Tag Archives: Aliens

New study: gamma ray bursts make life impossible in 90% of galaxies

Galactic Habitable Zone
Galactic Habitable Zone

When you argue for theism from science, you typically use arguments like these:

  • the origin of the universe from nothing (the Big Bang)
  • the fine-tuning of cosmic constants and quantities
  • the origin of the first living cell
  • the sudden origin of animal phyla in the Cambrian explosion
  • the fine-tuning of the galaxy for complex, embodied mind
  • the fine-tuning of the solar system for complex, embodied mind
  • the fine-tuning of the planet (and moon)  for complex, embodied mind

This is a peer-reviewed article from Science, one of the most prestigious peer-reviewed journals. It speaks to the fine-tuning of the galaxy for life.

The article says:

Of the estimated 100 billion galaxies in the observable universe, only one in 10 can support complex life like that on Earth, a pair of astrophysicists argues. Everywhere else, stellar explosions known as gamma ray bursts would regularly wipe out any life forms more elaborate than microbes. The detonations also kept the universe lifeless for billions of years after the big bang, the researchers say.

[…]Astrophysicists once thought gamma ray bursts would be most common in regions of galaxies where stars are forming rapidly from gas clouds. But recent data show that the picture is more complex: Long bursts occur mainly in star-forming regions with relatively low levels of elements heavier than hydrogen and helium—low in “metallicity,” in astronomers’ jargon.

Using the average metallicity and the rough distribution of stars in our Milky Way galaxy, Piran and Jimenez estimate the rates for long and short bursts across the galaxy. They find that the more-energetic long bursts are the real killers and that the chance Earth has been exposed to a lethal blast in the past billion years is about 50%. Some astrophysicists have suggested a gamma ray burst may have caused the Ordovician extinction, a global cataclysm about 450 million years ago that wiped out 80% of Earth’s species, Piran notes.

The researchers then estimate how badly a planet would get fried in different parts of the galaxy. The sheer density of stars in the middle of the galaxy ensures that planets within about 6500 light-years of the galactic center have a greater than 95% chance of having suffered a lethal gamma ray blast in the last billion years, they find. Generally, they conclude, life is possible only in the outer regions of large galaxies. (Our own solar system is about 27,000 light-years from the center.)

Things are even bleaker in other galaxies, the researchers report. Compared with the Milky Way, most galaxies are small and low in metallicity. As a result, 90% of them should have too many long gamma ray bursts to sustain life, they argue. What’s more, for about 5 billion years after the big bang, all galaxies were like that, so long gamma ray bursts would have made life impossible anywhere.

But are 90% of the galaxies barren? That may be going too far, Thomas says. The radiation exposures Piran and Jimenez talk about would do great damage, but they likely wouldn’t snuff out every microbe, he contends. “Completely wiping out life?” he says. “Maybe not.” But Piran says the real issue is the existence of life with the potential for intelligence. “It’s almost certain that bacteria and lower forms of life could survive such an event,” he acknowledges. “But [for more complex life] it would be like hitting a reset button. You’d have to start over from scratch.”

The analysis could have practical implications for the search for life on other planets, Piran says. For decades, scientists with the SETI Institute in Mountain View, California, have used radio telescopes to search for signals from intelligent life on planets around distant stars. But SETI researchers are looking mostly toward the center of the Milky Way, where the stars are more abundant, Piran says. That’s precisely where gamma ray bursts may make intelligent life impossible, he says: “We are saying maybe you should look in the exact opposite direction.”

You need to be able to pick up enough heavy elements from surrounding supernovae to make a metal-rich star, but you have to be far enough away from other stars to avoid getting blasted with gamma rays. The metal-rich star is needed to be able to support the circumstellar habitable zone, which is the zone where liquid water exists on the planet’s surface.

It’s important to understand that this factor in the study just a few of the things you need in order to get a planet that supports life. The more factors you add, the more unexpected complex, embodied life of any kind becomes.

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

There’s a good video on the galactic habitable zone for you to watch right here:

It takes a lot to make just one planet that can support complex, embodied life of any kind.

What makes a planet suitable for supporting 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.

Pew survey: evangelical Christians least likely to believe superstitious nonsense

The Pew Research survey is here.

They are trying to see which groups believe in superstitions and new age mysticism.

Here are the parts that I found interesting:

Click for full image.

Click for full image.

Notice the numbers for Republicans vs Democrats, conservatives vs. liberals, and church-attending vs non church-attending. The least superstitious people are conservative evangelical Republicans, while the most superstitious people are Democrat liberals who don’t attend church. I think there is something to be learned from that. It’s consistent with the results of a Gallup survey that showed that evangelical Christians are the most rational people on the planet.

Here’s the Wall Street Journal article about the Gallup survey entitled “Look Who’s Irrational Now“.


The reality is that the New Atheist campaign, by discouraging religion, won’t create a new group of intelligent, skeptical, enlightened beings. Far from it: It might actually encourage new levels of mass superstition. And that’s not a conclusion to take on faith — it’s what the empirical data tell us.

“What Americans Really Believe,” a comprehensive new study released by Baylor University yesterday, shows that traditional Christian religion greatly decreases belief in everything from the efficacy of palm readers to the usefulness of astrology. It also shows that the irreligious and the members of more liberal Protestant denominations, far from being resistant to superstition, tend to be much more likely to believe in the paranormal and in pseudoscience than evangelical Christians.

The Gallup Organization, under contract to Baylor’s Institute for Studies of Religion, asked American adults a series of questions to gauge credulity.

[…]The answers were added up to create an index of belief in occult and the paranormal. While 31% of people who never worship expressed strong belief in these things, only 8% of people who attend a house of worship more than once a week did.

Even among Christians, there were disparities. While 36% of those belonging to the United Church of Christ, Sen. Barack Obama’s former denomination, expressed strong beliefs in the paranormal, only 14% of those belonging to the Assemblies of God, Sarah Palin’s former denomination, did. In fact, the more traditional and evangelical the respondent, the less likely he was to believe in, for instance, the possibility of communicating with people who are dead.

When I think of the “weird” things that evangelical Christians believe, I think of the origin of the universe, the cosmic fine-tuning, the origin of life and the sudden origin of animal body plans in the Cambrian. All of this is superstition to an atheist, and yet all of it is rooted in mainstream science. Not just that, but they’ve grown stronger as science has progressed. I can accept the fact that an atheist may be ignorant of the science that defeats his atheism, but that’s something that has to be remedied with more studying of the evidence, not less. If you generate a worldview by 1) your desire to dispense with moral judgment and/or 2) your desire to prefer Star Trek and Star Wars to mainstream science, then of course you are going to have an irrational worldview. I’m not saying that all atheists do this, surely someone like Peter Millican does not. But for rank-and-file Dawkins acolytes, I think this is pretty accurate, and it’s why we get the survey results that we do.

How likely is it for blind forces to sequence a functional protein by chance?

How likely is it that you could swish together amino acids randomly and come up with a sequence that would fold up into a functional protein?

Evolution News reports on research performed by Doug Axe at Cambridge University, and published in the peer-reviewed Journal of Molecular Biology.


Doug Axe’s research likewise studies genes that it turns out show great evidence of design. Axe studied the sensitivities of protein function to mutations. In these “mutational sensitivity” tests, Dr. Axe mutated certain amino acids in various proteins, or studied the differences between similar proteins, to see how mutations or changes affected their ability to function properly.10 He found that protein function was highly sensitive to mutation, and that proteins are not very tolerant to changes in their amino acid sequences. In other words, when you mutate, tweak, or change these proteins slightly, they stopped working. In one of his papers, he thus concludes that “functional folds require highly extraordinary sequences,” and that functional protein folds “may be as low as 1 in 10^77.”11 The extreme unlikelihood of finding functional proteins has important implications for intelligent design.

Just so you know, those footnotes say this:

[10.] Douglas D. Axe, “Estimating the Prevalence of Protein Sequences Adopting Functional Enzyme Folds,” Journal of Molecular Biology, 1-21 (2004); Douglas D. Axe, “Extreme Functional Sensitivity to Conservative Amino Acid Changes on Enzyme Exteriors,” Journal of Molecular Biology, Vol. 301:585-595 (2000).

[11.] Douglas D. Axe, “Estimating the Prevalence of Protein Sequences Adopting Functional Enzyme Folds,” Journal of Molecular Biology, 1-21 (2004).

And remember, you need a lot more than just 1 protein in order to create even the simplest living system. Can you generate that many proteins in the short time between when the Earth cools and the first living cells appear? Even if we spot the naturalist a prebiotic soup as big as the universe, and try to make sequences as fast as possible, it’s unlikely to generate even one protein in the time before first life appears.

Here’s Doug Axe to explain his research:

If you are building a protein for the FIRST TIME, you have to get it right all at once – not by building up to it gradually using supposed Darwinian mechanisms. That’s because there is no replication before you have the first replicator. The first replicator cannot rely on explanations that require replication to already be in place.

John Lennox and Paul Davies discuss aliens and the origin of life

An amazing debate about the origin of life and the cosmic fine-tuning between a Christian and a materialist agnostic. John Lennox is AWESOME in this debate, and he only talks for a tiny part of the debate. He’s very gracious, and focused the discussion on the areas that we care about. Paul Davies is an EXCELLENT scientist and well aware of what Christians believe. This is a great debate, very easy to listen to. Justin, the moderator, does a great job controlling a fantastic discussion.

The MP3 file is here.


What does it take for life to get going in our universe? Is there intelligence in the stars or right under our nose? Renowned astrophysicist Paul Davies chats to Oxford Professor of Mathematics John Lennox.

A popular science author, Davies is also the Chair of the SETI post detection task force. His latest book “The Eerie Silence” which marks SETI’s 50th anniversary examines the likelihood of the universe producing life elsewhere.

John Lennox is a Christian Mathematician and philosopher. He is the author of “God’s Undertaker: has science buried God?” and has debated Richard Dawkins on several occasions.

Davies’ work on the fine tuning of the universe for life has been sympathetic to theism. In this programme Lennox challenges Davies to look to design not just in cosmology but in the cell. They also chat about what the discovery of ET would mean for Christian theology.



  • Is there meaning in the universe?


  • We have no evidence for or against intelligent life elsewhere in the universe
  • The vastness of the universe makes me think there is life elsewhere
  • Humans are capable of observing and understanding the universe
  • It seems the universe has the ability to create observers to understand it
  • If one species has this ability, then we should expect others to do it


  • The fact that we can observe the universe and do science has cosmic significance
  • Our rare habitable planet and our ability to do science is suggestive of purpose
  • So science itself points to an extra-terrestrial intelligence: GOD
  • The complexity of life and consciousness itself points away from atheism
  • Monotheism gave birth to science
  • Human minds capable of doing science are not compatible with atheistic materialism


  • Why do you say that either we are the only life or there are many different kinds of life?


  • There are lots of factors that have to be met to have a site for simple life
  • These are related to the fine-tuning of cosmic constants, e.g. gravitational force
  • But there are also factors that have to be met for originating intelligent life
  • Things like convergence, self-organization, etc.
  • So the cosmic requirements and evolutionary requirements are different
  • Darwinian evolution doesn’t solve the problem of the origin of life
  • 50 years ago, skepticism about alien life existing anywhere was excessive
  • Today, credulity about alien life exiting everywhere is excessive
  • The naturalist is searching for a process that creates life easily


  • Paul agrees that there is no theory for a naturalistic origin of life
  • This is fatal for the idea that life can emerge elsewhere in the universe
  • We have not discovered any law that produces life without an intelligence
  • Consider the method used by SETI used to detect an alien intelligence
  • Why can’t this method be applied to the origin of life on Earth?
  • Why can’t an intelligence created specified complexity (functional information)?
  • Why can’t an intelligence created epigenetics and protein folding?


  • Darwinian evolution can add new biological information after life begins


  • Darwinian evolution assumes a mutating replicating life form to act on


  • You can’t generate specified complexity by using physical laws
  • You can’t generate specified complexity by chance
  • At this point we are guessing as to how life might have formed


  • Why do we have to rule out an intelligent cause a priori
  • If you can recognize an intelligence in outer space, why not in living systems?


  • I don’t mind the word “intelligence”, it’s the word “signal”
  • I oppose the idea that God or aliens manipulated physical stuff to create life
  • It’s an “ugly explanation and very unappealing both theologically and scientifically”
  • I prefer the idea that the universe has processes to self-organize and create complexity
  • When it comes to supernatural meddling by God, “I don’t want that”
  • If I were God, I would create the universe so that I would not have to intervene
  • I think God would be more clever if he did not have to intervene
  • My preferences about what is “clever” determines what scientific conclusions are allowed


  • Humans already have experience with their non-material minds to move atoms (matter)
  • If God is a mind, then there is no reason why he cannot move atoms (matter)


  • My mind is physical, so are you saying that God is physical?
  • If God intervenes in the universe, then what is he doing now?


  • There is a distinction between acts of creation and providential upholding the universe
  • God is also speaking to people and drawing humans toward him
  • God is spirit, not material


  • How can a non-physical entity cause effects on the physical world?


  • What science reveals that there is information needed for the origin of life
  • Information requires an intelligence to create it, just as with human who write books
  • That’s not God of the gaps – it’s an inference based on what we know today


  • We may be able to explain the origin of life later, using matter, law and chance
  • What you’re saying is that God tinkers with the genome
  • If you say that God intervened once, then he intervenes all the time, everywhere!
  • I don’t want a God who tinkers in the genome
  • if God could intervene in the universe that would remove its intelligibility


  • Look at the cover of this book – when I read words, I infer an intelligence
  • There are bad gaps that the progress of science closes
  • There are good gaps that science opens, showing the need for intelligence
  • On the one hand, you say we have no theory of the origin of life
  • On the other hand, you know that an intelligent designer wasn’t involved
  • If we don’t know how life began, why do you rule God out a priori?


  • What scientists want to do is to explain the universe without involving God
  • naturalists want to use science to discover only materialist explanations
  • The purpose of SETI is to prove that there is other life in the universe
  • This would then show that there is a naturalistic way of making life
  • I agree that information in living systems is real hard to explain materialistically
  • I believe in the power of emergence
  • We might discover laws that prove that complexity can emerge without intelligence
  • The discovery of alien life would help to show that no intelligence is needed to make life


  • What sort of cosmic fine-tuning is needed at the Big Bang for life to occur?


  • It’s true that the universe appears extremely fine-tuned for life to exist
  • The typical answer from naturalists is that there is a multiverse
  • But the multiverse “falls far short” of providing a good answer to the fine-tuning
  • It’s irrational to appeal to massive numbers of unseen universes to explain fine-tuning
  • The design and purpose seen in the universe may be due to God or it may be emergent


  • The fine-tuning is real and the multiverse is a desperate attempt to evade the creator
  • Sir Martin Rees (an atheist) says he “prefers” the multiverse to a designer
  • Scientists are not supposed to prefer anything except what is true


  • Would the discovery of aliens hurt Christianity, because of the belief in the uniqueness of humans?


  • Christians believe that Jesus came to save HUMANS specifically, not animals or aliens
  • If we were to discover intelligent aliens, it would challenge traditional religions
  • What will God do with alien races? Multiple incarnations? Or just preach the gospel to them?


  • We don’t know if the aliens exist, first of all – it’s speculative
  • The Bible teaches that humans bear the image of God
  • We just don’t know whether alien species are also made in God’s image