.157) According to the Standard Theory, all matter in the universe is made from different combinations of two types of sub-atomic particles. Fermions, such as electrons and quarks, are the bricks or fundamental building blocks of matter. A different type of particle, called bosons, are the mortar. Bosons are the carriers or forces like electromagnetism and gravity, which hold the bricks of our universe together. Peter Higgs postulated around 1970 that the Higgs boson, usually invisible, creates a field through which subatomic particles, such as quarks and electrons, pass. Experiments in 2001 found that muon spin modification in a magnetic field varied from that predicted by the Standard Model. When the temperature dropped below 1 trillion degrees or so, the Higgs field flipped on and some particles began interacting with Higgs bosons. In 2012 Nicholas Mee authored “Higgs Force: The Symmetry-Breaking Force That makes the World an Interesting Place. Jim Baggott authored “The Quantum Story: A History in 40 Moments."
    (LSA, Fall 1995, p.34)(SFC, 11/4/00, p.A14)(SFC, 2/9/01, p.A5)(Econ, 3/3/12, p.94)

3 Minutes    Up to this time the temperature was so high and the collisions in the plasma so violent that no nucleus could cohere. The temperature at 3 minutes was about a billion degrees, a little less than a hundred times hotter than the temperature at the center of the sun.
     (JST-TMC,1983, p.26)
    Between the ages of 3 minutes and 500,000 years, the universe consisted of an expanding plasma with no atoms present. The nuclei in the plasma were protons, deuterons, helium 3, and helium 4. All other nuclei were synthesized in stars after the formation of galaxies.
    (JST-TMC,1983, p.25-26)

3 Min, 3.5 sec    Helium was formed following the Big Bang.
    (WSJ, 11/30/00, p.A12)

3k Years PBB     Post Big Bang. Matter Domination. With cooling matter became the primary source of gravity.
    (NG, p.12, Jan, 94)

10k PBB    Atoms formed after the big bang.
    (NG, May 1985, J. Boslough, p. 650)

300k PBB    The universe was composed of vast waves of radiation with clumpy structures of hydrogen stretched across empty space. This was supported by data gathered by the "Boomerang" telescope mission in 1998-1999, which also supported the idea of a flat universe expanding forever.
    (SFC, 4/27/00, p.A7)
300k PBB    Not until the universe was this old did light break away from matter and begin to travel freely through our expanded speck of space. Hydrogen gas condensed and clumped into contracting clouds that were the seeds for stars. These photons later became known as the cosmic microwave background (CMB)
    (NG, p.12, Jan, 94)(SFC, 1/10/98, p.A2)(Econ, 6/25/05, p.79)

400k PBB    The universe cooled enough that charged electrons and protons combined to form hydrogen atoms, which allowed photons to escape the hot gas of the Big Bang.
    (SFC, 1/12/05, p.A2)

500k PBB    The universe suddenly underwent a change that had the effect of lessening the probability that radiation would collide with matter.
    (JST-TMC,1983, p.15)

1Mil PBB    The present stage of the universe was ushered in by the "freezing" of the hot plasma into a collection of atoms less than a million years after the Big Bang. Under the influence of gravity, the expanding material began to come together in clumps. The aggregations would eventually form the galaxies.
    (JST-TMC,1983, p.24)

150Mil - 1Bil PBB     The first quasars formed from gravitational collapse. The intense radiation they emit reionizes the surrounding universe. From this point on, most of the universe is composed of plasma.

200Mil PBB    Galaxy formation. Matter continued to clump in the areas of concentration and over eons was condensed by gravity.
    (NG, p.12, Jan, 94)(SFC, 2/12/03, p.A4)

300Mil PBB    It took an estimated 300 million years for the universe to cool and for the first stars to form from hydrogen and helium.
    (AP, 1/7/04)

500Mil    PBB    Evidence from the Hubble Space Telescope in 2001 suggested that the peak of star formation came about 500 million years after the Big Bang and has declined ever since.
    (SFC, 1/9/02, p.A11)

750Mil    PBB    In 2004 a team of astrophysicists said they have detected a tiny galaxy, the farthest known object from Earth, formed when the universe was just 750 million years old.
    (AP, 2/16/04)

800MilPBB    In 2015 astronomers said they have identified a galaxy dating to about this time and named it CR7, short for Cosmos Redshift 7, after the method by which distant objects are dated.
    (SFC, 6/18/15, p.D3)

1Bil PBB    Quasars that formed less than a billion years after the big bang were identified in 2000 under the Sloan Digital Sky Survey program. The term quasar was coined by Chinese-born US astrophysicist Hong-Yee Chiu in 1964, in Physics Today, to describe these puzzling objects.
    (SFC, 4/14/00, p.A17)(http://en.wikipedia.org/wiki/Quasar)

106 Bill - 1014 PBB    The Stelliferous or Star-Filled Era.
    (LSA, Spg/97, p.30)
    On Apr 20, 1997 an article in the Astrophysics Journal identified some of the missing matter (dark matter) of the universe as ionized hydrogen and helium gas spread out between the galaxies. The atoms were stripped of their electrons early in the formation of the universe. It was later reported that only 5% of the universe was made of ordinary matter. Dark matter formed 25% and dark energy composed 70%.
    (SFC, 4/21/97, p.A3)(SFC, 9/23/02, p.A4)


The time reference is now BC, i.e. before the Christian era.

20Bil BC - 8 Bil BC    Estimates of the age of the universe are in this range, but most astronomers believe it all began about 15 billion years ago.
    (NG, p.9, Jan, 94)

15.8Bil BC    In 2006 a new finding implied that the universe is about 15.8 billion years old and about 180 billion light-years wide. New evidence suggested that the Hubble constant, a number that measures the expansion rate and age of the universe, is actually 15% smaller than other studies have found.
    (AP, 8/7/06)(http://tinyurl.com/jnc7x)

13.9Bil BC ¬- 13.3 Bil BC    The best available measurements as of 2010 suggest that the initial conditions of the Big Bang occurred between 13.3 and 13.9 billion years ago.

13.8Bil BC Scientists in 2013 calculated age of the universe to be about 13.8 billion years.
    (SFC, 2/22/13, p.A4)

13.7Bil BC    Scientists in 2002, using data from the Hubble Space Telescope, confirmed that the universe began about this time. Evidence also confirmed that the universe is flat and expanding and not closing in on itself. In 2003 astronomers used data from the Wilkinson Microwave Anisotropy Probe (WMAP) and concluded that age of the cosmos to be 13.7 bil years.
    (SFC, 4/25/02, p.A2)(SFC, 5/24/02, p.A2)(SFC, 2/12/03, p.A4)
13.7Bil BC    In 2006 NASA released data backing the Big Bang theory that the universe sprang from marble size to infinity in less than a trillion-trillionth second.
    (WSJ, 3/17/06, p.A1)
13.7Bil BC    Scientists in 2009 recorded an explosion that occurred during the so-called "cosmic dark ages", which started a mere 400,000 years after the Big Bang set the Universe in motion some 13.7 billion years ago. Dubbed GRB 090423, the stunning gamma-ray burst was first spotted by the NASA satellite Swift.
    (AFP, 10/29/09)

13.23Bil BC    In 2004 French and Swiss astronomers detected the most distant galaxy ever observed, 13.23 billion light-years from Earth.
    (WSJ, 3/2/04, p.A1)

13.1Bil BC    In 2010 European astronomers calculated that a galaxy, hidden in a Hubble Space Telescope photo taken earlier in 2010, dated back to about this time, when the universe was very young, just shy of 600 million years old. Scientists dubbed it "the high red-shift blob."
    (AP, 10/20/10)
13.1Bil BC    In 2012 astronomers reported a protocluster of galaxies viewed through the Hubble Space Telescope that dated to about this time.
    (SFC, 1/13/12, p.A5)

13Bil BC    In 1999 astronomers used the Hubble Space Telescope to detect a galaxy, dubbed "Sharon." It was the oldest and most distant object ever detected.
    (SFC, 4/15/99, p.A7)
13Bil BC    In 2003 scientists reported that the oldest planet ever detected is nearly 13 billion years old and more than twice the size of Jupiter, locked in orbit around a whirling pulsar and a white dwarf located near the heart of a globular star cluster some 5,600 light-years from Earth in the constellation Scorpius.
    (AP, 7/11/03)
13Bil BC    In 2008 astronomers took pictures of a galaxy, named A1689-xD1, that had formed some 13 billion ears earlier, when the universe was about 700 million years old.
    (SFC, 2/13/08, p.A9)
13Bil BC    In 2009 a gamma ray burst was spotted by a NASA satellite that dated to this time. A typical burst "puts out in a few seconds the same energy expended by the sun in its whole 10 billion year life span." Researchers announced in 2011 that they have gathered data placing the blast more than 13 billion light years away, meaning that the event took place when the universe was still in its infancy.
    (AP, 5/27/11)
13Bil BC    In 2011 a team of int’l. astronomers reported the finding of the oldest black holes ever observed. Their observations put the black holes 13 billion light years from Earth, meaning that they were being observed just as they looked 1 billion years after the formation of the universe.
    (SFC, 6/16/11, p.A6)

12.9Bil BC    In 2015 astronomers said they have identified a galaxy dating to about this time and named it CR7, short for Cosmos Redshift 7, after the method by which distant objects are dated.
    {HistoryBC, Universe}
    (SFC, 6/18/15, p.D3)

12.22Bil BC    The galaxy listed as RD1 was detected in Sept. 1997 and estimated to have come into being 820 million years after the Big Bang. It was estimated to be 12.22 billion light-years distant.
    (SFC, 3/13/98, p.A2)
12.1Bil BC    In 2005 NASA and other institutions reported a huge galaxy, HUDF-JD2, dating from about 800 million years after the Big Bang. Odds on the date were given at 75%. The galaxy was said to be unusually massive and mature for its place in the young universe.
    (SFC, 10/10/05, p.A4)

12.1Bil BC - 12.2Bil BC     Reionization of the cosmos occurred when the universe was 6-7% of its current age. This marked the end of the Dark Age as stars generated high energy photons that split the hydrogen atoms fogging up the universe.
    (NH, 7/02, p.72)

12Bil BC    Astronomers in 1998 reported sighting galaxies 12 billion light-years away using the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope.
    (USAT, 10/9/98, p.10A)
12Bil BC    Tentative new results from the European satellite Hipparcos in 1997 indicated this as the approximate age of the universe and that the oldest stars were about 11 billion years old.
    (SFC, 2/17/97, p.A2)
12Bil BC    A group of astronomers in 1999 concluded that the universe was about 12 billion years old based on data from the Hubble telescope. This group calculated the Hubble constant at 70 km per sec. Other astronomers still argued for an age from 14 to 18 billion years.
    (SFC, 5/26/99, p.A1)(SFC, 5/26/99, p.A1,13)

12Bil BC - 10Bil BC    Observations by the Hubble telescope determined that the universe must be at least 10-12 billion years old.
    (SFC, 4/24/00, p.A10)

11.2Bil BC    The star Kepler-444 formed about this time and in 2015 astronomers announced that it was orbited by five rocky planets.
    (Econ, 1/31/15, p.72)

11Bil BC    In 1996 astronomers using the Hubble space telescope discovered a galaxy under construction. They say 18 gigantic star clusters packed within a space just 2 million light years across and apparently on the verge of forming a brand new galaxy.
    (SFC, 9/5/96, p.A3)

10Bil BC    In 1998 scientists of the Supernova Cosmology Project (SCP) detected a supernova with a 1.2 redshift from this time. SN1998ex was nicknamed Albinoni.
    (CW, Spring ‘99, p.6)

9.8Bil BC    About this time dark energy got the upper hand over gravity speeding up the universal expansion.
    (Econ, 8/24/13, p.70)

9Bil BC    In 1999 astronomers reported a gamma ray burster, GRB 990123, near the constellation Bootes that originated about this time.
    (SFC, 3/26/99, p.A2)

9Bil BC - 8Bil BC    By 2009 scientists believed that dark matter was smoothly distributed around elliptical galaxies by this time.
    (Econ, 8/15/09, p.74)
9Bil BC - 6Bil BC    The Helmi stream star group remained after its mini-galaxy was devoured by the Milky Way during this period. In 2010 a hot, gaseous and fast-spinning planet was found orbiting a dying star of the Helmi stream on the edge of the Milky Way, in the first such discovery of a planet from outside our galaxy.
    (AFP, 11/18/10)    

7.5Bil BC    In 2008 astronomers recorded the explosion of a star in a gamma ray burst from about this time. The light took 7.5 billion light-years to reach Earth.    .
    (SFC, 3/22/08, p.A2)

7Bil BC    In 1997 scientists of the Supernova Cosmology Project (SCP) detected a supernova with a .83 redshift from this time, which they named SN1997ap.
    (CW, Spring ‘99, p.6)
7Bil BC     About this time, when the universe was about half its current age, two stellar black holes crashed into each other. One was 66 times the mass of the sun and the other a husky 85 times the mass of the sun. The result was an intermediate black hole, 142 times the mass of the sun. This was detected by scientists in 2019.
    (AP, 9/2/20)

5Bil BC - 4.5Bil BC    The sun is now about 5 billion years old. A rapidly rotating gas cloud will spin off some of the material at its equator into a disk. This explains why all planets orbit in roughly the same plane and direction and why they all move in near circular orbits around the Sun.
    (JST-TMC,1983, p.210)(Nat. Hist., 3/96, p.63)(SFC, 4/22/98, p.A11)
    The early sun went through a stormy period called the T-Tauri phase, when powerful winds and radiation blew outward.
    (SFC, 9/27/96, p.A10)

4.5Bil BC    The abiogenic theory of Thomas Gold holds that hydrocarbons were a component of the material that formed Earth through accretion of solids. In 1999 Gold authored "The Deep Hot Biosphere."
    (NH, 12/98, p.12)


5.0Bil BC - 4.5Bil BC    As the earth became molten the nickel-iron migrated inwards, gravitated to form the core. The lighter materials, largely silicates, were left behind as outer layers, mantle and crust. The formation of Earth took between 120 and 290 million years following the explosion of a nearby supernova.
    (DD-EVTT, p.114)(SFC, 11/10/00, p.D7)
    The formation of the earth was a process of accrual where numerous planetesimals crashed together and eventually formed a large enough mass to attract more floating matter to the hot fireball of earth.
    (TMP, KCTS-Video, 1987)
    In 1996 it was proposed that the early Earth during this period may have been covered by a thick atmosphere that was blown away by storms from the young sun.
    (SFC, 9/27/96, p.A12)

4.6Bil BC    Earth formed about this time and its gravity pulled in countless meteorites. As the crust cooled, the oceans condensed.
    (NG, V184, No. 4, Oct. 1993, R. Gore, p.128)

4.6Bil BC - 4Bil BC    This was a period of heavy meteor bombardment on Earth.
    (NH, 9/97, p.84)

4.6Bil BC - 3.8Bil BC    In 2008 scientists reported that water was abundant on Mars during this period.
    (SFC, 7/17/08, p.A2)

4.6Bil BC - 3.6Bil BC    Eogeological time. Almost no trace remains of the Earth crust formed at this time.
    (DD-EVTT, p.139)

4.6Bil BC - 3.5Bil BC    This represents the Noachian period on Mars.
    (SFC, 7/7/97, p.A4)

4.55Bil BC - 4.45Bil BC    Researchers in 2010 found that a slab of mantle under Baffin Island, Canada, was believed to date to this period. This would be the oldest rock found thus far on earth.

4.5Bil BC    Our moon formed about this time when an iron-rich, Mars-sized planet or asteroid plowed into Earth while it was forming. Much of the iron ended up in the Earth’s core, whereas the cloud of dust ejected from the impact consolidated into the moon.
    (PacDis, Winter ’97, p.28)(Econ, 2/21/09, p.81)
4.5Bil BC    Molten rock on Mars crystallized. The Allan Hills 84001 meteorite, found in Antarctica in 1984, was analyzed to this age.
    (SFC, 8/7/96, p.A9)(SFC, 11/1/96, p.A16)
4.5Bil BC    A meteor of this age, named the Canyon Diablo meteorite, was later held by the Smithsonian Institute.
    (SJSVB, 9/9/96, p.14A)
4.5Bil BC    Eros, a near Earth asteroid, dated to about this time.
    (SFC, 9/22/00, p.A7)
4.5Bil BC    The planet Mercury formed about this time.
    (Econ., 4/25/15, p.75)

4.5Bil BC - 3.8 Bil BC    Hadean Time: The 1st 500 million years of Earth’s history. BYA = Billion Years Ago.
4.5Bil BC - 3.5Bil BC    An initial period of crater forming impacts bombarded the Earth.
    (SFC, 3/10/00, p.A4)

4.4Bil BC - 4.3 Bil BC     In 2001 a tiny crystal of zircon from northwestern Australia was estimated at this age and suggested that the Earth was already cool enough to hold a solid crust.
    (SFC, 1/11/01, p.A2)

4.4Bil BC - 4.1Bil BC    Spectrometer mappings by the Mars Express, launched in 2003 by the European Space Agency (ESA), identified a clay forming period on Mars that dated to this period.
    (Econ, 4/22/06, p.76)

4.37Bil BC    Scientists in 2014 reported that a zircon crystal discovered in Western Australia in 2010 has been determined to be 4.374 billion years old, making it the oldest rock ever discovered on Earth. In 2005 Scientists had used the radioactive decay rate of uranium to date zircons from Western Australia to 4.3Bil BC - 4.1Bil BC. The evidence pointed to a watery world well-suited for life to emerge.
    (SFC, 5/7/05, p.A4)(SSFC, 1/4/15, p.C12)

4.28Bil BC    In 2008 scientists reported that a pinkish tract of bedrock on the eastern shore of Canada's Hudson Bay contains the oldest known rocks on Earth, formed 4.28 billion years ago, not long after the planet was formed. In 2010 older rock, dating from 4.55 to 4.45 was found on Baffin Island, Canada.
    (Reuters, 9/25/08)

4.2Bil BC    The first lithosphere formed very roughly about this time.
    (NOHY, Weiner, 3/90, p.5)

4.2Bil BC ¬- 4Bil BC    Abiogenesis, the study of how life on Earth could have arisen from inanimate matter, could have happened as early as this period. If it occurred at the surface of the earth abiogenesis could only have occurred between 4.0Bil BC and 3.7Bil BC.
    In 1922 Alexander Ivanovich Oparin, Soviet biochemist, outlined a way in which basic organic chemicals might form into microscopic localized systems possible precursors of the biology cells from which primitive living things could develop. Oparin suggested that different types of coacervates might have formed in the Earth's primordial ocean and been subject to a selection process leading eventually to life.
    In 1999 Paul Davies published "The Fifth Miracle: The Search for the Origin and Meaning of Life."
    (SFEC, 2/28/99, BR p.1)

4Bil BC    Northwest Canada was formed.
    (NG, March 1990, J. Boslough p. 126)
4Bil BC    The Archaea branch of life may have begun this far back in time.
    (SFC, 8/23/96, p.A21)
4Bil BC    In 2000 evidence in sedimentary rocks off of Greenland indicated chemical evidence of early life from about this time.
    (SFC, 12/1/00, p.A21)
4Bil BC    A giant impact crater was formed about this time on the Earth’s moon that later came to be called Mare Imbrium.
    (Econ., 3/14/15, p.82)

4Bil BC - 3.5Bil BC    Volcanic activity on Mars began during this period and lasted a few hundred million years. Sulphur rich gases transformed the planet into a very acidic environment.
    (Econ, 4/22/06, p.77)

4Bil BC - 543 Mil BC    The Precambrian Period

4Bil BC - 3.8Bil BC    The likely period of time over which life first developed on Earth.
    (NH, 9/97, p.84)

4Bil BC - 0    In 1998 Richard Fortey published "Life: A Natural History of the First Four Billion Years of Life on Earth.
    (SFEC, 4/12/98, BR p.7)

3.98Bil BC    Rocks dating to this time, +/-170 million years, occur in west Greenland. They reveal features that are not seen in any younger formations. They are very metamorphosed rocks and granites, showing sworled and whispy structures more involved and complex than any that have been produced on a wide scale since. In 2010 older rock was identified on Baffin Island, Canada.
    (DD-EVTT, p.36,89)(http://geology.com/press-release/ancient-mantle-rocks/)

3.9Bil BC    The first cells of the superfamily of organisms called eukaryotes (cells with nuclei) began. A gene that codes for the enzyme telomerase was thought to date back to this time.
    (SFC, 8/15/97, p.A3)

3.9Bil BC    Meteorites reached Earth after being ejected from the Moon from the impact of massive unknown objects at about this time.
    (SFC, 12/1/00, p.A21)
3.9Bil BC    Astronomers in 2008 reported that a giant meteorite crashed into Mars about this time and created a huge elliptical scar in the northern lowlands.
    (SFC, 6/26/08, p.A4)

3.9Bil BC - 3.5Bil BC    Life originated as single-celled organisms during this period. The dense atmosphere was primarily carbon dioxide. In 1981 Lynn Margulis wrote "Symbiosis in Cell Evolution," where she proposed that 3 types of prokaryotes had fused biologically to create the first living cells with nucleic structures.
    (NG, V184, No. 4, Oct. 1993, p.129)(Wired, 2/98, p.174)

3.85Bil BC    Scientists published evidence that rocks from the Greenland island of Akilia showed evidence of life that dates back to before this time. Tiny grains of a phosphate mineral called appetite, often produced by living organisms, were found. Also carbon in the rock with a ratio of isotope 12 to isotope 13 indicative of life. In 2002 scientists suggested that formations were caused by molten rock at temperatures too hot for life.
    (SFC, 11/7/96, p.A2)(PacDis, Winter ’97, p.34)(SFC, 5/27/02, p.A6)

3.8Bil BC - 2.5Bil BC    Archaean Time lasted for over a billion years and gave way to the Proterozoic Age.

3.77Bil BC    Scientists in 2017 reported that microfossils of tiny tubular structures in ancient Canadian rocks dated to about this time and were believed to be microbes. The rocks from Quebec dated back to between 3.8 and 4.3 billion years.
    (SFC, 3/2/17, p.A6)(Econ, 3/4/17, p.63)

3.7Bil BC    In 2013 NASA telescopes recorded a massive, record-setting gamma ray burst, indicating the death of a star and the formation of a black hole, 3.7 billion light-years away.
    (SFC, 11/22/13, p.A18)
3.7Bil BC    In 2016 Australian scientists unveiled fossils dating back 3.7 billion years. Tiny structures called stromatolites were found in ancient rock along the edge of Greenland's ice cap. The earliest evidence of life on Earth ahead of the Greenland discovery came from near-3.5 million-year-old stromatolites found in western Australia in 2006.
    (AFP, 9/1/16)

3.6Bil BC    Fossils of bacteria from Western Australia and south Africa date to about this time.
    (SFC, 8/23/96, p.A21)(NH, 7/98, p.22)
3.6Bil BC    Scientists believe that a comet crashed into the moon about this time and made a huge crater in which ice was believed detected in 1996.
    (SFC, 12/3/96, p.A2)
3.6Bil BC    Crystallized carbonate minerals formed on a piece of rock on Mars that was later knocked into space and became a meteorite that then fell to Earth in Antarctica about 11,000 BC. The environment of Mars was hospitable to life.
    (SFC, 8/7/96, p.A9)(SFC, 8/9/96, p.A15)(SFC, 9/1/96, p.A22)

3.6Bil BC - 2.6Bil BC    Katarchaean time. The crust of the earth seems to have acquired both granitic and basaltic rocks. The continental shields formed.
    (DD-EVTT, p.89,139)

3.5Bil BC    Astronomers in 2007 found evidence that most, if not all, huge galaxies in the far reaches of the universe generated cavernous black holes during their youth, when about 3.5 billion years old.
    (AFP, 10/26/07)
3.5Bil BC    Earth's first fossils, single-celled bacterial filaments, appear in rocks so dated. Rocks from the Ukraine are said to give radiometric dates of this age.
    (NG, V184, No. 4, Oct. 1993, R. Gore, p.128)(DD-EVTT, p.139)
3.5Bil BC    The Apex Chert of Australia indicate that by this time at least 11 kinds of bacteria existed.
    (PacDis, Winter ’97, p.34)
3.5Bil BC    The first fossils of cyanobacteria appeared.
    (USAT, 8/5/99, p.1D)
3.5Bil BC    The oldest known fossilized prokaryotes were laid down about this time, only about 1 billion years after the formation of the Earth's crust.
3.5Bil BC    A huge object crashed into Mars about this time gouging out a crater and causing ground water to rise and transform crustal calcium and sulfur into gypsum. In 2011 the robot rover Opportunity discovered the gypsum indicating the presence of water.
    (SFC, 12/8/11, p.A16)
3.5Bil BC    In 2013 NASA’s Curiosity rover uncovered signs that a lake existed about this time at the Martian equator.
    (SFC, 12/10/13, p.A6)
3.5Bil BC - 3.1Bil BC    At least five of the shield regions were intruded by large masses of basaltic rocks called anorthosites.
    (DD-EVTT, p.138)

3.47Bil BC    An asteroid some 12 miles wide struck the earth. Scientists in 2002 reported debris from the asteroid in both South Africa and Australia.
    (SFC, 8/23/02, p.A11)

3.465        In 1993 paleobiologist J.W. Schopf reported the discovery of microfossils dating to this time in the Apex chert of the Warrawoona group in Western Australia. In 2002 Martin Brasier of the Univ. Of Oxford said the fossils were just mineral artifacts.
    (SFC, 8/22/11, p.A2)

3.41Bil BC    In 2004 Michael Tice, Stanford graduate student, report finding evidence of fossilized microbes of this age from a mountain near Barberton, South Africa.
    (SFC, 9/30/04, p.A2)

3.4Bil BC    Scientists in 2006 reported that stromatolites in western Australia, created about this time, were likely formed when dirt sediments mixed with carbon dioxide, expelled from bacteria, along with water and minerals trapped in the microbe’s sticky mucilage.
    (SFC, 6/8/06, p.A6)
3.4Bil BC    A team of scientists in 2011, led by David Wacey and Martin Brasier, reported the discovery of fossilized, single-celled organisms dating to this time in sandstone of the Strelley Pool rock formation in Western Australia.
    (SFC, 8/22/11, p.A2)
3.4Bil BC    The earliest greenstone belts of the Canadian shield were small, and seem to have been deposited in definite sags or basins in the granitic crust. Rocks of this age have been identified by isotope dating in Transvaal and Rhodesia. They include 17,000 meters of volcanic rock seemingly floating in a sea of granite.
    (DD-EVTT, p.142)(DD-EVTT, p.147)
    The Fig Tree Series of Rhodesia show remains of algae, bacteria, fungi, and other plants in shales and cherts of which this is the oldest. There seems little reason to doubt that photosynthesis was established by this time.
    (DD-EVTT, p.158)

3.3Bil BC - 2.5Bil BC    Basalt floods inundated the greenstone (metamorphosed rocks that were once basaltic lavas and ashes) basins.
    (DD-EVTT, p.138)

3.2Bil BC    The fossilized remains of threadlike microbes from this time were identified by an Australian researcher looking at the sulphide rock formation at Pilbara Craton.
    (SFC, 6/8/00, p.A10)

3.2Bil BC    The bacterium Eobacterium isolatum from the eastern part of South Africa dates to at least this age. Single-celled blue-green algae also date back to this time.
    (E&IH, 1973, p.111)

3.2Bil BC - 2.8Bil BC    The lighter materials bearing with them most of the radioactive elements in the earth would have been left behind near the outer part of the planet and during this time their heat production would have been three or four times what it is now and it would have been generated by the elements thorium, potassium, and rubidium as well as by uranium.
    (DD-EVTT, p.88)

3.1Bil BC - 2.3Bil BC    Two great episodes of metamorphism and granite intrusions into the Australian shield are known in this period. Radio isotope dates cluster around 3.1 and 2.65 Billion.
    (DD-EVTT, p.150)

3.0Bil BC    The oldest African granites are about this age. The oldest water laid sedimentary rocks are about this age. Grains of pyrite, an iron sulfide mineral, in these sediments were not oxidized. This indicates that there was little or no oxygen around at the time.
    (DD-EVTT, p.147)(DD-EVTT, p.152)
3.0Bil BC    The Earth day is only 6 hours long. Scientists say they learned this by counting growth rings in 3-billion-year-old "whatchamacallits."
    (SFC, 5/11/96, p.E-4)

3 - 2Bil BC    Sedimentary strata of this age contain unique layers of iron oxide precipitated on shallow sea floors from the combination of iron and oxygen contained in seawater. Younger strata lack this type of sedimentary iron but do contain red iron oxides from the combination of atmospheric oxygen and iron. This indicates that the plants had begun to create more free oxygen than the oceans could absorb. Analysis in 1999 indicated that plants invaded land from fresh water rather than from the sea.
    (E&IH, 1973, p.120)(SFC, 8/5/99, p.A6)

3.0Bil BC - 1.9Bil BC    The Saamo-Karelian structural zone in the north-east of the Baltic shield evolved in this time and contains highly metamorphosed rocks and granites.
    (DD-EVTT, p.144)

2.7Bil BC    The oldest stromatolites, cabbage-shaped laminated bodies of limestone or silica, are at least this old and indicate that photosynthesis had been developed by then. Today such structures are produced by blue-green algae living in tropical tidal waters.
    (DD-EVTT, p.158)
2.7Bil BC    In 1999 Australian geologists under Jochen J. Brocks reported fossil "biomolecules" from this time. Traces of steranes produced by eukaryotes, and methylhopanes from cyanobacteria were reported.
    (SFC, 8/13/99, p.A1,21)

2.6Bil BC    African rocks from South Africa’s Eastern Transvaal in 2000 indicated primitive microbes on dry land from about this time.
    (SFC, 12/1/00, p.A21)

2.6Bil BC - 2.0Bil BC    Many continental movements and collisions during this Archaean time. We can draw notions of how the Canadian shield formed. Possibly there were four primary continental nuclei to start with--slabs or "bergs" of granitic material which had somehow arisen from the mantle. They have been called the Slave, Hudson, Ungava and Superior proto-continents and they already existed at the earliest Archaean time.
    (DD-EVTT, p.139)

2.6Bil BC - 2.5Bil BC    The great Kenoran orogeny spread its convulsive effects throughout the Canadian shield before the proterozoic sediments were deposited.
    (DD-EVTT, p.142)

2.5Bil BC    The Proterozoic Age began.
    (SFC, 8/13/99, p.A21)
2.5Bil BC    The center of the North American continent has rocks older than this age.
    (E&IH, 1973, p.82)
2.5Bil BC    The appearance of oxygen in the Earth’s atmosphere is dated to about this time along with fossil stromatolites and banded-iron formations.
    (USAT, 8/5/99, p.1D)(Econ, 7/30/16, p.65)

2.5Bil BC - 1Bil BC    Rocks surrounding the center of the North American continent show this age range.
    (E&IH, 1973, p.82)

2.5BBil BC - 543Bil BC    The Proterozoic Era

2.4Bil BC    The Peninsular India shield’s oldest structural belt, the Dharwar, lies in the south-west of the country. Very probably the Dharwar belt acted as a kind of stable nucleus to which other belts became attached.
    (DD-EVTT, p.146)
2.4Bil BC    Photosynthesis began about this time.
    (Econ, 10/10/09, p.83)

2.3Bil BC - 1.5Bil BC    The Sveco-Fennian structural zone in the south part of the Baltic shield formed in this time.
    (DD-EVTT, p.144)

2.2Bil BC    Rust appeared in rocks indicating the accumulation of oxygen.
    (USAT, 8/5/99, p.1D)

2.1Bil BC - 1.9Bil BC    Oxygen accumulation rapidly increased. Large single-celled organisms appeared. Multi-celled life originated. In 2003 Nick Lane authored "Oxygen: The Molecule That Made the World." In 2010 it was believed that docoshexaenoic acid (DHA) played a major role in converting light into electricity in single-celled organisms, giving them a crude form of vision.
    (NG, V184, No. 4, Oct. 1993, R. Gore, p.129)(NH, Jul, p.60)(Econ, 5/29/10, p.81)
2.1Bil BC    A meteorite, dubbed  NWA 7034, blasted to Earth from Mars about this time and landed in the Sahara Desert. Analysis in 2012 revealed that it contained water.
    (SFC, 1/4/13, p.A7)

2Bil BC    The first traces of extensive ice cover appeared in the geological record only in the Late Precambrian Era, more than 2 billion years ago.
    (NOHY, Weiner, 3/90, p.5)
2Bil BC    The Grand Canyon floor was formed. Joseph Wood Krutch in 1957 wrote his book "Grand Canyon: Today and All Its Yesterdays." In 1998 Stephen J. Pyne wrote: "How the Canyon Became Grand."
    (SFEC, 10/4/98, BR p.12)
2Bil BC    Radiometric ages of the Eburnian structural provinces in west Africa. North of the city of San Luis in Brazil the Precambrian is 2 billion years old. More parallel data at 550 million.
    (DD-EVTT, p.194)
2Bil BC    Fossils found in rock from Ontario, Canada consist of bacteria and blue-green algae.
    (E&IH, 1973, p.111)
2Bil BC    In the 1950s Elso Barghoorn and Stanley Tyler reported fossils of unicellular life in chert beds at least this old.
    (NH, 7/98, p.22)
c2Bil BC    A Mount Everest-sized object crashed near Sudbury, Canada about this time and left a crater covering 1,800 sq. km.
    (PacDis, Winter ’97, p.35)
c2Bil BC    Scientists in 1972 discovered an extinct natural nuclear reactor in a uranium mine in Gabon. Research soon revealed that it had operated intermittently for a few million years about 2 billion years ago.
    (SFC, 11/29/04, p.A4)
2Bil BC    A meteorite impacted Earth in South Africa. The discovery of the Vredefort Crater, 250-300 km in diameter, was announced in 1994.
2Bil BC    Astronomers in 2010 noticed that a galaxy quickly increased in brightness by a factor of hundreds. Over the next year a star was ripped apart and devoured by a black hole. Light from this event had taken about 2 billion years to reach Earth.
    (SSFC, 5/20/12, p.C11)
2Bil BC    About this time a bacterium became symbiotic with the cell from which animals and plants developed. Chromosomes from this bacterium’s mitochondria later carried 37 genes in the human body. The bacterium came from a group called the Alphaproteobacteria. The ancestral eukaryote was later believed to be a Lokiarchaeote.
    (Econ, 10/27/12, p.79)(Econ, 5/9/15, p.74)

2Bil BC - 1Bil BC    Biological evolution became greatly enriched by the invention of sexual reproduction.
    (E&IH, 1973, p.119)

1.9Bil BC    Earth’s landmasses collided about this time to form the supercontinent Nuna.
    (SFC, 6/20/12, p.A10)

1.85Bil BC    In Ontario, Canada, near the town of Sudbury, a meteor that was at least 10 miles across struck down. The remaining crater is 60 by 45 miles and was found to contain a profusion of "buckyballs" (peculiar hollow molecules of carbon) with samples of ancient star stuff packed inside.
    (SFC, 4/12/96, p.A-7)

1.8Bil BC    An orogenic period in the Australian shield.
    (DD-EVTT, p.150)
1.8Bil BC    Eastern coast of Antarctica has yielded rocks thought to be this old.
    (DD-EVTT, p.150)

1.8Bil BC – 1.3Bil BC     A rare type of granite formed as molten material, deep below the Earth’s crust, rose to just beneath the surface and crystallized. This granite contained heavy metal elements that eroded helped propel the development of multicellular organisms.
    (SFC, 6/20/12, p.A10)

1.7Bil BC    The Hudsonian orogeny of the Canadian shield.
    (DD-EVTT, p.142)

1.7Bil BC - 1.2Bil BC    Another bout of anorthosite intrusions from below into most of the shields. Anorthosite has virtually never penetrated the crust since then.
    (DD-EVTT, p.138)

1.6Bil BC    Late Precambrian phase of the Siberian (Angara) Shield saw the spread of both sandy strata and limestones. Many of these beds contain great numbers of stromatolites, the limestone structures produced by lime-secreting algae. These large mound-like growths, a meter or more high, grew in the intertidal zones of the coast with warm waves splashing between them.
    (DD-EVTT, p.145)
1.6Bil BC    The Eastern Ghats belt of the Indian shield shows dates of this time.
    (DD-EVTT, p.146)

1.6Bil BC – 1.2Bil BC    Multicellular life on Earth evolved during this period.
    (SFC, 6/20/12, p.A10)

1.5Bil BC    Four regions had emerged as stable area in the evolving crust of Africa. These were a large part of west Africa, two large regions in what is now central Africa, and an area now occupied by Rhodesia and the Transvaal. From this time on these regions have had virtually no severe geological disturbance.
    (DD-EVTT, p.148)

1.5Bil BC - 1Bil BC    On Mars this is the Hesperian period when surface waters had dried up but still lay in large quantities below the surface.
    (SFC, 7/7/97, p.A4)

1.4Bil BC    Another orogenic period in the Australian shield.
    (DD-EVTT, p.150) 

1.35Bil BC    The Elsonian orogeny of the Canadian shield.
    (DD-EVTT, p.143)

1.3Bil BC    Fungi may have originated about this time.
    (SFC, 8/10/01, p.D3)
1.3Bil BC    Two black holes collided about this time to form a single black hole and in the process sent out gravitational waves (GW150914) that were detected by the LIGO project on Sep 14, 2015.
    (https://en.wikipedia.org/wiki/LIGO)(Econ, 2/13/15, p.77)

1.2Bil BC    Scientists reported in 2002 that sandstone rocks from the Sterling Range of Australia showed evidence of wormlike creatures from about this time.
    (SFC, 5/10/02, p.A2)

1.2Bil BC - 1.0Bil BC    Researchers reported in the journal Science that the emergence of true animals dates back to this period. The creatures would have been very small and soft-bodied and not have left fossil remains.
    (SFC, 10/25/96, p.A2)

1.2Bil BC - .9Bil BC    The Sveco-Norwegian structural zone of the Baltic shield in south-west Sweden and southern Norway came into existence in this time.
    (DD-EVTT, p.144)

1Bil BC    Major continental collisions.
    (DD-EVTT, p.139)
1Bil BC    A billion years ago several mini-continents collided together to form a super-continent called Gondwana, creating a mountain range at the point of impact. Periods of rifting, some 250 million years ago and again about 100 million years ago, pulled Gondwana apart in tectonic agony. This created a 3,000-km (2,000-mile) fracture in the planet's crust that extends from East Antarctica across the ocean to India. A residual "root," combined with the rifting, helped force up the land that is now East Antarctica. Some 34 million years ago, the mountains became smothered by the East Antarctic icesheet, an area the size of Canada.
    (AP, 11/17/11)
1Bil BC    Bacteria teamed up with animal and plant cells about this time. This resulted in the formation of cellular mitochondria, which provided bodies power by burning glucose and using the energy created to form ATP, a molecule that is biology’s universal fuel.
    (Econ, 5/31/14, p.72)
1Bil BC    The Satpura belt of the Indian shield beneath the edges of the Deccan traps dates to this time.
    (DD-EVTT, p.146)
1Bil BC    In 1998 trace fossils of worm burrows were reported from what was a shallow sea in Central India about this time.
    (SFC, 10/1/98, p.A2)
1Bil BC    A worm later named Urbilateria lived about this time and gave rise to two of the great animal kingdoms: the protostomes, whose members include insects, mollusks and all manner of worms; and deuterostomes, whose surviving members include all vertebrates.
    (Econ, 4/21/07, p.90)
1Bil BC    Fossils from rock in central Australia include plant organisms of many cells.
    (E&IH, 1973, p.112)
1Bil BC    A meteor named Nakhla arrived from Mars more than a billion years ago.
    (SJSVB, 9/9/96, p.14A)

1Bil BC - 800Mil BC    Metazoans diverge from bacteria, fungi, and algae. Oxygen levels rise. Plant life spread from the oceans to land.
    (NG, V184, No. 4, Oct. 1993 p.128)(SFC, 8/10/01, p.D3)

1Bil BC - 350Mil BC    The mini-continent of Avalon. When Africa, Europe and North America were separated, granite of Avalon stuck to the East Coast of North America.
    (Nat. Hist., 4/96, p.50)

955Mil BC    The Grenvillian orogeny of the Canadian shield.
    (DD-EVTT, p.142)

900Mil BC - 800Mil BC    The Kibaran orogenies welded wide strips of metamorphosed granitic crust around the margins of the central and southern cratons of Africa.
    (DD-EVTT, p.148)

850Mil BC - 635Mil BC The Cryogenian period.
    (Econ, 3/23/13, p.84)

800Mil BC    Hundreds of fossil specimens of primitive sea animals have been discovered in South Australia in strata older than Cambrian and perhaps of this age. A segmented worm, Spriggina floundersi was about 2 inches in diameter. A jellyfish-like animal, Cyclomedusa davidi, was about 1 inch long.
    (E&IH, 1973, p.111)

750Mil BC    Scientists in 2004 reported that Earth may have been covered in snow at this time. Much of Earth, welded into a single massive continent known as Rodinia, began to break up.
    (SFC, 3/18/04, p.A4)
750Mil BC    The India shield dated at this time: North of the Satpura belt lies the Arawalli belt and imposed upon at least part of this is the Delhi belt.
    (DD-EVTT, p.146)
750Mil BC    Researchers at UC Riverside in 2009 reported evidence in rock sediments that indicated the presence of sponges dating back from 750 million to 635 million years ago. Sponges were believed to be one of the first animals to evolve from single-celled organisms.
    (SFC, 2/6/09, p.A8)

760Mil BC - 550Mil BC    In 2012 researchers said tiny vase-shaped creatures' fossils were found in Namibia's Etosha National Park and other sites around the country in rocks dating to this period. A 10-member team of international researchers published their paper in the South African Journal of Science. The discovery pushed the emergence of animal life back millions of years.
    (AFP, 2/6/12)

750Mil BC - 580Mil BC    Scientists in 2000 proposed that 2-4 cycles, lasting 10 million years each, of freezing and global warming took place during this period. Volcanic activity was responsible for the rising temperatures. The oceans may have frozen in this period and it has been called the Snowball Earth era.
    (SFC, 4/8/00, p.A7)(SFC, 8/10/01, p.D3)

725Mil BC - 541 Mil BC “Snowball Earth" later referred to a series of ice ages that took place during this period.
    (Econ, 3/23/13, p.83)

650Mil BC    In 2008 Australian scientists said they had discovered in an outback mountain range a reef that was under water at this time.
    (AFP, 9/22/08)
650Mil BC    Namibia’s Fish River Canyon, the 2nd largest natural gorge in the world, began forming about this time.

635Mil    The end of the Marinoan glaciation marks the boundary between the Cryogenian period (850Mil BC) and the Ediacaran.
    (Econ, 3/23/13, p.84)

635Mil BC - 541Mil BC The Ediacaran Period featured pre-Cambrian animals whose fossils were later found in Australia, Canada, the English Midlands and China. Creatures called rangeomorphs dated to this period.
    (Econ, 3/23/13, p.83)(Econ, 8/16/14, p.64)   

632Mil BC    Rocks form the Doushantuo formation of China dated to this time and showed signs of creatures more complex than tiny sponges.
    (Econ, 8/29/15, p.64)

630Mil BC - 542Mil BC    This is known as the Ediacaran Period, during which animals began to appear according to the fossil record. It is named after the locality in Australia where they were first discovered.

620Mil BC    In 1975 animal fossils of about this time were discovered in North Carolina.

600Mil BC     Late Precambrian: Eocambrian period shows evidence of an ice-age involving a large part of the earth’s surface about this time. The picture is one of a world devoid of vegetation, much of it in the grip of snow and ice.
    (DD-EVTT, p.161-162)
600Mil BC    This begins the Phanerozoic eon and continues to the present. The Previous span of time, six to eight times as long is called the Cryptozoic eon. An eon in the American system is a period of one billion years.
    (DD-EVTT, p.35,312)
    The Phanerozoic eon began perhaps with a single continent, Pangaea, in process of breaking up. This was Pangaea I, ...only to return to each other’s company at the end of the early Paleozoic.
    (DD-EVTT, p.225,230)
    It seems Pangaea I lay predominantly in the southern hemisphere with the Gondwana continents grouped tightly together and twisted round through about 180 degrees and ‘North America’ and ‘Europe’ strung out a little to the east of South America and west of Angara (north-east Asia). No trace of land plants was to be seen.
    (DD-EVTT, p.231)
600Mil BC    The North American continent began to break apart in the middle and then stopped, leaving the area beneath the Mississippi River fractured and weak.
    (Arch, 1/06, p.35)
600Mil BC    Glaciers near the equator reached sea level.
    (NG, V184, No. 4, Oct. 1993, R. Gore, p.128)
600Mil BC    Oxygen had risen to occupy 1 per cent or more of its present level in the atmosphere by the dawn of the Cambrian period.
    (DD-EVTT, p.160)
600Mil BC    The outer edges of the North American continent consist of rocks younger than this age.
    (E&IH, 1973, p.83)
600Mil BC    Layers of lava and ash from volcanic activity of this time were later evident at Green Gardens, Newfoundland, Canada.
    (SSFC, 8/17/03, p.C7)

600Mil BC - 580Mil BC    Fossils of primitive multi-celled embryos with no bones or shells, possibly dating to this time, were found in 1998 in a phosphate mine near the town of Weng ‘an in China’s Guizhou province. Scientists named the bilaterians Vernanimalcula guizhouena (small spring animal).
    (SFC, 2/5/98, p.A1,11)(SFC, 6/3/04, A2)

600Mil BC - 500Mil BC    Cambrian period of the Paleozoic Era. Life comes ashore, the first coral reefs, and fish appear.
    (DD-EVTT, p.21)
600Mil BC - 500Mil BC     Pre-Paleozoic-Cambrian: The Adelaide series of Southern Australia is a group of sandy rocks laid down over a long period of pre-Paleozoic and Cambrian time. Here was a gently but persistently subsiding basin. it existed for a 100 million years or so, until the late Cambrian when there was a full-scale orogeny.
    (DD-EVTT, p.235)
600Mil BC - 500Mil BC    Early fossils from the Burgess Shale in British Columbia and from China already show a clear distinction between the ancestors of spiders and insects.
    (PacDis, Summer ’97, p.3)

600Mil BC - 450Mil BC    The dinoflagellates originated about this time.
    (Nat. Hist. 3/96, p.17)

580Mil BC    The last planet wide glaciation occurred around this time.
    (NH, Jul, p.16)
580Mil BC    Fossils of primitive multi-celled embryos with no bones or shells, possibly dating to this time, were found in 1998 in a phosphate mine near the town of Weng ‘an in China’s Guizhou province.
    (SFC, 2/5/98, p.A1,11)
580Mil BC    The Doushantuo, a geological formation in southern China, preserved many fossils from this time.
    (Econ, 3/23/13, p.83)

575Mil BC - 160Mil BC    Rangeomorphs, a world-wide feathery life form, lived during this period known as the Ediactaran. They fed by filtering tiny organisms from seawater were later considered as the 1st examples of complex animal life.
    (SFC, 8/20/04, p.A12)

570Mil BC    The oldest triploblastic animals, preserved as phosphatized embryos in rocks from southern China, were reported discovered in 1998.
    (NH, 7/98, p.62)

570Mil BC - 230Mil BC    North America has several well-known arches and domes south of the Canadian Shield, and a few to the north of it too. They seem to have originated mostly in the Paleozoic era, with little movement taking place in the Mesozoic or Cainozoic. From what we can see of the Cambrian and early Ordovician rocks, these warps were not present in the basement then.
    (DD-EVTT, p.171,172)   
570Mil BC - 230Mil BC    In northern Alberta is the Peace River Arch; the Transcontinental Arch extends from Minnesota to Arizona and in Montana is the Montana Dome. The Ozark Mountains lie on the site of a dome and from Nashville, Tennessee, north to Michigan lies the Cincinnati Arch. Between Peace River, north-west Canada, and Montana and occupying much of Saskatchewan is the Williston Basin. Michigan lies four-square upon the Michigan Basin, while much of Illinois and Indiana is underlain by the Illinois Basin. Most of these broad, gentle features developed during Paleozoic time and have been dormant ever since.
    (DD-EVTT, p.172)
570Mil BC - 230Mil BC    The Caledonian syncline in Europe and the Appalacian syncline in North America is the region between the Canadian and Baltic Shields, and stretched from the northern margins of these basement blocks through what is now western Scandinavia, east Greenland, and Britain into the Appalachians and on into south-eastern USA. These are the most closely studied of the early Paleozoic geosynclines.
    (DD-EVTT, p.233)

560Mil BC    In 2003 a fossil of a 2.56-inch fishlike animal from the Flinders Ranges of southern Australia was believed to be at least 560 million years old, 30 million years older than the previous record.
    (AP, 10/23/03)
560Mil BC    The final Precambrian glacial period began about this time and continued for 9 million years.
    (Econ, 3/23/13, p.84)
560Mil BC    The Fermeuse formation of Newfoundland, Canada, dated to about this time. In 2014 scientists identified traces of muscle in a cnidarian, Haootia quadriformis, a creature related to modern jellyfish, sea anemones and coral. 
    (Econ, 8/30/14, p.70)

550Mil BC    The marella, a fossil of the Cambrian.
        Radiometric ages of the pan-African structural provinces in west Arica parallel the age of rock south and east of Sao Luis in Brazil. It all seems good evidence that the continents were joined together 550 million years ago but had begun to separate before 50 million years ago.
    (DD-EVTT, p.194)
550Mil BC    A gene that regulates limb formation in insects called the Distal-less gene was considered to be at least this old.
    (NH, 2/97, p.31)

545Mil BC    The emergence of higher animals was dated to about this time until 1996 when researchers gathered data that suggested the emergence began 1.2 billion years ago over a span of 200 million years.
    (SFC, 10/25/96, p.A2)

545Mil BC - 500Mil BC    A 2nd period of crater forming impacts bombarded the Earth at about this period of the Cambrian explosion.
    (SFC, 3/10/00, p.A4)

543Mil BC    A mass extinction of unknown cause wiped out the Ediacaran primitives and initiated the Cambrian explosion that gave modern triploblasts an opportunity to shine.
    (NH, 7/98, p.65)

543Mil BC - 530Mil BC    The first phase of the Cambrian is called the Manakayan, and featured small shelly fossils.
    (NH, 7/98, p.60)

543Mil BC - 490Mil BC    Cambrian period

Over 900 species of marine creatures are known from the lower Cambrian rocks. The Cambrian sea floor was peopled with a great variety of trilobites. Nine-tenths of all Cambrian fossils known are trilobites. Almost all of the five great divisions or super-families of them alive during this period died out at the end of it.
    (DD-EVTT, p.248)
    Small-shelled bivalve creatures known as brachiopods were mostly of the horny kind in the Cambrian.
    (DD-EVTT, p.249)
    Among the stationary animals to colonize the sea floor, the sponges and corals were both much in evidence. There were other animals, known as archaeocyathids, that seem to have been a cross between the two and to have had a cone-shaped housing of calcium carbonate 10-20 cm. high. These creatures grew together in clusters that were quite like mats or thickets of small corals in California, Newfoundland, Australia and Russia.
    (DD-EVTT, p.250)
    There were many different classes of echinodermata, the ‘spiny-skinned,’ in the Cambrian seas.
    (DD-EVTT, p.251)
    In North America during early and mid-Cambrian times sea level rose steadily, or the basement sank uniformly, until waters spread across the entire continent. Although it was extensive it seems to have nowhere as much as 30 meters deep. Limestone beds near the geosynclines in the east and west reach 600-700 meters in thickness.
    (DD-EVTT, p.172-173)

543Mil BC - 248Mil BC     Paleozoic Era         
        The Paleozoic Era is characterized by the appearance of marine invertebrates, primitive fishes, land plants, and primitive reptiles. It includes the Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, and Permian periods.
    (DD-EVTT, p.21)(AHD, 1971, p.944)

542Mil BC    The appearance of small shelly fauna marked the beginning of the Cambrian period.
    (Econ, 8/29/15, p.64)

540Mil BC    Precambrian/Cambrian boundary. The "Cambrian explosion" occurred and many families of multi-celled creatures began to develop. It was later believed that this occurred as a result of the formation of hard shells.
    (NG, V184, No. 4, Oct. 1993, p.129)(SFC, 2/5/98, p.A1)(Econ, 6/2/07, p.90)
540Mil BC    The common ancestor of insects and spiders lived at least this long ago in the ocean.
    (PacDis, Summer ’97, p.3)

535Mil BC    The earliest echinoderm fossils date to this time.
    (NH, 12/98, p.41)

535Mil BC - 520Mil BC    In 1997 scientists proposed that the Earth underwent a continental flip during this period. Concentrated land mass near the poles lead to an imbalance that resulted in a shift by centrifugal force of excess bulk to the equator. Siberia and northern Europe were large islands called Baltica. The North American part of Laurentia went from the south pole to straddle the equator. Northern Europe slid south. East Africa went from the tropics to the south pole. The changes took place but the reasons for the change were still controversial. The process was suspected to have contribute to the great explosion of bio-diversity known as the "Cambrian explosion."
    (NPR, SFC, 7/25/97, p.A1)

530Mil BC    Chengjiang fauna from the Yunnan Province of China. Specimens include: the arthropod Jianfengia, Facivermis, Trilobites (arthropod to 27"), Eldonia (a possible echinoderm), Microdictyon, Dinomischus, Sponges, Hyolith (possible mollusk), Anomalocaris, Xianguangia, and early brachiopods.
    (NG, V184, No. 4, Oct. 1993, R. Gore, p.133)
530Mil BC    Fishlike creatures, early agnathans, with marks of an early spine were found in 1998 in the Chengjiang fossil field.
    (SFC, 11/4/99, p.A8)
530Mil BC    During the Cambrian explosion the various animal phyla were established. This date was pushed back in 1996 to 1.2 billion years.
    (WSJ, 9/25/96, p.A23)(SFC, 10/25/96, p.A2)
530Mil BC    Brachiopods (lampshells) appeared about this time.
    (Econ, 8/29/15, p.64)

530Mil BC - 520Mil BC    The 2nd two phases of the Cambrian are called the Tommotian and Atdabanian. The Cambrian explosion featured the first appearance of all animal phyla with skeletons subject to easy preservation.
    (NH, 7/98, p.60)

525Mil BC    Sirius Passet fauna from Greenland. Specimens include: Sponges, Hyoliths, Trilobites, Unnameds (an arthropod), and Halkieriids (possible mollusks).
    (NG, V184, No. 4, Oct. 1993, R. Gore, p.128)

520Mil BC    An arthropod called a fuxhianhuiid, with primitive limbs under its head, as well as the earliest example of a nervous system that extended past the head, lived about this time. A 2013 study reported on fossils of the creature which lived nearly 50 million years before animals first emerged from the sea onto land.
    (Live Science, 2/27/13)
520Mil BC    An eyeless worm later dubbed Collinsium ciliosum filtered food from the ocean floor using frontal appendages developed into sieving baskets. Fossils of the armored creature were found in the rocks of China’s Yunnan province.
    (Econ, 7/4/15, p.67)

515Mil BC    Residue of evaporated seawater trapped in rock salts from this time contained three times as much calcium as samples from 545 million years ago.
    (NG, 11/04, Geographica)
515Mil BC    The Burgess Shale, a rock formation amid the glaciated mountains from British Columbia to Utah, created by mud slides that swept shallow water Cambrian creatures over a marine cliff and buried them almost instantly. Specimens include: Pikaia (a chordate, ancestor of fish, reptiles, and mammals), Odontogriphus, Amiskwia, Ottoia (a Priapulid worm), Wiwaxia (a Polychaete worm or mollusk), Burgessochaeta (an annelid worm), Opabinia, Sanctacaris (arthropod, forerunner of spiders and scorpions), Canadaspis (arthropod, early crustacean), Aysheaia (possible arthropod), Eldonia, Hyolith, Brachiopods, Dinomischus, Anomalocaris, Sponges and Trilobites. In 1989 Stephen Jay Gould authored "Wonderful Life: The Burgess Shale and the Nature of History." In 1998 Simon Conway Morris authored "The Crucible of Creation: The Burgess Shale and the Rise of Animals."
    (NG, V184, No. 4, Oct. 1993, p.124)(NH, 12/98, p.48)(SFC, 11/5/07, p.A3)
515Mil BC    A clawed critter later called Lyrarapax unguispinus lived on the seabed of what became southwest China. It belonged to an extinct early arthropod group called anomalocaridids.
    (Econ, 7/19/14,p.68)

510Mil BC    End of Cambrian
    (NG, V184, No. 4, Oct. 1993, R. Gore, p.122)
    By the end of the Cambrian Pangaea had split into four continents. The intervening seaways became the sites where the sediments of the Appalacian, Hercynian, and Uralian geosynclines were to form.
    (DD-EVTT, p.225)
    Towards the end of the Cambrian times there were shallow seas throughout much of the equatorial region. Lime-secreting organisms, plant and animal, flourished and great volumes of carbonate mud accumulated over much of the previously sandy sea floor.
    (DD-EVTT, p.232)
    In Southern Australia there was a full scale orogeny. Nothing so rigorous was in progress anywhere else in the world. No late Cambrian mountain-building episodes are known elsewhere.
    (DD-EVTT, p.235)
    Mollusks first come to our attention.
    (DD-EVTT, p.250)


507Mil BC - 492Mil BC    In 2000 scientists reported that they had found a dramatic shifting of the Earth's crust that tilted the whole globe some 90 degrees over a period of 15 million years about this time. The shift was suggested as a cause of the "Cambrian explosion" of multicellular organisms."
    (SFC, 1/21/00, p.A3)

505Mil BC    Scientists in 2007 reported that that fossils of tiny jellyfish, most barely a quarter inch in diameter, had been found in the Burgess shale of Utah and dated to this time, when shallow seas covered the area.
    (SFC, 11/5/07, p.A3)
505Mil BC    In 2014 researchers described a fish named Metaspriggina walcotti that dated to about this time. It was collected in the Burgess Shale of British Colombia and featured large eyes and a notochord running along its back.
    (Econ, 6/14/14, p.74)

500Mil BC    Geophysicists believe that at this time it took the planet only 20 hours to make it through the day.
    (NG, March 1990, J. Boslough p. 121)
500Mil BC    A 30-mile size crater, a mile underneath the bed of Lake Huron, just north of Port Huron, Michigan, marks the impact of a meteor. It was discovered in 1990 by scientists from the Geological Survey of Canada.
    (LSA, Spring 1995, p.31)
500Mil BC    A huge shellfish-type creature called anomalocaris lived about this time. In 2011 Australian scientists hailed the discovery of a pair of insect-like eyes belonging to a freakish prehistoric super-predator. The fossilized eyes measuring three cm (1.2 inches) across and with a whopping 16,000 individual lenses.
    (AFP, 12/8/11)
500Mil BC     Gondwanaland seems to have been formed about this time.
    (DD-EVTT, p.203)
500Mil BC    Vertebrates and insects (arthropods) had a common ancestor about half a billion years ago.
    (PacDis, Fall/’96, p.48)(NH, 2/97, p.68)
500Mil BC    Bone evolved about this time.
    (NH, 6/97, p.14)
500Mil BC    Sex was first recognized in the fossil records more than 500 million years ago.
    (Reuters, 9/13/02)

500Mil BC - 480Mil BC    Scientists in 2002 reported that sandstone from this period found north of lake Ontario, Canada, contained tracks of foot-long critters with at least 8 pairs of walking legs. They may have been euthycarcinoids, whose segmented bodies included outer shells and long legs.
    (SFC, 6/4/02, p.A2)

500Mil BC - 440Mil BC    The Ordovician period
    (DD-EVTT, p.21,171)
        The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3~+mn~1.7 to 443.7~+mn~1.5 million years ago. It follows the Cambrian Period and is followed by the Silurian Period.
Nearly all the continent of N. America was covered by transgressive seas in the Ordovician and the Devonian, and again in the Cretaceous.
    (DD-EVTT, p.21,171)
500Mil BC - 435Mil BC
        From simple, perhaps segmented ancestors living on the sea floor there arose in Ordovician time snails, clams, and many kinds of squid-like creatures in cone shaped shells up to a meter or two in length.
    (DD-EVTT, p.250)
500Mil BC - 435Mil BC    By Ordovician time large fragments were drifting away from the rest (of Pangaea). In North America, Europe and on the margins of Asia violent volcanic activity broke out and earth movements grew in size and frequency along the eastern margins of North America and the facing coasts of Europe.
    (DD-EVTT, p.232)
        At the end of the early Ordovician epoch the gains won by the sea from the land were rapidly lost, uplift of the shield or the lowering of sea level affected thousands of square km. of the continent. By late Ordovician time the entire continental interior was submerged: from Mexico to the Arctic islands and Greenland the sea spread out. In the west it merged wit5h the deeper waters of the Cordilleran geosyncline and in the Appalacian area earth movements had given rise to a land mass from which mud and sand were now coming.
    (DD-EVTT, p.173)
500Mil BC - 435Mil BC    The Appalacian ocean began closing from Ordovician times onwards.
    (DD-EVTT, p.226)
        From paleo-magnetic evidence and fossils the inference is drawn that the Ordovician equator ran across North America from California to northern Greenland, across the British isles and over central Europe.
    (DD-EVTT, p.233)
        There is the remarkable evidence of an Ordovician glacial period in the Sahara area. Probably this part of Africa was then sufficiently far from the equatorial zone, fed by snow and high enough to preserve ice for several million years.
    (DD-EVTT, p.235-236)
        Paleomagnetic data give indications that this part of Africa and the northern end of South America were indeed in far southerly latitudes. Cold polar winds would have swept moisture up from the southern ocean into the continental interior.
    (DD-EVTT, p.245)
500Mil BC - 1995    In 1995 John A. Long authored “The Rise of Fishes: Five Hundred Million Years of Evolution."
    (NH, 3/1/04, p.77)

490Mil BC - 443Mil BC    The Ordovician Period [see 510 - 445MYA]

480Mil BC    Scientists in 2019 said fossils found in Morocco suggest the practice of forming orderly lines may date back to this time and could have had evolutionary advantages. Their study described groups of blind trilobites — known as Ampyx — all facing in the same direction, apparently maintaining contact via their long rearward spines.
    (AP, 10/17/19)

470Mil BC    Liverworts made a leap from the oceans to dry land about this time. In 1998 scientists found that liverworts lacked 3 pieces of ancient genetic material called introns that is present in most plants. Liverworts were like aquatic green algae in this respect.
    (SFC, 8/25/98, p.A4)

470Mil BC - 400Mil BC    The gradual closure of the Caledonian and Appalacian geosynclines in the mid-Ordovician and Devonian brought about a series of orogenies that had drastic effects in a region stretching from what is now Spitsbergen in the north as far south as New York.
    (DD-EVTT, p.234)
        The stone corals, or at least several extinct branches of that group, put in an appearance in mid-Ordovician time. Together with lime-secreting algae and, locally, the colonies of calcareous bryozoa or moss-animals, they produced a completely new kind of sea floor.
    (DD-EVTT, p.251)
    The oldest pieces of bony material occur in middle Ordovician marine rocks in America.
    (DD-EVTT, p.252)

460Mil        The shark family and the bony fish families split about this time.
    (LiveScience, 6/13/12)

450Mil BC    A 650- to 700-foot meteorite crashed into the earth at speeds up to 67,500 mph. The impact dislodged rocks and created a massive hole in a 4-mile area called Rock Elm about 70 miles east of Minneapolis, Wisc.
    (AP, 4/26/04)
450Mil BC    Cincinnati at this time was covered by a sea, 100 to 200 feet deep. Primitive shellfish lived in it. But no fish. In 2011 a mysterious 150-pound fossil, more than 6 feet long and 3 feet wide, was recovered in northern Kentucky and dated to about this time.
    (AP, 4/25/12)

443Mil BC - 417Mil BC     The Silurian Period
    The early Silurian was a time when the sea withdrew once again to the north and south before returning in full flood to cover virtually the whole continent (N. America) again. Throughout this active period the Transcontinental Arch generally separated the seas of the Mississippi Valley and the Williston Basin. The Ozark Dome and the Appalacian fold belt similarly stood out against the waves.
    (DD-EVTT, p.21)(DD-EVTT, p.174)
    The Silurian continued the spread of very shallow seas over much of northern and western South America and north-western Africa and parts of Arabia. The sediments deposited in them were muddy and sandy, not at all like the great carbonates of the North American and Russian cratons.
    (DD-EVTT, p.236)
    Simple, jawless marine vertebrates make an appearance in the Silurian scene.
    (DD-EVTT, p.252)

440Mil BC    Ice Age in the Sahara.
    (DD-EVTT, p.21)
440Mil BC    A five-mile size crater in Michigan in Cass County by the village Calvin Center marks the impact of a meteor the size of a football field. It was discovered in 1987.
    (LSA, Spring 1995, p.31)   

440Mil BC - 425Mil BC    The oldest known mass extinction, the Ordovician extinction, occurred about this time. A long ice age followed, but it is unknown if this was a cause or an effect. It was later speculated that a supernova within 10,000 light years of Earth may have been the cause.
    (SFEC, 8/22/99, Par p.12)(SFC, 1/8/04, p.A4)

430Mil BC    Aquatic animals began to develop jaws.
    (NYT, 6/7/96, p.B1)
430Mil BC     Late Silurian.    In late Silurian times there was a shallowing of the seas across North America and they may have withdrawn completely from several regions. To the north-west and in the east large expanses of the sea were cut off from the open water. Under the hot, arid climate these giant lagoon-like areas acted as great evaporating basins. In the Michigan basin and the New York area, for example, as much as 900 meters of salt was laid down.
    (DD-EVTT, p.174)
    Green, buff and russet colored patches of vegetation may in late Silurian days have begun to spring up beside the rivers, lakes and other waterways.
    (DD-EVTT, p.246)
    By late Silurian times some of the earliest and most primitive vertebrates were indeed poking about in fresh waters.
    (DD-EVTT, p.252)

425Mil BC    British researchers reported that an ancestor of modern water fleas, found in rocks in Britain, is the earliest clear example of a male animal. The fossil crustacean, named Colymbosathon ecplecticos (swimmer with a large penis), is unusually well-preserved, allowing scientists to see it had gills and an advanced circulatory system.
    (Reuters, 12/5/03)(SFC, 12/5/03, p.A2)
425Mil BC    In 2020 it was reported that a fossilized millipede-like creature discovered in Scotland may represent the oldest-known land animal. The humble pioneer of terrestrial lived about this time. Researchers said the fossil of the Silurian Period creature, called Kampecaris obanensis and unearthed on the island of Kerrera in the Scottish Inner Hebrides, inhabited a lakeside environment and likely ate decomposing plants.
    (Reuters, 5/30/20)

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