Physics Colloquium
University of Delaware
Bartol Research Foundation
Intimations fromOrder
of a Mind Behindthe Universe
Introduction
How does one recognize an artifact?
e.g.,distinguish between natural chipped stones & humanly prepared flints?
How does one recognize an intelligent message?
e.g.,SETI – pulsars or little green men?
Stonemarkings – inscriptions or plow marks?
Certainly thereare difficult boundary cases, but basically the question is one of the level oforder encountered.
Is Life anArtifact or an Accident? TheOrganization in Living Systems
Carl Sagan on thesimplest living cell:
"The information content of asimple cell has been estimated as around 10 to the 12th power bits,comparable to about a hundred million pages of the Encyclopaedia Britannica
The production of order by random processes:
"Give enough monkeys enough time,and they will eventually type our the entire Encyclopaedia Britannica
How much time? How many monkeys? A Gedankenexperiment:
(1) Type thetitle only, all caps.
(2) Usemonkey-proof typewriters, with 33 keys: alphabet, all caps; space; punctuation.
(3) Have trainedmonkeys to type, at 3 characters per second.
(4) Our"word" is 24 chacters long, with 33 possibilities at each location.
(5) How long totype all combinations, assuming no repeats?
(6) The job willtake 3 x 1028 monkey-years. In the 15 billion years since the big bang, would need 2 x 1018monkeys!
A samplecalculation for protein construction: Molecules move faster than monkeys, but an analogous calculation can bedone for constructing a simple protein from amino acids:
(1) Contruct theprotein of 100 amino acids, about the smalles that is functional.
(2) We haveabout 20 different amino acids in living systems, so this is equivalent totyping a 100-letter word/phrase with a 20-letter alphabet.
(3) Somesimplifying assumptions:
(a) The systemonly forms 100-link chains, never repeating the same pattern.
(b) The chainschange randomly at the rate an amino acid moves (say) 10 Angstroms at standardtemperature, i.e, 3 x 1011 combinations per second.
(4) How longwill it take to produce all combinations, assuming no repeats?
(5) Case #1:time (Tss) to form all possibilities in our solar system:
(a) Assume oneamino acid for every nitrogen atom in the solar system.
(b) Relativeabundance of N = 1.2 x 10-4.
(c) Tss= 1061 years.
(6) Case #2:time (Tgal) to form all possibilities in our galaxy:
(a) Number ofstars in our galaxy = 1011.
(b) Tgal= 1050 years.
(7) Case #3:time (Thr) to form within Hubble radius:
Is theUniverse an Artifact or Accident? The Organization in the Universe
Nuclei: C12is crucial to life in forming long chain molecules.
Formation instars: a rare thee-He collision, but thermal energy in stars is right at the C12resonance!
Destruction instars: C + He => O, but the thermal energy in stars is above the O16resonance, so C12 is preserved (according to Hoyle; see Davies, AccidentalUniverse, 117-18).
This produces abottleneck, giving a large abundance of C in the universe.
Molecules: water(see Hayward, God Is, 59-61)
Very smallmolecule (weight 18 vs N2 at 28, O2 at 32), yet it isluquid at temperatures suitable for life due to polymerization (2x or 3x), soable to work as liquid in chemical reactions for life processes; but gaseousstate is not polymeric, so behaves as lighter than air gas, not hugging surfaceand stifling life. No othersubstance has this property.
Universalsolvent: carries solid chemicals in blood stream, plant sap, and in fluidwithin the cell; other comparable solvents are desctuctive to living tissue.
High heatcapacity: moderates earth's climate, stabilizes body temperatures.
Expands onfreezing: a very rare property; prevents ocean freeze-up, aids soil formation.
Earth-Sun System
Lifetime over 4billion years:
Enough UV forlife (say 10% of sun's):
Probably need asingle-star system to form planets.
Star cannot havetoo much luminosity variation
Earth:
While Lsunwas increasing 25%, CO2 replaced by O2 in just such a waythat Tearth stayed in life-support range.
Meanwhile, theright kinds of changes were taking place in life in order to be able to copewith the rising O2 in the atmosphere.
Putting these featurestogether, we get a very narrow window for survival of life on earth over 4billion years:
(1) If earth 5%nearer sun, then runaway greenhouse effect near the beginning of the period.
(2) If earth 1%farther from sun, then runaway glaciation at about 2 billion years
(see MichaelHart, Icarus 37 [1979]: 351-57)
Suggest about 1star in 105 to 107 would fit these constraints; so onlyabout 20 thousand to 2 million in our galaxy.
Universe
(1) mneutron– mproton = 10-3 x mproton = melectron;together with relative sizes of G (gravity) and gweak, this meansneutrons and protons "freeze out" in the early universe withcomparable numbers of each, instead of nearly all n or all p (actually, about 1/10are n, 9/10 are p).
(a) If abundanceof n about equal abundance of p, little H formed.
(b) If abund n<< abund p, little He formed.
(2) If gweakmuch smaller, no supernovas, as neutrinos would not interact with and explodethe outer shell of the star, to scatter heavy elements; if gweakmuch stronger, no supernovas, as neutrionos could not escape core of star toscatter heavy elements; thus if gweak much different, no heavyelements (including C, N, O) outside cores of stars, so no life, no people.
(3) If gstrongmuch weaker, fewer stable elements:
If gstrong5% less, Deuterium would not exist, and stars would not burn.
If gstronga few % larger, diproton would be stable, p + p => D would go by the strongforce, and stars would burn catastrophically.
There is adelicate balance of cosmic expansion and gravity:
The currentmatter density of the universe is between 1/10 and 10 times the criticaldensity.
This means thatat the Planck time (10-43 sec after the big bang), the matterdensity differed from the critical density by less than one part in 1060.
(1) If thedensity were much larger than this, the universe would have quickly collapsed,and there would be no life.
(2) If thedensity were much smaller than this, the universe would have expanded tooquickly to form galaxies; again, no life.
Conclusions
We have onlygiven a few examples here. Moreare given in P. C. W. Davies, The Accidental Universe(Cambridge, 1982) and Alan Hayward, God Is (Nelson, 1978).
How do we explainthese things?
No matter howunlikely the chances, if the universe couldn't support life, we wouldn't behere to observe it. Improbabilityis therefore selected by the presence of intelligent obervers.
It is hard toargue with this position, but it is not much of an explanation.
It thisexplanation falsifiable? Whatwould count against such a view, other than divine revelation?
Is there anyevidence for other universes (whether sequential or contemporary) to raise theprobability?
The rarity ofevents calculated above goes far beyond the experimental basis of reandomness;compare this to the idea of ice forming in a pan on a hot stove, or all the airmoving to one end of a room.
(2) IntelligentUniverse? => Strong Anthropic Principle
Somehow theuniverse itself guides the values of the relevant parameters in order toproduce (intelligent) life.
Is there anyevidence for this?
(3) God?