When I look at your heavens, the work of your fingers
The moon and the stars, which you have set in place
What is man that you are mindful of him?
And the son of man, that you care for him?
Yet you have made him a little lower than the angels
And crowned him with glory and honor
– Psalm 8
There have been two particularly interesting developments in astronomy in the last few decades. The first is the discovery of exosolar planets – that is, planets outside our solar system. The second is the discovery of liquid water on planets and moons inside our solar system. Both developments have accelerated in recent years and show no signs of stopping. Both have fascinating implications for our understanding of our place in the universe.
Humans are the most dominant living creatures on a little round ball that teems with life, from the deepest hydrothermal vents to the coldest poles and highest mountaintops. This fertile sphere exists in a mind-boggling vast universe that, as far as we know, has no other life in it. There are numerous ways to make sense of all this, but they tend to fall into two broad camps: Special and Not-So-Special.
Special Or Not So Special, That Is The Question
The Special camp says that we appear to be alone in the universe because we are special. A representative sample of this kind of philosophy can be found in the “Rare Earth hypothesis,” which says that the origin of life and any progression to intelligence require such “an improbable combination of astrophysical and geological events and circumstances” that extraterrestrial life, especially the complex or intelligent variety, is likely to be extremely rare, if it exists at all. The hypothesis emphasizes how our planet is in the right location in the right kind of galaxy, orbiting at the right distance from the right type of star, with the right arrangement of planets, in a continuously stable orbit, with a solid surface and an atmosphere and plate tectonics and a large moon, and so on, and so forth.
A Special Earth does not demand that it was created by God, nor does belief in God demand a Special Earth, but they generally tend to suggest each other. (See “The Privileged Planet“.) If our existence within this universe is sufficiently improbable, it’s rather compelling to suggest that Something – or Someone – outside our universe intentionally set it up with that outcome in mind. Of course, such a Someone could have set up our universe with intelligent life teeming across other stars and galaxies as well. But many religions tend to assume some centrality to humanity and planet Earth. The Christian’s Bible does not (in my opinion) explicitly rule out life on other planets, but it certainly portrays God as more interested in humanity than anything else of his creation, from the beginning of this universe to its end.
By contrast, the Non-Special camp claims Earth is “a typical rocky planet in a typical planetary system, located in a non-exceptional region of a common barred-spiral galaxy.” This “mediocrity principle” tends to view the universe’s contents as spread out along fairly uninteresting statistical distributions. Wherever life does arise, it might think of itself as special due to its own selection bias, lack of imagination, and circular reasoning, but Non-Specialists see no objective reason to posit such a thing. Earth appears to exist under finely-tuned circumstances, but they view that as reversed logic and see no reason to assume that life couldn’t have simply developed differently, with a similar appearance of fine-tuning, if any given parameter had been different.
With the variety and vast quantities of stars and galaxies, Non-Specialists believe the universe is overwhelmingly abundant in life. The fact that we have not yet discovered any of that life is known as the Fermi Paradox. WaitButWhy has an entertaining and informative post that describes many of the speculative explanations for this paradox. After all, most stars are pretty far away and our technology is still pretty limited.
A Non-Special Earth does not demand atheistic origins, nor do atheistic beliefs demand a Non-Special Earth, but they generally tend to go together as well (see Lawrence Krauss, Richard Dawkins, etc). If the unfolding of the universe was not guided by any intelligent purpose, it tends to follow that there is nothing special about our existence. If we are simply one of billions of life forms across the galaxies, that doesn’t disprove God as creator of it all, but it certainly makes such views less compelling than the idea that everything was specially designed just for us. For Christians, if intelligent life – if the very image of God – isn’t special to humanity, it introduces sticky questions about sin and salvation and the whole theology of God becoming Man.
The Story Thus Far
It might be natural to think of the arc of scientific progress as bending from Special to Non-Special for a long time. The ancients assumed the sun and the planets all went around the Earth. Now we know our planet orbits the sun just like the others. We used to think of the sun as a distinct object in the sky. Now we know it’s a giant nuclear fusion factory orbiting a black hole like all the other stars in our galaxy. We used to think all stars were part of our galactic system. Now we know there are about as many galaxies out there as stars in the Milky Way, spreading across a universe that is far vaster than we had ever imagined.
Yet in that vastness we have reclaimed our significance. We ooh and aah over the Hubble Space Telescope’s images of vibrant galaxies as demonstrations of God’s power and creativity. The heavens declare the glory of God, like never before.
We contrast the hostility of the vast dark and cold and radiation and black holes and gamma ray bursts with the charming comfort of our planet. Its protective ozone layer and magnetic fields and our large neighbor to scoop up deadly asteroids and all those other properties make our home feel so safe and Special in the context of all that outer death and darkness.
Guillermo Gonzalez argues in The Case For A Creator that our inconspicuous off-center position in the galaxy puts us in an excellent position to observe and discover the rest of the universe. Intriguingly, the relative sizes and distances of our sun and moon create perfect solar eclipses that have helped us learn about the contents of stars and confirm general relativity. “The very time and place where perfect solar eclipses appear in our universe also corresponds to the one time and place where there are observers to see them.”
In other words, it’s not just that it seems special that we are here at all to comprehend our own existence. It takes even more specialness – being in the right place to discover the vastness of the universe – to be able to comprehend that our existence is special! Special upon Special…
In that sense, nothing has really changed since David penned his psalm under the spiral arm of the Milky Way in the night sky three thousand years ago. Modern discovery has exponentially amplified the dynamics, but it’s the same story: God’s created universe is amazing, and what a mystery that humanity is so Special within it!
The New Kids In The Universe
Yet the very progress of astronomy that has enhanced our Special place for so long is now threatening to undo it.
Ever since science revealed our sun to be one of the stars, humans have speculated that other stars might have planets, too, but the technology wasn’t there to verify it. When I was born in the late 1980’s, scientists still had not confirmed a single exoplanet. We were just beginning to uncover possibilities – looking for the brief but regular dimming of stars being transited by giant planets whose orbital plane happened to cross our line of sight, or the subtle but regular shift in a star’s radial velocity from the gravitational effect of a near, giant orbiting planet.
The first exoplanet was confirmed in 1992. More planets trickled in as we grew up. Technology improved, new detection methods were found, smaller and smaller planets became observable. The trickle became a stream, and then a torrent – at the beginning of this year (2015) NASA announced confirmation of the 1000th exoplanet. Nine months later the number has already almost doubled, with thousands more candidates waiting for the due diligence of confirmation. Direct imaging is now within our limits. Further technological advances will only increase all of this.
We have just entered a golden age of discovery. Every few months now, it seems, NASA announces a new milestone crossed in the search for planets: new candidates of “near-Earth” size in the “habitable zone”; the closest rocky planet yet found! Each announcement serves to underscore the huge gap still separating Earth from all the others, yet at the same time increasing the confidence that more of the gap will be filled by the relentless mathematics of astronomical numbers. (See the wiki “exoplanet” article for much more.)
How special is a one-in-a-million property if there are 200 billion planets in the Milky Way? Is Earth the only one with a tilt-stabilizing moon in a circular-enough orbit in the habitable zone for liquid water?
Speaking of liquid water, this brings us to the other accelerating major development in astronomy: the detection and confirmation of water throughout the solid bodies of our own solar system.
Jupiter’s moon Europa was suspected for decades to have liquid water under its icy surface. Gravitational and magnetic measurements in the late 90’s from the Galilean missions strengthened such theories. In 2013 plumes of water eruptions venting from the subsurface ocean were announced by Hubble. In 2014, active plate tectonics were confirmed.
In 2005, the Cassini spacecraft spotted geysers venting from Saturn’s icy moon Enceladus. Last year, scientists detected signs of a subsurface ocean near the southern pole. Last month, they announced signs that the ocean is global.
Magnetic readings in 2000 suggested the possibility of an ocean on Ganymede, Jupiter’s largest moon. Spring 2015 saw the announcement of even stronger aurora-based indications of a global saltwater ocean with more water volume than Earth’s.
Mars has seen a steady stream of water-related discoveries in the last few decades, from indications of liquid water under the polar ice caps to evidence of powerful streams and vast oceans in the past to moisture in the present soil to last month’s headline of patterns of salty brine emerging just under the surface.
Potential candidates for future headlines include Callisto, Titan, Triton, and more. (See the wiki “extraterrestial liquid water” article for more information and a cool infographic.)
What’s the big deal with liquid water? Water is a special property, a sort of “Earth among chemicals,” with its ability to dissolve almost anything and allow other substances to play around with each other. Its solid form expands and floats on top, protecting instead of crushing what lies below. As far as we know it is utterly necessary not only to sustain life, but to allow life to arise from non-life at all (assuming that such a thing is actually possible, that is).
We used to think it was only possible for liquid water to consistently exist within a pretty narrow “habitable range” of a star on a rocky planet with a proper atmosphere and rotation. Too close: boiled. Too far: frozen. Locked in orbit with the same side facing the sun: both. Earth was only object in our solar system that was even close to qualifying.
But now: Earth. Mars. Jupiter. Saturn. Fully half the planetary bodies seem to be qualifiers, either themselves or through their moons. We wrote off gas giants as totally inhospitable to life! But what does that matter if their moons have liquid oceans hiding under the surface of that protective ice?
We haven’t even begun to detect exosolar moons. Jupiter alone oversees two oceans – at least! This potentially expands not just one major limiting factor of the rare Earth hypothesis, but several: maybe you don’t need an atmosphere or magnetic field to protect whatever might develop under ice, either.
Does this bump up the odds of life by an order of magnitude by itself? Is the Special theory too narrow after all?
Many Non-Specialists seem to think so. There are corners of the Internet practically giddy in anticipation at finding life hiding under every dihydrogen-monoxide collection in the cosmos. Some seem to have an overwhelming confidence that given the right time and conditions, well, “life finds a way,” and we’re finding the conditions everywhere!
In my opinion, such confidence springs more from Hollywood than science. Liquid water could exist on every moon and planet in the galaxy and still leave far longer odds than many seem to realize. But if the aforementioned factors can be bested by such unanticipated discoveries, who knows what other possibilities may exist out there that we haven’t imagined, either?
But there is still a fundamental mystery. We don’t know whether or not we’re going to find life. For the first time in the history of humanity, we’re on the verge of being able to quantify how special the Earth really is as a planet in the universe. As the reports of new planets keep rolling in, with candidates of ever-increasing similarities to Earth – just as you’d expect from a random statistical distribution – our home seems to be on the verge of finally losing its Special thunder.
Yet as we continue to fail to discover life despite a continual increase in potential habitability, the Not-So-Special Fermi Paradox only deepens. Water, water, everywhere, and not a drop of life?! Just as the vastness of a hostile universe made Earth seem more Special than ever, the emptiness of a habitable universe makes life on Earth seem more Special than ever. Maybe time plus conditions can’t equal life on its own. Maybe life doesn’t just “find a way.”
But what if we do discover life out there one day?
If the history of astronomy is any indication, I predict it won’t come in the form of an alien spaceship or a poem on a distant radio wave. If it comes, it will come in fits and hints and pieces. Instrument readings of oxygen and carbon dioxide on some distant planet, or microscopic fossils on an outer moon that aren’t quite conclusive, or bacteria on a rover that just might have hitched a ride from Earth, until more evidence trickles in and skepticism starts to diminish and finally it becomes apparent after years and years that, yes, life has, at least once, maybe in the past, undeniably lived somewhere besides Earth.
It would be the most stunning scientific discovery in history. And we will ask ourselves again: Are we still Special?
The answer in large part will depend on what we find, and how much of it. Perhaps the Special line will simply move up to complex life or intelligent life, with the Not-So-Specialers continuing to expect it to one day vanish altogether. Will that life have the same kind of DNA? Would that suggest a Universal Programmer? Or more outlandish theories of panspermia?
Let’s consider the worst case scenario for the Special camp: we discover intelligent life abundant in the universe. Earth, life, even humans become unequivocally Not Special. Maybe not even the most dominant creature of all creation. What would that mean for theology?
Such prospects are exceedingly speculative. Nevertheless, I predict that many atheists would see this as vindication of their ever more compelling worldview. (Though I think they should be careful what they wish for; we very well may find ourselves asking why a blind universe seems programmed to develop so much life.)
But I predict that theism would not go quietly into the night. Christians who previously insisted that the Bible ruled out alien life would reinterpret it as not speaking to the issue one way or another. And through the intergalactic crowds and chatter, we would reclaim the mystery of Special once again. If God answers prayers and performs miracles, if Jesus rose from the dead, if the Holy Spirit transforms the lives of men and women from depravity to glory – these are truths that are unaffected by the existence or non-existence of life on other worlds, intelligent or not, just as they are and always have been unaffected by the shape of the Earth, or its age, or its position in the universe. The existence of other life would simply elevate these truths of God’s interest in man to another level of wonder, and we would cry out yet again, with a deeper emotion than ever before,
What is man, that you are mindful of him?