Tag Archives: Habitability

Polemics

What conditions are needed to create a habitable planet?

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UPDATE: Welcome, visitors from Post-Darwinist! Thanks for the link Denyse! New visitors may be interested in this post, which is a jumping off point for all of posts on science and faith issues.

Everyone who isn’t Christopher Hitchens or Richard Dawkins already knows about the standard fine-tuning argument. But have you ever considered what it takes to make a planet that is capable of supporting the minimal requirements of living systems? The area of science that specializes in answering this question is called astrobiology. Let’s take a look!

I will be working from a lecture (with Q&A) delivered in October 2007 at California State University – Fresno, by two of my favorite scholars, Jay Wesley Richards and Guillermo Gonzalez.

The Copernican Principle

Richards introduces the idea of the Copernican Principle. This principle states that the progress of science will show that there is nothing special (designed) about man’s place in the universe.

The minimal requirements for life

I’ve written about this before here, but basically life requires a minimum amount of encoded biological information to allow it to replicate itself. The only element in the periodic table that allows you to encode information is carbon. Carbon is the hub of large molecules which form the paper and text of biological information. No carbon = no life.

Secondly, you need some environment in which to form molecules around the carbon, such as amino acids and proteins. That environment is liquid water. And you need the liquid water to be at the surface the planet where you want life to exist.

The requirements of a habitable planet

Here are just a few of the requirements mentioned in the lecture.

  • a solar system with a single massive Sun than can serve as a long-lived, stable source of energy
  • a terrestrial planet (non-gaseous)
  • the planet must be the right distance from the sun in order to preserve liquid water at the surface – if it’s too close, the water is burnt off in a runaway greenhouse effect, if it’s too far, the water is permanently frozen in a runaway glaciation
  • the solar system must be placed at the right place in the galaxy – not too near dangerous radiation, but close enough to other stars to be able to absorb heavy elements after neighboring stars die
  • a moon of sufficient mass to stabilize the tilt of the planet’s rotation
  • plate tectonics
  • an oxygen-rich atmosphere
  • a sweeper planet to deflect comets, etc.
  • planetary neighbors must have non-eccentric orbits

Note that these requirements are connected. If you mess with one, some of the others will be thrown out of tune. For more habitability requirements, see this article by Gonzalez and Richards.

What are the probabilities that we will get these conditions?

Richards explains that the question of whether this is designed is like winning the lottery. Your chance of winning depends on two things:

  1. the odds of getting all the conditions correct
  2. the number of tries that you get

If the odds of winning are 1 in a million, you could still win by buying a million tickets with all the different numbers. In the universe, there are only about 10^22 possible solar systems. So if the odds of getting a habitable planet are 1 in 10^9, you’ll get tons of life. But what if the odds are 1 in 10^40? Then you’re not likely to win.

But this is not the argument that these two are making, because even though there are a lot of factors needed for a habitable planet, we still can’t say for certain how likely it is that each of these conditions will obtain. Therefore, we can’t make the argument except by estimating the odds of getting each condition.

Although you could use very generous estimates, it would still be guessing, and you can win a debate by guessing. So are we stuck?

How to make a design argument using habitability

Gonzalez explains why you can still make an argument for design by arguing that the coorelation between habitability and measurabiliy is intentional. (By measurability, he really means the ease of making scientific discoveries). And you do this by correlating the conditions for sustaining life with the conditions for allowing scientific discoveries.

Gonzalez gives two examples:

  1. Solar eclipses require that the sun and moon have certain sizes and certain distances from the sun. The surface of the Earth is the optimal location in our solar system for observing solar eclipses. We were able to make many valuable discoveries due to this fine-tuning, not the least of which was confirming the theory of general relativity, which was cruicial to the science of cosmology.
  2. The location of our solar system is fine-tuned within two spiral arms of a spiral galaxy. We escape from radiation and other dangers, but to also allow use to capture heavy elements that are needed to make a suitable Sun and humans bodies, too. But the same conditions that allow life also allow us to make scientific discoveries, such as star formation theory and cosmic microwave background radiation measurements, which was needed in order to confirm the creation of the universe out of nothing (the big bang).

Spooky. And what until they list off a half-dozen more examples in their book “The Privileged Planet”. It’s downright terrifying!

Conclusion

Richards sums up the argument with an illustration. He asks why scientists construct observatories high up on mountains. The answer is in order to avoid “light pollution” from nearby cities, which ruin the ability of scientists to observe the stars and make discoveries. And this is what we see with our planet and solar system. No one builds a planet that can be used to make scientific discoveries in a place that doesn’t support life. It turns out that the very places in the universe that are good for making observations are also the best places for supporting life.

Further study

I would recommend checking out the documentary DVD, if you find the book too scary. There is also a university lecture DVD with both authors, filmed at Biola University. If you want to see the DVD online for FREE, then click here (narrated by John-Rhys Davies). Awesome! Go science!

Polemics

Is there scientific evidence for an intelligent designer?

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Dr. Walter L. Bradley
Dr. Walter L. Bradley

Dr. Walter L. Bradley (C.V. here) is the Distinguished Professor of Engineering at Baylor, and a great example of the integration of Christian faith and a stellar academic career. He is not a “secret-service” Christian. Rejecting the notion of safe, private Christianity, he instead projects his Christian faith outward, where his students and colleagues can be aware of his beliefs.

Below I analyze a lecture I chose from the hundreds of public lectures he has given all over the world on the integration of Christian faith with other public, testable areas of knowledge. In this lecture, entitled “Is There Scientific Evidence for an Intelligent Designer?“, Dr. Bradley explains how the progress of science has made the idea of a Creator and Designer of the universe more acceptable than ever before.

Evidence #1: The design of the universe

1. The correspondence of natural phenomena to mathematical law

  • All observations of physical phenomena in the universe, such as throwing a ball up in the air, are described by a few simple, elegant mathematical equations.

2. The fine-tuning of physical constants and rations between constants in order to provide a life-permitting universe

  • Life has certain minimal requirements; long-term stable source of energy, a large number of different chemical elements, an element that can serve as a hub for joining together other elements into compounds, etc.
  • In order to meet these minimal requirements, the physical constants, (such as the gravitational constant), and the ratios between physical constants, need to be withing a narrow range of values in order to support the minimal requirements for life of any kind.
  • Slight changes to any of the physical constants, or to the rations between the constants, will result in a universe inhospitable to life.
  • The range of possible ranges over 70 orders of magnitude.
  • Although each individual selection of constants and ratios is as unlikely as any other selection, the vast majority of these possibilities do not support the minimal requirements of life of any kind. (In the same way as any hand of 5 cards that is dealt is as likely as any other, but you are overwhelmingly likely NOT to get a royal flush. In our case, a royal flush is a life-permitting universe).

Examples of finely-tuned constants and ratios: (there are more examples in the lecture)

a) The strong force: (the force that binds nucleons (= protons and neutrons) together in nucleus, by means of meson exchange)

  • if the strong force constant were 2% stronger, there would be no stable hydrogen, no long-lived stars, no hydrogen containing compounds. This is because the single proton in hydrogen would want to stick to something else so badly that there would be no hydrogen left!
  • if the strong force constant were 5% weaker, there would be no stable stars, few (if any) elements besides hydrogen. This is because you would be able to build up the nuclei of the heavier elements, which contain more than 1 proton.
  • So, whether you adjust the strong force up or down, you lose stars than can serve as long-term sources of stable energy, or you lose chemical diversity, which is necessary to make beings that can perform the minimal requirements of living beings. (see below)

b) The conversion of beryllium to carbon, and carbon to oxygen

  • Life requires carbon in order to serve as the hub for complex molecules, but it also requires oxygen in order to create water.
  • Carbon is like the hub wheel in a tinker toy set: you can bind other elements together to more complicated molecules (e.g. – “carbon-based life), but the bonds are not so tight that they can’t be broken down again later to make something else.
  • The carbon resonance level is determined by two constants: the strong force and electromagnetic force.
  • If you mess with these forces even slightly, you either lose the carbon or the oxygen.

3. Fine-tuning to allow a habitable planet

  • A number of factors must be fine-tuned in order to have a planet that supports life
  • Initial estimates predicted abundant life in the universe, but revised estimates now predict that life is almost certainly unique in the galaxy, and probably unique in the universe.
  • Even though there are lots of stars in the universe, the odds are against any of them supporting complex life.
  • Here are just a few of the minimal requirements for habitability: must be a single star solar system, in order to support stable planetary orbits, the planet must be the right distance from the sun in order to have liquid water at the surface, the planet must sufficient mass in order to retain an atmosphere, etc.

The best current atheist response to this is to speculate that there may be an infinite number of unobservable and untestable universes. (I.e. – the Flying Spaghetti Monster did it)

Evidence #2: The origin of the universe

1. The progress of science has shown that the entire physical universe came into being out of nothing (= “the big bang”). It also shows that the cause of this creation event is non-physical and non-temporal. The cause is supernatural.

  • Atheism prefers an eternal universe, to get around the problem of a Creator having to create the universe.
  • Discovery #1: Observations of galaxies moving away from one another confirms that the universe expanded from a single point.
  • Discovery #2: Measurements of the cosmic background radiation confirms that the universe exploding into being.
  • Discovery #3: Predictions of elemental abundances prove that the universe is not eternal.
  • Discovery #4:The atheism-friendly steady-state model and oscillating model were both falsified by the evidence.
  • And there were other discoveries as well, mentioned in the lecture.

The best atheistic response to this is to speculate that there is an unobservable and untestable hyper-universe outside our own. (I.e. – the Flying Spaghetti Monster did it)

Evidence #3: The origin of life

1. The progress of science has shown that the simplest living organism contains huge amounts of biological information, similar to the Java code I write all day at work. This is a problem for atheists, because the sequence of instructions in a living system has to come together all at once, it cannot have evolved by mutation and selection – because there was no replication in place prior to the formation of that first living system!

  • Living systems must support certain minimum life functions: processing energy, storing information, and replicating.
  • There needs to be a certain amount of complexity in the living system that can perform these minimum functions.
  • But on atheism, the living system needs to be simple enough to form by accident in a pre-biotic soup, and in a reasonable amount of time.
  • The minimal functionality in a living system is a achieved by DNA, RNA and enzymes. DNA and RNA are composed of sequences of proteins, which are in turn composed of sequences of amino acids.

Consider the problems of building a chain of 100 amino acids

  • The amino acids must be left-handed only, but left and right kinds are equally abundant in nature. How do you sort out the right-handed ones?
  • The amino acids must be bound together using peptide bonds. How do you prevent other types of bonds?
  • Each link of the amino acid chain needs to be carefully chosen such that the completed chain with fold up into a protein. How do you choose the correct amino acid for each link from the pool of 20 different kinds found in living systems?
  • In every case, a human or other intelligence could solve these problems by doing what intelligent agents do best: making choices.
  • But who is there to make the choices on atheism?

The best current atheistic response to this is to speculate that unobservable and untestable aliens seeded the earth with life. (I.e. – the Flying Spaghetti Monster did it)

The problem of the origin of life is not a problem of chemistry, it is a problem of engineering. Every part of car functionality can be understood and described using the laws of physics and chemistry. But an intelligence is still needed in order to assemble the components into a system that has the minimal requirements for a functioning vehicle.

Conclusion

In all three areas, scientists expected that the data would be consistent with atheism. First, scientists expected that life could exist even if the physical constants and ratios were altered. The progress of science said NO. Second, scientists expected that the universe would be eternal. The progress of science said NO. Third, scientists expected that the origin of life would be simple. The progress of science said NO.