Tag Archives: Habitability

What conditions support the minimum requirements for 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.

Guillermo Gonzalez lectures at UC Davis on the requirements for life

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:

Habitability 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.

What is intelligent design?

Dr. Stephen C. Meyer explains the concept of intelligent design in a lecture, with lots of visual aids.

He is also the author of “Signature in the Cell“, the best book on intelligent design. (A Times Literary Supplement Book of the Year selection)

Related DVDs

Illustra also made two other great DVDs on intelligent design. The first two DVDs “Unlocking the Mystery of Life” and “The Privileged Planet” are must-buys, but you can watch them on youtube if you want, for free.

Here are the 2 playlists:

I also recommend “Darwin’s Dilemma”. All three of these are on sale from Amazon.com.

Three ways that the progress of science conflicts with naturalistic speculations

I just got into a debate with some atheists recently on whether the progress of science is more compatible with theism or atheism. (People who have friended me on Facebook got to see me in action)

I offered the Facebook atheists 3 arguments:

  1. the kalam argument from the origin of the universe
  2. the cosmic fine-tuning (habitability) argument
  3. the argument from information in the first replicator (origin of life)

These arguments are all supported by scientific evidence:

  1. An explanation of 3 of the 6 experimental evidences for the Big Bang cosmology (From an article from Caltech)
  2. Examples of cosmic fine-tuning (there at least 40 examples of cosmic fine-tuning), (From the New Scientist)
  3. Evidence that functional protein sequences are beyond the reach of chance, (from Doug Axe’s JMB article)

They replied to my 3 arguments with 3 points of their own:

  1. Maybe the Big Bang cosmology will be overturned by the Big Crunch/Bounce so that the universe is eternal and has no cause
  2. Maybe there is a multiverse: an infinite number of unobservable, untestable universes which makes our finely-tuned one more probable
  3. Maybe the origin of life could be the result of chance and natural processes

Ever heard any of these?

Below I list some resources to help you to respond to the 3 points from the Facebook atheists.

1) The Big Crunch/Bounce has been disproved theoretically and experimentally.

Theoretically:

Nature 302, 505 – 506 (07 April 1983); doi:10.1038/302505a0

The impossibility of a bouncing universe

ALAN H. GUTH* & MARC SHER†

*Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

†Department of Physics, University of California, Irvine, California 92717, USA

Petrosian1 has recently discussed the possibility that the restoration of symmetry at grand unification in a closed contracting Robertson–Walker universe could slow down and halt the contraction, causing the universe to bounce. He then went on to discuss the possibility that our universe has undergone a series of such bounces. We disagree with this analysis. One of us (M.S.) has already shown2 that if a contracting universe is dominated by radiation, then a bounce is impossible. We will show here two further results: (1) entropy considerations imply that the quantity S (defined in ref. 1 and below), which must decrease by ~1075 to allow the present Universe to bounce, can in fact decrease by no more than a factor of ~2; (2) if the true vacuum state has zero energy density, then a universe which is contracting in its low temperature phase can never complete a phase transition soon enough to cause a bounce.

Experimentally:

The universe is not only expanding, but that expansion appears to be speeding up. And as if that discovery alone weren’t strange enough, it implies that most of the energy in the cosmos is contained in empty space — a concept that Albert Einstein considered but discarded as his “biggest blunder.” The new findings have been recognized as 1998’s top scientific breakthrough by Science magazine.

[…]The flood of findings about the universe’s expansion rate is the result of about 10 years of study, said Saul Perlmutter, team leader of the Supernova Cosmology Project at Lawrence Berkeley National Laboratory.

Perlmutter and others found such a yardstick in a particular kind of exploding star known as a Type 1A supernova. Over the course of several years, the astronomers developed a model to predict how bright such a supernova would appear at any given distance. Astronomers recorded dozens of Type 1A supernovae and anxiously matched them up with redshifts to find out how much the universe’s expansion was slowing down.

To their surprise, the redshift readings indicated that the expansion rate for distant supernovae was lower than the expansion rate for closer supernovae, Perlmutter said. On the largest scale imaginable, the universe’s galaxies appear to be flying away from each other faster and faster as time goes on.

“What we have found is that there is a ‘dark force’ that permeates the universe and that has overcome the force of gravity,” said Nicholas Suntzeff of the Cerro Tololo Inter-American Observatory, who is the co-founder of another group called the High-z Supernova Search Team. “This result is so strange and unexpected that it perhaps is only believable because two independent international groups have found the same effect in their data.”

There has only been one creation of the universe, and the universe will never reverse its expansion, so that it could oscillate eternally. That view is popular, perhaps in part because many people watched videos of Carl Sagan speculating about it in public school classrooms, but all it was was idle naturalistic speculation, (Sagan was a naturalist, and held out hope that science would vindicate naturalism), and has been contradicted by good experimental science. You should be familiar with the 3 evidences for the Big Bang (redshift, light element abundances (helium/hydrogen) and the cosmic microwave background radiation. There are others, (radioactive element abundances, second law of thermodynamics, stellar lifecycle), but those are the big three. Point out how the experimental evidence for the Big Bang has piled up, making the problem even worse for the eternal-universe naturalists. Leave no doubt.

2) The multiverse has not been tested experimentally, it’s pure speculation.

Speculation:

Multiverse thinking or the belief in the existence of parallel universes is more philosophy or science fiction than science. ”Cosmology must seem odd to scientists in other fields”.

George Ellis, a well-known mathematician and cosmologist, who for instance has written a book with Stephen Hawking, is sceptical of the idea that our universe is just another universe among many others.

A few weeks ago, Ellis, professor emeritus of applied mathematics at the University of Cape Town, reviewed Brian Greene’s book The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos (Knopf/Allen Lane, 2011) in the journal Nature. He is not at all convinced that the multiverse hypothesis is credible: ”Greene is not presenting aspects of a known reality; he is telling of unproven theoretical possibilities.”

According to professor Ellis, there is no evidence of multiverses, they cannot be tested and they are not science.

Ellis is not the only multiverse sceptic in this universe. A few months ago, science writer John Horgan wrote a column in Scientific American, expressing his doubt in multiverses.

When you get into a debate, you must never ever let the other side get away with asserting something they have no evidence for. Call them on it – point out that they have no evidence, and then hammer them with evidence for your point. Pile up cases of fine-tuning on top of each other and continuously point out that they have no experimental evidence for their speculations. Point out that more evidence we get, the more cases of fine-tuning we find, and the tougher the problem gets for naturalists. Leave no doubt.

3) Naturalistic theories for the origin of life have two problems: can’t make the amino acids in an oxydized atmosphere and can’t make protein and DNA sequences by chance in the time available.

Building blocks:

The oxidation state of Hadean magmas and implications for early Earth’s atmosphere

Dustin Trail, E. Bruce Watson & Nicholas D. Tailby

Nature 480, 79–82 (01 December 2011) doi:10.1038/nature10655

[…]These results suggest that outgassing of Earth’s interior later than ~200?Myr into the history of Solar System formation would not have resulted in a reducing atmosphere.

Functional protein sequences:

J Mol Biol. 2004 Aug 27;341(5):1295-315.

Estimating the prevalence of protein sequences adopting functional enzyme folds.

Axe DD.

The Babraham Institute, Structural Biology Unit, Babraham Research Campus, Cambridge CB2 4AT, UK. doug.axe@bbsrc.ac.uk

Proteins employ a wide variety of folds to perform their biological functions. How are these folds first acquired? An important step toward answering this is to obtain an estimate of the overall prevalence of sequences adopting functional folds.

[…]Starting with a weakly functional sequence carrying this signature, clusters of ten side-chains within the fold are replaced randomly, within the boundaries of the signature, and tested for function. The prevalence of low-level function in four such experiments indicates that roughly one in 10(64) signature-consistent sequences forms a working domain. Combined with the estimated prevalence of plausible hydropathic patterns (for any fold) and of relevant folds for particular functions, this implies the overall prevalence of sequences performing a specific function by any domain-sized fold may be as low as 1 in 10(77), adding to the body of evidence that functional folds require highly extraordinary sequences.

So atheists are in double jeopardy here. They don’t have a way to build the Scrabble letters needed for life, and they don’t have a way to form the Scrabble letters into words and sentences. Point out that the more research we do, the tougher the problem gets to solve for naturalists, and the more it looks like an effect of intelligence. Write out the calculations for them. Leave no doubt.

I do think it’s important for Christians to focus more on scientific apologetics and to focus their academic careers in scientific fields. So often I look at Christian blogs, and I see too much G. K. Chesterton and other postmodern stuff. We need to bring the hard science, and stop making excuses about not being able to understand it because it’s too hard. It’s not too hard. Everyone can understand “Who Made God?” by Edgar Andrews – start with that! Then get Lee Strobel’s “The Case for a Creator“. That’s more than enough for the average Christian on science apologetics. We all have to do our best to learn what works. You don’t want to be anti-science like atheists are.