Perfectly Suited for Life (as we know it)

The universe, what is known of it, is vast beyond measure.  It is estimated that there are about 100 billion galaxies in the universe with each containing about 100 billion stars each.  Among all of those stars, one medium sized star hosts eight or nine planets, one of which we call home – Earth – a tiny speck of dust in a measureless universe.

That’s the opening of the latest post to appear on the ICR’s Your Origins Matter website, What’s So Special About our Blue Planet? The planet Earth being perfect for life – and that there is none like it in the universe – is a common creationist argument. You’d think, then, that the author of this YOM article could have done some research and not just written down what sounded about right. “Eight or nine planets” indeed – we can’t have those astronomers telling us what is and isn’t a planet now can we?

But what makes Earth so special?  For one thing, Earth is perfectly suited for life as we know it.  Some scientists, however, find it difficult to believe that Earth is the only planet in the entire universe capable of supporting life.  For that reason, they spend billions of dollars “listening” for intelligence “out there” somewhere, or sending probes to Mars to find evidence that life once existed there or maybe still exists in one form or another.  They probe the stars for evidence of habitable planets, but to date, no evidence for life has been found anywhere other than here on our beautiful blue planet.

We have in the Earth a single data point. Is there other life in our universe? We simply can’t tell from the evidence available, and so we go looking for more. We spend many trillions blowing ourselves up, so perhaps checking to see if there’s anyone out there pointing and laughing is money well spent?

So what makes earth so special and especially suited for life?

YOM has a short list, and it’s this that seems to have been poorly researched:

The average surface temperature of Earth, according to NASA figures, is 15°C (59°F).  Three main reasons for this are:

  • Earth’s distance from the sun – not too close, not too far
  • The tilt of Earth’s axis (23.5°) that gives us our seasons
  • The rotation of the earth once every 24 hours helps maintain an even temperature

I would not have picked rotation in there – any rotation would do that, there really is nothing special about the period of time we have arbitrarily declared to be 24 hours. What I would have picked is the composition of the atmosphere, which is what brings that figure of 15°C up above freezing.

But they do remember it for their next item, at least:

Earth’s atmosphere is a perfect blend of gasses: Nitrogen (78%), Oxygen (21%), Argon (<1%) and Carbon Dioxide (0.03%). They are essential for sustaining life and protecting us from harmful radiation.

The implicit claim in this is that the precise percentages matter. The amount of oxygen and carbon dioxide in the atmosphere especially has been known to vary significantly over the ages, and of course the percentage of CO2 is increasing of late. In other words, they’re not completely fixed – life, at least, will go on.

How much of a role does the atmosphere have in protecting us from radiation? The ozone layer certainly does, as well as the magnetic field (not mentioned) – I suppose the atmosphere as a whole must contribute, though I don’t know quite how much.

The density of our atmosphere is ideal for insulating us from the coldness of space.

Earth’s diameter also factors directly into the density of the atmosphere.

  • A larger diameter would increase the density of the atmosphere and increase Earth’s temperatures.
  • A smaller diameter would decrease the density of the atmosphere and make the earth colder.

The correlation between size and atmosphere can’t be perfect, as both Venus and Titan (above) have much thicker atmospheres than we do. Much of the way that a change in diameter would change the atmosphere is to do with the planet’s formation and evolution over billions of years. God could probably have given us almost as thick an atmosphere as he wanted to, irrespective of diameter and other considerations, if he only needed it to stick around a few thousand years. Our atmosphere is built to last.

Water is a rare compound in space, but it is abundant here on earth.

  • Liquid water has unique chemical and physical properties making it ideal as the primary component of life.
  • As the universal solvent, water makes it possible for essential nutrients needed for life to be dissolved and assimilated.
  • Water’s transparency makes it possible for ocean plant life to perform photosynthesis below the surface and for ocean animals to see through the water.
  • Water expands when it freezes, keeping our rivers, lakes and oceans from freezing from the bottom up.
  • Water captures and retains solar heat thereby absorbing more of the sun’s energy than equal areas of land.  This helps maintain Earth’s average temperatures.
  • Ocean currents caused by the earth’s rotation serve to circulate seawater and prevent the equatorial seas from becoming too hot and the polar seas from becoming too cold and freezing completely.

Water – at least in non-liquid states – is quite common in the universe. It’s in that third state here due to our position in the solar system (along with other factors influencing temperature), already covered. The other items are just natural consequences of the underlying properties of the substance.

Earth’s continents cover less than one-third of our planet’s surface.  If we were to scrape off the continents and place them in the deeper parts of the ocean to make an earth of common elevation, we would have an earth covered with approximately 8,000 feet of water!  That is something to consider next time someone questions the feasibility of a global flood!

The problem with that explanation of the flood is that a scraping of the continents is not what the biblical account describes. The “two-thirds water” element to our planet has the consequence of preventing human habitation on the majority of the surface. We can’t live on much of the land to boot – neither Antarctica nor the Himalayan peaks are particularly habitable.

Of the four inner planets in our solar system, only Earth has a moon.

  • The moon is the perfect size and distance from the earth
  • Its size and distance make for perfect eclipses, providing a precise time record confirming the chronological systems employed by O.T. scribes.
  • The moon’s gravitational pull on the earth gives us our tides which prosper ocean life and cleanse the shorelines.

Mars has two moons, of course, but they aren’t like ours. In fact, no planet in the solar system has a moon quite like ours, though the dwarf planet Pluto comes quite close with its moon Charon. Our moon’s orbit is elliptical, which means that on some occasions total solar eclipses aren’t quite total due to the moon appearing slightly smaller or larger than the Sun. The upshot of this, of course, is that there is quite a bit of give to the size and orbital distance the moon needs to have to produce perfect eclipses at least some of the time.

I was unaware that eclipses confirm “the chronological systems employed by O.T. scribes” – I suspect they don’t. Eclipses are mentioned in the Bible, of course, but there is no decent chronology there for them to ‘confirm.’ Other cultures, however, do have such chronologies, and these would appear to go back too far for Ussher.

Tides are tides, you get them to some degree with any sized moon. Over the millennia the moon has been drifting further away – and the Earth’s rotation has slowed – which means that in the past the tides have been much more intense than they are now. There was life then, there is life now.

The final item touches on the water cycle:

Earth’s weather patterns and water cycle ensure that the land is watered regularly.

Again, that’s really a natural consequence of convection and other processes. Titan has a methane cycle, we have a water cycle.

The post concludes:

So much more could be said about our incredible home.  It would seem that it was designed specifically with man in mind.

Psalm 19:1 says, “The heavens declare the glory of God; And the firmament shows His handiwork.” Can you give specific examples of this?

This whole article is an example of Douglas Adams’ puddle. It’s not that the Earth is perfectly designed for us, but that we are adapted for the Earth. An omnipotent God could have created us so that we didn’t need to breathe oxygen, that we didn’t need protection from things that until recently we didn’t even know existed (radiation, asteroids). But we do need those things, and we have evolved to rely upon them.

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4 thoughts on “Perfectly Suited for Life (as we know it)

  1. It is amazing to me that there are PEOPLE who find it so amazing to THEM to find life in environs naturally suited for the life found thriving there; for ME what would be amazing (and therefore require special explanation) would be to find life in environs naturally UNsuitable for the life found thriving there! And so, is Earth’s physical environment “fine-tuned” to the life that thrives here, or is the live that thrives here “fine-tuned” (evolutionarily adapted) to Earth’s physical environment? Seems like a no-brainer to me, especially in view of the mountain of diverse empirical evidence of life’s natural history on Earth.

  2. Good to see you thinking through these ideas Peter. No-one is ever going to change the thought patterns of those in the ICR that write this stuff, but if you treat it as an exercise in logical thinking and fact checking, you can always craft a useful opportunity for your own development.
    I wrote a little piece relevant to the anthropic universe idea recently myself – you might be interested in taking a look to hone some of your counter arguments on this score – http://rockysubjects.wordpress.com/2012/10/10/i-wouldnt-start-from-here-gina-historical-contingency-and-the-anthropic-principle/

    All the best

  3. “Its size and distance make for perfect eclipses, providing a precise time record confirming the chronological systems employed by O.T. scribes.”

    Pardon me?

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