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Evidence for design: earth and solar system
1. Introduction - two conflicting viewpoints
2. Factors that make the earth habitable
3. Quantifying – is the earth one in a thousand,
one in a million, one in a trillion?
4. What does this mean (to you)?
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Evidence for design in the universe
Physical sciences.
.
.
fine-tuning
anthropic coincidences
habitability
discoverability
intelligibility
physical laws
etc
Biological sciences.
.
.
origin of life
molecular machines
hardware and software of cells
micro and macro evolution
basic charact. of fossil record
etc
Cognitive sciences.
.
.
mind/brain
consciousness
personhood
free will
etc
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The universe is fine-tuned for life
Physical sciences.
.
.
fine-tuning
anthropic coincidences
habitability
discoverability
intelligibility
physical laws
etc
https://aeon.co/essays/cosmopsychism-explains-
why-the-universe-is-fine-tuned-for-life
A “fact” discovered by science
Aeon
https://aeon.co/essays/cosmopsychism-explains-why-the-universe-is-fine-tuned-for-life
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Evidence for design in the universe
The laws of physics, the fundamental constants, and the
initial conditions of our Universe, are fine-tuned to allow
for the possibility of life
1. God
2. Infinite universes – must be one “just right”
3. Our universe is a computer program (like The Matrix)
Possible Explanations:
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How exceptional is the Earth?
2000 2004 2014
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The Copernican principle vs
the anthropic coincidences
"However we are not able to make cosmological models without some
admixture of ideology. In the earliest cosmologies, man placed himself
in a commanding position at the centre of the universe. Since the time of
Copernicus we have been steadily demoted to a medium sized planet
going round a medium sized star on the outer edge of a fairly
average galaxy, which is itself simply one of a local group of galaxies.
Indeed we are now so democratic that we would not claim that our
position in space is specially distinguished in any way. We shall,
following Bondi (1960), call this assumption the Copernican principle.”
Hawking, S.W. and Ellis, G.F.R., The Large Scale Structure of Space-
Time, Cambridge University Press, Cambridge, p. 134, 1973.
The Copernican principle
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The Copernican principle vs
the anthropic coincidences
"However we are not able to make cosmological models without some
admixture of ideology. In the earliest cosmologies, man placed himself
in a commanding position at the centre of the universe. Since the time of
Copernicus we have been steadily demoted to a medium sized planet
going round a medium sized star on the outer edge of a fairly
average galaxy, which is itself simply one of a local group of galaxies.
Indeed we are now so democratic that we would not claim that our
position in space is specially distinguished in any way. We shall,
following Bondi (1960), call this assumption the Copernican principle.”
Hawking, S.W. and Ellis, G.F.R., The Large Scale Structure of Space-
Time, Cambridge University Press, Cambridge, p. 134, 1973.
The Copernican principle
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How exceptional is the Earth?
“Most of the Universe is too cold, too hot, too dense, too vacuous, too dark, too bright, or not composed of the right
elements to support life. … of all the known celestial
bodies, Earth is unique in both its physical properties and
its proven ability to sustain life….”
“From the biased viewpoint of Earthlings, however, it does appear that Earth is quite a charmed planet.”
P. Ward and D. Brownlee, Rare Earth, 2000, p 37.
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How exceptional is the Earth?
“The Earth is a precious jewel in space possessing a rare combination of qualities that happen to make it almost
perfect for life. … Personally, I no longer have doubts.
The evidence points towards the Earth being a very
peculiar place; perhaps the only highly-habitable planet we
will ever find.
..almost too good to be true.
David Waltham, Lucky Planet, 2013, p 1,2.
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Probability of another habitable planet
( )x1
100( )x
1
100( )x
1
100( )x
1
100 ( )x1
100( )
1
100
11012
~ 1011 planets in our galaxy
If 6 finely-tuned factors exist, then we have no right to expect another
earth-like planet in the entire galaxy!!
( )x1
100( )x
1
100( )x
1
100( )x
1
100 ( )x1
100( )x
1
100( )x
1
100( )x
1
100( )x
1
100( )x
1
100( ) =
1
100
11022
~ 1022 planets in the observable universe
If 11 finely-tuned factors exist, then we have no right to expect another
earth-like planet in the entire observable universe!!
=
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Movies
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Required factors for habitability
orbital distance
orbital eccentricity
tilt angle
moon (size and proximity)
planet size
other planets – low eccentricity, coplanar, a Jupiter-like
amount of atmosphere
amount of O2 in atmosphere
amount of CO2 in atmosphere
amount of water
amount of radioactive elements
amount of Fe and nickel
crustal composition
plate tectonics
etc
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Earth’s size
“Earth’s size is just about right - not too small that its gravity was too weak to hold the atmosphere and not so
large that its atmosphere would hold too much atmosphere
including harmful gases …
F. Press and R. Siever, Earth, 1986, p 4. Quoted in
Nature’s Destiny p 92
Earth’s size is also important for a sufficiently strong magnetic field
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Earth’s orbit around the sun
“One of Earth’s most basic life-supporting attributes is indeed its location, its seemingly
ideal distance from the sun.”
Rare Earth, p 16.
“Astrobiologists James Kasting and his colleagues … estimated in 1993 that the width
of the CHZ is from 0.95 to 1.15 AU.”
(1 AU = distance from the Earth to the Sun)
Rare Earth, p 19.
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Earth’s orbit around the sun
Freezing and
boiling of
water set
conservative
limits
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Kepler: Recent discoveries of exoplanets
Kepler’s region of study
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Kepler study
PNAS 110, 19273, 2013
10 earth-sized
planets in
habitable zone
out of 603
1.7%
After correcting for survey incompleteness for smaller planets, they estimate 22%
of sun-like stars have earth-sized planets in habitable zone
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Habitable Zone
Mars and Venus are “earth-like planets” in the habitable zone
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Earth’s tilt about spin axis
“Although our viewpoint is certainly biased, our
planet’s tilt axis seems to be “just right”.
Rare Earth, p 224.
larger tilt - temperature extremes
smaller tilt - rain not distributedPrivileged Planet, p 5.
+/- 1 deg for several thousand yrs
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Earth’s tilt about spin axis
“Constancy of the tilt angle is a factor that provides long-term stability of the Earth’s temperature. If the polar tilt axis had undergone wide deviations from its present value, Earth’s climate would have been much less hospitable…..
Rare Earth, p 224.
These results show that the situation of the Earth is very
peculiar. The common status for all the terrestrial planets is to
have experienced very large scale chaotic behavior for their
obliquity, which in the case of the Earth and in the absence of
the Moon, may have prevented the appearance of evoluted
forms of life. We owe our exceptional climate stability to an
exceptional event - the presence of the moon.
Jacques Laskar, quoted in Rare Earth p 224.
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The Moon
Just right size and distance from the Earth to
-stabilize tilt
-slow Earth’s rate of rotation
“our moon is somewhat of a freak because of its large size in comparison to its parent planet.”
Rare Earth p 222.
“Without the moon it is … likely that no birds, redwoods, whales, trilobites, or other advanced life would ever have graced Earth. …
Although there are dozens of moons in the solar system, the
familiar ghostly white moon that illuminates our night sky is
highly unusual, and its presence played a surprisingly important
role …”Rare Earth p 222.
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The Moon
“We owe our present climate stability to an exceptional event:the presence of the Moon.”
Jacques Laskar, quoted in Rare Earth p 224.
Produced by a “just right” collision?
“to produce such a massive moon, the impacting body had to be the right size, it had to impact the right point on the Earth, and
the impact had to have occurred at just the right time in the
Earth’s growth process.”Rare Earth p 231.
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The Moon – Giant Impact Hypothesis
When worlds collide: Final stages of planet formation
Movie of this simulated collision of two planetesimals can be
found in the Links portion of the textbook web site
What if habitability requires a stabilizing large satellite, like our Moon?
Chances are small it would happen twice. Could instead
end up with catastrophic destruction of both bodies as shown below.
Typical: catastrophic destruction
of both bodiesarguments for impact hypoth:
-explain why moon is so large and so close
-may explain why little water on moon
-may explain similar isotopic compositions
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The Moon – Giant Impact Hypothesis
“a very freakish event”
Physics Today Nov 2014
ang. momentum – yes
composition - no
ang. momentum – no
composition - yes
ang. momentum – no
composition - yes
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In a recent survey of debris disks nearby newly forming stars, 1 star
in 500 showed a hot dense debris disk that likely was the result of a
large collision.
Gorlova et al, The Astrophysical Journal 2007, 670, 516
Just right collision to form a moon that is large and close like ours
(1/500) x (??)
(prob, of a large collision) (fraction of collisions that form moon)
The Moon – Giant Impact Hypothesis
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Earth’s atmosphere
“… differs greatly from those of other terrestrial planets, which range from essentially no atmosphere (Mercury) to a
CO2 atmosphere a hundred times denser (Venus) and a CO2atmosphere a hundred times less dense (Mars).”
Ward and Brownlee, Rare Earth, p 52.
“It is difficult to see how the actual concentrations of these gases could be very different from what they are in any
atmosphere supporting a carbon-based biosphere.”
M. Denton, Nature’s Destiny, p 55.
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Earth’s atmosphere
“ It is surely a coincidence ofenormous significance that several
essential conditions are satisfied in this
one tiny region of space of all possible
atmospheres. Fire is possible, but
runaway combustion is avoided, oxygen
toxicity is relatively low, the solubility
of oxygen is sufficient to support
oxidative metabolism, and the density is
sufficiently low that the work of
breathing during strenuous exercise is
not prohibitive.”
M. Denton, Nature’s Destiny p 128.M. Denton, Nature’s Destiny
min. pressure is
required to retain
liquid water
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The right amount of water
If too much water - all land is covered
“with even twice as much water, Earth would have ended up as an abyssal planet entirely covered with deep blue water -
a true “water world” …”Ward and Brownlee Rare Earth, p 47
“thus the planet’s remarkable mixture of land and oceans is a balancing act. … This fortuitous combination may be
the most important factor that ultimately made life possible.
Ward and Brownlee Rare Earth, p 53.
If too little water - global temperatures would fluctuate too
much
Ward and Brownlee Rare Earth, p 264
0.1% water
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“Discovering how Earth acquired its supply of water is one of the most critical concerns of the new field of astrobiology.
As we pointed out in an earlier chapter, water was not
abundant in the inner regions of the solar system when
planets formed. There was far more water in the outer
regions of the solar system than among the inner planets.
Where did our water come from?”
Still subject of debate, comets - heavy bombardment?
Ward and Brownlee Rare Earth, p 261.
The right amount of water
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“An enigma of Earth’s formation is its composition and particular location in the solar system…. A grand paradox of terrestrial planets
is that if they form close enough to the star to be in its habitable
zone, they typically end up with very little water and a dearth of
primary life-forming elements such as nitrogen and oxygen,
compared with bodies that formed in the outer solar system. In
other words, the planets that are in the right place, and thus have
warm surfaces, contain only minor amounts of the ingredients
necessary for life”.
“the origin of biogenic elements is a subject of considerable speculation.”
from “asteroidal and cometary debris” ?
Rare Earth, p 45, 48.
The right amount of water
-
The right amount of water
One of the
planets visited
was a “water
world”
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Earth’s elemental composition
Enough metal for iron- and nickel-rich liquid core
Enough radioactive elements for long period of radioactive heating
(uranium, thorium, potassium)
Composition allowed very thin outer crust of low density - plate tectonics
“The thickness, and stability of the Earth’s core, mantle, and crust could have come about only through the fortuitous assemblage of the correct elemental
building blocks”.
Ward and Brownlee, Rare Earth, p 51.
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Earth’s elemental composition
“… the Earth’s interior is a delicately balanced heat engine fueled by
radioactivity … were it running too slowly … the continents might not
have evolved to their present form… Iron may never have melted and
sunk to the liquid core, and the magnetic field would never have
developed…. If there had been more radioactive fuel, and therefore a
faster running engine, volcanic dust would have blotted out the Sun, the
atmosphere would have been oppressively dense, and the surface would
have been racked by daily earthquakes and volcanic explosions.”
F. Press and R. Siever, Earth, 1986, p 4.
radioactive elements: uranium 238 – 0.0004% (by mass)
thorium 232 – 0.0012%
potassium 40 – 0.0028%
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Earth’s elemental composition
the Earth’s delicately balanced heat engine is disrupted
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Earth’s cycles
Hydrological cycle
Plate tectonics (earth, but nowhere else in solar system)
Ensure the physical and chemical constancy of our environment
-regulates greenhouse gases
-builds continents
-global thermostat (5 C - 40 C)
-magnetic field (T difference across core, convection cells)
“Like two gigantic cogwheels engineered to fit perfectly together, these two great cycles have turned together in perfect unison … ensuring the
continual turnover and essential recycling of the vital elements of life.”
M. Denton, Nature’s Destiny, p 84.
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The sun
-
main sequence stars:
fusing hydrogen to
helium
Hertzsprung-Russel StarData.png
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Comparison of some star types
% (galaxy): 5% 80%
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The sun
Just-right size:
bigger - hotter, burns faster, more erratic
smaller - cooler, habitable zone closer in, its
gravity would slow a planet’s rotation too much
5% of stars in our galaxy are similar to our sun
~80% are red dwarf stars (highly unlikely to support habitable planets)
(G-type, main sequence)
-
M stars: Habitable Zone = tidally locked
M-type stars - thousand or million times more active ( flares) than sun
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Jupiter and outer planets
Jupiter: just-right size and location:
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Jupiter and outer planets
Jupiter: just-right size and location:
“without a large planet positioned precisely where Jupiter is, the earth would have been struck a thousand times more frequently in
the past by comets and meteors and other interplanetary debris.”“…we wouldn’t be around to study the solar system.”
G. W. Wetherill, Nature 1995, 373: 470; Discover 1993, p 15.
However, if Jupiter were too large, or too close, it would perturb
Earth’s orbit.
-
Jupiter: right size and location
The statistics of extrasolar planetary systems indicate that the default mode of planet
formation generates planets with orbital periods shorter than 100 days and masses
substantially exceeding that of the Earth. When viewed in this context, the Solar System is
unusual. Here, we present simulations which show that a popular formation scenario for
Jupiter and Saturn, in which Jupiter migrates inward from a > 5 astronomical units (AU) to
a ≈ 1.5 AU before reversing direction, can explain the low overall mass of the Solar
System’s terrestrial planets,
In this scenario, the Solar System’s terrestrial planets formed from gas-starved mass-depleted debris that remained after the primary period of dynamical evolution.
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Jupiter: right size and location
http://theconversation.com/rarity-of-jupiter-like-planets-means-
planetary-systems-exactly-like-ours-may-be-scarce-52116
from survey of 1100
stars, probability of
Jupiter analogue is 3%
(not published)
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Our position in the Milky Way
-
Our solar system
All planets in our solar system have almost circular orbits that lie within a
nearly flat disc called the ecliptic plane
-
Most locations in the galaxy are not habitableSome ways in which certain locations in our Galaxy might have low
probabilities of planet formation or might be hazardous for life.
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Our position in the Milky Way
Moreover, the Sun's circular orbit about the galactic center is just right;
through a combination of factors it manages to keep out of the way of
the Galaxy's dangerous spiral arms. Our solar system is also far enough
away from the galactic center to not have to worry about disruptive
gravitational forces or too much radiation. …
More than 95 percent of stars in the Galaxy, says Gonzalez, wouldn't be
able to support habitable planets simply because their rotation is not
synchronized with the rotation of the galaxy's spiral arms. Add all the
other factors involved in keeping a solar system habitable, and it seems
that the odds of finding another solar system in a Galactic Habitable
Zone are close to impossible.
Galactic Habitable Zones, Astrobiology Magazine, May 18, 2001
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What does it take to make a habitable planet?
( )x1
100( )x
1
100( )x
1
100( )x
1
100 ( )x1
100( )
1
100
11012
~ 1011 planets in our galaxy
If 6 finely-tuned factors exist, then we have no right to expect another
earth-like planet in the entire galaxy!!
=
( ) x22
100( ) x
5
100
earth-
sized
in
habitable
zone(PNAS, 110
19273, 2013)
G-type,
main
sequence
starmoon
(large,
close)
( ) x1
100 ( )1
500
right
amount
of water
magnetic
field
(liquid
iron core)
plate
tectonics
galactic
habitable
zone(Icarus 152
185-200,
2001; the
physics
arXiv blog)
( ) x1
100( ) x
1
100( ) x
1
2
rocky
( ) x ….1
100
right
atmosphere
(Venus and
Mars)
( ) x1
100
right
amount
of
radioactive
elements
( ) x1
100( ) x
1
100
?
other
planets:
low
eccentricity
coplanar
Jupiter(PNAS 113,
11431, 2016)
( ) x3
100( )1
2
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How exceptional is the Earth?
https://www.youtube.com/watch?v=QmIc42oRjm8
2004
https://www.youtube.com/watch?v=QmIc42oRjm8
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Guillermo Gonzalez – Privileged Planet
Two years prior to his consideration for tenure, approximately 130
members of the faculty of Iowa State University signed a statement
co-authored by assistant professors Michael Clough, James Colbert
and Hector Avalos, opposing "all attempts to represent Intelligent
Design as a scientific endeavor."
Wikipedia
https://en.wikipedia.org/wiki/Tenurehttps://en.wikipedia.org/wiki/Hector_Avalos
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Why this was controversial
Naturalism
Evolution
Science
Rational
Objective
Reality
Theism
Creation
Religion
Irrational
Subjective
Fantasy
Science can only be on one side!
Cause(s)
outside nature
Nature is all
there is
scie
nce
?
We are all on the side of science
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How exceptional is the Earth?
http://channel.nationalgeographic.com/u/kcOIVhcWjca1n65QtmFg_5vIMZ9j1S1
CXT46o65HkAANx6SUvJvQAQfYjGC0CkQwGNSgnX54f2aoFg/?_ga=2.1336
86797.2068496915.1521591357-1729018746.1430339770
http://channel.nationalgeographic.com/u/kcOIVhcWjca1n65QtmFg_5vIMZ9j1S1CXT46o65HkAANx6SUvJvQAQfYjGC0CkQwGNSgnX54f2aoFg/?_ga=2.133686797.2068496915.1521591357-1729018746.1430339770
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How exceptional is the Earth?
National Geographic March 2018
13 things that make life on earth possible
1. Our planet recycles life friendly carbon over time
2. We have an ozone layer to block harmful rays
3. We have a big moon to stabilize our axial wobble
4. Earth’s varied surfaces support many life-forms
5. Our magnetic field deflects solar tempests
6. We’re at just the right distance from the sun
7. We’re safely away from gas giants
8. The sun is a stable long-lasting star
9. We have the right stuff to host a dynamic core
10. We have giant planets that protect us from afar
11. Our sun offers protection from galactic debris
12. Our galatic path steers us clear of hazards
13. Our location is far from stellar crowds
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Recent headlines or articles:
Two Billion Earthlike Planets in the Milky Way: How Many Will Prove to
Support Advanced Life?
Found: An Earthlike Planet, at Last Time Sept 2010
Earth-like planets pile up Nature.com Newsblog Aug 19, 2011
“NASA’s ‘holy grail’: Entire new solar system that could support alien life
discovered”
In all, there might be 40 billion potentially habitable worlds sitting just in our
galaxy, the Milky Way, astronomers estimate.
The Independent 2017
-
Jan 7
2015
-
What does it take to make a habitable planet?
Nature 470, 5, 2011
-
What does it take to make a habitable planet?
Nature 470, 5, 2011
-
What does it take to make a habitable planet?
Nature 470, 5, 2011Nature 470, 5, 2011
-
Jan 7
2015
-
What does this mean (to you)?
-
What does this mean (to you)?
Science vs Philosophy
-
“How is it that hardly any major religion has looked at science and
concluded, “This is better than we thought! The Universe is much bigger
than our prophets said, grander, more subtle, more elegant?” Instead they
say, “No, no, no! My god is a little god, and I want him to stay that way.” A
religion, old or new, that stressed the magnificence of the Universe as
revealed by modern science might be able to draw forth reserves of
reverence and awe hardly tapped by the conventional faiths.”
Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space
What does this mean (to you)?
-
What does it take to make a habitable planet?
For this is what the LORD says - he who created the
heavens, he is God; he who fashioned and made the earth, he
founded it; he did not create it to be empty, but formed it
to be inhabited - he says: I am the LORD and there is no
other.
Isaiah 45:18
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How much of an outlier is the earth?#ofhabitabilityfactors
planets
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#ofhabitabilityfactors
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