Wintery Knight

…integrating Christian faith and knowledge in the public square

What makes a planet suitable for supporting complex life?

The Circumstellar Habitable Zone (CHZ)

What do you need in order to have a planet that supports complex life? First, you need liquid water at the surface of the planet. But there is only a narrow range of temperatures that can support liquid water. It turns out that the size of the star that your planet orbits around has a lot to do with whether you get liquid water or not. A heavy, metal-rich star allows you to have a habitable planet far enough from the star so  the planet can support liquid water on the planet’s surface while still being able to spin on its axis. The zone where a planet can have liquid water at the surface is called the circumstellar habitable zone (CHZ). A metal-rich star like our Sun is very massive, which moves the habitable zone out further away from the star. If our star were smaller, we would have to orbit much closer to the star in order to have liquid water at the surface. Unfortunately, if you go too close to the star, then your planet becomes tidally locked, like the moon is tidally locked to Earth. Tidally locked planets are inhospitable to life.

Circumstellar Habitable Zone

Circumstellar Habitable Zone

Here, watch a clip from The Privileged Planet: (Clip 4 of 12, full playlist here)

But there’s more.

The Galactic Habitable Zone (GHZ)

So, where do you get the heavy elements you need for your heavy metal-rich star?

You have to get the heavy elements for your star from supernova explosions – explosions that occur when certain types of stars die. That’s where heavy elements come from. But you can’t be TOO CLOSE to the dying stars, because you will get hit by nasty radiation and explosions. So to get the heavy elements from the dying stars, your solar system needs to be in the galactic habitable zone (GHZ) – the zone where you can pickup the heavy elements you need but not get hit by radiation and explosions. The GHZ lies between the spiral arms of a spiral galaxy. Not only do you have to be in between the arms of the spiral galaxy, but you also cannot be too close to the center of the galaxy. The center of the galaxy is too dense and you will get hit with massive radiation that will break down your life chemistry. But you also can’t be too far from the center, because you won’t get enough heavy elements because there are fewer dying stars the further out you go. You need to be in between the spiral arms, a medium distance from the center of the galaxy.

Like this:

Galactic Habitable Zone

Galactic Habitable Zone and Solar Habitable Zone

Here, watch a clip from The Privileged Planet: (Clip 10 of 12, full playlist here)

The GHZ is based on a discovery made by astronomer Guillermo Gonzalez, which made the front cover of Scientific American in 2001. That’s right, the cover of Scientific American. I actually stole the image above of the GHZ and CHZ (aka solar habitable zone) from his Scientific American article (linked above).

These are just a few of the things you need in order to get a planet that supports life.

Here are a few of the more well-known ones:

  • 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

By the way, you can watch a lecture with Guillermo Gonzalez explaining his ideas further. This lecture was delivered at UC Davis in 2007. That link has a link to the playlist of the lecture, a bio of the speaker, and a summary of all the topics he discussed in the lecture. An excellent place to learn the requirements for a suitable habitat for life.

Filed under: Polemics, , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Astronomer Guillermo Gonzalez lectures on intelligent design and habitability

The 5 video clips that make up the full lecture.

The playlist for all 5 clips is here.

About the speaker

Guillermo Gonzalez is an Associate Professor of Physics at Grove City College. He received his Ph.D. in Astronomy in 1993 from the University of Washington. He has done post-doctoral work at the University of Texas, Austin and at the University of Washington and has received fellowships, grants and awards from such institutions as NASA, the University of Washington, the Templeton Foundation, Sigma Xi (scientific research society) and the National Science Foundation.

Learn more about the speaker here.

The lecture

Here’s part 1 of 5:

And the rest are here:

Topics:

  • What is the Copernican Principle?
  • Is the Earth’s suitability for hosting life rare in the universe?
  • Does the Earth have to be the center of the universe to be special?
  • How similar to the Earth does a planet have to be to support life?
  • What is the definition of life?
  • What are the three minimal requirements for life of any kind?
  • Requirement 1: A molecule that can store information (carbon)
  • Requirement 2: A medium in which chemicals can interact (liquid water)
  • Requirement 3: A diverse set of chemical elements
  • What is the best environment for life to exist?
  • Our place in the solar system: the circumstellar habitable zone
  • Our place in the galaxy: the galactic habitable zones
  • Our time in the universe’s history: the cosmic habitable age
  • Other habitability requirements (e.g. – metal-rich star, massive moon, etc.)
  • The orchestration needed to create a habitable planet
  • How different factors depend on one another through time
  • How tweaking one factor can adversely affect other factors
  • How many possible places are there in the universe where life could emerge?
  • Given these probabilistic resources, should we expect that there is life elsewhere?
  • How to calculate probabilities using the “Product Rule”
  • Can we infer that there is a Designer just because life is rare? Or do we need more?

The corelation between habitability and measurability.

  • Are the habitable places in the universe also the best places to do science?
  • Do the factors that make Earth habitable also make it good for doing science?
  • Some places and times in the history of the universe are more habitable than others
  • Those exact places and times also allow us to make scientific discoveries
  • Observing solar eclipses and structure of our star, the Sun
  • Observing stars and galaxies
  • Observing the cosmic microwave background radiation
  • Observing the acceleration of the universe caused by dark matter and energy
  • Observing the abundances of light elements like helium of hydrogen
  • These observations support the big bang and fine-tuning arguments for God’s existence
  • It is exactly like placing observatories on the tops of mountains
  • There are observers existing in the best places to observe things
  • This is EXACTLY how the universe has been designed for making scientific discoveries

This lecture was delivered by Guillermo Gonzalez in 2007 at the University of California at Davis.

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Walter Bradley: three scientific evidences that point to a designed universe

Dr. Walter L. Bradley

Dr. Walter L. Bradley

Dr. Walter L. Bradley (C.V. here) is the Distinguished Professor of Engineering at Baylor.

Here’s a bio:

Walter Bradley (B.S., Ph.D. University of Texas at Austin) is Distinguished Professor of Engineering at Baylor. He comes to Baylor from Texas A&M University where he helped develop a nationally recognized program in polymeric composite materials. At Texas A&M, he served as director of the Polymer Technology Center for 10 years and as Department Head of Mechanical Engineering, a department of 67 professors that was ranked as high as 12th nationally during his tenure. Bradley has authored over 150 refereed research publications including book chapters, articles in archival journals such as the Journal of Material Science, Journal of Reinforced Plastics and Composites, Mechanics of Time-Dependent Materials, Journal of Composites Technology and Research, Composite Science and Technology, Journal of Metals, Polymer Engineering and Science, and Journal of Materials Science, and refereed conference proceedings.

Dr. Bradley has secured over $5.0 million in research funding from NSF grants (15 yrs.), AFOSR (10 years), NASA grants (10 years), and DOE (3 years). He has also received research grants or contracts from many Fortune 500 companies, including Alcoa, Dow Chemical, DuPont, 3M, Shell, Exxon, Boeing, and Phillips.

He co-authored The Mystery of Life Origin: Reassessing Current Theories and has written 10 book chapters dealing with various faith science issues, a topic on which he speaks widely.

He has received 5 research awards at Texas A&M University and 1 national research award. He has also received two teaching awards. He is an Elected Fellow of the American Society for Materials and the American Scientific Affiliation (ASA), the largest organization of Christians in Science and Technology in the world. He is President elect of the ASA and will serve his term in 2008.

You can read more about his recent research in this article from Science Daily.

Below, I analyze a 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.

The MP3 file is here.

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 NOT 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 non-theistic response to this argument is to postulate a multiverse, but that is very speculative and there is no experimental evidence that supports 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 non-theistic response to this argument is to postulate a hyper-universe outside of ours, but that is very speculative and there is no experimental evidence that supports 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 non-theistic response to this is to speculate that aliens may have seeded the Earth with life at some point in the past.

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.

Filed under: Podcasts, , , , , , , , , , , , , , , , , , , , , ,

Scientists troubled by lack of simple explanation for our life-permitting moon

This entire article from Evolution News is a must-read. It talks about a recent paper by a naturalist named Robin Canup which appeared in Nature, the most prestigious peer-reviewed science journal.

So, there’s too much to quote here. I’ll grab a few snippets to give you the gist of it, then you click through and read the whole thing. 

The moon is important for the existence of a life permitting planet:

Canup knows our moon is important for life:

The Moon is more than just a familiar sight in our skies. It dictates conditions on Earth. The Moon is large enough to stabilize our planet’s rotation, holding Earth’s polar axis steady to within a few degrees. Without it, the current Earth’s tilt would vary chaotically by tens of degrees. Such large variationsmight not preclude life, but would lead to a vastly different climate.

The moon requires an improbable sequence of events:

Canup states that “No current impact model stands out as more compelling than the rest.” All are equally improbable, in other words. Indeed, they are:

It remains troubling that all of the current impact models invoke a process after the impact to effectively erase a primary outcome of the event — either by changing the disk’s composition through mixing for the canonical impact, or by changing Earth’s spin rate for the high-angular-momentum narratives.

Sequences of events do occur in nature, and yet we strive to avoid such complexity in our models. We seek the simplest possible solution, as a matter of scientific aesthetics and because simple solutions are often more probable. As the number of steps increases, the likelihood of a particular sequence decreases. Current impact models are more complex and seem less probable than the original giant-impact concept.

This is a good challenge to naturalism, but it lends support to one part of the habitability argument.

Previously, I blogged about a few of the minimum requirements that a planet must satisfy in order to support complex life.

Here they are:

  • 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

This is a good argument, so if you want to learn more about it, get the “The Privileged Planet” DVD, or the book of the same name.

Filed under: News, , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

How Earth-like are the 8.8 billion Earth-like planets from a recent estimate?

Previously, I blogged about a few of the minimum requirements that a planet must satisfy in order to support complex life.

Here they are:

  • 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

Now what happens if we disregard all of that, and just classify an Earth-like planet as one which only has to potentially support liquid water at the surface? Well, you get a very high estimate of Earth-like planets.

Science journalist Denyse O’Leary responds to a recent estimate based on this questionable criterion, which placed the number of Earth-like planets at 8.8 billion.

Excerpt: (links removed)

A current official definition of habitable planets is “in the zone around the star where liquid water could exist,” but the ones discovered so far are unsuitable in many other ways.

Then a new cosmology term hit the media, “super-Earths.” It means “bigger than Earth,” but smaller than gas giant Neptune. Super-Earths could be the most numerous type of planet, in tight orbits around their star — which is actually bad news for life.Nonetheless, some insist, they may be more attractive to life than Earth is. Indeed, the Copernican Principle allows us to assume that some are inhabited already.

In reality, even the rocky exoplanets (known as of early 2013) that are Earth-sized are not Earth-like. For example, the Kepler mission’s first rocky planet find is described as follows: “Although similar in size to Earth, its orbit lasts just 0.84 days, making it likely that the planet is a scorched, waterless world with a sea of lava on its starlit side.” As space program physicist Rob Sheldon puts it, Earth is a rocky planet but so is a solid chunk of iron at 1300 degrees orbiting a few solar radii above the star. In any event, a planet may look Earth-like but have a very different internal structure and atmosphere.”

David Klinghoffer notes that the study is estimating that 8.8 billion number, but the actual number of Earth-like planets we can see is much lower.

He writes:

The study is supposed to be a major step forward because of its unprecedented accuracy:

For the first time, scientists calculated — not estimated — what percent of stars that are just like our sun have planets similar to Earth: 22 percent, with a margin of error of plus or minus 8 percentage points.

Oh! You see, they calculated. They didn’t just estimate.

Because there are probably hundreds of planets missed for every one found, the study did intricate extrapolations to come up with the 22 percent figure — a calculation that outside scientists say is fair.

Oh. They calculated in the sense of “extrapolating” to “come up” with a figure. In other words, they estimated. The figure of “8.8 billion stars with Earth-size planets in the habitable temperature zone” comes down a bit too when you talk about actual planets that have been observed instead of being merely conjectured and “calculated.”

Scientists at a Kepler science conference Monday said they have found 833 new candidate planets with the space telescope, bringing the total of planets they’ve spotted to 3,538, but most aren’t candidates for life.

Kepler has identified only 10 planets that are about Earth’s size circling sun-like stars and are in the habitable zone, including one called Kepler 69-c.

Ah hah. So from the initial, trumpets-blaring figure of 8.8 billion we’re down more realistically to 10. Not 10 billion, just 10. Meanwhile the silence from space continues absolutely unabated.

That’s the way it tends to go with stories like this, the blaring headline and the inevitable letdown.

One part of the AP press release makes the point that the estimate does not include all the minimum requirements for life. For example, you need an atmosphere, as I stated above. Do the estimated 8.8 billion Earth-like planets have an Earth-like atmosphere? How about an oxygen-rich atmosphere, do the 8.8 billion Earth-like planets have that?

NO:

The next step, scientists say, is to look for atmospheres on these planets with powerful space telescopes that have yet to be launched. That would yield further clues to whether any of these planets do, in fact, harbor life.

You know, after the whole global warming hoax, you would think that these headline writers would have learned their lesson about sensationalizing wild-assed guesses in order to scare up more research money. But a lot of true-believing naturalists are just going to read the headline and not the rest of the article, and they will never know that they’ve been had. Again. I love experimental science, but I don’t love the politicization of science. 

Filed under: Polemics, , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

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