EVOLUTION L03 Age of Earth 2016 - Claremont...
Transcript of EVOLUTION L03 Age of Earth 2016 - Claremont...
9/5/2016
1
EVOLUTIONBiology 145
Lecture 3 –The age of the Earth
1
Theological approaches
James Ussher (1581‐1656)
Summed generations in Old Testament
Creation: 4004 B.C.
(October 26th)
Koran: "a day in the sight of your Lord is like 1,000 years of your reckoning" (22:47).
Jewish calendar: 5776.
Christian calendar: 6020
Islamic year 1437.
2
9/5/2016
2
An archaeological approach
Nicholas Steno
Etruscan city of Volterra ~ 3000 years old in AD 1669
Build on sediments of “The Flood”, hence Flood subsided no later than 1331 BC
Historical records show Lydia (W. Anatolia, Turkey) 1000 years older than Volterra; hence 2331 BC.
3
Sea bed: accumulates sharks teeth
Sea bed lithified into limestone
Limestone uplifted to form island of Malta
Maltese society develops and quarrying starts
TIME
Malta: not much time for events!
Flood
4
9/5/2016
3
Geological Arguments
James Hutton (1726 – 1797) Uniformitarianism
“The result, therefore, of our present enquiry is that we find no vestige of a beginning, no prospect of an end”.
“Hutton’s Unconformity”;Siccar Point, Scotland
5
Geological arguments (2)
Charles Darwin
Erosion of the WealdenValley, England
300 million years!6
9/5/2016
4
Beachy Head
7
Geological arguments (3)
John Joly 1857 ‐ 1933
Salination of the Oceans
8
9/5/2016
5
9
Arguments from Physics
William Thompson (Lord Kelvin) 1824 ‐ 1907
The geothermal gradient (~ 1 degree F / 100 ft)
100 million +/‐ factor of 4
Clarence King –USGS – 24 million.10
9/5/2016
6
Uranium – lead dating
Ernest Rutherford Nobel Prize 1908; “split” atom in 1917
Ca(UO2)2(PO4)2
1907 – first date.400 – 2200 million
11
Uranium – lead dating
4.468∙109 a
238U 4.468∙109 a 218Po 3.1 mins
12
9/5/2016
7
Uranium – lead dating
Boltwood: 1640 ma, Archean of Ceylon
λ = decay constant
13
RADIOCARBON DATING
Formation of 14C
10n +
147N
11H +
146C
Result: 1 part 14C per trillion parts 12C
Willard Libby ‐ 1960 Nobel prize.
14
9/5/2016
8
RADIOCARBON DATING
Decay of 14C
146C
147N + B
‐ + v + 0.156 MeV
Specific activity in modern atmosphere is 13.56 +/‐ 0.07 disintegrations/minute per gram C
Half‐life is 5730 +/‐ 40 years
15
RADIOCARBON DATING
Decay of 14C
0
2
4
6
8
10
12
14
16
0 10000 20000 30000 40000 50000 60000 70000
14C
TIME (years)
Disintegrations per g C/min
16
9/5/2016
9
RADIOCARBON DATING
Decay of 14C
Limit ~ 10 half‐lives, i.e. 1/210= ~ 0.002
Atmospheric abundance ~ 1 part per trillion
17
RADIOCARBON DATING
18
9/5/2016
10
RADIOCARBON DATING
3000 BP = 1224 BC
19
Age of the Universe
Edwin Hubble – 1929
Mt Wilsonmegaparsec = 3.26 million light years 20
9/5/2016
11
Age of the Universe
Value of Hubble constant H0 changes through time, according to a deceleration parameter, q
If q = 0, then the reciprocal of H0 = “Hubble Time”; ie. the time since the Big Bang
4.35×1017 s or 13.8 billion years
CMB estimate = 13.798±0.037
21
22
9/5/2016
12
23