Tag Archives: Habitability

Dr. Walter Bradley lectures on scientific evidence the creation and design of the universe

This lecture is special to me, because I bought a VHS tape of it just after I started working full-time, and watched it a million times. A lot of people come to their convictions about God’s existence because of parents or church or intuitions, but for me it’s all about the scientific evidence. This lecture changed my life. I wish more people taught their children about this evidence! This lecture was delivered at the University of California, Santa Barbara.

About the speaker:

Dr. Bradley received his B.S. in Engineering Science and his Ph.D. in Materials Science from the University of Texas in Austin.

Dr. Bradley taught for eight years at the Colorado School of Mines before assuming a position as Professor of Mechanical Engineering at Texas A&M University (TAMU) in 1976.

During his 24 years at Texas A&M, Dr. Bradley served as Head of the Department of Mechanical Engineering at Texas A&M University and as Director of the Polymer Technology Center, and received five College of Engineering Research Awards. He has received over $4,500,000 in research grants and has published over 140 technical articles and book chapters. He has also co-authored “The Mystery Of Life’s Origin: Reassessing Current Theories. He is a Fellow of the American Society for Materials and of the American Scientific Affiliation and serves as a consultant for many Fortune 500 companies.

He currently serves as Distinguished Professor of Engineering at Baylor University.

The lecture: (63 minutes lecture, 25 minutes audience Q&A)

Summary slide:

This slide summarizes the content of the lecture
This slide summarizes the content of the lecture


  • At the beginning of the 20th century, people believed that the progress of science was pointing away from an intelligent Creator and Designer, and towards naturalism
  • A stream of new discoveries has shifted the support of science towards theism, and away from naturalism
  • Richard Dawkins, an atheist, says that nature only has the appearance of design, but that if you look closer, naturalistic mechanisms can account for the appearance of design
  • When deciding between design and apparent design (“designoid”), it matters whether you think there is an intelligence there to do the designing

Evidence #1: The Big Bang:

  • an eternal “steady state” universe is more compatible with naturalism, but a created universe is more compatible with a Creator
  • In 1929, Hubble used telescopes to observe that the light from distant galaxies was redshifted. The further away galaxies were, the faster they were moving away. Therefore, space is expanding in all directions, suggesting an explosive origin of the universe
  • In 1965, the discovery of the cosmic microwave background radiation matched a prediction of the Big Bang cosmology, and of the creation event
  • In 1992, the COBE space telescope allowed us to test four specific predictions of the Big Bang model, especially the predictions for light element abundances (hydrogen and helium), which matched the predictions of the creation model

Evidence #2: Simple mathematical structure of the physical laws

  • the simple mathematical structure of natural laws allows us to understand these laws, make discoveries, and engineer solutions to problems
  • early scientists saw the mathematical structure of the universe to mean that nature was designed by an intelligent to be understood
  • the fundamental equations of the laws of the universe can be easily written on one side of one sheet of paper
  • Eugene Wigner’s famous paper, “The Unreasonable Effectiveness of Mathematics in the Physical Sciences” makes the point that this simple structure is an unexpected gift that allows is to do science

Evidence #3: fine-tuning of the physical constants and quantities

  • in order for any kind of complex life to survive, we need stars that provide energy within specific ranges for long periods of time
  • in order for any kind of complex life to survive, we need planets with stable orbits that will not suffer from extreme temperature swings as it varies in distance from its star
  • in order for any kind of complex life to survive, we need stable atomic structure
  • in order for any kind of complex life to survive, we need to have chemical diversity and correct relative abundances of each element
  • organic life has minimum requirements: process energy, store information, replicate, and you can’t fulfill those functions if there is only one element, e.g. – hydrogen
  • the energy level from the photons from the sun have to match the energy levels of the different elements in order to drive the chemical bonding needed for life
  • These requirements for life of any imaginable type depend on the values of the constants and quantities. The constants and quantities cannot vary much from what they are, or the universe will lose the characteristics (above) that allow it to support complex life of any imaginable time
  • For example, ratio of strong force to electromagnetic force:
    – if 2% larger, then no stable hydrogen, no long-lived stars, no compounds containing hydrogen, e.g. – water
    – if 5% smaller, no stable stars, heavy hydrogen would be unstable, few elements other than hydrogen

Evidence #4: initial conditions for habitability

  • Universe: expansion rate of the universe must be fast enough to avoid a re-collapse, but slow enough to allow matter to clump together and form stars and planets for complex life to live on
  • Planet: right distance from the star to get the right climate
  • Planet: right mass to retain the right atmosphere

Evidence #5: origin of life and information theory

  • It’s possible to explain every process in an automobile engine using plain old naturalistic mechanisms – no supernatural explanation is necessary to understand the processes
  • But the existence of engine itself: engineering all the parts has to be explained by the work of an intelligence
  • Similarly, we can understand how living systems work, but the existence of the living systems requires an intelligence
  • Even the simplest living system has to perform minimal function: capture energy, store information and replicate
  • Living systems are composed of objects like proteins that are composed of sequences of components complex such that the order of the components gives the overall structure function
  • Developing the components for a simple living cell is very improbable – even given the large number of galaxies, stars and planets in the universe, it is unlikely that complex, embodied life would exist anywhere in the universe

Evidence #6: more initial conditions for habitability

  • Location within the galaxy: you need to be away from the center of the galaxy, because the explosions from dying stars, and excessive radiation will kill life
  • Location within the galaxy: you need to be close enough to the center in order catch the heavy elements you need for life from the explosions of other stars
  • Location within the galaxy: the best location is between two arms of  a spiral galaxy, where you can get the heavy elements you need from dying stars, but without being hit with explosions and harmful radiation
  • Star mass: determines rate at which the sun burns, determines the energy level of photons that are used to drive chemical bonding reactions, determines the length of time the star will be stable
  • Star mass: star mass must be the correct value in order to allow liquid water on the planet’s surface, while still preserving stable orbit

I wish there was more curiosity about science in churches, and young Christians understood how critical science is for grounding the rationality of the Christian worldview. We need to be training up more scientists who think about the big questions, like Dr. Walter Bradley.

Brian Auten interviews Jay Richards about Christian apologetics

Recently, I picked up the audio book version of “The Privileged Planet”, which is a book by philosopher / economist Jay Richards and astronomer Guillermo Gonzalez. This book is different from books about the origin of the universe and cosmic fine-tuning. It talks about what it takes to make a habitable planet. And it talks about how the habitable places in the universe are also the best places to make scientific discoveries.

Christian scholar Jay Richards was interviewed by Brian Auten of Apologetics 315.

The MP3 file is here.


  • What is intelligent design (ID)?
  • Is ID specifically Christian?
  • How does ID helpful to Christian apologetics?
  • What does ID prove?
  • Is it OK to use an argument that doesn’t prove Christianity specifically?
  • What is the difference between deism and theism?
  • Do ID arguments get you to deism or theism?
  • What is materialism, and how can you challenge it?
  • How do opponents of ID define ID?
  • What factors do you need to make a habitable planet?
  • Are habitable planets common or rare in the universe?
  • What is “The Privileged Planet” hypothesis?
  • Is there an overlap between habitability and suitability for making scientific discoveries?
  • What is the “Copernican Principle”?
  • Has the progress of science made Earth seem common and ordinary?
  • What is the most Earth-like planet that we’ve ever discovered?
  • How should ID proponents respond to the objection that creatures aren’t perfect?
  • Does having a big moon make a planet more or less habitable?
  • Does a planet’s distance to the Sun make that planet more or less habitable?
  • How do these two habitability factors affect the observability of solar eclipses?
  • What does co-relation between habitability and “discoverability” tell us about God?
  • How important is training in philosophy to Christian apologetics?
  • What one thing should a Christian apologist work on to be more effective?

If you’d like to learn more about his book “The Privileged Planet”, you can find out more here. I recently bought the audio book version of the book.

Study: galactic habitable zone depends on fine-tuning of cosmological constant

The galactic habitable zone (GHZ) is shown in green against a spiral galaxy
The galactic habitable zone (GHZ) is shown in green superimposed on a spiral galaxy

This is going to be old news to readers of this blog who are familiar with the Michael Strauss, Walter Bradley and Guillermo Gonzalez lectures on habitability and fine-tuning. But, it’s nice to see these ideas show up in one of the most prestigious peer-reviewed science journals in the world (if not the most prestigious).

Here’s the article from Science.

It says:

Scientists have known for several years now that stars, galaxies, and almost everything in the universe is moving away from us (and from everything else) at a faster and faster pace. Now, it turns out that the unknown forces behind the rate of this accelerating expansion—a mathematical value called the cosmological constant—may play a previously unexplored role in creating the right conditions for life.

That’s the conclusion of a group of physicists who studied the effects of massive cosmic explosions, called gamma ray bursts, on planets. They found that when it comes to growing life, it’s better to be far away from your neighbors—and the cosmological constant helps thin out the neighborhood.

“In dense environments, you have many explosions, and you’re too close to them,” says cosmologist and theoretical physicist Raul Jimenez of the University of Barcelona in Spain and an author on the new study. “It’s best to be in the outskirts, or in regions that have not been highly populated by small galaxies—and that’s exactly where the Milky Way is.”

Jimenez and his team had previously shown that gamma ray bursts could cause mass extinctions or make planets inhospitable to life by zapping them with radiation and destroying their ozone layer. The bursts channel the radiation into tight beams so powerful that one of them sweeping through a star system could wipe out planets in another galaxy. For their latest work, published this month in Physical Review Letters, they wanted to apply those findings on a broader scale and determine what type of universe would be most likely to support life.

The research is the latest investigation to touch on the so-called anthropic principle: the idea that in some sense the universe is tuned for the emergence of intelligent life. If the forces of nature were much stronger or weaker than physicists observe, proponents note, crucial building blocks of life—such fundamental particles, atoms, or the long-chain molecules needed for the chemistry of life—might not have formed, resulting in a sterile or even completely chaotic universe.

Basically, the best place for a galaxy that permits complex, embodied life to exist is one where you can pick up enough heavy elements from dying stars nearby, but not be in an area that is so crowded by stars that you will be murdered by intense gamma radiation when they die.

The cosmological constant has to be set just right that we spread out enough to make space between spiral arms for life-permitting solar systems, but no so spread out that we cannot pick up the heavy elements we need for a metal-rich star, a moon, and the bodies of the intelligent agents themselves.


As it turns out, our universe seems to get it just about right. The existing cosmological constant means the rate of expansion is large enough that it minimizes planets’ exposure to gamma ray bursts, but small enough to form lots of hydrogen-burning stars around which life can exist. (A faster expansion rate would make it hard for gas clouds to collapse into stars.)

Jimenez says the expansion of the universe played a bigger role in creating habitable worlds than he expected. “It was surprising to me that you do need the cosmological constant to clear out the region and make it more suburbanlike,” he says.

Remember, this is only one of many characteristics that must obtain in order for a have a location in the universe that can support complex, embodied life of any conceivable kind.

Let’s review the big picture

Time for me to list out some of the things that are required for a galaxy, solar system and planet to support complex embodied life. Not just life as we know it, but life of any conceivable kind given these laws of physics.

  • 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

It’s not easy to make a planet that supports life. For those who are interested in reaching out to God, he has left us an abundance of evidence for his existence – and his attention to detail.

Oh, and there’s also a circumstellar habitable zone:

Circumstellar Habitable Zone
Circumstellar Habitable Zone

And remember, these requirements for a habitable planet are downstream from the cosmic fine-tuning of constants and quantities that occurs at the Big Bang. No point in talking about the need for plate tectonics if you only have hydrogen in your universe. The habitability requirements are a further problem that comes after the fine-tuning problem.


The best book to read on this topic is “The Privileged Planet“, by Guillermo Gonzalez and Jay W. Richards. The latter is one of my absolute favorite Christian scholars, a real renaissance man. If the book is too much, there is a DVD by the same name that covers everything you need to know at a high level. Just FYI, Gonzalez made the cover of Scientific American in 2001, for his research on habitable zones. This is real evidence you can discuss with anyone, anywhere.

You can also watch the DVD for FREE on YouTube. Not sure how long that will be there. If you like it, buy the DVD, so you can show your friends.

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