Laws of physics are not fine-tuned for life, says cosmologist

The value of the cosmological constant suggests that the laws of nature could not have been fine-tuned for life by an omnipotent being, says a cosmologist:

Here's the thinking. The cosmological constant is a number that determines the energy density of the vacuum. It acts like a kind of pressure that, depending on its value, acts against gravity to push the universe apart or acts with gravity to pull the universe together towards a final Big Crunch.

Until recently, cosmologists had assumed that the constant was zero, a neat solution. But the recent evidence that the universe is not just expanding but accelerating away from us, suggests that the constant is positive.

But although positive, the cosmological constant is tiny, some 122 orders of magnitude smaller than Planck's constant, which itself is a small number.

So Page and others have examined the effects of changing this constant. It's straightforward to show that if the the constant were any larger, matter would not form into galaxies and stars meaning that life could not form, at least not in the form we know it.

So what value of the cosmological constant best encourages galaxy and star formation, and therefore the evolution of life? Page says that a slightly negative value of the constant would maximise this process. And since life is some small fraction of the amount of matter in galaxies, then this is the value that an omnipotent being would choose.

In fact, he says that any positive value of the constant would tend to decrease the fraction of matter that forms into galaxies, reducing the amount available for life.

Therefore the measured value of the cosmological constant, which is positive, is evidence against the idea that the constants have been fine-tuned for life.

My thoughts:

• As observers, we don't necessarily have to reside within a universe that is perfectly optimized for life—it just needs to be good enough to foster the emergence and sustenance of life. In the space of all possible life sustaining universes, ours may be but one example of many other viable models.
• Our universe may not be fine-tuned for life, but it may be optimized for something else. Our universe, for example, may actually be an exquisite black hole generator. Or something we don't yet know. 

New estimate for the number of habitable planets in the Milky Way: 2.5 billion!

Check out this article from Bad Astronomer: How many habitable planets are there in the galaxy?

By now you may have heard the report that as many as 1/4 of all the sun-like stars in the Milky Way may have Earth-like worlds. Briefly, astronomers studied 166 stars within 80 light years of Earth, and did a survey of the planets they found orbiting them. What they found is that about 1.5% of the stars have Jupiter-mass planets, 6% have Neptune-mass ones, and about 12% have planets from 3 – 10 times the Earth’s mass.

This sample isn’t complete, and they cannot detect planets smaller than 3 times the Earth’s mass. But using some statistics, they can estimate from the trend that as many as 25% of sun-like stars have earth-mass planets orbiting them!

His conclusion: There are over 2.5 billion habitable planets in our Galaxy. Whoa, my mind just melted.

Read more.

Sunspots on the decline

Scientists studying sunspots for the past two decades have concluded that the magnetic field that triggers their formation has been steadily declining. If the current trend continues, by 2016 the sun's face may become spotless and remain that way for decades—a phenomenon that in the 17th century coincided with a prolonged period of cooling on Earth.

The last solar minimum should have ended last year, but something unexpected has been happening. Although solar minimums normally last about 16 months, the current one has stretched over 26 months—the longest in a century. A reason, according to one source may be that the magnetic field strength of sunspots appears to be waning.

Tracking and predicting solar minimums and maximums is growing in importance given the potential for devastating solar flares.

New 'static universe' theory challenges the Big Bang

A growing number of cosmologists are becoming increasingly dissatisfied (or is that frustrated?) with the Big Bang Theory. One such person is David F. Crawford who recently posited a static theory of the universe which he claims better explains the properties of the cosmos than the Big Bang and avoids the nagging problems of dark matter and dark energy.

From Technology Review:

The idea that the universe began in an event called the Big Bang some 13 billion years ago has a special place in science and in our society. We like the idea of a beginning.

And the evidence is persuasive. Distant galaxies all appear to be moving away from us at great speed, which is exactly what you'd expect if they were created in a Big Bang type event many billions of years ago. Such an event might also have left an echo, exactly like the one we can see as the cosmic microwave background radiation.

The Big Bang seems so elegant an explanation that we're prepared to overlook the one or two anomalies that don't quite fit, like the fact that distant galaxies aren't travelling fast enough to have moved so far since the Big Bang, a problem that inflation was invented to explain. Then there are the problems of dark matter and dark energy, which still defy explanation.

So a legitimate question, albeit an uncomfortable one, is whether there is an alternative hypothesis that also explains the observations. We looked at one here and today, David Crawford at the University of Sydney in Australia gives us another. He says all this can be explained just as well by a static universe in which spacetime is curved. He says this explains most of the major characteristics of our universe without the need for dark matter or dark energy. Neither is there any need for inflation in a static universe.

Continue reading.

Novae produce gamma-rays. Damn.

Bad news: Novae emit gamma-rays.

We've known for a long time that supernovae produce gamma-rays, but until now it was assumed that novae lacked the power to emit such high-energy radiation. This is bad because novae occur at much greater frequency than super- and hypernovae; we are therefore at a much greater risk of being wiped out by a blast of gamma-ray radiation than previously thought.

The Milky Way experiences about 30 to 60 novae per year, with a likely rate of about 40. Roughly 25 novae brighter than about magnitude 20 are discovered in the Andromeda Galaxy each year and smaller numbers are seen in other nearby galaxies.

Contrast that with supernovae which occur about five times every hundred years.

A nova event should not be confused with a supernova. It is a cataclysmic nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner. A supernova, on the other hand, is a stellar explosion that is more energetic than a nova. Supernovae are extremely luminous and cause a burst of radiation that can outshine an entire galaxy before fading from view over several weeks or months. During this short interval a supernova can radiate as much energy as the Sun is expected to emit over its entire life span. The explosion expels much or all of a star's material at a velocity of up to 30,000 km/s (10% of the speed of light), driving a shock wave into the surrounding interstellar medium.

Though not as powerful as a supernova, novae are still immensely energetic, emitting the equivalent of about 1,000 times the energy emitted by our Sun every year. And now we can add gamma-rays to its list of nasty excretions.

To say that a gamma-ray blast would be bad for us here on Earth would be a gross understatement. Combined with the effects of a cataclysmic stellar explosion, it is one of the most powerful forces in the Universe, able to sterilize massive swaths of the galaxy. Supernovae can shoot out directed beams of gamma-rays to a distance of 100 light years, while hypernovae disburse gamma ray bursts as far as 500 to 1,000 light years away.

As for novae, the explosion creates a hot, dense, expanding shell called a shock front, composed of high-speed particles, ionized gas and magnetic fields. These shock waves expand at 7 million miles per hour—or nearly 1% the speed of light. The magnetic fields trap particles within the shell and whip them up to tremendous energies. Before they can escape, the particles reach velocities near the speed of light. Scientists say that the gamma rays likely result when these accelerated particles smashed into the red giant's wind.

Previous to this discovery, it was known that the remnants of much more powerful supernova explosions can trap and accelerate particles like this, but no one suspected that the magnetic fields in novae were strong enough to do it as well. Supernova remnants endure for 100,000 years and produce radiations that affect regions of space thousands of light-years across.

These explosions produce highly collimated beams of hard gamma-rays that extend outward from a nova or supernova. Any unfortunate life-bearing planet that should come into contact with those beams would suffer a mass extinction (if not total extinction depending on its proximity to the event). Gamma-rays would eat up the ozone layer and indirectly cause the onset of an ice age due to the prevalence of NO2 molecules.

Life on Earth just got that much more tenuous.

The future of space telescopes

With the Hubble Telescope project slowly winding down, it's time to look ahead to the next generation of space-based telescopes. There are two projects currently in the works that will undoubtedly revolutionize space telescopy and yield extraordinary results once put into use: The James Webb Space Telescope and the Advanced Technology Large-Aperture Space Telescope.

The James Webb Space Telescope

The James Webb Space Telescope (JWST) will be an infrared space observatory with the main scientific goal of observing the most distant objects in the universe beyond the reach of either ground based instruments or the Hubble. The JWST is a NASA project with international collaboration from the European Space Agency and the Canadian Space Agency, including contributions from fifteen nations.

Current plans call for the telescope to be launched on an Ariane 5 rocket in June 2014 (or mid 2015) and put on a five-year mission. The JWST will orbit the Sun in Earth's partial shadow, approximately 1,500,000 km on the far side of Earth at the L2 Lagrange point. Objects at the L2 point orbit the Sun in synchrony with the Earth, which will allow JWST to use one radiation shield, positioned between the telescope and the Earth, to protect it from both the Sun's and the Earth's heat and light. It's also possible for the same shield to block moonlight as the telescope is much further from Earth than the Moon.

The JWST's primary scientific mission has four main components:

1. Search for light from the first stars and galaxies which formed in the Universe after the Big Bang
2. Study the formation and evolution of galaxies
3. Understand the formation of stars and planetary systems
4. Study planetary systems and the origins of life

All of these tasks are more effectively done in the near-infrared than the visible. For this reason the JWST will not have the Hubble Telescope's visible light and ultraviolet capability but will be able to see much further into the infrared. Because of this, JWST will be able to see many more and much older stars than Hubble.

In addition, visible spectrum views cannot peer through much of the gas and dust that may obscure an image like infrared views can. Almost all of the gas and dust obscuring images in visible spectrum views may entirely disappear if viewed in the infrared, so that the stars lying behind the gas and dust will become easier to see. Infrared astronomy can penetrate dusty regions of space (such as molecular clouds), detect objects such as planets, and also view highly red-shifted objects from the early days of the universe.

The most distant stars in view are also the "youngest," that is, they were formed during a time period closer in time to that of the Big Bang than those stars less distant to us, such as our Sun. Because the universe is expanding, the light reaching us from those younger stars becomes red-shifted and are therefore easier to see if viewed in the infrared. Infrared light is also useful for observing the cores of active galaxies which are often cloaked in gas and dust.

The Advanced Technology Large-Aperture Space Telescope

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is still in the design and approval stage. If constructed, it will be a 8 to 16.8-meter (320 to 660-inch) UV-optical-NIR space telescope with the ability to obtain spectroscopic and imaging observations of astronomical objects in the ultraviolet, optical, and Infrared wavelengths. It will have substantially better resolution than either HST or the JWST. And like JWST, ATLAST will be launched to the Sun-Earth L2 Lagrange point.

ATLAST is envisioned as a flagship mission of the 2025 to 2035 period and will be designed to address the question of whether or not life exists elsewhere in the Galaxy. It will work to accomplish this by detecting biosignatures like molecular oxygen, ozone, water, and methane in the spectra of terrestrial exoplanets.

In addition to this, ATLAST will assist in uncovering the underlying physics that drives star formation and the complex interactions between dark matter, galaxies, and the intergalactic medium. Because of the large leap in observing capabilities that ATLAST will provide, it is not fully known which types of investigations will dominate its use—just as the creators of HST did not foresee its pioneering roles in characterizing the atmospheres of Jupiter-mass exoplanets or measuring the acceleration of cosmic expansion using distant supernovae. ATLAST will likely have the versatility to outlast the scientific vision of current-day astronomers.

Implications

Technological advances have worked to drive science forward for centuries. There's no reason to believe that JWST and ATLAST won't do the same. Given the insights gleaned from Hubble, we may discover completely new things about the Universe, our Galaxy, and other solar systems.

We should also probably brace ourselves for what we may find. Our place in the Universe will undoubtedly get smaller and increasingly insignificant—that has been the trend for quite some time now as we continually gaze deeper into space.

In addition, I suspect that we'll start to find solar systems that more closely resemble our own. To date, we have only been able to find systems in which gas giants reside in the inner solar system. As it stands, our solar system, with its outer gas giants, is atypical—but that may be the result of an observation selection effect caused by limited telescopic technology.

Lastly, we should be on the lookout out for signatures that may reveal the presence of extraterrestrial intelligence. Specifically, we should look for signs of megascale engineering (Dysonian structures and megascale computers) and so-called calling-card objects.

The 'Rare Earth' delusion

In my experience, the most common solution given to the Fermi Paradox is the Rare Earth hypothesis -- the idea that life in the Galaxy is exceptionally rare and that planets like ours are freakishly uncommon. For many, this conveniently explains why we haven't been visited by little green men. Or more accurately, extraterrestrial machine intelligences.

I've always thought, however, that given cosmologically large numbers that this sort of thinking is symptomatic of our small minds and limited imaginations. It's easy for us to throw up our hands and sheepishly declare that we're somehow special. Such a conclusion, however, needs to be qualified against the data involved, and by the mounting evidence in support of the notion that ours appears to be a life-friendly universe.

What Do You Mean, 'Rare'?

Let's pause for a moment and look at the numbers.

Recent figures place the total number of stars in the Milky way at an astounding three trillion. I don't need to tell you that that is a huge number. But given how poor the human mind is at groking large figures I'm going to play with this number for a bit:

• 3 trillion fully expressed is 3,000,000,000,000 (12 zeros)
  
• As an exponent it can be expressed as 3 x 10¹²
• Re-phrased, it is 3 thousand billions, or 3 million millions

Which necessarily leads to this question: given such a ginormous figure, what does it mean to be rare?

Even if the Earth is a one in a million occurrence, that means there are still 3 million Earthlike planets in the Galaxy (assuming one Earthlike planet per star). Does that qualify as rare? Not in my books.

If, on the other hand, the Earth is a one in a billion occurrence, then there are only 3,000 Earths in the galaxy. That sounds a bit more rare to me -- but one in a billion!? Seriously?

We also have to remember that the 3 trillion stars only accounts for what exists right now in the Milky Way. There have been well over a billion trillion stars in our past Universe. As Charles Lineweaver has noted, planets began forming in our Galaxy as long as 9 billion years ago. We are relative newcomers to the Galaxy.

Our Biophilic Universe

But all this numerological speculation might be moot. We're overlooking the mounting evidence indicating that we live in a universe exceedingly friendly to life. What we see in the physical laws and condition of the universe runs contrary to the expectations of the Rare Earthers.

Indeed, we are discovering that the Galaxy is littered with planets. Scientists have already cataloged 321 extrasolar planets -- a number that increases by a factor of 60 with each passing year. Yes, many of these are are so-called "hot Jupiters," but the possibility that their satellites could be habitable cannot be ruled out. Many of these systems have stable circumstellar habitable zones.

And shockingly, the first Earthlike planet was discovered in 2007 orbiting the red star Gilese 581. It's only 20 light-years away, 1.5 times the diameter of Earth, is suspected to have water and an atmosphere, and its temperature fluctuates between 0 and 40 degrees Celsius.

If we are one in a billion, then, and considering that there are only 0.004 stars per cubic light-year, what are the odds that another Earthlike planet is a mere 20 light-years away?

Indeed, given all this evidence, the Rare Earthers are starting to come under attack. Leading the charge these days is Alan Boss who recently published, The Crowded Universe. Boss estimates that there may be billions of Earthlike planets in the Milky Way alone. "I make the argument throughout the book that we already know that Earths are likely to be incredibly common—every solar-type star probably has a few Earth-like planets, or something very close to it," says Boss. "To my mind, at least, if one has so many habitable worlds sitting around for five billion or 10 billion years, it's almost inevitable that something's going to start growing on the majority of them."

Life Abounds

And it gets worse for the Rare Earthers. They also have to contend with the conclusions of astrobiologists.

It's a myth, for example, that it took life a long time to get going on Earth. In reality it was quite the oppoite. Our planet formed over 4.6 billion years ago and rocks began to appear many millions of years later. Life emerged relatively quickly thereafter some 600 million years after the formation of rocks. It's almost as if life couldn't wait to get going once the conditions were right.

We also live in a highly fertile Galaxy that's friendly to extremophiles. The Panspermia hypothesis suggests that 'life seeds' have been strewn throughout the Galaxy; evidence exists that some grains of material on Earth have come from beyond our solar system.

Recent experiments have shown that microorganisms can survive dormancy for long periods of time and under space conditions. We also now know that rocks can travel from Mars to Earth and that simple life is much more resilient to environmental stress than previously imagined. Consequently, biological diversity is probably much larger than conventionally assumed.

Common Earth

My feeling is that the Rare Earth hypothesis is a passing scientific fad. There's simply too much evidence growing against it.

In fact, the only thing going for it is the Fermi Paradox. It's comforting to think that the Great Silence can be answered by the claim that we're exceptionally special. Rare Earth steers us away from other, more disturbing solutions --namely the Great Filter hypothesis.

But such is the nature of scientific inquiry. We're not always going to like what we find, even if it is the truth.

As for the Fermi Paradox, we'll have to look for answers elsewhere.

Larger Milky Way has implications for the Drake Equation and the Great Silence -- or does it?

Apropos of Russell Blackford's recent posts about the Fermi Paradox, it should be mentioned that the Milky Way is 50% larger than previously thought. This will likely have implications to our appreciation of the Drake Equation and the Fermi Paradox.

What tipped cosmologists off was the discovery that our galaxy is spinning 15% faster than formerly assumed. The lead researcher on the project, Mark Reid of the Harvard-Smithsonian Center for Astrophysics in Cambridge, estimates that the Milky Way's spin is about 914,000 km/hour, significantly higher than the widely accepted value of 792,000 km/hour.

The only thing that could account for this increased spin rate was more mass -- a lot more mass. As a result of Reid's findings, our models now need to account for a galaxy that is 50% heavier, 15% wider and contains a mind-boggling 3 trillion stars! That is an astounding 750% increase from 400 billion.

You might want to pause for a moment and think about this.

This is remarkable news and the implications of these findings are going to take a while to sink in. My first reaction was to consider the implications to the Fermi Paradox. Does a significantly larger Milky Way accentuate or diminish the problem that is the Great Silence?

First off, it throws previous Drake Equation estimates out the window. Blogger Paul Hughes has already crunched some numbers and has come up with his own estimate: he believes there may be as many as 12 billion Earth-like planets in our galaxy capable of supporting liquid water and in turn carbon-based life as we know it (Hughes doesn't take the equation beyond that as he was inquiring into the number of potentially habitable planets).

But as many of my readers know, I'm not a great fan of the Drake Equation to begin with. It's in dire need of an upgrade and it completely fails to account for the cosmological development of the galaxy and other temporal aspects. That said, it's safe to assume that the probability of extraterrestrial life emerging in the Galaxy is now significantly higher than it was before -- both in the Galaxy's long history and now.

Second, the new and improved Milky Way throws off previous calculations as to how long it would take an advanced civilization to inhabit all four corners of the galaxy. An extraterrestrial migration wave would likely be comprised of self-replicating colonization probes that spread out across the galaxy at an exponentially increasing rate. Previous estimates placed complete Galaxy-wide colonization at a few million years. Given that we were wrong about the size of the Milky Way and the number of stars, we have to conclude that it would take longer to colonize the entire galaxy.

Just how much longer I'm not sure [sounds like a future project in the making], but given that we're talking about exponentially increasing migration rates I would have to think that we are not talking about an order of magnitude. And even if it does take significantly longer, we still have to take the extreme age of the Milky Way into consideration and the likelihood that intelligence may have emerged in the Galaxy as long as 4.5 billion years ago. The age of the Galaxy is still disproportionately longer than even the most pessimistic colonization rate estimates.

What does all this mean?

Well, nothing really. The Great Silence is obviously still in effect and something's still screwy with the Universe. A bigger Milky Way means that there's likely more intelligent life in the Galaxy than we had previously assumed, but that interstellar colonization and communication rates are slightly longer.

The Fermi Paradox lives on.

Our holographic universe

This month's New Scientist features a cover article about the theoretic possibility that our universe may be a giant hologram. This revelation isn't anything new, but there now appears to be potential evidence in favor of the suggestion.

For a number of months, team-members working on the GEO600, a device that measures gravity waves, were confused about some inexplicable noise that was plaguing the giant detector. Researcher Craig Hogan offered an explanation: the GEO600 has stumbled upon the fundamental limit of space-time - the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into "grains," just as a newspaper photograph dissolves into dots as you zoom in.

"If the GEO600 result is what I suspect it is," says Hogan, "then we are all living in a giant cosmic hologram." The New Scientist article explains:

The holograms you find on credit cards and banknotes are etched on two-dimensional plastic films. When light bounces off them, it recreates the appearance of a 3D image. In the 1990s physicists Leonard Susskind and Nobel prizewinner Gerard 't Hooft suggested that the same principle might apply to the universe as a whole. Our everyday experience might itself be a holographic projection of physical processes that take place on a distant, 2D surface.

Confirming the holographic principle would be a big help to researchers trying to unite quantum mechanics and Einstein's theory of gravity. Hogan contends that if the holographic principle is confirmed, it rules out all approaches to quantum gravity that do not incorporate the holographic principle. Conversely, it would be a boost for those that do, like those derived from string theory and matrix theory. "Ultimately," says Hogan, "we may have our first indication of how space-time emerges out of quantum theory."

My favorite quote from the article comes from Hogan: "It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time."

Mmmmm, microscopic quantum convulsions of space-time.

Okay, so you're a hologram. Carry on.

Photo Credit: Kenn Brown of Mondolithic Studios.

Our non-arbitrary universe: A SentDev Classic

As scientists delve deeper and deeper into the unsolved mysteries of the universe, they are discovering that a number of cosmological parameters are excruciatingly specific. So specific, in fact, that any minor alteration to key parameters would throw the entire universe off kilter and result in a system completely unfriendly to life.

Consequently, some have considered this as evidence for a designer, giving rise to teleological arguments like intelligent design. Others claim that the universe is spontaneously finely tuned.*

There are several theories that try to explain why the universe is so finely tuned: 1) anthropic observation in consideration of an ensemble of universes [Carter, Leslie], 2) the "participatory anthropic principle" which implies that observers force the universe into existence [Wheeler], and 3) that natural selection has endowed the universe with its particular characteristics [Smolin, Smart].

On the last point, that of natural selection, the obvious question is, if the universe is a replicating entity, and if its attributes are the result of natural selection, why must the universe also be so biophilic? In other words, couldn't the physics of the universe develop such that it was merely a replicating entity that didn't necessarily have to support life?

One possible answer is that there are many types of spontaneously replicating universes, some of which support life, and some of which do not. If this is the case, we happen to observe one such universe that supports life, and our existence is irrelevant to our universe's life cycle.

However, if we find that the universe we live in is the only feasible type of universe possible, and that it is a replicative system prone to selectional processes, then we might have to conclude that intelligent life plays a crucial role in the universe's life cycle. In other words, advanced intelligences help the universe to replicate.

As Freeman Dyson once wrote, "The more I examine the universe and study the details of its architecture, the more evidence I find that the universe in some sense must have known that we were coming. There are some striking examples in the laws of nuclear physics of numerical accidents that seem to conspire to make the universe habitable."

I first encountered this argument via John Smart's developmental singularity hypothesis, where he suggests that advanced intelligences may spawn new baby universes soon after the technological singularity event. More recently, I discovered an article on KurzweilAI by James N. Gardner in which he argues for the selfish biocosm hypothesis.

Gardner's argument is quite interesting. He writes that two recent discoveries have imparted a renewed sense of urgency to investigations of the anthropic qualities of our cosmos, specifically 1) the value of dark energy density is exceedingly small but not quite zero, and 2) the number of different solutions permitted by M-theory is astronomical -- measured not in millions or billions but in googles or googleplexes. Again, what he's suggesting is that the universe is finely tuned to the point of absurdity.

According to Gardner's theory, "the laws and constants of physics function as the cosmic equivalent of DNA, guiding a cosmologically extended evolutionary process and providing a blueprint for the replication of new life-friendly progeny universes."

As Gardner notes, theories of cosmological eschatology have previously been articulated by Kurzweil, Wheeler and Dyson, all of whom have essentially predicted that, in Gardner's words, "the ongoing process of biological and technological evolution is sufficiently robust and unbounded that, in the far distant future, a cosmologically extended biosphere could conceivably exert a global influence on the physical state of the cosmos." Some cosmologists, like Milan Cirkovic, have argued that the universe's life cycle should not be studied without referrence to the influence of intelligent life.

Specifically, it is thought that intelligences, in conjunction with advancing technologies, will act as "von Neumann controllers" within a cosmologically extended biosphere and function as a "von Neumann duplicator" in a hypothesized process of cosmological replication.

I find this topic to be exceptionally interesting, and I hope that more consideration is given to it in the coming years, particularly the issue of cosmological eschatology and the role that intelligences may have in the life cycle of the universe.
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*Browsing through Wikipedia, I found some examples of 'fine tuning':

• The nuclear strong force holds together the particles in the nucleus of an atom. If the strong nuclear force were slightly weaker, by as little as 2%, multi-proton nuclei would not hold together and hydrogen would be the only element in the universe. If the strong force were slightly stronger, by as little as 1%, hydrogen would be rare in the universe and elements heavier than iron (elements resulting from fusion during the explosion of supernovae) would also be rare.
• The nuclear weak force affects the behavior of leptons (e.g. neutrinos, electrons, and muons) that do not participate in strong nuclear reactions. If the weak force were slightly larger, neutrons would decay more readily, and therefore would be less available, and little or no helium would be produced from the big bang. Without the necessary helium, heavy elements sufficient for the constructing of life as we know it would not be made by the nuclear furnaces inside stars. If the weak force were slightly smaller, the big bang would burn most or all of the hydrogen into helium, with a subsequent over-abundance of heavy elements made by stars, and life as we know it would not be possible.
• The electromagnetic coupling constant binds electrons to protons in atoms. The characteristics of the orbits of electrons about atoms determines to what degree atoms will bond together to form molecules. If the electromagnetic coupling constant were different atoms and molecules would be different; maybe not even exist.
• The ratio of electron to proton mass also determines the characteristics of the orbits of electrons about nuclei. A proton is 1836 times more massive than an electron. If the electron to proton mass ratio were different, atoms and molecules would be different — or maybe not even exist.
• The entropy level of the universe affects the condensation of massive systems. The universe contains about one billion photons for every baryon. This makes the universe extremely entropic, i.e. a very efficient radiator and a very poor engine. If the entropy level for the universe were slightly larger, no galactic systems would form (and therefore no stars). If the entropy level were slightly smaller, the galactic systems that formed would effectively trap radiation and prevent any fragmentation of the systems into stars. In either case, the universe would be devoid of stars and solar systems.
• The force of gravity affects the interaction of particles. In order for life as we know it to form, the force of gravity must be 1040 (10 to the 40th power) times weaker than the force of electromagnetism. The relationship of gravity to electromagnetism as it currently exists is this: The positively charged particles must equal in charge the numbers negatively charged particles or else electromagnetism will dominate gravity, and stars, galaxies and planets will not form. The numbers of electrons must equal the numbers of protons to better than one part of 1037 (10 to the 37th power).

This article was originally published on March 2, 2006.

One year ago on SentDev: How will our Universe die?

Last year at this time I tackled the question: How will our Universe die?
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An interesting theory has emerged which predicts that trillions of years into the future, the information that currently allows us to understand how the universe expands will have disappeared over the visible horizon. All that will remain will be "an island universe" made from the Milky Way and its nearby galactic Local Group neighbors. What's left will be a dark and lonely void.

The theory was put out by physicists Lawrence Krauss from Case Western Reserve University and Robert J. Scherrer from Vanderbilt University. Their research article, titled, "The Return of the Static Universe and the End of Cosmology," will be published in the October issue of the Journal of Relativity and Gravitation.

This brings to mind a number of different theories in the field of cosmological eschatology.

The Big Crunch

The work of Krauss and Scherrer stands in sharp contrast to another end-state theory, namely the Big Crunch. In this model, the momentum of the Big Ban will eventually wane causing the Universe to collapse in on itself. But due to the recent revelation that the Universe is not just expanding but that its expansion is speeding up, newer theories have suggested that the Universe will continue to expand forever.

The Big Rip

This has lead to some rather bizarre conclusions, including the emergence of a theory known as the Big Rip. According to this theory, the Universe will start to expand at such a rapid rate that all its elements, from galaxies to atoms, will be torn apart by the extreme expansion rate of the Universe. This is scheduled to happen about 20 billion years from now.

The force that is causing the Universe's matter to push outwards is what's known as dark energy. This is why galaxies are moving away from each other -- and why they will continue to do so until gravity will be too weak to hold them together.

Eventually, in the final months of the Universe, our solar system will be gravitationally unbound. In the last minutes, stars and planets will be torn apart. And in the Universe's final spastic salvo all atoms will be destroyed.

Heat Death

Another possibility is the Heat Death of the Universe, also known as The Big Freeze. In this model the Universe would continue to expand forever, but it would enter into a state of maximum entropy in which all matter and energy is evenly distributed; consequently, there would be no 'gradient' to the Universe -- a characteristic that is needed to sustain information processing, including life.

Other theories

Other possibilities include the False Vacuum, where the laws and constants of the Universe are subject to radical change, and various multiverse theories in which the cosmos is expressed in a infinite number of iterations for an infinity.

Another more radical possibility is that the future of the Universe will be influenced by intelligent life. Theories already exist in regards to stellar engineering -- where a local sun could be tweaked in such a way as to extend its lifespan. Future civilizations may eventually figure out how to re-engineer the Universe itself (such as re-working the constants) or create an escape hatch to basement universes.

Thinkers who have explored this possibility include Milan Cirkovic, John Smart, Ray Kurzweil, Alan Guth and James N. Gardner.

Read more here.

One year ago on SentDev: When hypergiants go hypernova

It was about a year ago around this time that scientists observed a star that went nova 238 million years ago. It turned out to be a hypernova that made a big badda boom.
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Scientists predicted that something like this could happen, and now they have actually observed it: a hypergiant star went nova.

About 238 million years ago a star in galaxy NGC 1260 ended its life. To say that it was a powerful explosion would be a gross understatement; the amount of explosive energy expelled by supernova SN 2006gy defies human comprehension.

Prior to its dramatic death, the hypergiant star, which was 150 times larger than our own, suffered a sudden and violent collapse. Extremely high levels of gamma radiation from the star's core caused its energy to transform to matter, and the drop in energy in turn caused the star to collapse. This resulted in a dramatic increase in the thermonuclear reactions that was burning within it. All this added energy overpowered the gravitational attraction causing the star to explode.

And explode it did.

Scientists claim that the supernova was over 150 times more powerful than any other observed to date. Physical models suggested that such a supernova was theoretically possible, but astronomers believed that such events were limited to the early Universe when stars tended to be hypergiant.

A hypernova like SN 2006gy can instantly expel about 10X46 joules. This is more energy than our sun produces over a period of 10 billion years.

According to the Astroprof blog,

At discovery, it was already as bright as a Type Ia supernova at its peak. But, instead of getting dimmer, SN 2006gy continued to get brighter for several weeks. The peak brightness seldom comes much more than a week after the explosion. Theoretical models suggest that SN 2006gy gets its light from both the expanding cloud of gas and a shock front as the cloud of gas expands into very dense gasses surrounding the progenitor star. But, the expanding gas cloud is so bright that it requires substantially more radioactive decay to heat it that would be present in almost any other supernova. The best way to get that much radioactive material, according to the model that the theorists have come up with, is for basically the whole core to be thrown out into the supernova, leaving little or nothing behind to form a neutron star or black hole. So much material is thrown out, that the supernova continues to be heated long after the explosion itself. In fact, even months later, SN 2006gy has faded in brightness only to as bright as the peak brightness of a Type Ia supernova!

In fact, astronomers were able to observe the hypernova's peak brightness for an astounding 70 days.

Supernovas can wreak tremendous havoc in its local area, effectively sterilizing the region. These explosions produce highly collimated beams of hard gamma rays that extend outward from the exploding star. Any unfortunate life-bearing planet that should come into contact with those beams would suffer a mass extinction (if not total extinction depending on its proximity to the supernova). Gamma rays would eat up the ozone layer and indirectly cause the onset of an ice age due to the prevalence of NO2 molecules.

Supernovas can shoot out directed beams of gamma rays to a distance of 100 light years, while hypernovas and gamma ray bursts can impact areas as far as 500 light years away.

Thankfully, hypergiant Eta Carinae, which is on the verge of going nova, is well over 7,500 light years away from Earth. We'll be safe when it goes off, but you'll be able to read by its light at night-time.

Latest podcast posted: 2008.03.18

The latest episode of the Sentient Developments Podcast is now available. Alternative audio formats are also available.

This episode: The Fermi Paradox is back with a vengeance, nanotechnology will reshape humanity, and why evolutionary psychology says we should cut Spitzer some slack.

The Fermi Paradox: Possible solutions and next steps

This article is partly adapted from my TransVision 2007 presentation, “Whither ET? What the failing search for extraterrestrial intelligence tells us about humanity's future.”

In my previous two articles I attempted to re-affirm the Fermi Paradox (FP) and circumscribe some of the possible interstellar activities and developmental aspects of advanced extraterrestrial intelligences (ETI’s).

In this article I will offer two broad solutions to the FP: 1) unavoidable self-destruction and 2) localized non-migratory existence.

It is not my intention at this time to provide a complete list of possible reconciliations, nor am I claiming to have found any kind of special answer; I just wish to explore these two particular possibilities.

At the conclusion of this article I offer some suggestions to help us move forward as we work to solve the observational problem that is the Great Silence.

Self-Destruction and the Great Filter

This is the most likely and philosophically satisfying answer to the Fermi Paradox – although hardly the most desirable.

Looking at ourselves as a typical example of a pre-Singularity civilization, what do we find? We find a species already in possession of apocalyptic technologies and on the verge of developing an entirely new generation of lethal weapons. In short order we will be required to manage an assortment of apocalyptic technologies; it will be akin to spinning plates. There are only so many that can be managed before one of them falls – and one is all that is needed to end the story.

Examples of pending existential risks include the ongoing threat of nuclear holocaust, a nanotechnological disaster, poorly programmed artificial superintelligence (ie Singularity as extinction event), catastrophic pandemic, and so on.

A counter-argument is often made that self-inflicted catastrophism could never be exclusive to all civilizations. How is it, ask critics, that all civilizations cannot escape such a fate? Robin Hanson attempted to answer this question by proposing the Great Filter hypothesis – the suggestion that a developmental stage exists for all life which is insurmountable. The question then: is the Great Filter behind us, or does it await us in our future?

I would argue, based on much of the data I presented earlier, that the Rare Earth hypothesis has to be rejected. Moreover, a healthy application of the self-sampling assumption strongly indicates that the filter is ahead of us should it exist. The Galaxy is likely brimming with life, including complex life.

As for as the search for extraterrestrial life is concerned, Hanson argues that the detection of ETI's would be bad. This would indicate, given our observation of an unperturbed, uncolonized galaxy, that the Great Filter is indeed still ahead of us.

Another disturbing data point as a self-sampling species is that we here on earth have come to possess apocalyptic technologies long before we have developed the capacity to live off-planet or live in self-contained biospheres. All our eggs are in one basket and they will continue to remain that way into the foreseeable future.

And then there's the disturbing Doomsday Argument which suggests that we're closer to the end than the beginning of human civilization.

Perhaps the most common and smug solution to the Fermi Paradox is the suggestion that we are the first. It is frequently used because it is said to best satisfy Occam’s Razor. But while it may be the simplest solution, it defies our sense of probability and disregards the central lesson of the Copernican Principle – the idea that we are not unique, and very likely a typical example.

Earlier I presented a picture of a biophilic Universe. If this issue is to be settled by a battle between Occam’s Razor and the Copernican principle, on this matter I’ll take Copernicus any day.

Interestingly, the longer we survive as a species without extraterrestrial contact, the more we can assume that we have passed the Great Filter.

Localized non-migratory digital existence

Now, the prospect of human extinction is quite obviously mere speculation. As Morpheus proclaimed in the Matrix: “We are still here!” Consequently, there are some non-extinction scenarios that I would like to explore.

The past 40 years of scientific progress has forced a re-evaluation of humanity’s potential. We appear to be headed for a transformation that takes us away from biological existence and towards a postbiological, or digital existence. Our future visions must take this into account. As Milan Cirkovic and Robert Bradbury have noted, we need to adopt a digital perspective (pdf).

Why leave the local system when everything can be accomplished at home? Localized existence may hold promise for all the aspirations that an advanced intelligence could conceivably conjure.

Specifically, advanced intelligences may engage in computational megaprojects and live virtual reality existences. It would be an existential phase transitioning into virtual space such that interstellar colonization would never emerge as a feasible option or experiment.

For example, advanced ETI’s may construct Jupiter (pdf) and Matrioshka Brains. A Jupiter Brain would utilize all the matter of entire planet for the purpose of computation, while a Matrioshka Brain (a kind of Dyson sphere) would utilizes the energy output of its parent star.

Determining an upper bound for computational power is difficult, but a number of thinkers have given it a shot. Eric Drexler has outlined a design for a system the size of a sugar cube that would perform 10^21 instructions per second. Robert Bradbury gives a rough estimate of 10^42 operations per second for a computer with a mass on order of a large planet. Seth Lloyd calculates an upper bound for a 1 kg computer of 5*10^50 logical operations per second carried out on ~10^31 bits – this would likely be done on a quantum computer or computers built of out of nuclear matter or plasma [see this article and this article for more information].

More radically, John Barrow has demonstrated that, under a very strict set of cosmological conditions, indefinite information processing (pdf) can exist in an ever-expanding universe.

This type of computational power is astounding and defies human comprehension. It’s like imagining a universe within a universe -- and that may be precisely be how it's used.

What would a future civilization do with all this power?

A civilization’s transition into high-speed digital mode may come about as natural consequence of its development. The switch from an analog civilization to a digital one – one in which the clock-speed would be accelerated to billions if not trillions of times faster than before – would preclude the desire to interact with the outside world.

Megascale computers may be used to support uploaded civilizations. It may prove to be the existential substrate of choice – one in which the potential for self-destruction is greatly mitigated.

Advanced civilizations may also use this computer power to run simulations for reasons of scientific research, running ancestor simulations or for entertainment (pdf) purposes. Simulations may also be run as a part of some sort of ethical or sociological necessity.

Another possibility is the Hedonistic Imperative, a term attributed to David Pearce. Given that virtually every religion has fantasized about an afterlife of bliss and an end to suffering, paradise engineering may come to represent the optimal end-state for intelligent life. Ultimately, societies will always be comprised of conscious individuals. The optimization of subjective experience may take precedence over colonial ambitions.

This tendency may be part of a broader, more 'existential' focus on life. Civilizational achievement may not be measured by the rate of imperialistic expanse or by how much energy it can consume, but in how individuals relate to themselves and their place in the Universe. This quest for introspective enlightenment may be characterized by efforts to optimize the mode of conscious experience.

What about long term survival?

In regards to long-term survival, Vernor Vinge has predicted that post-Singularity intelligences will build local secondary systems to ensure the near-immortality of the infocomplex. These could exist in off-planet repositories. Shields composed of nanotechnology and femtotechnology could deal with the issue of gamma ray bursters and other cosmological threats.

As for the local star, it could be given added life through stellar-engineering projects in which the crucially low elements are re-introduced. Eventually, however, migration to a younger star would be necessary.

There may also be unknown reasons for this type of existence. But what is certain is that wide-scale colonization is not in the cards.

Moving Forward

Admittedly, these two broad solutions -- self-destruction and non-migration scenarios -- are unsatisfactory. The notion that not even one civilization can escape self-destruction is difficult to believe. Moreover, localized digital existence and the proliferation of colonization waves are not either/or scenarios; one can imagine a civilization embarking on both paths.

As we move forward in attempting to solve the FP we need to apply much stricter methodologies to the problem.

Solutions to the FP must avoid the trappings of sociological analyses, which often present non-exclusive scenarios. Answers like the ‘zoo hypothesis,’ ‘non-interference,’ or ‘they wouldn’t find us interesting,' tend to be projections of the human psyche and our own modern-day realities. Moreover, these sorts of solutions, while they may account for some of the actions of advanced civilizations, cannot account for all.

Instead, a more rigid and sweeping methodological frame needs to be applied– one which takes cosmological determinism and sociological uniformitarianism into account. In other words, we need to be concerned with cosmological limits and the pressure of physical and resource constraints.

This is what is Nick Bostrom refers to as the strong convergence hypothesis -- the idea that all sufficiently advanced civilizations converge towards the same optimal state. This is a hypothesized developmental tendency akin to a Dawkinsian fitness peak -- the suggestion that identical environmental stressors, limitations and attractors will compel intelligences to settle around optimal existential modes. This theory does not favour the diversification of intelligence – at least not outside of a very strict set of living parameters.

The trick will be to predict what these deterministic constraints are. One can imagine factors such as limited resources, access to energy, computational requirements (including heat dissipation, error correction, and latency problems) and self-preservational modes (i.e. political and social orientations that eliminate the possibility of self-destruction).

A side benefit of this exercise is that it doubles as a foresight activity. The better we become at predicting the make-up of advanced ETI's, the better we will be at predicting our own future.

Consequently, our very own survival may depend on it.

Part I: The Fermi Paradox: Back With a Vengeance

Part II: The Fermi Paradox: Advanced Civilizations Do Not...

The Fermi Paradox: Advanced civilizations do not…

This article is partly adapted from my TransVision 2007 presentation, “Whither ET? What the failing search for extraterrestrial intelligence tells us about humanity's future.”

As I stated in my previous article, “The Fermi Paradox: Back with a vengeance”:

The fact that our Galaxy appears unperturbed is hard to explain. We should be living in a Galaxy that is saturated with intelligence and highly organized. Thus, it may be assumed that intelligent life is rare, or, given our seemingly biophilic Universe, our assumptions about the general behaviour of intelligent civilizations are flawed.

A paradox is a paradox for a reason: it means there’s something wrong in our thinking.

So, let’s try to figure out what’s going on. Given the Great Silence, and knowing what we may be capable of in the future, we can start to make some fairly confident assumptions about the developmental characteristics of advanced civilizations.

But rather than describe the possible developmental trajectories of extraterrestrial intelligences (ETI's) (a topic I’ll cover in my next article), I’m going to dismiss some commonly held assumptions about the nature of advanced ETI’s – and by consequence some assumptions about our very own future.

Advanced civilizations do not…

…advertise their presence to the local community or engage in active efforts to contact

As SETI is discovering (but is in denial about), space is not brimming with easily detectable radio signals. SETI’s work during the past 40 years indicates that the quest to detect signals will not be easy.

This problem is not as simple as it sounds. A common apology is that we’ve only recently started our search and we have only scratched the surface. The trouble, however, is that it would be no problem for an ETI to communicate with us if they wanted to.

To do this all they would need to do is seed the Galaxy with Bracewell probes (a self-replicating communications beacon). This scenario was explored in Carl Sagan’s Contact in which a Bracewell probe was lying in wait about 26 light years from Earth in the Vega system. The probe was activated by our radio signals, causing it to direct powerful radio signals at Earth – signals that would not be overlooked.

We know that no such object exists in our solar system or within a radius of about 25 to 50 light years. Our radio activity should have most certainly activated any probe lying dormant in our local vicinity by know. It is also reasonable to assume that if ETI’s embarked on such a communications mission that every solar system would likely have its own Bracewell probe.

Which in turn raises a more troubling question: if ETI’s could construct and distribute probes in this way, why haven’t they gone the extra mile and spread other types of self-replicating devices such as uplift or colonization probes?

…engage in any kind of megascale engineering or stellar re-engineering that is immediately obvious to us within our light cone

All stellar phenomenon that we have observed to this point in time appears ‘natural’ and unmodified. We see no clusters of perfectly aligned stars, nor do we signs of Kardashev III civilizations utilizing the energy output of the entire Milky Way.

As for our light cone, the Milky Way is 100,000 light years in diameter; given the possibility that our Galaxy has been able to support intelligent life for about 4.5 billion years, a 100 million year time lag (at its worst) is not severe enough to cause observational problems (except for distant Galaxies).

…colonize the Galaxy

Our Galaxy remains uncolonized despite the theoretical potential for advanced ETI’s to do so – namely the time and the technology. All that would be required is a self-replicating Von Neumann probe that proliferates outward at an exponential rate. Technologies required to build such a spacecraft would include artificial intelligence, molecular assembling nanotechnology, and an advanced propulsion scheme like anti-matter rockets, beamed energy, or interstellar ram-jets.

The reason for non-colonization is not obvious (hence the Fermi Paradox). In addition to technological feasibility there is the issue of economic and sociological imperatives for colonization.

…sterilize the Galaxy

Finally, some good news. We know the Galaxy is not sterile because we exist here on Earth.

Like the colonization potential, the prospect for an advanced ETI to sterilize the Galaxy exists through the use of berserker probes (a term attributed to Fred Saberhagen). These probes could steer NEO’s at planets, unleash nanotechnological phages, or toast planets with directed beams of highly concentrated light.

And like the Bracewell scenario, if a beserker was lying dormant in our solar system it should have destroyed us by now. If sterilization is the goal, there is no good reason for it to wait – particularly as our own civilization hurtles towards a Singularity transition.

Reasons for unleashing fleets of berserkers can be conceived, including xenophobic sociological imperatives or a malign artificial superintelligence (pdf). And all it would take is one civilization to do it. But as Robert Freitas has stated, "The present observational record can only support the much more restricted conclusion that no rapacious galactic civilisations are currently loose in the Galaxy."

…uplift or interact with pre-Singularity intelligences and biospheres

As a civilization that has been left to fend for itself, we have to assume that we, like any other civilization out there, goes it alone. No one is coming to help us. The Great Silence will continue.

Moreover, our presence on Earth and our civilizational development can be explained by naturalistic phenomena. Our existence and ongoing progress has been devoid of extraterrestrial interventions. If we’re going to survive the Singularity, or any other existential risks for that matter, it will have to be of our own devices.

…re-engineer the cosmos

A number of prominent futurists, a list that includes Ray Kurzweil and Hans Moravec, have speculated that the destiny of advanced intelligence is to re-work the cosmos itself. This has been imagined as an ‘intelligence explosion’ as advanced life expands outward into the cosmos like a bubble. The entire Galaxy would be re-organized with much of its matter converted into computronium. Eventually, it is thought that the laws of the Universe will be re-tuned to meet the needs of advanced civilizations.

Unfortunately, we do not appear to inhabit a Universe that even remotely resembles this model. The cosmos appears natural and unperturbed.

This is reminiscent of the God problem and the presence of evil. We live in a Universe that is hostile, indifferent and pointless. If advanced ETI’s had the capacity to re-engineer the Universe such that it was safer, more meaningful and paradisical they would have done so by now. By virtue of the fact that we observe such a dangerous Universe we should probably conclude that such a project is not an option.

In the final part of this series I will make an effort to explain why advanced civilizations don’t do these things and what they might be doing instead.

Part I: Fermi Paradox: Back With a Vengeance

Part III: Fermi Paradox: Possible Solutions and Next Steps

The Fermi Paradox: Back with a vengeance

This article is partly adapted from my TransVision 2007 presentation, “Whither ET? What the failing search for extraterrestrial intelligence tells us about humanity's future.”

The Fermi Paradox is alive and well.

As our sciences mature, and as the search for extraterrestrial intelligence continues to fail, the Great Silence becomes louder than ever. The seemingly empty cosmos is screaming out to us that something is askew.

Our isolation in the Universe has in no small way shaped and defined the human condition. It is such an indelible part of our reality that it is often taken for granted or rationalized to extremes.

To deal with the cognitive dissonance created by the Great Silence, we have resorted to good old fashioned human arrogance, anthropocentrism, and worse, an inter-galactic inferiority complex. We make excuses and rationalizations like, ‘we are the first,’ ‘we are all alone,’ or, ‘why would any advanced civilization want to bother with us backward humans?’

Under closer scrutiny, however, these excuses don’t hold. Our sciences are steadily maturing and we are discovering more and more that our isolation in the cosmos and the dearth of observable artificial phenomenon is in direct violation of our expectations, and by consequence, our own anticipated future as a space-faring species.

Indeed, one of the greatest philosophical and scientific challenges that currently confronts humanity is the unsolved question of the existence of extraterrestrial intelligences (ETI's).

We have yet to see any evidence for their existence. It does not appear that ETI’s have come through our solar system; we see no signs of their activities in space; we have yet to receive any kind of communication from them.

Adding to the Great Silence is the realization that they should have been here by now -- the problem known as the Fermi Paradox.

The Fermi Paradox
The Fermi Paradox is the contradictory and counter-intuitive observation that we have yet to see any evidence for the existence of ETI’s. The size and age of the Universe suggests that many technologically advanced ETI’s ought to exist. However, this hypothesis seems inconsistent with the lack of observational evidence to support it.

Largely ignored in 1950 when physicist Enrico Fermi famously asked, “Where is everybody,” and virtually dismissed at the seminal SETI conference in 1971, the conundrum was given new momentum by Michael Hart in 1975[1] (which is why it is sometimes referred to as the Fermi-Hart Paradox).

Today, 35 years after it was reinvigorated by Hart, it is a hotly contested and relevant topic -- a trend that will undoubtedly continue as our sciences, technologies and future visions develop.

Back with a vengeance
A number of inter-disciplinal breakthroughs and insights have contributed to the Fermi Paradox gaining credence as an unsolved scientific problem. Here are some reasons why[2]:

Improved quantification and conceptualization of our cosmological environment
The scale of our cosmological environment is coming into focus. Our Universe contains about 10^11 to 10^12 galaxies, giving rise to a total of 10^22 to 10^24 stars[3]. And this is what exists right now; there have been a billion trillion stars in our past Universe. [4]

The Milky Way itself, which is considered a giant as far as galaxies go, contains as many as 400 billion stars and has a diameter of 100,000 light years.[5]

Improved understanding of planet formation, composition and the presence of habitable zones
The Universe formed 13.7 billion years ago. The Milky Way Galaxy formed a mere 200 million years later, making our Galaxy nearly as old as the Universe itself. Work by Charles Lineweaver has shown that planets also began forming a very long time ago; he places estimates of Earth-like planets forming 9 billion years ago (Gyr).

According to Lineweaver, the median age of planets in the Galaxy is 6.4+/0.7 Gyr which is significantly more than the Earth’s age. An average terrestrial planet in the Galaxy is 1.6 Gyr older than the Earth. It is estimated that three quarters of earth-like planets in the Galactic habitable zone are older than the Earth.

We have a growing conception of where habitation could be sustained in the Galaxy. The requirements are a host star that formed between 4 to 8 Gyr ago, enough heavy elements to form terrestrial planets, sufficient time for biological evolution, an environment free of sterilization events (namely super novae), and an annular region between 7 and 9 kiloparsecs from the galactic center that widens with time. [6]

The discovery of extrasolar planets
Over 240 extrasolar planets have been discovered as of May 1, 2007[7]. Most of these are so-called “hot Jupiters,” but the possibility that their satellites could be habitable cannot be ruled out. Many of these systems have stable circumstellar habitable zones.

Somewhat shockingly, the first Earth-like planet was discovered earlier this year orbiting the red star Gilese 581; it is 20 light years away, 1.5 times the diameter of Earth, is suspected to have water and an atmosphere, and its temperature fluctuates between 0 and 40 degrees Celsius.[8]

Confirmation of the rapid origination of life on Earth
The Earth formed 4.6 Gyr ago and rocks began to appear 3.9 Gyr ago. Life emerged quickly thereafter 3 Gyr ago. Some estimates show that life emerged in as little as 600 million years after the formation of rocks.[9]

Growing legitimacy of panspermia theories
There is a very good chance that we inhabit a highly compromised and fertile Galaxy in which ‘life seeds’ are strewn about. The Earth itself has been a potentially infectious agent for nearly 3 billion years.

Evidence has emerged that some grains of material in our solar system came from beyond our solar system. Recent experiments show that microorganisms can survive dormancy for long periods of time and under space conditions. We also now know that rocks can travel from Mars to Earth.[10]

Discovery of extremophiles
Simple life is much more resilient to environmental stress than previously imagined. Biological diversity is probably much larger than conventionally assumed.

Developing conception of a biophilic Universe in which the cosmological parameters for the existence of life appear finely tuned
As scientists delve deeper and deeper into the unsolved mysteries of the Universe, they are discovering that a number of cosmological parameters are excruciatingly specific. So specific, in fact, that any minor alteration to key parameters would throw the entire Universe off kilter and result in a system completely unfriendly to life. The parameters of the Universe that are in place are so specific as to almost suggest that spawning life is in fact what the Universe is supposed to do. [11]

Cosmological uniformitarianism implies that that anthropic observation need not be and cannot be specific to human observers, but rather to any observer in general; in other words, the Universe can support the presence of any kind of observer, whether they be here on Earth or on the other side of the cosmos.

Confirmation of the early potential for intelligent life
My own calculations have shown that intelligence could have first emerged in the Universe as long as 4.5 Gyr ago -- a finding that is consistent with other estimates, including those of Lineweaver and David Grinspoon.[12]

Refinement of evolutionary biology, computer science and systems theories
Evolution shows progressive trends towards increasing complexity and in the direction of increasing fitness. There has also been the growing acceptance of Neo-Darwinism.

Advances in computer science have reshaped our conception of what is possible from an informational and digital perspective. There is the growing acceptance of systems theories which take emergent properties and complexity into account. Game theory and the rise of rational intelligence add another level to this dynamic mix.

Development of sociobiological observations as they pertain to the rapid evolution of intelligent life and the apparent radical potential for advanced intelligence
Exponential change. Moore’s Law. Kurzweil’s Law of Accelerating Returns. Steady advances in information technologies. Artificial intelligence. Neuroscience. Cybernetics, and so on.

And then there is the theoretic potential for a technological Singularity, digital minds, artificial superintelligence, molecular nanotechnology, and other radical possibilities. There is also emerging speculation about the feasibility of interstellar travel, colonization and communication.

In other words….
There are more stars in the Universe than we can possibly fathom. Any conception of ‘rare,’ ‘not enough time’ or ‘far away’ has to be set against the inability of human psychology to grasp such vast cosmological scales and quantities. The Universe and the Milky Way are extremely old, our galaxy has been able to produce rocky planets for quite some time now, and our earth is a relative new-comer to the galaxy.

The composition of our solar system and the Earth itself may not be as rare as some astronomers and astrobiologists believe. These discoveries are a serious blow to the Rare Earth Hypothesis – the idea that the genesis, development and proliferation of life is an extremely special event[13]. It’s also a blow to Brandon Carter’s anthropic argument which takes a very human-centric approach to understanding cosmology, suggesting that our existence as observers imposes the sort of Universe that only we can observe.

Finally, the Universe appears capable of spawning radically advanced intelligence – the kind of advanced intelligence that transhumanists speculate about, namely post-Singularity, post-biological machine minds. Given intelligent life's ability to overcome scarcity, and its tendency to colonize new habitats, it seems likely that any advanced civilization would seek out new resources and colonize first their star system, and then surrounding star systems. Indeed, estimates place the time to colonize the Galaxy anywhere from one million to 100 million years.[14]

The fact that our Galaxy appears unperturbed is hard to explain. We should be living in a Galaxy that is saturated with intelligence and highly organized. Thus, it may be assumed that intelligent life is rare, or, given our seemingly biophilic Universe, our assumptions about the general behaviour of intelligent civilizations are flawed.

A paradox is a paradox for a reason: it means there’s something wrong in our thinking.

So, where is everybody?

Part II: The Fermi Paradox: Advanced Civilization Do Not...

Part III: The Fermi Paradox: Possible Solutions and Next Steps

---

[1] Hart, M. H. "An Explanation for the Absence of Extraterrestrial Life on Earth," Quarterly Journal of the Royal Astronomical Society, 16, 128-135 (1975).

[2] This list, which is not intended to be a complete re-affirmation of the Fermi Paradox, was inspired and partly adapted from: Ćirković , Milan M. and Bradbury, Robert J. "Galactic Gradients, Postbiological Evolution and the Apparent Failure of SETI", New Astronomy, vol. 11, pp. 628-639 (2006).

[3] "How many stars are there in the Universe?" European Space Agency, Space Scientist, February 23, 2004: http://www.esa.int/esaSC/SEM75BS1VED_index_0.html.

[4] Hanson, R. 1999, “Great Filter,” (preprint at http://hanson.berkeley.edu/greatfilter.html).

[5] See Harvey Mudd and S. E. Levine: “Mass of the Milky Way and Dwarf Spheroidal Stream Membership.”

[6] Gonzalez, G., Brownlee, D., and Ward, P. 2001, “The Galactic Habitable Zone: Galactic Chemical Evolution,” Icarus 152, 185-200; Lineweaver, Charles H., Fenner , Yeshe, and Gibson, Brad K. 2004, “The Galactic Habitable Zone and the Age Distribution of Complex Life in the Milky Way.”; M. Noble , Z. E. Musielak , and M. Cuntz: 2002, "Orbital Stability of Terrestrial Planets inside the Habitable Zones of Extrasolar Planetary Systems"

[7] "A Rush of New Planets," Astrobiology Magazine: Jun 02, 2007: http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=2351

[8] "All Wet? Astronomers Claim Discovery of Earth-like Planet," Scientific American, April 24, 2007: http://www.sciam.com/article.cfm?articleID=25A261F0-E7F2-99DF-313249A4883E6A86&chanID=sa007

[9] See Stephen J. Mojzsis: http://spot.colorado.edu/~mojzsis/

[10] Raulin-Cerceau, F., Maurel, M.-C., and Schneider, J. 1998, “From panspermia to bioastronomy, the evolution of the hypothesis of universal life,” Orig. Life Evol. Biosph. 28, 597; "Encore: Great Debates Part VI," Astrobiology Magazine, Aug 19, 2002: http://www.astrobio.net/news/article254.html

[11] The Wikipedia entry on the Fine Tuning argument has some good links and references: http://en.wikipedia.org/wiki/Fine-tuned_universe

[12] Dvorsky, George: 2006, “When Did Intelligent Life First Emerge in the Universe?” http://sentientdevelopments.blogspot.com/2006/06/when-did-intelligence-first-emerge-in.html;

[13] Ward, P. D. and Brownlee, D. 2000, Rare Earth: Why Complex Life Is Uncommon in the Universe (Springer, New York). Lineweaver, Charles H., Fenner , Yeshe, and Gibson, Brad K. 2004; Grinspoon, David, Lonely Planets, Ecco; 1st edition (November 4, 2003).

[14] Ćirković , Milan M., 2003: "On the Importance of SETI for Transhumanism." As it pertains to reframing the Fermi Paradox, Ćirković recommends Lytkin, Finney, and Alepko (1995; for Tsiolkovsky), Jones (1985; for Fermi), Viewing (1975), and Hart (1975), (Tipler 1980), Boyce (1979).