Tierra: El Planeta Privilegiado

En la cultura popular se sostiene la idea de que el universo esta lleno de vida con miles o millones de culturas en el.

Lo podríamos considerar una idea romántica que no se basa en evidencia científica sino mas bien en series de television como Star Trek o peliculas como Start Wars o Cuando la Tierra se detuvo. 

Sin embargo en base a los conocimientos que tenemos sobre el cosmos sabemos que un planeta como la Tierra que pueda albergar vida inteligente es extremadamente raro en un universo que es inhóspito para la vida.

El geólogo Peter D. Ward y el astrónomo Donal Brownlee ambos de la Universidad de Seattle es su libro controversial y exitoso Rare Earth (Tierra rara) después de presentar evidencias sobre el aspecto único de un plante como el nuestro preguntan:

"Que tal si es del todo única: el único planeta con animales en esta galaxia, o inclusive, en el universo visible..?"

Después de presentar evidencia de una amplia variedad de disciplinas científicas para apoyar su caso con respecto a que "no solo la vida inteligente, sino hasta las mas simples de forma animal, es extremadamente rara en nuestra galaxia y en el universo.

El sistema solar y la Tierra.

La vida humana esta en un balance mas fino que el de una navaja, por ejemplo veamos que pasaría si un humano se encontrara de manera natural en nuestro vecindario del sistema solar:

Mercurio:  Morimos cocinamos en segundos.

Venus:       Morimos cocinamos en segundos además el planeta es toxico.

Marte:        Morimos congelados en invierno o cocinados en verano la atmósfera es toxica.

Júpiter:     Las ráfagas de aire nos destrozarían, es toxico, y nos congelariamos.

Saturno:   Ni siquiera hay suelo, nos congelariamos y es toxico.

Urano:      Moriríamos congelados, las ráfagas de aire nos destrozarían y es toxico.

Neptuno: Moriríamos congelados, es toxico además la gravedad es casi inexistente.

Espacio:  Cocinados o congelados dependiendo de la distancia al Sol y sofocados.

La Tierra el sitio para la vida

Existen diferentes factores que permiten que la Tierra sea un santuario para la vida en el cosmos  reduciendo de manera drásticas las posibilidades de que en otro planeta se haya levantado vida de manera naturalista.

1) La galaxia correcta

No todas las galaxias pueden generar un planeta como  la tierra que sustenta una biodiversidad tan grande de organismos entre ellos los humanos.

Se sabe hasta ahora que solo las galaxias espirales son las que pudieran sostener un planeta  con vida como la tierra. Solo el 5% de las galaxias en el universo son espirales mientras el 95% son elípticas o irregulares.

El astrofísicos Hugh Ross comenta:

"En las galaxias elípticas, la formación de estrellas se detiene antes que el medio interestelar se haya enriquecido suficientemente con elementos pesados. Para la vida, los sistemas estelares tienen que formarse lo suficientemente tarde como para que puedan incorporar este material enriquecido con elementos pesados. El problema con las galaxias grandes e irregulares es que tienen núcleos activos. Estos núcleos escupen radiación y material destructivo para la vida. En tanto, la mayoría de las galaxias pequeñas e irregulares tienen cantidades insuficiententes de los elementos pesados esenciales para la vida"(Ross,1999,P. 173).

Los físicos R.E. Davies y R. H. Koch comentan que el desarrollo del sistema solar emergente necesitaria suficientes elementos pesados para poder formar planetas como  la tierra. De hecho su estudio concluye en que las supernovas, que proveen los elementos pesados, tuvieron que haber ocurrido lo suficientemente temprano en la historia de la galaxia para que un planeta como el nuestro se pueda formar  tan temprano.

"La frecuencia de las erupciones de supernovas (por unidad de volumen) es fuertemente dependiente de la ubicación. El sistema solar debe estar situado en la parte correcta del brazo espiral, y ese brazo espiral debe estar a la distancia correcta del centro de la galaxia"(Ross, 1999, P. 174).

Esto elimina a muchas galaxias, porque si tomamos en cuenta las irregulares o pequeñas las supernovas estarían destruyendo la vida de manera constante con su radiación.

No solo eso, si una galaxia espiral llega a tener un planeta como la tierra, el planeta tiene que estar en el lugar indicado porque si esta demasiado cerca al centro de la galaxia la radiación no hubiera dejado que la vida se formara.

Además con el telescopio espacial Hubble ahora sabemos que casi todas las galaxias tienen un agujero negro en el centro, y estas cosas son en verdad peligrosas para cualquier objeto que se acerque a ellas. Estos agujeros negros al devorar objetos como estrellas lanzan al espacio una gran cantidad de energía, rayos gamma, rayos X, radiación de partículas y todo en la región interior de la galaxia se somete a altos niveles de radiación.

El astrónomo Guillermo Gonzalez comenta:

".... la composición de una galaxia espiral cambia mientras se esta alejado del centro. La abundancia de elementos pesados es mayor hacia el centro, porque ahí es donde la formación de estrellas ha sido mas vigorosa durante la historia de la galaxia. Así es como ha sido capaz de "cocinar" el hidrógeno y el helio y transformarlos en elementos mas rápidamente, mientras que en el disco mas externo de la galaxia, la formulación de estrellas ha ocurrido mas lentamente durante los años, por lo tanto, la abundancia de elementos pesados no es tan alta. En consecuencia, en las regiones externas al disco es mas improbable que existan planetas del tipo de la Tierra"(Strobel, 2005, P. 209).

No solo necesitamos la galaxia correcta: Una Espiral. Pero también necesitamos la zona correcta y para hacerlo mas complicado es improbable que en la zona correcta puedan existir planetas como el nuestro.

2) La estrella correcta

No solo es el tipo correcto de galaxia la que se necesita para que exista un planeta que pueda albergar vida inteligente como la tierra, sino se necesita una estrella especifica sobre la cual gire el planeta. Ya que un planeta que se haya alejado de su estrella y vague por el espacio sera demasiado frió por lo tanto prohibitivo para la vida lo mismo se puede decir de estrellas en un sistema binario.

Si un planeta gira sobre un sistema binario a menudo su órbita se alejara los suficiente de la estrella/s que cambiara drasticamente su temperatura. Por lo tanto se necesita una estrella soltera.

El astrofísico Hugh Ross comenta:

"Solo una cuarta parte, aproximad amente, de las estrellas en nuestra galaxia cumplen con el criterio de ser estrellas solteras"(Ross, 1999, P. 176).

No todas las estrellas como hemos visto son buenas candidatas para tener un planeta con vida inteligente. Tomemos de ejemplo nuestra galaxia, si escojemos una estrella en la masa central de estrellas o muy dentro de los brazos espirales de la galaxia, estarán muy cercas de otras estrellas, por lo tanto los niveles de calor y radiación serian prohibitivos para la vida.

El astrónomo Guillermo Gonzalez comenta:

".... el sol realmente es poco usual después de todo. Por ejemplo, se encuentra entre el diez por ciento de las estrellas mas masivas de la galaxia. En realidad, si se elige a una estrella al azar, es muy probable que se escoja una que es muchisimo menos masiva que el sol, normalmente enanas rojas, las que constituyen cerca del ochenta por ciento de las estrellas...¿.Son ellas propicias para tener planetas que soporten la vida y que las orbiten?, No lo creo. Por varias razones. En primer lugar, las enanas rojas emiten la mayor parte de su radiación en la parte roja del espectro lo que hace que la fotosintesis se menos eficiente. Pero un problema mucho mayor es que mientras decrece la masa de una estrella, también decrece su luminosidad. Un planeta tendría que órbita este tipo de estrella a una distancia mucho mas cercana para poder tener el calor suficiente para mantener el agua en estado liquido sobre superficie. El problema es que la fuerza de atracción entre la estrella y el planeta se vuelve mas poderosa mientras se mueve, así que el planeta dejaría de girar y con el paso del tiempo terminaria en lo que se denomina un estado cerrado de atracción. Esto significa que siempre presentaría la misma cara hacia la estrella"(Strobel, 2005, P. 217).

Esto quiere decir si elegimos una estrella enana roja, de las estrellas mas comunes, el planeta debería de estar lo suficientemente cercano a esa pequeña estrella para tener una temperatura adecuada sin embargo el problema es que esto generaría un estado cerrado de atracción, como el de la Luna.

Así que una cara del planeta siempre estaría frente al sol, con temperaturas inaceptables para la vida mientras la otra cara la oscura seria muy fría.

Si esto no fuera suficiente este tipo de estrellas tiene llamaradas como el sol, pero al ser tan pequeñas estas estrellas estas cambiaran su luminosidad lo que implica diferencias de temperatura graves en el planeta que gire al rededor de ella.

Resumen

Hugh Ross da la lista de parámetros que hace que un planeta como la tierra pueda albergar vida inteligente:

1. galaxy cluster type
   • if too rich: galaxy collisions and mergers would disrupt solar orbit
   • if too sparse: insufficient infusion of gas to sustain star formation for a long enough time
2. galaxy size
   • if too large: infusion of gas and stars would disturb sun’s orbit and ignite too many galactic eruptions.
   • if too small: insufficient infusion of gas to sustain star formation for long enough time.
3. galaxy type
   • if too elliptical: star formation would cease before sufficient heavy element build-up for life chemistry.
   • if too irregular: radiation exposure on occasion would be too severe and heavy elements for life chemistry would not be available.
4. galaxy mass distribution
   • if too much in the central bulge: life-supportable planet will be exposed to too much radiation.
   • if too much in the spiral arms: life-supportable planet will be destabliized by the gravity and radiation from ad-jacent spiral arms.
5. galaxy location
   • if too close to a rich galaxy cluster: galaxy would be gravitationally disrupted
   • if too close to very large galaxy(ies): galaxy would be gravitationally disrupted.
   • if too far away from dwarf galaxies: insufficient infall of gas and dust to sustain ongoing star formation
6. decay rate of cold dark matter particles
   • if too small: too few dwarf spheroidal galaxies will form which prevents star formation from lasting long enough in large galaxies so that life-supportable planets become possible.
   • if too great: too many dwarf spheroidal galaxies will form which will make the orbits of solar-type stars unsta-ble over long time periods and lead to the generation of deadly radiation episodes.
7. hypernovae eruptions
   • if too few not enough heavy element ashes present for the formation of rocky planets.
   • if too many: relative abundances of heavy elements on rocky planets would be inappropriate for life; too many collision events in planetary system
   • if too soon: leads to a galaxy evolution history that would disturb the possibility of advanced life; not enough heavy element ashes present for the formation of rocky planets.
   • if too late: leads to a galaxy evolution history that would disturb the possibility of advanced life; relative abun-dances of heavy elements on rocky planets would be inappropriate for life; too many collision events in planetary system
8. supernovae eruptions
   • if too close: life on the planet would be exterminated by radiation
   • if too far: not enough heavy element ashes would exist for the formation of rocky planets.
   • if too infrequent: not enough heavy element ashes present for the formation of rocky planets.
   • if too frequent: life on the planet would be exterminated.
   • if too soon: heavy element ashes would be too dispersed for the formation of rocky planets at an early enough time in cosmic history
   • if too late: life on the planet would be exterminated by radiation.
9. white dwarf binaries
   • if too few: insufficient flourine would be produced for life chemistry to proceed.
   • if too many: planetary orbits disrupted by stellar density; life on planet would be exterminated.
   • if too soon: not enough heavy elements would be made for efficient flourine production.
   • if too late: flourine would be made too late for incorporation in protoplanet.
10. proximity of solar nebula to a supernova eruption
    • if farther: insufficient heavy elements for life would be absorbed.
    • if closer: nebula would be blown apart.
11. timing of solar nebula formation relative to supernova eruption
    • if earlier: nebula would be blown apart.
    • if later: nebula would not absorb enough heavy elements.
12. number of stars in parent star birth aggregate
    • if too few: insufficient input of certain heavy elements into the solar nebula.
    • if too many: planetary orbits will be too radically disturbed.
13. star formation history in parent star vicinity
    • if too much too soon: planetary orbits will be too radically disturbed.
14. birth date of the star-planetary system
    • if too early: quantity of heavy elements will be too low for large rocky planets to form.
    • if too late: star would not yet have reached stable burning phase; ratio of potassium-40, uranium-235 & 238, and thorium-232 to iron will be too low for long-lived plate tectonics to be sustained on a rocky planet.
15. parent star distance from center of galaxy
    • if farther: quantity of heavy elements would be insufficient to make rocky planets; wrong abundances of sili-con, sulfur, and magnesium relative to iron for appropriate planet core characteristics.
    • if closer: galactic radiation would be too great; stellar density would disturb planetary orbits; wrong abun-dances of silicon, sulfur, and magnesium relative to iron for appropriate planet core characteristics.
16. parent star distance from closest spiral arm
    • if too large: exposure to harmful radiation from galactic core would be too great.
17. z-axis heights of star’s orbit
    • if more than one: tidal interactions would disrupt planetary orbit of life support planet
    • if less than one: heat produced would be insufficient for life.
18. quantity of galactic dust
    • if too small: star and planet formation rate is inadequate; star and planet formation occurs too late; too much exposure to stellar ultraviolet radiation.
    • if too large: blocked view of the Galaxy and of objects beyond the Galaxy; star and planet formation occurs too soon and at too high of a rate; too many collisions and orbit perturbations in the Galaxy and in the planetary system.
19. number of stars in the planetary system
    • if more than one: tidal interactions would disrupt planetary orbit of life support planet
    • if less than one: heat produced would be insufficient for life.
20. parent star age
    • if older: luminosity of star would change too quickly.
    • if younger: luminosity of star would change too quickly.
21. parent star mass
    • if greater: luminosity of star would change too quickly; star would burn too rapidly.
    • if less: range of planet distances for life would be too narrow; tidal forces would disrupt the life planet’s rota-tional period; uv radiation would be inadequate for plants to make sugars and oxygen.
22. parent star metallicity
    • if too small: insufficient heavy elements for life chemistry would exist.
    • if too large: radioactivity would be too intense for life; life would be poisoned by heavy element concentrations.
23. parent star color
    • if redder: photosynthetic response would be insufficient.
    • if bluer: photosynthetic response would be insufficient.
24. galactic tides
    • if too weak: too low of a comet ejection rate from giant planet region.
    • if too strong too high of a comet ejection rate from giant planet region.
25. H3+ production
    • if too small: simple molecules essential to planet formation and life chemistry will not form.
    • if too large: planets will form at wrong time and place for life.
26. flux of cosmic ray protons
    • if too small: inadequate cloud formation in planet’s troposphere.
    • if too large: too much cloud formation in planet’s troposphere.
27. solar wind
    • if too weak: too many cosmic ray protons reach planet’s troposphere causing too much cloud formation.
    • if too strong: too few cosmic ray protons reach planet’s troposphere causing too little cloud formation.
28. parent star luminosity relative to speciation
    • if increases too soon: runaway green house effect would develop.
    • if increases too late: runaway glaciation would develop.
29. surface gravity (escape velocity)
    • if stronger: planet’s atmosphere would retain too much ammonia and methane.
    • if weaker: planet’s atmosphere would lose too much water.
30. distance from parent star
    • if farther: planet would be too cool for a stable water cycle.
    • if closer: planet would be too warm for a stable water cycle.
31. inclination of orbit
    • if too great: temperature differences on the planet would be too extreme.
32. orbital eccentricity
    • if too great: seasonal temperature differences would be too extreme.
33. axial tilt
    • if greater: surface temperature differences would be too great.
    • if less: surface temperature differences would be too great.
34. rate of change of axial tilt
    • if greater: climatic changes would be too extreme; surface temperature differences would become too extreme.
35. rotation period
    • if longer: diurnal temperature differences would be too great.
    • if shorter: atmospheric wind velocities would be too great.
36. rate of change in rotation period
    • if longer:surface temperature range necessary for life would not be sustained.
    • if shorter:surface temperature range necessary for life would not be sustained.
37. planet age
    • if too young: planet would rotate too rapidly.
    • if too old: planet would rotate too slowly.
38. magnetic field
    • if stronger: electromagnetic storms would be too severe; too few cosmic ray protons would reach planet’s tro-posphere which would inhibit adequate cloud formation.
    • if weaker: ozone shield would be inadequately protected from hard stellar and solar radiation.
39. thickness of crust
    • if thicker: too much oxygen would be transferred from the atmosphere to the crust.
    • if thinner: volcanic and tectonic activity would be too great.
40. albedo (ratio of reflected light to total amount falling on surface)
    • if greater: runaway glaciation would develop.
    • if less: runaway greenhouse effect would develop.
41. asteroidal and cometary collision rate
    • if greater: too many species would become extinct.
    • if less: crust would be too depleted of materials essential for life.
42. mass of body colliding with primordial Earth
    • if smaller: Earth’s atmosphere would be too thick; moon would be too small.
    • if greater: Earth’s orbit and form would be too greatly disturbed.
43. timing of body colliding with primordial Earth.
    • if earlier: Earth’s atmosphere would be too thick; moon would be too small.
    • if later: sun would be too luminous at epoch for advanced life.
44. collision location of body colliding with primordial Earth
    • if too close to grazing: insufficient debris to form large moon; inadequate annihilation of Earth’s primordial at-mosphere; inadequate transfer of heavy elements to Earth.
    • If too close to dead center: damage from collision would be too destructive for future life to survive.
45. oxygen to nitrogen ratio in atmosphere
    • if larger: advanced life functions would proceed too quickly.
    • if smaller: advanced life functions would proceed too slowly.
46. carbon dioxide level in atmosphere
    • if greater: runaway greenhouse effect would develop.
    • if less: plants would be unable to maintain efficient photosynthesis.
47. water vapor level in atmosphere
    • if greater: runaway greenhouse effect would develop.
    • if less: rainfall would be too meager for advanced life on the land.
48. atmospheric electric discharge rate
    • if greater: too much fire destruction would occur.
    • if less: too little nitrogen would be fixed in the atmosphere.
49. ozone level in atmosphere
    • if greater: surface temperatures would be too low.
    • if less: surface temperatures would be too high; there would be too much uv radiation at the surface.
50. oxygen quantity in atmosphere
    • if greater: plants and hydrocarbons would burn up too easily.
    • if less: advanced animals would have too little to breathe.
51. nitrogen quantity in atmosphere
    • if greater: too much buffering of oxygen for advanced animal respiration; too much nitrogen fixation for sup-port of diverse plant species.
    • if less: too little buffering of oxygen for advanced animal respiration; too little nitrogen fixation for support of diverse plant species.
52. ratio of 40K, 235,238U, 232Th to iron for the planet
    • if too low: inadequate levels of plate tectonic and volcanic activity.
    • if too high: radiation, earthquakes, and volcanoes at levels too high for advanced life.
53. rate of interior heat loss
    • if too low: inadequate energy to drive the required levels of plate tectonic and volcanic activity.
    • if too high: plate tectonic and volcanic activity shuts down too quickly.
54. seismic activity
    • if greater: too many life-forms would be destroyed.
    • if less: nutrients on ocean floors from river runoff would not be recycled to continents through tectonics; not enough carbon dioxide would be released from carbonates
55. volcanic activity
    • if lower: insufficient amounts of carbon dioxide and water vapor would be returned to the atmosphere; soil mineralization would become too degraded for life.
    • if higher: advanced life, at least, would be destroyed.
56. rate of decline in tectonic activity
    • if slower: advanced life can never survive on the planet.
    • if faster: advanced life can never survive on the planet.
57. rate of decline in volcanic activity
    • if slower: advanced life can never survive on the planet.
    • if faster: advanced life can never survive on the planet.
58. timing of birth of continent formation
    • if too early: silicate-carbonate cycle would be destabilized.
    • if too late: silicate-carbonate cycle would be destabilized.
59. oceans-to-continents ratio
    • if greater: diversity and complexity of life-forms would be limited.
    • if smaller: diversity and complexity of life-forms would be limited.
60. rate of change in oceans-to-continents ratio
    • if smaller: advanced life will lack the needed land mass area.
    • if greater: advanced life would be destroyed by the radical changes.
61. global distribution of continents (for Earth)
    • if too much in the southern hemisphere: seasonal differences would be too severe for advanced life.
62. frequency and extent of ice ages
    • if smaller: insufficient fertile, wide, and well-watered valleys produced for diverse and advanced life forms; in-sufficient mineral concentrations occur for diverse and advanced life.
    • if greater: planet inevitably experiences runaway freezing.
63. soil mineralization
    • if too nutrient poor: diversity and complexity of life-forms would be limited.
    • if too nutrient rich: diversity and complexity of life-forms would be limited.
64. gravitational interaction with a moon
    • if greater: tidal effects on the oceans, atmosphere, and rotational period would be too severe
    • .if less: orbital obliquity changes would cause climatic instabilities; movement of nutrients and life from the oceans to the continents and vice versa would be insufficent; magnetic field would be too weak.
65. Jupiter distance
    • if greater: too many asteroid and comet collisions would occur on Earth.
    • if less: Earth’s orbit would become unstable.
66. Jupiter mass
    • if greater: Earth’s orbit would become unstable.
    • if less: too many asteroid and comet collisions would occur on Earth.
67. drift in major planet distances
    • if greater: Earth’s orbit would become unstable.
    • if less: too many asteroid and comet collisions would occur on Earth.
68. major planet eccentricities
    • if greater: orbit of life supportable planet would be pulled out of life support zone.
69. major planet orbital instabilities
    • if greater: orbit of life supportable planet would be pulled out of life support zone.
70. mass of Neptune
    • if too small: not enough Kuiper Belt Objects (asteroids beyond Neptune) would be scattered out of the solar system.
    • if too large: chaotic resonances among the gas giant planets would occur.
71. Kuiper Belt of asteroids (beyond Neptune)
    • if not massive enough: Neptune’s orbit remains too eccentric which destabilizes the orbits of other solar system planets.
    • if too massive: too many chaotic resonances and collisions would occur in the solar system.
72. separation distances among inner terrestrial planets
    • if too small: orbits of all inner planets will become unstable in less than 100,000,000 million years.
    • if too large: orbits of the most distant from star inner planets will become chaotic.
73. atmospheric pressure
    • if too small: liquid water will evaporate too easily and condense too infrequently; weather and climate variation would be too extreme; lungs will not function.
    • if too large: liquid water will not evaporate easily enough for land life; insufficient sunlight reaches planetary surface; insufficient uv radiation reaches planetary surface; insufficient climate and weather varia-tion; lungs will not function.
74. atmospheric transparency
    • if smaller: insufficient range of wavelengths of solar radiation reaches planetary surface
    • if greater: too broad a range of wavelengths of solar radiation reaches planetary surface.
75. magnitude and duration of sunspot cycle
    • if smaller or shorter: insufficient variation in climate and weather.
    • if greater or longer: variation in climate and weather would be too much.
76. continental relief
    • if smaller: insufficient variation in climate and weather.
    • if greater: variation in climate and weather would be too much.
77. chlorine quantity in atmosphere
    • if smaller: erosion rates, acidity of rivers, lakes, and soils, and certain metabolic rates would be insufficient for most life forms.
    • if greater: ersosion rates, acidity of rivers, lakes, and soils, and certain metabolic rates would be too high for most life forms.
78. iron quantity in oceans and soils
    • if smaller: quantity and diversity of life would be too limited for support of advanced life; if very small, no life would be possible.
    • if larger: iron poisoning of at least advanced life would result.
79. tropospheric ozone quantity
    • if smaller: insufficient cleansing of biochemical smogs would result.
    • if larger: respiratory failure of advanced animals, reduced crop yields, and destruction of ozone-sensitive spe-cies would result.
80. stratospheric ozone quantity
    • if smaller: too much uv radiation reaches planet’s surface causing skin cancers and reduced plant growth.
    • if larger: too little uv radiation reaches planet’s surface causing reduced plant growth and insufficient vitamin production for animals.
81. mesospheric ozone quantity
    • if smaller: circulation and chemistry of mesospheric gases so disturbed as to upset relative abundances of life essential gases in lowe atmosphere.
    • if greater: circulation and chemistry of mesospheric gases so disturbed as to upset relative abundances of life essential gases in lower atmosphere.
82. quantity and extent of forest and grass fires
    • if smaller: growth inhibitors in the soils would accumulate; soil nitrification would be insufficient; insufficient charcoal production for adequate soil water retention and absorption of certain growth inhibitors.
    • if greater: too many plant and animal life forms would be destroyed.
83. quantity of soil sulfer
    • if smaller: plants will become defieient in certain proteins and die.
    • if larger: plants will die from sulfur toxins; acidity of wate and soil will become too great for life; nitrogen cy-cles will be disturbed.
84. biomass to comet infall ratio
    • if smaller: greenhouse gases accumulate, triggering runaway surface temperature increase.
    • if larger: greenhouse gases decline, triggering a runaway freezing.

Segun el astrofisico Hugh Ross la probabilidad de encontrar un planeta con esas caracteristicas es de 1 en 10^138. En otras palabras es mas probables encontrar un atomo especifico en el universo que un planeta que sustente vida inteligente.

Por lo tanto es mas razonable la explicacion de que la tierra esta diseñada para sostener vida humana en ella.

Cuando analizamos estos argumentos con lo diseño justo del universo el argumento a favor del diseño por lo tanto de la existencia de Dios es infinitamente mas grande que el esceptisismo ateo.

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