Tag Archives: Planet

How tidal effects improve the habitability of a planet

Circumstellar Habitable Zone
Circumstellar Habitable Zone

Science Daily reports on a new factor that affects planetary habitability: tides. Specifically, tides can affect the surface temperature of a planet, which has to be within a certain range in order to support liquid water – a requirement for life of any conceivable kind.

Excerpt:

Tides can render the so-called “habitable zone” around low-mass stars uninhabitable. This is the main result of a recently published study by a team of astronomers led by René Heller of the Astrophysical Institute Potsdam.

[…]Until now, the two main drivers thought to determine a planet’s temperature were the distance to the central star and the composition of the planet’s atmosphere. By studying the tides caused by low-mass stars on their potential earth-like companions, Heller and his colleagues have concluded that tidal effects modify the traditional concept of the habitable zone.

Heller deduced this from three different effects. Firstly, tides can cause the axis of a planet`s rotation to become perpendicular to its orbit in just a few million years. In comparison, Earth’s axis of rotation is inclined by 23.5 degrees — an effect which causes our seasons. Owing to this effect, there would be no seasonal variation on such Earth-like planets in the habitable zone of low-mass stars. These planets would have huge temperature differences between their poles, which would be in perpetual deep freeze, and their hot equators which in the long run would evaporate any atmosphere. This temperature difference would cause extreme winds and storms.

The second effect of these tides would be to heat up the exoplanet, similar to the tidal heating of Io, a moon of Jupiter that shows global vulcanism.

Finally, tides can cause the rotational period of the planet (the planet’s “day”) to synchronize with the orbital period (the planet’s “year”). This situation is identical to the Earth-moon setup: the moon only shows Earth one face, the other side being known as “the dark side of the moon.” As a result one half of the exoplanet receives extreme radiation from the star while the other half freezes in eternal darkness.

The habitable zone around low-mass stars is therefore not very comfortable — it may even be uninhabitable.

Here is my previous post on the factors needed for a habitable planet. Now we just have one more. I actually find this article sort of odd, because my understanding of stars was that only high-mass stars could support life at all. This is because if the mass of the planet was too low, the habitable zone wouldbe very close to the star. Being too close to the star causes tidal locking, which means that the planet doesn’t spin on its axis at all, and the same side faces the star. This is a life killer.

This astrophysicist who teaches at the University of Wisconsin explains it better than me.

Excerpt:

Higher-mass stars tend to be larger and luminous than their lower-mass counterparts. Therefore, their habitable zones are situated further out. In addition, however, their HZs are much broader. As an illustration,

  • a 0.2 solar-mass star’s HZ extends from 0.1 to 0.2 AU
  • a 1.0 solar-mass star’s HZ extends from 1 to 2 AU
  • a 40 solar-mass star’s HZ extends from 350 to 600 AU

On these grounds, it would seem that high-mass starts are the best candidates for finding planets within a habitable zone. However, these stars emit most of their radiation in the far ultraviolet (FUV), which can be highly damaging to life, and also contributes to photodissociation and the loss of water. Furthermore, the lifetimes of these stars is so short (around 10 million years) that there is not enough time for life to begin.

Very low mass stars have the longest lifetimes of all, but their HZs are very close in and very narrow. Therefore, the chances of a planet being formed within the HZ are small. Additionally, even if a planet did form within the HZ, it would become tidally locked, so that the same hemisphere always faced the star. Even though liquid water might exist on such a planet, the climactic conditions would probably be too severe to permit life.

In between the high- and low-mass stars lie those like our own Sun, which make up about 15% percent of the stars in the galaxy. These have reasonably-broad HZs, do not suffer from FUV irradiation, and have lifetimes of the order of 10 billion years. Therefore, they are the best candidates for harbouring planets where life might be able to begin.

This guy is just someone I found through a web search. He has a support-the-unions-sticker on his web page, so he’s a liberal crackpot. But he makes my point, anyway, so that’s good enough for me.

Maybe the new discovery is talking about this now, but I already knew about the tides and habitability, because I watched The Privileged Planet DVD. Actually that whole video is online, and the clip that talks about the habitable zone and water is linked in this blog post I wrote before.

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.

Why does God allow so much natural evil from earthquakes?

My friend Eric Chabot of Ratio Christi shared this video with me, which features chemist Fazale Rana.

The video runs under 4 minutes:

Basically, there was an atheist who challenged the idea that nature is designed because there are things in nature which cause suffering, like earthquakes and volcanoes.

Now the first thing to note is that atheists commonly think that God’s job is to make humans happy. If he doesn’t make humans feel happy – regardless of their knowledge of him and relationship with him – then he is a big failure. Many atheists think that, it is one of the most common reasons why people become atheists. But of course anyone who reads the Bible and reads the story of Jesus knows that the purpose of life on God’s view is for humans to know him and to be disciples of a suffering Messiah who sacrifices himself in order to obey God the Father.  So that’s the first thing to say – purpose of life not happiness, but knowledge of God and being a disciple of Jesus. This may involve all kinds of suffering, and that’s to be expected.

Second, there is a response to the problem of evil based on the necessity of natural laws. The argument goes that you can’t have genuine morality without a predictable, knowable system of natural laws.

But I want to talk about something different in this post. In the video, Dr. Rana thinks that many of the things that cause suffering in the natural world are actually necessary for life to exist at all. He provides the example of plate tectonics in his video above, and I want to take that one and add to it the example of heavy element production and the stellar lifecycle. These are both from a book called “Rare Earth”, which is written by two non-Christians – Peter Ward and Donald Brownlee, but I’ll link to web sites to make the case.

Plate tectonics.

Here’s an article from Reasons to Believe by Dr. David Rogstad, who has a PhD in physics from Caltech – the top school for experimental science. The article not only goes over the basic plate tectonics to carbonate-silicate cycle connection, but it adds a newer discovery to boot.

Excerpt:

Earthquakes are a byproduct of plate tectonics, a theory in geology developed in recent years for explaining motions near the surface of the Earth. One of the benefits from plate tectonics is that Earth maintains the right levels of carbon dioxide (CO2) in the atmosphere to compensate for the Sun’s increasing luminosity. This is accomplished by what is called the carbonate-silicate cycle. CO2 is removed from the atmosphere through weathering. The weathered products are eventually drawn into the Earth’s interior via plate tectonics. Processes inside the Earth’s interior release the CO2 back into the atmosphere via volcanoes. While all aspects of this mechanism are not yet fully understood, it has been instrumental in providing a stable environment for life on the Earth for billions of years.

New research provides yet another component that appears fine-tuned for life. In a letter in the September 27, 2007 issue of Nature together with a corresponding news release from the University of Bonn, Arno Rohrbach and his colleagues have discussed another mechanism similar to the carbonate-silicate cycle. It also depends on plate tectonics but, in this case, the mechanism controls the amount of oxygen on the surface of the Earth.

Oxygen becomes bound up in various oxides which are then drawn into the Earth’s interior, where various processes result in its being incorporated into an exotic mineral called majorite. The results reported in this letter established that majorite functions as a kind of “reservoir” for oxygen, and when the majorite ascends nearer to the surface of the Earth it breaks down and releases its oxygen. Some of this oxygen also binds with hydrogen released from the interior of the Earth to form water. The authors have referred to the whole process as an “oxygen elevator.”

They go on to say that “without the ‘oxygen elevator’ in its mantle the Earth would probably be a barren planet hostile to life. According to our findings, planets below a certain size hardly have any chance of forming a stable atmosphere with a high water content.”

This research confirms the existence of one more finely tuned mechanism that depends on plate tectonics and contributes to an environment that can support life. It also gives humans one more reason to be appreciative rather than dismayed when we experience an earthquake that breaks some precious possessions beyond repair.

Astronomer Dr. Hugh Ross who has a PhD in Astronomy from the University of Toronto and did a 5-year post-doctoral work at Caltech, adds to this with another discovery.

Excerpt:

In the December 2007 issue of Astrobiology Stanford University geophysicists Norman H. Sleep and Mark D. Zoback note that the higher tectonic activity during Earth’s early history could have played a key role in cycling critically important nutrients and energy sources for life. The production of numerous small faults in the brittle primordial crust released trapped nutrients. Such faults could also release pockets of methane gas and molecular hydrogen. The methane and hydrogen could then provide crucial energy sources for nonphotosynthetic life. Finally, the production of faults could bring water to otherwise arid habitats, such as rocks far below Earth’s surface.

Faulting, generated by active and widespread tectonics, allowed a youthful Earth to support diverse and abundant life. This enhanced diversity and abundance of life quickly transformed Earth’s surface into an environment safe for advanced life. Also, the buildup of biodeposits for the support of human civilization occurred more rapidly due to active tectonics.

The more rapid preparation of Earth for humanity is critical. Without such rapid preparation, humans could not come upon the terrestrial scene before the Sun’s increasing luminosity would make their presence impossible (due to excessive heat).

So that’s the science behind earthquakes. So that’s a brief look at why we need plate tectonics for life, and we just have to buck up and take the earthquakes with it. It’s not God’s job to give us happiness and health. That’s not his plan. People who complain about earthquakes have to show how God could get the life-permitting effects of earthquakes without wrecking his ability to succeed in his plan to make people know him and follow him. But how can an atheist do that? They can’t. I think that people just need to realize that humans are not in charge here and we have to live with that. We have to accept that we didn’t make the universe, and we don’t get to decide what purpose it has. God decides.

On to star formation.

Star formation

Atheists often complain that the universe is too big or too old (which is actually the same thing, since the more time passes, the more it expands). The fact of the matter is that life appeared the earliest it could appear – we needed the universe to be a certain age before it could support life.

Dr. Hugh Ross explains in this article.

Excerpt:

The second parameter of the universe to be measured was its age. For many decades astronomers and others have wondered why, given God exists, He would wait so many billions of years to make life. Why did He not do it right away? The answer is that, given the laws and constants of physics God chose to create, it takes about ten to twelve billion years just to fuse enough heavy elements in the nuclear furnaces of several generations of giant stars to make life chemistry possible.

Life could not happen any earlier in the universe than it did on Earth. Nor could it happen much later. As the universe ages, stars like the sun located in the right part of the galaxy for life (see chapter 15) and in a stable nuclear burning phase become increasingly rare. If the universe were just a few billion years older, such stars would no longer exist.

The Rare Earth book explains the details on p. 40-4:

The trick for getting from helium to the generation of planets, and ultimately to life, was the formation of carbon, the key element for the success of life and for the production of heavy elements in stars. Carbon could not form in the early moments following the Big Bang, because the density of the expanding mass was too low for the necessary collisions to occur. Carbon formation had to await the creation of giant red stars, whose dense interiors are massive enough to allow such collisions. Because stars become red giants only in the last 10% of their lifetimes (when they have used up much of the hydrogen in their cores), there was no carbon in the Universe for hundreds of millions to several billion years after the Big Bang—and hence no life as we know it for that interval of time.

[…]The sequence of element production in the Big Bang and in stars provided not only the elements necessary for the formation of Earth and the other terrestrial planets but also all of the elements critical for life—those actually needed to form living organisms and their habitats.

[…]The processes that occurred during the billions of years of Earth’s “prehistory” when its elements were produced are generally well understood. Elements are produced within stars; some are released back into space and are recycled into and out of generations of new stars. When the sun and its planets formed, they were just a random sampling of this generated and reprocessed material. Nevertheless, it is believed that the “cosmic abundance” mix of the chemical elements—the elemental composition of the sun—is representative of the building material of most stars and planets, with the major variation being the ratio of hydrogen to heavy elements.

[…]Many stars are similar in composition, but there is variation, mainly in the abundance of the heavier Earth-forming elements relative to hydrogen and helium. The sun is in fact somewhat peculiar in that it contains about 25% more heavy elements than typical nearby stars of similar mass. In extremely old stars, the abundance of heavy elements, may be as low as a thousandth of that in the sun. Abundance of heavy elements is roughly correlated with age. As time passed, the heavy-element content of the Universe as a whole increased, so newly formed stars are on the average more “enriched” in heavy elements than older ones.

[…]The matter produced in the Big Bang was enriched in heavier elements by cycling in and out of stars. Like biological entities, stars form, evolve, and die. In the process of their death, stars ultimately become compact objects such as white dwarfs, neutron stars, or even black holes. On their evolutionary paths to these ends, they eject matter back into space, where it is recycled and further enriched in heavy elements. New stars rise from the ashes of the old. This is why we say that each of the individual atoms in Earth and in all of its creatures—including us—has occupied the interior of at least a few different stars.

What he’s saying is that heavy elements are created gradually because of the star formation lifecycle. The first generation of stars are metal-poor. The next generation of stars is better. And so on until we get to stars that can support life by providing a steady, stable amount of energy – as well as other benefits like planets with an atmosphere.  Our planet is 4.5 billion years old, and the universe is about 14 billion years old. Simple life appears about 4 billion years ago on Earth. That means we got life practically immediately, given that we had to develop the heavy elements needed to make a life-supporting star, a life-supporting planet and our physical bodies

How common is it for a star to support complex, embodied life?

Circumstellar Habitable Zone
Circumstellar Habitable Zone

I blogged a while back about the need for a star to be massive, in order to push out the habitable zone far enough that the planet in the zone does not get tidally locked, killing the planet’s ability to support life. Recently, I blogged about another factor that’s needed – large planets further out which catch comets for us have to have a circular orbit, or they will pull us out of the habitable zone.

That’s two factors. But 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.

Why does God allow so much natural evil from earthquakes?

My friend Eric Chabot of Ratio Christi shared this video with me, which features chemist Fazale Rana.

The video runs under 4 minutes:

Basically, there was an atheist who challenged the idea that nature is designed because there are things in nature which cause suffering, like earthquakes and volcanoes.

Now the first thing to note is that atheists commonly think that God’s job is to make humans happy. If he doesn’t make humans feel happy – regardless of their knowledge of him and relationship with him – then he is a big failure. Many atheists think that, it is one of the most common reasons why people become atheists. But of course anyone who reads the Bible and reads the story of Jesus knows that the purpose of life on God’s view is for humans to know him and to be disciples of a suffering Messiah who sacrifices himself in order to obey God the Father.  So that’s the first thing to say – purpose of life not happiness, but knowledge of God and being a disciple of Jesus. This may involve all kinds of suffering, and that’s to be expected.

Second, there is a response to the problem of evil based on the necessity of natural laws. The argument goes that you can’t have genuine morality without a predictable, knowable system of natural laws.

But I want to talk about something different in this post. In the video, Dr. Rana thinks that many of the things that cause suffering in the natural world are actually necessary for life to exist at all. He provides the example of plate tectonics in his video above, and I want to take that one and add to it the example of heavy element production and the stellar lifecycle. These are both from a book called “Rare Earth”, which is written by two non-Christians – Peter Ward and Donald Brownlee, but I’ll link to web sites to make the case.

Plate tectonics.

Here’s an article from Reasons to Believe by Dr. David Rogstad, who has a PhD in physics from Caltech – the top school for experimental science. The article not only goes over the basic plate tectonics to carbonate-silicate cycle connection, but it adds a newer discovery to boot.

Excerpt:

Earthquakes are a byproduct of plate tectonics, a theory in geology developed in recent years for explaining motions near the surface of the Earth. One of the benefits from plate tectonics is that Earth maintains the right levels of carbon dioxide (CO2) in the atmosphere to compensate for the Sun’s increasing luminosity. This is accomplished by what is called the carbonate-silicate cycle. CO2 is removed from the atmosphere through weathering. The weathered products are eventually drawn into the Earth’s interior via plate tectonics. Processes inside the Earth’s interior release the CO2 back into the atmosphere via volcanoes. While all aspects of this mechanism are not yet fully understood, it has been instrumental in providing a stable environment for life on the Earth for billions of years.

New research provides yet another component that appears fine-tuned for life. In a letter in the September 27, 2007 issue of Nature together with a corresponding news release from the University of Bonn, Arno Rohrbach and his colleagues have discussed another mechanism similar to the carbonate-silicate cycle. It also depends on plate tectonics but, in this case, the mechanism controls the amount of oxygen on the surface of the Earth.

Oxygen becomes bound up in various oxides which are then drawn into the Earth’s interior, where various processes result in its being incorporated into an exotic mineral called majorite. The results reported in this letter established that majorite functions as a kind of “reservoir” for oxygen, and when the majorite ascends nearer to the surface of the Earth it breaks down and releases its oxygen. Some of this oxygen also binds with hydrogen released from the interior of the Earth to form water. The authors have referred to the whole process as an “oxygen elevator.”

They go on to say that “without the ‘oxygen elevator’ in its mantle the Earth would probably be a barren planet hostile to life. According to our findings, planets below a certain size hardly have any chance of forming a stable atmosphere with a high water content.”

This research confirms the existence of one more finely tuned mechanism that depends on plate tectonics and contributes to an environment that can support life. It also gives humans one more reason to be appreciative rather than dismayed when we experience an earthquake that breaks some precious possessions beyond repair.

Astronomer Dr. Hugh Ross who has a PhD in Astronomy from the University of Toronto and did a 5-year post-doctoral work at Caltech, adds to this with another discovery.

Excerpt:

In the December 2007 issue of Astrobiology Stanford University geophysicists Norman H. Sleep and Mark D. Zoback note that the higher tectonic activity during Earth’s early history could have played a key role in cycling critically important nutrients and energy sources for life. The production of numerous small faults in the brittle primordial crust released trapped nutrients. Such faults could also release pockets of methane gas and molecular hydrogen. The methane and hydrogen could then provide crucial energy sources for nonphotosynthetic life. Finally, the production of faults could bring water to otherwise arid habitats, such as rocks far below Earth’s surface.

Faulting, generated by active and widespread tectonics, allowed a youthful Earth to support diverse and abundant life. This enhanced diversity and abundance of life quickly transformed Earth’s surface into an environment safe for advanced life. Also, the buildup of biodeposits for the support of human civilization occurred more rapidly due to active tectonics.

The more rapid preparation of Earth for humanity is critical. Without such rapid preparation, humans could not come upon the terrestrial scene before the Sun’s increasing luminosity would make their presence impossible (due to excessive heat).

So that’s the science behind earthquakes. So that’s a brief look at why we need plate tectonics for life, and we just have to buck up and take the earthquakes with it. It’s not God’s job to give us happiness and health. That’s not his plan. People who complain about earthquakes have to show how God could get the life-permitting effects of earthquakes without wrecking his ability to succeed in his plan to make people know him and follow him. But how can an atheist do that? They can’t. I think that people just need to realize that humans are not in charge here and we have to live with that. We have to accept that we didn’t make the universe, and we don’t get to decide what purpose it has. God decides.

On to star formation.

Star formation

Atheists often complain that the universe is too big or too old (which is actually the same thing, since the more time passes, the more it expands). The fact of the matter is that life appeared the earliest it could appear – we needed the universe to be a certain age before it could support life.

Dr. Hugh Ross explains in this article.

Excerpt:

The second parameter of the universe to be measured was its age. For many decades astronomers and others have wondered why, given God exists, He would wait so many billions of years to make life. Why did He not do it right away? The answer is that, given the laws and constants of physics God chose to create, it takes about ten to twelve billion years just to fuse enough heavy elements in the nuclear furnaces of several generations of giant stars to make life chemistry possible.

Life could not happen any earlier in the universe than it did on Earth. Nor could it happen much later. As the universe ages, stars like the sun located in the right part of the galaxy for life (see chapter 15) and in a stable nuclear burning phase become increasingly rare. If the universe were just a few billion years older, such stars would no longer exist.

The Rare Earth book explains the details on p. 40-4:

The trick for getting from helium to the generation of planets, and ultimately to life, was the formation of carbon, the key element for the success of life and for the production of heavy elements in stars. Carbon could not form in the early moments following the Big Bang, because the density of the expanding mass was too low for the necessary collisions to occur. Carbon formation had to await the creation of giant red stars, whose dense interiors are massive enough to allow such collisions. Because stars become red giants only in the last 10% of their lifetimes (when they have used up much of the hydrogen in their cores), there was no carbon in the Universe for hundreds of millions to several billion years after the Big Bang—and hence no life as we know it for that interval of time.

[…]The sequence of element production in the Big Bang and in stars provided not only the elements necessary for the formation of Earth and the other terrestrial planets but also all of the elements critical for life—those actually needed to form living organisms and their habitats.

[…]The processes that occurred during the billions of years of Earth’s “prehistory” when its elements were produced are generally well understood. Elements are produced within stars; some are released back into space and are recycled into and out of generations of new stars. When the sun and its planets formed, they were just a random sampling of this generated and reprocessed material. Nevertheless, it is believed that the “cosmic abundance” mix of the chemical elements—the elemental composition of the sun—is representative of the building material of most stars and planets, with the major variation being the ratio of hydrogen to heavy elements.

[…]Many stars are similar in composition, but there is variation, mainly in the abundance of the heavier Earth-forming elements relative to hydrogen and helium. The sun is in fact somewhat peculiar in that it contains about 25% more heavy elements than typical nearby stars of similar mass. In extremely old stars, the abundance of heavy elements, may be as low as a thousandth of that in the sun. Abundance of heavy elements is roughly correlated with age. As time passed, the heavy-element content of the Universe as a whole increased, so newly formed stars are on the average more “enriched” in heavy elements than older ones.

[…]The matter produced in the Big Bang was enriched in heavier elements by cycling in and out of stars. Like biological entities, stars form, evolve, and die. In the process of their death, stars ultimately become compact objects such as white dwarfs, neutron stars, or even black holes. On their evolutionary paths to these ends, they eject matter back into space, where it is recycled and further enriched in heavy elements. New stars rise from the ashes of the old. This is why we say that each of the individual atoms in Earth and in all of its creatures—including us—has occupied the interior of at least a few different stars.

What he’s saying is that heavy elements are created gradually because of the star formation lifecycle. The first generation of stars are metal-poor. The next generation of stars is better. And so on until we get to stars that can support life by providing a steady, stable amount of energy – as well as other benefits like planets with an atmosphere.  Our planet is 4.5 billion years old, and the universe is about 14 billion years old. Simple life appears about 4 billion years ago on Earth. That means we got life practically immediately, given that we had to develop the heavy elements needed to make a life-supporting star, a life-supporting planet and our physical bodies