Tag Archives: Habitability

Is the probability of getting a universe that supports complex life 100%?

Apologetics and the progress of science
Apologetics and the progress of science

Let’s have a quick review of the famous fine-tuning argument to start.

The argument from cosmic fine-tuning looks at various constants and quantities in our universe that are set at particular values and notes that if any of the values of these constants and quantities were to change, then complex embodied life of any kind could not exist. The argument is fully in line with the standard Big Bang cosmology, and is based on mainstream science.

There are two kinds of finely-tuned initial conditions: 1) constants and 2) quantities. These constants and quantities have to be set within a narrow range in order to permit intelligent life. There are three explanations for this observation: law, chance or design. Law is rejected because the numerical values of constants and quantities are set at the beginning of the universe – when there was no matter, space or time. The values of the constants and quantities were not determined by anything causally prior to the moment the universe began to exist. Chance is not a good explanation, because the probabilities are far, far too small for us to reasonably believe them (e.g. – the chance is 1 in X, where X is much higher than the number of subatomic particles in the visible universe). Since the fine-tuning is not due to law or chance, it must be due to design.

Here’s one example of something that is set correctly to allow complex, embodied life from The New Scientist:

The feebleness of gravity is something we should be grateful for. If it were a tiny bit stronger, none of us would be here to scoff at its puny nature.

The moment of the universe‘s birth created both matter and an expanding space-time in which this matter could exist. While gravity pulled the matter together, the expansion of space drew particles of matter apart – and the further apart they drifted, the weaker their mutual attraction became.

It turns out that the struggle between these two was balanced on a knife-edge. If the expansion of space had overwhelmed the pull of gravity in the newborn universe, stars, galaxies and humans would never have been able to form. If, on the other hand, gravity had been much stronger, stars and galaxies might have formed, but they would have quickly collapsed in on themselves and each other. What’s more, the gravitational distortion of space-time would have folded up the universe in a big crunch. Our cosmic history could have been over by now.

Only the middle ground, where the expansion and the gravitational strength balance to within 1 part in 1015 at 1 second after the big bang, allows life to form.

Changing the value at all means there would be no complex, embodied life of any kind anywhere in this universe.

Here’s a quick video clip to explain what The New Scientist is saying:

Now, this is going to surprise you, but there are some non-theists who try to argue that the finely-tuned constants and quantities that were set up at the beginning of the universe – long before we ever existed – are actually explained by our existence today. 

Atheist Jeffery Lowder summarizes a debate between William Lane Craig and Doug Jesseph, and Jesseph says something like this:

Craig’s argument is like asking the question, “What are your chances of landing in a universe hospitable to life, assuming you were tossed into any old universe whatever.” That is precisely not the point. It’s presupposed in the question that you’re already in a universe which favors life. Confuses conditional probability with unconditional probability.

Unlike me, Lowder is never snarky in his summaries, so this is guaranteed to be accurate.

Here’s what Dr. William Lane Craig says to that idea that our being here explains the fine-tuning:

Now some people have tried to avoid this conclusion by saying that we really shouldn’t be surprised at the enormous improbability of the fine-tuning of the universe because, after all, if the universe were not fine-tuned then we wouldn’t be here to be surprised about it. Given that we are here we should expect the universe to be fine-tuned. But I think the fallacy of this reasoning can be made clear simply by a parallel illustration. Imagine that you were traveling abroad in a third world country and you were arrested on trumped up drug charges, and you were dragged in front of a firing squad of 100 trained marksmen, all with rifles aimed at your heart to be executed. And you hear the command given – “Ready, aim, fire!” And you hear the deafening roar of the guns. And then you observe that you are still alive, that all of the 100 marksmen missed! Now, what would you conclude? Well, I guess I really shouldn’t be surprised that they all missed; after all, if they hadn’t all missed I wouldn’t be here to be surprised about it. Given that I am here, I should expect them all to miss. Of course not. You would immediately suspect that they all missed on purpose. That the whole thing was a set up engineered by some person for some reason. And in exactly the same way, given the incomprehensible improbability of the fine-tuning of the initial conditions for intelligent life, it is rational to believe that this is not the result of chance but of design.

Does it make sense? It’s true that any arrangement of bullet holes in a condemned spy is as unlikely as any other, but the vast majority of possible arrangements of 100 bullet holes result in you being dead. Being marksmen, the shooters definitely know how to hit a target at close range. It doesn’t matter if some hit your head and some hit your heart and some hit your throat – the most common consequence of a hundred bullets fired by expert marksmen at you is “dead you” – regardless of the specific arrangement of bullet holes. If you find yourself not dead, that requires an explanation. The explanation is design.

Four ways the Earth is fine-tuned for life, and one more

Circumstellar Habitable Zone
Circumstellar Habitable Zone

This is a post from J. Warner Wallace, over at Cold Case Christianity.

Let’s see his four ways first, then I’ll add one that I know.

He writes:

  1. The Earth’s Relationship to the Sun Is Favorable to Life
  2. The Earth’s Atmospheric Conditions Are Favorable to Life
  3. The Earth’s Terrestrial Nature Is Favorable to Life
  4. The Earth’s Relationship to the Moon Is Favorable to Life

I’ve blogged about the moon and plate tectonics before, so we won’t pick #3 and #4 to look at. And I blogged about the stellar habitable zone before, so we won’t pick #1, either.

Let’s look at #2:

The Earth’s Atmospheric Conditions Are Favorable to Life:
The surface gravity of Earth is critical to its ability to retain an atmosphere friendly to life. If Earth’s gravity were stronger, our atmosphere would contain too much methane and ammonia. If our planet’s gravity were weaker, Earth wouldn’t be able to retain enough water. As it is, Earth’s atmosphere has a finely calibrated ratio of oxygen to nitrogen—just enough carbon dioxide and adequate water vapor levels to promote advanced life, allow photosynthesis (without an excessive greenhouse effect), and to allow for sufficient rainfall.

Ok, that’s very good.

Now here is one from me… well, it’s from Science Daily, but I found it. Actually, ECM found it. But he told me.

Excerpt:

They suggest that the size and location of an asteroid belt, shaped by the evolution of the Sun’s protoplanetary disk and by the gravitational influence of a nearby giant Jupiter-like planet, may determine whether complex life will evolve on an Earth-like planet.

This might sound surprising because asteroids are considered a nuisance due to their potential to impact Earth and trigger mass extinctions. But an emerging view proposes that asteroid collisions with planets may provide a boost to the birth and evolution of complex life.

Asteroids may have delivered water and organic compounds to the early Earth. According to the theory of punctuated equilibrium, occasional asteroid impacts might accelerate the rate of biological evolution by disrupting a planet’s environment to the point where species must try new adaptation strategies.

The astronomers based their conclusion on an analysis of theoretical models and archival observations of extrasolar Jupiter-sized planets and debris disks around young stars. “Our study shows that only a tiny fraction of planetary systems observed to date seem to have giant planets in the right location to produce an asteroid belt of the appropriate size, offering the potential for life on a nearby rocky planet,” said Martin, the study’s lead author. “Our study suggests that our solar system may be rather special.”

So, that’s 5 ways that the Earth and our solar system are fine-tuned to be habitable for complex, embodied minds. Somebody is looking out for you, so be thankful and recognize.

 

The connection between our moon, plate tectonics and habitability

Christianity and the progress of science
Christianity and the progress of science

I found an interview with Peter Ward (atheist) and Donald Brownlee (agnostic) discussing astrobiology in Forbes magazine. They were asked about how important plate tectonics are for a planet to be able to support complex life.

Excerpt:

Astrobiologists often cite the sheer numbers of stars and galaxies as evidence that complex life elsewhere must surely have evolved somewhere. But is probability enough?

Without a moon, we don’t have any idea of how commonly a planet could have the long-term stability needed for complex life. Until we “get” that, going to the sheer numbers argument is useless. Without that moon-forming collision, we wouldn’t have plate tectonics. Without plate tectonics, we might have microbes but we’d never get to animals.

What about the rarity of earth’s crustal dichotomy of oceans and continents?

If you can’t make granite, you’re not going to have continents. But granite formation is a consequence of our moon-forming collision. That scrambled the entire density of our crust. Mars doesn’t have granite; all it’s got is this volcanic basalt. To build granite you need a planetary subduction [or plate tectonic] process.

In triggering complex life, how important were plate tectonics’ role in the continual recycling of earth’s atmosphere?

It’s this recycling that allows for a very rich planetary atmosphere with an extended life. Photosynthesis gets you oxygen, but how do you get enough photosynthesis to get oxygen at 10 to 20 percent? You’ve got to have a shoreline next to a rich sea with rocks eroding into it in order to provide the nitrogen and phosphates for [plant] photosynthesis.

This article from Astrobiology explains more about the importance of plate tectonics.

Excerpt:

Plate tectonics is the process of continents on the Earth drifting and colliding, rock grinding and scraping, mountain ranges being formed, and earthquakes tearing land apart. It makes our world dynamic and ever-changing. But should it factor into our search for life elsewhere in the universe?

Tilman Spohn believes so. As director of the German Space Research Centre Institute of Planetary Research, and chairman of ESA’s scientific advisory committee, he studies worlds beyond our Earth. When looking into the relationship between habitability and plate tectonics, some fascinating possibilities emerged.

It is thought that the best places to search for life in the Universe are on planets situated in “habitable zones” around other stars. These are orbital paths where the temperature is suitable for liquid water; not so close to the star that it boils away, and not so far that it freezes. Spohn believes that this view may be outdated. He elaborates, “you could have habitats outside those, for instance in the oceans beneath ice covers on the Galilean satellites, like Europa. But not every icy satellite would be habitable. Take Ganymede, where the ocean is trapped between two layers of ice. You are missing a fresh supply of nutrition and energy.”

So planets and moons that lie beyond habitable zones could host life, so long as the habitat, such as an ocean, is not isolated. It needs access to the key ingredients of life, including hydrogen, oxygen, nitrogen, phosphorous and sulphur. These elements support the basic chemistry of life as we know it, and the material, Spohn argues, must be regularly replenished. Nature’s method of achieving this on the Earth appears to be plate tectonics.

Spohn found that the further he delved into the issue, the more important plate tectonics seemed to be for life. For example, it is believed that life developed by moving from the ocean to the kind of strong and stable rock formations that are the result of tectonic action. Plate tectonics is also involved in the generation of a magnetic field by convection of Earth’s partially molten core. This magnetic field protects life on Earth by deflecting the solar wind. Not only would an unimpeded solar wind erode our planet’s atmosphere, but it also carries highly energetic particles that could damage DNA.

Another factor is the recycling of carbon, which is needed to stabilize the temperature here on Earth. Spohn explains, “plate tectonics is known to recycle carbon that is washed out of the atmosphere and digested by bacteria in the soil into the interior of the planet from where it can be outcast through volcanic activity. Now, if you have a planet without plate tectonics, you may have parts of this cycle, but it is broken because you do not have the recycling link.”

It has also been speculated that the lack of tectonic action on Venus contributed to its runaway greenhouse effect, which resulted in the immense temperatures it has today.

Most planets don’t have a moon as massive as ours is, and the collision that formed the moon is very fine-tuned for life. This is just one of the many factors that needs to be present in order to have a planet that supports complex, carbon-based life.

If you want to learn more about this data, I recommend watching “The Privileged Planet” DVD, and someone posted it on YouTube:

If you haven’t seen it, and have 90 minutes, this is time well-spent.

New 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 presitigious peer-reviewed science journals in the world (if not the most presitigious).

Here’s the article from Science. (H/T Gunter)

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.

More:

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.

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.

Resources

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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New study: survey of 700 quintillion terrestrial exoplanets suggests Earth is special

The Circumstellar Habitable Zone, where liquid water could potentially exist
The Circumstellar Habitable Zone, where liquid water could potentially exist

This is from Scientific American. (H/T William)

Excerpt:

More than 400 years ago Renaissance scientist Nicolaus Copernicus reduced us to near nothingness by showing that our planet is not the center of the solar system. With every subsequent scientific revolution, most other privileged positions in the universe humans might have held dear have been further degraded, revealing the cold truth that our species is the smallest of specks on a speck of a planet, cosmologically speaking. A new calculation of exoplanets suggests that Earth is just one out of a likely 700 million trillion terrestrial planets in the entire observable universe. But the average age of these planets—well above Earth’s age—and their typical locations—in galaxies vastly unlike the Milky Way—just might turn the Copernican principle on its head.

Astronomer Erik Zackrisson from Uppsala University and his colleagues created a cosmic compendium of all the terrestrial exoplanets likely to exist throughout the observable universe, based on the rocky worlds astronomers have found so far. In a powerful computer simulation, they first created their own mini universe containing models of the earliest galaxies. Then they unleashed the laws of physics—as close as scientists understand them—that describe how galaxies grow, how stars evolve and how planets come to be. Finally, they fast-forwarded through 13.8 billion years of cosmic history. Their results, published to the preprint server arXiv (pdf) and submitted to The Astrophysical Journal, provide a tantalizing trove of probable exoplanet statistics that helps astronomers understand our place in the universe.

Discover magazine, which is all in for Darwinism and aliens everywhere, says this about the study:

Zackrisson found that Earth appears to have been dealt a fairly lucky hand. In a galaxy like the Milky Way, for example, most of the planets Zackrisson’s model generated looked very different than Earth — they were larger, older and very unlikely to support life.

[…]Zackrisson’s work suggests an alternative to the commonly held assumption that planets similar to Earth must exist, based on the sheer number of planets out there.

[…]One of the most fundamental requirements for a planet to sustain life is to orbit in the “habitable zone” of a star — the “Goldilocks” region where the temperature is just right and liquid water can exist. Astronomers have, to this point, discovered around 30 exoplanets in the habitable zones of stars. Simply extrapolating that figure based on the known number of stars suggests that there should be about 50 billion such planets in the Milky Way alone. Probability seems to dictate that Earth-twins are out there somewhere.

But according to Zackrisson, most planets in the universe shouldn’t look like Earth. His model indicates that Earth’s existence presents a mild statistical anomaly in the multiplicity of planets. Most of the worlds predicted by his model exist in galaxies larger than the Milky Way and orbit stars with different compositions — an important factor in determining a planet’s characteristics. His research indicates that, from a purely statistical standpoint, Earth perhaps shouldn’t exist.

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.

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