New paper finds that mass of asteroid belts affect habitability of planets

Science Daily reports. (H/T Evolution News via ECM)

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.”

There’s a long list of factors that have to be present for a planet to support life – and more keep appearing every day. Here’s another recent one from the journal Nature.

Related posts

• Three ways that the progress of science conflicts with naturalistic speculations
• What conditions support the minimum requirements for complex life?
• Guillermo Gonzalez lectures at UC Davis on the requirements for life
• Does the progress of science lead to theism or atheism?
• Walter Bradley explains three scientific arguments for God’s existence
• Brian Auten interviews Jay Richards about Christian apologetics
• Harvard astrophysicist backs the Rare Earth hypothesis

Filed under: News, Aliens, Are We Alone, Astrobiology, Carbon, Carbon-based Life, CHZ, Circumstellar Habitable Zone, Class M Planet, Copernican Principle, Cosmology, Exoplanet, Galactic Habitable Zone, GHZ, Habitability, Intelligent Design, Main Sequence Star, Moon, Orbit, Oxygen Atmosphere, Planetary Rotation, Rare Earth, Star Formation, Star Trek, Terrestrial Planet, The Privileged Planet, Tilt, Universal Solvent

What conditions support the minimum requirements for complex life?

You need to have a certain amount of elemental diversity to support the minimal requirements of living systems. For example, you need carbon, hence “carbon-based life”.

The Circumstellar Habitable Zone (CHZ)

Human bodies are made of carbon, and many other heavy elements. You need many different heavy elements in order to make up your physical body. Our star, the Sun, is also made of heavy elements. You also need heavy elements in order to crate a metal-rich star like our Sun. A heavy metal-rich star is required in order to support complex carbon-based life in any solar system. The metal-rich star is required because you need to make sure that it can burn stably for a LONG period of time. A metal-rich star also allows you to have a habitable planet far enough from that metal-rich star so that the planet can support liquid water on the planet’s surface. The zone where a planet can have liquid water at the surface is called the circumstellar habitable zone (CHZ). A solar system is therefore a lot like a campfire – you can’t get too close or you get set on fire, and you can’t get too far or you freeze to death. With planets, you need to keep away so your water doesn’t evaporate from the surface, but not so far away that your water freezes. Liquid water on the surface is needed in order to act as a universal solvent in the chemistry of life.

Circumstellar Habitable Zone

Here, watch a clip from The Privileged Planet: (Clip 4 of 12, full playlist here)

A metal-rich star like the Sun is very massive, which allows planets to stay in orbit much further away. Notice that the smaller the star, the closer you have to go to the star. If you go too close to the star then your planet is “tidally locked” – your planet no longer spins on it’s axis – and that’s very bad for life)

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 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, 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. You can be too close to the center of the galaxy, it’s too dense there and you will get hit with massive radiation that will break down your life chemistry. And you can’t be to far from the center, because you won’t get enough heavy elements from the lower number of dying stars in the spiral arms.

Galactic 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. That’s when this was discovered.

By the way, you can watch a lecture with Guillermo Gonzalez explaining his ideas further. The 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. The GHZ and CHZ are ONLY TWO of the requirements for a habitat for life – there are a lot more requirements! Once you list them all out, the odds of getting even one place that is suitable are quite low. If you like this sort of evidence, I recommend the DVD of “The Privileged Planet”, which you can get on Amazon. Or just watch it for free on YouTube.

Positive arguments for Christian theism

• The kalam cosmological argument and the Big Bang theory
• The fine-tuning argument from cosmological constants and quantities
• The origin of life, part 1 of 2: the building blocks of life
• The origin of life, part 2 of 2: biological information
• The sudden origin of phyla in the Cambrian explosion
• Galactic habitable zones and circumstellar habitable zones
• Irreducible complexity in molecular machines
• The creative limits of natural selection and random mutation
• Angus Menuge’s ontological argument from reason
• Alvin Plantinga’s epistemological argument from reason
• William Lane Craig’s moral argument

Filed under: Polemics, Aliens, Apologetics, Are We Alone, Astrobiology, Carbon, Carbon-based Life, CHZ, Circumstellar Habitable Zone, Class M Planet, Copernican Principle, Cosmology, Exoplanet, Galactic Habitable Zone, GHZ, Guillermo Gonzalez, Habitability, Intelligent Design, Jay Richards, Main Sequence Star, Moon, Orbit, Oxygen Atmosphere, Planetary Rotation, Rare Earth, Star Formation, Star Trek, Terrestrial Planet, The Privileged Planet, Tilt, Universal Solvent

New study on tidal heating strengthens stellar habitability argument

Circumstellar Habitable Zone

Note: If you need a refresher on the habitability argument, click here.

Here’s an article entitled “Tidal heating shrinks the ‘goldilocks zone’: Overlooked factor suggests fewer habitable planets than thought”. It appeared in Nature, the most prestigious peer-reviewed science journal.

The gist of it is that tidal forces can alter orbits so that planets don’t spend all of their orbit in the habitable zone. If planets go outside the habitable zone, it damages their supply of liquid water, and any life chemistry going on in there is disrupted.

Excerpt:

A previously little-considered heating effect could shrink estimates of the habitable zone of the Milky Way’s most numerous class of stars — ‘M’ or red dwarfs — by up to one half, says Rory Barnes, an astrobiologist at the University of Washington in Seattle. That factor — gravitational heating via tides — suggests a menagerie of previously undreamt-of planets, on which tidal heating is a major source of internal heat. Barnes presented the work yesterday at a meeting of the American Astronomical Society’s Division on Dynamical Astronomy in Timberline Lodge, Oregon.

The habitable zone is the orbital region close enough to a star for a planet to have liquid water, but not so close that all of the water evaporates. For our Sun, the zone extends roughly from the inner edge of the orbit of Mars to the outer edge of that of Venus. For smaller, cooler stars, such as M-class dwarfs, the zone can be considerably closer to the star than Mercury is to the Sun. And because close-in planets are easier to spot than more distant ones, such stars have been a major target for planet hunters seeking Earth-like worlds.

There’s just one problem with finding habitable planets around such stars, says Barnes. Because tidal forces vary dramatically with the distance between a planet and its star, closer orbits also result in massively larger tidal forces.

Since planets do not have perfectly circular orbits, these tidal forces cause the planet to flex and unflex each time it moves closer to or further from its star; kneading its interior to produce massive quantities of frictional heat. Substantial heat can be produced, he added, with even slight deviations from a perfectly circular orbit. And, Barnes notes, other factors — such as the rate of the planet’s rotation and its axial tilt — can also influence heat production.

A similar tidal process makes Jupiter’s moon Io the most volcanic body in the Solar System. “I’m just scaling that Io–Jupiter system up by a factor of 1,000 in mass,” Barnes said at the meeting. “It’s the same process, on steroids.”

So, stars that are smaller and cooler will have a habitable zone that is closer to the star, exposing them to more tidal forces. More tidal forces makes their orbits less likely to stay circular – within the habitable zone around the star. These variations cause an increase in heat production on the planet. Too much heat means that the planet is unable to support liquid water on the surface, making it inhospitable for life. Therefore, solar systems with less massive stars can be ruled out as possible sites for life, because of these tidal forces.

Filed under: News, Agnosticism, Aliens, Astrobiology, Astronomy, Astrophysics, Atheism, Atheist, Belief, Carbon-based Life, CHZ, Circumstellar Habitable Zone, Complex Life, Earth, Exoplanet, Faith, Flying Spaghetti Monster, Freethought, Galactic Habitable Zone, Galaxy, GHZ, God, Guillermo Gonzalez, Hugh Ross, Life, Non-Theism, Planet, Privileged Planet, Reasons to Believe, Research, Science, Solar System, The Privileged Planet

What conditions support the minimum requirements for complex life?

You need to have a certain amount of elemental diversity to support the minimal requirements of living systems. For example, you need carbon, hence “carbon-based life”.

The Circumstellar Habitable Zone (CHZ)

Human bodies are made of carbon, and many other heavy elements. You need many different heavy elements in order to make up your physical body. Our star, the Sun, is also made of heavy elements. You also need heavy elements in order to crate a metal-rich star like our Sun. A heavy metal-rich star is required in order to support complex carbon-based life in any solar system. The metal-rich star is required because you need to make sure that it can burn stably for a LONG period of time. A metal-rich star also allows you to have a habitable planet far enough from that metal-rich star so that the planet can support liquid water on the planet’s surface. The zone where a planet can have liquid water at the surface is called the circumstellar habitable zone (CHZ). A solar system is therefore a lot like a campfire – you can’t get too close or you get set on fire, and you can’t get too far or you freeze to death. With planets, you need to keep away so your water doesn’t evaporate from the surface, but not so far away that your water freezes. Liquid water on the surface is needed in order to act as a universal solvent in the chemistry of life.

Circumstellar Habitable Zone

Here, watch a clip from The Privileged Planet: (Clip 4 of 12, full playlist here)

A metal-rich star like the Sun is very massive, which allows planets to stay in orbit much further away. Notice that the smaller the star, the closer you have to go to the star. If you go too close to the star then your planet is “tidally locked” – your planet no longer spins on it’s axis – and that’s very bad for life)

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 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, 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. You can be too close to the center of the galaxy, it’s too dense there and you will get hit with massive radiation that will break down your life chemistry. And you can’t be to far from the center, because you won’t get enough heavy elements from the lower number of dying stars in the spiral arms.

Galactic 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. That’s when this was discovered.

By the way, you can watch a lecture with Guillermo Gonzalez explaining his ideas further. The 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. The GHZ and CHZ are ONLY TWO of the requirements for a habitat for life – there are a lot more requirements! Once you list them all out, the odds of getting even one place that is suitable are quite low. If you like this sort of evidence, I recommend the DVD of “The Privileged Planet”, which you can get on Amazon. Or just watch it for free on YouTube.

Related posts

• The origin of the universe from nothing
• The fine-tuning of the cosmological constants to permit life
• The fine-tuning of the galaxy, solar system, and planet to permit life
• Origin of the building blocks in the simplest replicating cell
• Origin of biological information in the simplest replicating cell
• Sudden origins of all major body plans in the Cambrian explosion
• Irreducible complexity in molecular machines
• The limits on what natural selection and random mutation can do
• Peer-reviewed paper says there is no atheistic explanation for the Cambrian explosion
• Does the Cambrian explosion disprove Darwinian evolution?

Filed under: Polemics, Aliens, Apologetics, Are We Alone, Astrobiology, Carbon, Carbon-based Life, CHZ, Circumstellar Habitable Zone, Class M Planet, Copernican Principle, Cosmology, Exoplanet, Galactic Habitable Zone, GHZ, Guillermo Gonzalez, Habitability, Intelligent Design, Jay Richards, Main Sequence Star, Moon, Orbit, Oxygen Atmosphere, Planetary Rotation, Rare Earth, Star Formation, Star Trek, Terrestrial Planet, The Privileged Planet, Tilt, Universal Solvent

Harvard astrophysicist backs the Rare Earth hypothesis

What is the Rare Earth hypothesis?

It’s the thesis of a recent book written by two scientists at the University of Washington.

Here’s the blurb:

What determines whether complex life will arise on a planet? How frequent is life in the Universe?

In this exciting new book, distinguished paleontologist Peter D. Ward and noted astronomer Donald Brownlee team up to give us a fascinating synthesis of what’s now known about the rise of life on Earth and how it sheds light on possibilities for organic life forms elsewhere in the Universe.

Life, Ward and Brownlee assert, is paradoxically both very common and almost nowhere. The conditions that foster the beginnings of life in our galaxy are plentiful. But contrary to the usual assumption that if alien life exists, it’s bound to be intelligent, the authors contend that the kind of complex life we find on Earth is unlikely to exist anywhere else; indeed it is probably unique to our planet.

With broad expertise and wonderful descriptive imagery, the authors give us a compelling argument, a splendid introduction to the emerging field of astrobiology, and a lively discussion of the remarkable findings that are being generated by new research. We learn not only about the extraordinary creatures living in conditions once though inimical to life and the latest evidence of early life on Earth, but also about the discoveries of extrasolar planets, the parts Jupiter and the Moon have played in our survival, and even the crucial role of continental drift in our existence.

Insightful, well-written, and at the cutting edge of modern scientific investigation, Rare Earth should interest anyone who wants to know about life elsewhere and gain a fresh perspective on life at home which, if the authors are right, is even more precious than we may ever have imagined.

And here’s a review by Library Journal:

“Renowned paleontologist Ward (Univ. of Washington), who has authored numerous books and articles, and Brownlee, a noted astronomer who has also researched extraterrestrial materials, combine their interests, research, and collaborative thoughts to present a startling new hypothesis: bacterial life forms may be in many galaxies, but complex life forms, like those that have evolved on Earth, are rare in the universe. Ward and Brownlee attribute Earth’s evolutionary achievements to the following critical factors: our optimal distance from the sun, the positive effects of the moon’s gravity on our climate, plate tectonics and continental drift, the right types of metals and elements, ample liquid water, maintainance of the correct amount of internal heat to keep surface temperatures within a habitable range, and a gaseous planet the size of Jupiter to shield Earth from catastrophic meteoric bombardment. Arguing that complex life is a rare event in the universe, this compelling book magnifies the significance — and tragedy — of species extinction. Highly recommended for all public and academic libraries.”

Note that Peter Ward is a militant atheist (he has debated against Stephen C. Meyer), and Donald Brownlee is an agnostic. These are not Christians, nor are they even theists. However, I have the book, I have read the book, and I recommend the book. I usually have this book on my shelf at work for show-and-tell.

Now for the latest news about the hypothesis of the book. (H/T Brian Auten of Apologetics 315)

There are always going to be optimistic predictions by scientists who need to attract research funding, but those are hopes and speculations. The data we have today says Earth is rare. The number of conditions required for complex life of any kind is too high for us to be optimistic about alien life in this galaxy, at least. And as the number of requirements for life roll in, the odds of finding alien life that can contact us get slimmer and slimmer.

From the UK Daily Mail. (H/T Peter S. Williams)

Excerpt:

Dr Howard Smith, a senior astrophysicist at Harvard University, believes there is very little hope of discovering aliens and, even if we did, it would be almost impossible to make contact.

So far astronomers have discovered a total of 500 planets in distant solar systems – known as extrasolar systems – although they believe billions of others exist.

But Dr Smith points out that many of these planets are either too close to their sun or too far away, meaning their surface temperatures are so extreme they could not support life.

Others have unusual orbits which cause vast temperature variations making it impossible for water to exist as a liquid – an essential element for life.

Dr Smith said: ‘We have found that most other planets and solar systems are wildly different from our own.

‘They are very hostile to life as we know it.’

‘The new information we are getting suggests we could effectively be alone in the universe.

‘There are very few solar systems or planets like ours. It means it is highly unlikely there are any planets with intelligent life close enough for us to make contact.’ But his controversial suggestions contradict other leading scientists – who have claimed aliens almost certainly exist.

These arguments are actually quite useful, and I include them in my standard list of scientific arguments for theism. (See below) You have to know this stuff cold. Most people believe in aliens because they watched movies made by artists. As a result, they think that humans are nothing special and that God is not interested in us in particular. Which is very convenient for them, because it means they can do whatever they want and not care what God thinks about what they are doing. If you want to defend against the idea that humans are nothing special, and that we were not placed here for a purpose, and that we are not accountable and obligated to seek and know the Creator/Designer, then you’ll need more than feelings. You’ll need science. You’ll need the best science available.

Related posts

• The origin of the universe from nothing
• The fine-tuning of the cosmological constants to permit life
• The fine-tuning of the galaxy, solar system, and planet to permit life
• Origin of the building blocks in the simplest replicating cell
• Origin of biological information in the simplest replicating cell
• Sudden origins of all major body plans in the Cambrian explosion
• Irreducible complexity in molecular machines
• The limits on what natural selection and random mutation can do
• Peer-reviewed paper says there is no atheistic explanation for the Cambrian explosion
• Does the Cambrian explosion disprove Darwinian evolution?

Filed under: News, Alien, Alien Life, Aliens, Astrobiology, Astrophysics, Atmosphere, Calculation, Cambrian Explosion, Carbon-based Life, Carl Sagan, Circumstellar Habitable Zone, Complex Life, Cosmos, Crust, Donald Brownlee, Drake Equation, Earth, Extra-Terrestrial Life, Extremophile, Frank Drake, Galactic Habitable Zone, Galaxy, Guillermo Gonzalez, Habitability, Habitable, Habitable Zone, Humans, Intelligent Design, Jupiter, Life, Liquid Water, Microbial Life, Milky Way, Moon, NASA, Odds, Origin of Life, Peter Ward, Planet, Plate Tectonics, Probabilities, Probability, Rare Earth, Science, SETI, Space, Star, Sun, Sweeper, The Privileged Planet, Universe, Water