Tag Archives: Life

Fine-tuning the habitable zone: tidal-locking and solar flares

Circumstellar Habitable Zone
Circumstellar Habitable Zone

Here’s an article from Evolution News that talks about liquid water and tidal locking, but it has even more factors that need to be fine-tuned for habitability.

Excerpt:

Stars with masses of 0.1-0.5 solar mass make up 75 percent of the stars in our Milky Way galaxy.6 These represent the red dwarfs, the M class. But these stars have low effective temperatures, and thus emit their peak radiation at longer wavelengths (red and near-infrared).7 They can have stable continuously habitable zones over long time scales, up to 10 billion years, barring other disruptions. It is also easier to detect terrestrial sized planets around them.8 But a serious problem with red dwarf stars in the K and M classes is their energetic flares and coronal mass ejection events. Potentially habitable planets need to orbit these stars closer, to be in these stars’ habitable zones. Yet the exposure to their stellar winds and more frequent and energetic flares becomes a serious issue for habitability. Because of these stars’ smaller mass, ejections get released with more violence.9 Any planet’s atmosphere would be subject to this ionizing radiation, and likely expose any surface life to much more damaging radiation.10 The loss of atmospheres in these conditions is likely, but the timescales are dependent on several factors including the planet’s mass, the extent of its atmosphere, the distance from the parent star, and the strength of the planet’s magnetic field.11 To protect its atmosphere for a long period, like billions of years, a planet with more mass and thus higher gravity could hold on to the gases better. But this larger planet would then hold on to lighter gases, like hydrogen and helium, and prevent an atmosphere similar to Earth’s from forming.12 Another consequence is that the increased surface pressure would prevent water from being in the liquid phase.13

So again, you need to have a huge, massive star in order to hold the planet in orbit over LONG distances. If it’s a short distance, you not only have the tidal-locking problem, but you also have this solar activity problem (flares, coronal ejections).

But wait! There’s more:

Another stellar parameter for advanced life has to do with UV (ultra-violet) radiation. The life-support star must provide just enough UV radiation, but not too much. UV radiation’s negative effects on DNA are well known, and any life support body must be able to sustain an atmosphere to shield them. Yet the energy from UV radiation is also needed for biochemical reactions. So life needs enough UV radiant to allow chemical reactions, but not so much as to destroy complex carbon molecules like DNA. Just this flux requirement alone requires the host star have a minimum stellar mass of 0.6 solar masses, and a maximum mass of 1.9 solar masses.14

So the ultra-violet radiation that is emitted has to be finely-tuned. (I’m guessing this assumes some sort of chemical origin-of-life scenario)

Still more:

Another requirement for habitable planets is a strong magnetic field to prevent their atmosphere from being lost to the solar winds. Planets orbiting a red dwarf star are also more affected by the star’s tidal effects, slowing the planet’s rotation rate. It is thought that strong magnetic fields are generated in part by the planet’s rotation.15 If the planet is tidally braked, then any potential for a significant magnetic field is likely to be seriously degraded. This will lead to loss of water and other gases from the planet’s atmosphere to the stellar winds.16 We see this in our solar system, where both Mercury and Venus, which orbit closer to the Sun than Earth, have very slow rotation rates, and very modest magnetic fields. Mercury has very little water, and surprisingly, neither does Venus. Even though Venus has a very dense atmosphere, it is very dry. This is due to UV radiation splitting the water molecules when they get high in the atmosphere, and then the hydrogen is lost to space, primarily, again, by solar wind.17

You have to hold on to your umbrella (atmosphere), or you get hit with dangerous rain (solar winds).

So a few more factors there, and remember, this is just the tip of the iceberg when it comes to circumstellar habitability constraints.

Six reasons why you should believe in non-physical souls

This podcast is a must-listen. Please take the time to download this podcast and listen to it. I guarantee that you will love this podcast. I even recommended it to my Dad and I almost never do that.

Details:

In this podcast, J. Warner examines the evidence for the existence of the mind (and inferentially, the soul) as he looks at six classic philosophical arguments. Jim also briefly discusses Thomas Nagel’s book, Mind and Cosmos and discusses the limitations of physicalism.

The MP3 file is here. (67 MB, 72 minutes)

Topics:

  • Atheist Thomas Nagel’s latest book “Mind and Cosmos” makes the case that materialism cannot account for the evidence of mental phenomena
  • Nagel writes in this recent New York Times article that materialism cannot account for the reality of consciousness, meaning, intention and purpose
  • Quote from the Nagel article:

Even though the theistic outlook, in some versions, is consistent with the available scientific evidence, I don’t believe it, and am drawn instead to a naturalistic, though non-materialist, alternative. Mind, I suspect, is not an inexplicable accident or a divine and anomalous gift but a basic aspect of nature that we will not understand until we transcend the built-in limits of contemporary scientific orthodoxy.

  • When looking at this question, it’s important to not have our conclusions pre-determined by presupposing materialism or atheism
  • If your mind/soul doesn’t exist and you are a purely physical being then that is a defeater for Christianity, so we need to respond
  • Traditionally, Christians have been committed to a view of human nature called “dualism” – human beings are souls who have bodies
  • The best way* to argue for the existence of the soul is using philosophical arguments

The case:

  • The law of identity says that if A = B’ if A and B have the exact same properties
  • If A = the mind and B = the brain, then is A identical to B?
  • Wallace will present 6 arguments to show that A is not identical to B because they have different properties

Not everyone of the arguments below might make sense to you, but you will probably find one or two that strike you as correct. Some of the points are more illustrative than persuasive, like #2. However, I do find #3, #5 and #6 persuasive.

1) First-person access to mental properties

  • Thought experiment: Imagine your dream car, and picture it clearly in your mind
  • If we invited an artist to come and sketch out your dream car, then we could see your dream car’s shape on paper
  • This concept of your dream car is not something that people can see by looking at your brain structure
  • Physical properties can be physically accessed, but the properties of your dream care and privately accessed

2) Our experience of consciousness implies that we are not our bodies

  • Common sense notion of personhood is that we own our bodies, but we are not our bodies

3) Persistent self-identity through time

  • Thought experiment: replacing a new car with an old car one piece at a time
  • When you change even the smallest part of a physical object, it changes the identity of that object
  • Similarly, your body is undergoing changes constantly over time
  • Every cell in your body is different from the body you had 10 years ago
  • Even your brain cells undergo changes (see this from New Scientist – WK)
  • If you are the same person you were 10 years ago, then you are not your physical body

4) Mental properties cannot be measured like physical objects

  • Physical objects can be measured (e.g. – use physical measurements to measure weight, size, etc.)
  • Mental properties cannot be measured

5) Intentionality or About-ness

  • Mental entities can refer to realities that are physical, something outside of themselves
  • A tree is not about anything, it just is a physical object
  • But you can have thoughts about the tree out there in the garden that needs water

6) Free will and personal responsibility

  • If humans are purely physical, then all our actions are determined by sensory inputs and genetic programming
  • Biological determinism is not compatible with free will, and free will is required for personal responsibility
  • Our experience of moral choices and moral responsibility requires free will, and free will requires minds/souls

He spends the last 10 minutes of the podcast responding to naturalistic objections to the mind/soul hypothesis.

*Now in the podcast, Wallace does say that scientific evidence is not the best kind of evidence to use when discussing this issue of body/soul and mind/brain. But I did blog before about two pieces of evidence that I think are relevant to this discussion: corroborated near-death experiences and mental effort.

You might remember that Dr. Craig brought up the issue of substance dualism, and the argument from intentionality (“aboutness”), in his debate with the naturalist philosopher Alex Rosenberg, so this argument about dualism is battle-ready. You can add it to your list of arguments for Christian theism along with all the other arguments like the Big Bang, the fine-tuning, the origin of life, stellar habitability, galactic habitability, irreducible complexity, molecular machines, the Cambrian explosion, the moral argument, the resurrection, biological convergence, and so on.

Guillermo Gonzalez lectures on the corelation between habitability and discoverability

There are 5 video clips that make up the full lecture, which took place in 2007 at the University of California, Davis.

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.

Click here to learn more about the speaker.

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 argument from the “discoverability” of the universe has now been picked up by famous Christian philosopher Robin Collins, so we should expect to hear more about it in the future.

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.

What does the concept of resurrection mean to Jewish theologians?

Here’s a helpful post from Eric Chabot talks about this and other interesting topics related to the resurrection.

Excerpt:

Where do we see resurrection in the Hebrew Bible?

As just stated, belief in a resurrection of persons from the dead are seen in eight passages: (Job 19:26; Ps. 17:15; 49:15; 73:24; Is. 26:19; 53:10; Dn. 12:2;12:13). The resurrection terminology is seen in two places (Ezek. 37:1-14; Hos. 6:2) to show a national and spiritual restoration brought about by the return from the exile. As far as the nature of the future bodily resurrection, it may involve a corpse or the receipt of a material body comparable to the present physical body (Job 19:26; Is. 26:19), or it may be a matter of transformation (Dn. 12:2-3 and perhaps 12:13); or glorification after reanimation, in the case of the righteous.

As far as the function of the resurrection, it may be personal vindication (Is. 26:16; 53:10-12). Resurrection may also have a function in relation to reward or punishment (Dn. 12:2; 12:13), an assumption to heaven and enriched fellowship with God (Ps. 49:15; 73:24,26), or preface to the beatific vision of God (Ps. 17:15 and possibly Job 19:26). (1)

The Greek word for resurrection is “anatasis” which means “a raising up” or “rising.” There are resuscitations in the Tanakh such as the example of Elijah and Elisha raising a person from death (1 Kings 17-23; 2 Kings 4:34-35). While these figures may have been raised in a resurrection sense, they were not raised immortal in the same way Jesus was.

Extra-Biblical Passages on Resurrection

There are also extra-biblical passages that speak about the resurrection (Enoch 92:2; 4 Ezra 7:32; Enoch 91:10; 2 Maccabees 7:9; 14; 28-29). Even the The Messiah Apocalypse, which is dated between 100 and 80 B.C.E mentions resurrection: “He [God] frees the captives, makes the blind see, and makes the bent over stand straight…for he will heal the sick, revive the dead, and give good news to the humble and the poor he will satisfy, the abandoned he will lead, and the hungry he will make rich.” (2)

In the Rabbinical literature there are explicit teachings on the resurrection. It says in the Mishnah 10.1, it says, “All Israelites have a share in the world to come; … and these are they that have no share in the world to come: he that says that there is no resurrection of the dead prescribed in the Law.” Moses Maimonides, a Jewish rabbi and a medieval Jewish philosopher who has forever influenced the Jewish and non-Jewish world said:

” The resurrection of the dead is one of the cardinal principles established by Moses our teacher. A person who does not believe this principle has no real religion, certainly not Judaism. However, resurrection is for the righteous. This is the earning of the statement in Breshit Rabbah, which declares: “the creative power of rain is both for the righteous and the wicked, but the resurrection of the dead is only for the righteous.” Our sages taught the wicked are called dead even when they are still alive; the righteous are alive even when they are dead” (Bab. Talmud Brakhot 18 b).

3 points are made here: 1. Resurrection is a cardinal principle taught in the Torah which all Jews must believe 2. It is for the righteous alone 3. All men must die and their bodies decompose. (3)

It’s important to understand that the concept of resurrection had a meaning before Christianity ever started. And it’s interesting to ask why the early Christians applied the notion of resurrection to Jesus. What is the best explanation for their decision to do such a strange thing? Why not just give up on him and deny that he was the Messiah when he was killed by the Romans?