From:    John Musselwhite
To:      All                                    Msg #745, Oct-16-93 00:25:48
Subject: Geologic Timetable

Hi All!

    This was posted in our local CALGARY echo and I thought some
people might appreciate the cross-post.
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CALGARY CHATTER
 From : Sid Lee                   1:134/122       Mon 11 Oct 93 20:19
 To   : All                                       Tue 12 Oct 93 01:13
 Subj : Geological Time Scales
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I promised last week to post answers to a question I posed at
 that time. The question was (paraphrased) "Without using a
 calculator, if the entire history of the Earth from it's
 creation approximately 5 billion years ago were represented in a
 length of time of 1 year, and if the human race became a
 recognizable entity approximately half a million years ago, when
 would that have been on our one year scale?"

 5 billion years is 5 followed by 9 zeros (5*10^9) and half a
 million years is 5 followed by 5 zeros (5*10^5). So half a
 million represents 5*10^5/5*10^9 or 1*10^-4 or 1/10,000 of the
 total. 1/365 would be 1 day on our scale so we must be in Dec 31
 somewhere! 1/1000 would be approximately 1/3 of a day (8 hrs) so
 we are after 16:00 hrs on Dec 31 and we still have another 1/10
 to go! 1/10 of 8 hrs is less than an hour so our rough
 conclusion is that on our one year time scale compression
 mankind appeared shortly after 23:00 (11 pm) on December 31!

 Turning to the calculator we can refine this to 23:07!

 Here are some other interesting "markers" (times given are from
 the Canadian Global Almanac 1993 [with formation of the earth assumed at
 00:00:01 on January 1]):

 Period       Time      Desc                            Scaled Time
 -------      -------   -----------------------------   -----------
 Cambrian      575 Mil  First Fishes appear and great   Nov 20
                        development of invertebrates
 Ordivician    480 Mil  Jawless fish. Algae become      Nov 26
                        plentiful
 Silurian      435 Mil  Coral, first amphibians,        Nov 30
                        Forests of fernlike trees
 Devonian      405 Mil  Oil & Gas formed, first insects Dec 2
 Pennsylvanian 310 Mil  Appalacian Mountains formed     Dec 9
                        First reptiles
 Triassic      225 Mil  Reptiles dominate the Earth     Dec 15
                        First mammals appear
 Jurassic      180 Mil  Dinosaurs achive largest sizes  Dec 18
                        First birds appear
 Cretaceous    130 Mil  Flowering plants appear,        Dec 22
                        Dinosaurs die at the end
 Tertiary       65 Mil  Mammals become common           Dec 27
                50 Mil  Primitive apes, early horses    Dec 28
                        and Elephants appear
                27 Mil  Flowering plants and trees      Dec 30
                        resemble modern ones
               1.5 Mil  Early Humans reach Europe and   Dec 31
                        North America

 Pyramids     5000 yrs  Dec 31 23:59:29!
 Christ       2000 yrs  Dec 31 23:59:48!
 Columbus      500 yrs  Dec 31 23:59:57!

 Puts an interesting perspective on things does it not?