You may believe that aliens have sent life to Earth from a far distant galaxy (the premise of that memorable drama from 2004, AVP: Alien vs. Predator). You may believe that the American government is hiding something outer spatial in Nevada’s mysterious Area 51. Or you may simply believe that there is undoubtedly intelligent life on other planets. In any case, we have all been raised on the assumption that, given enough time, intelligent life will spring up anywhere in the cosmos (with perhaps a few more eyeballs or reptilian features). Yet new evidence from cosmology is really saying the opposite.
The reality is that we live on an extremely rare planet perfectly positioned in an extremely rare solar system, ideally located in an extremely rare galaxy, within a highly improbable universe. Let’s look at our rare Earth.
Water. Earth has an abundance of water, which is essential for life. Mars once had water and therefore might have harbored life. But water is only one of many requirements for life.
Oxygen. Earth is the only planet in our solar system in which we can breathe. Attempting to breathe on other planets, such as Mars or Venus, would be instantly fatal, Mars having virtually no atmosphere and Venus having mostly carbon dioxide and almost no oxygen.
Earth’s distance from the Sun. If the Earth were merely one percent closer to the Sun, the oceans would vaporize, preventing the existence of life. On the other hand, if our planet were just two percent farther from the Sun, the oceans would freeze and the rain that enables life would be nonexistent.
Plate tectonic activity on Earth. Scientists have determined that if the plate tectonic activity were greater, human life could not be sustained and greenhouse-gas reduction would overcompensate for increasing solar luminosity. Yet, if the activity was smaller, life-essential nutrients would not be recycled adequately and greenhouse-gas reduction would not compensate for increasing solar luminosity.
Ozone level in the atmosphere. Life on Earth survives because the ozone level is within the safe range for habitation. However, if the ozone level were either much less or much greater, plant growth would be inadequate for human life to exist.
For life to exist, these, as well as many other conditions needs to be just right.¹
ONE BLOOMING ROCK
University of Washington professors Peter Ward and Donald Brownlee conclude in their book, Rare Earth, that the conditions favorable for life must be so rare in the universe that “not only intelligent life, but even the simplest of animal life is exceedingly rare in our galaxy and in the universe.”² This has led their readers to the conclusion expressed by the reviewer from the New York Times: “Maybe we are alone in the universe, after all.”³
If Ward and Brownlee are right, what does that mean to us?
Michael Denton, senior research fellow in human molecular genetics at the University of Otago in New Zealand, tells us why this remarkable fine-tuning has reopened the discussion on the importance of man in our lonely universe.4
No other theory or concept imagined by man can equal in boldness and audacity this great claim … that all the starry heavens, and every species of life, that every characteristic of reality exists for mankind. … And today, four centuries after the scientific revolution, the doctrine is again reemerging. In the last decades of the twentieth century, its credibility is being enhanced by discoveries in several branches of fundamental science.
It seems ludicrous to claim that life exists on only one tiny speck in a universe of ten billion trillion stars. Yet, incredibly, Earth appears to sit alone in a hostile universe devoid of life, a reality portrayed recently in National Geographic:
If life sprang up through natural processes on the Earth, then the same thing could presumably happen on other worlds. And yet when we look at outer space, we do not see an environment teeming with life.
We see planets and moons where no life as we know it could possibly survive. In fact we see all sorts of wildly different planets and moons—hot places, murky places, ice worlds, gas worlds—and it seems that there are far more ways to be a dead world than a live one.5
The incredibly precise numerical values required for life confront scientists with obvious implications. Stephen Hawking observes, “The remarkable fact is that the values of these numbers seem to have been very finely adjusted to make possible the development of life.”6
1 Hugh Ross, The Creator and the Cosmos, 3rd ed. (Colorado Springs, CO: NavPress, 2001), 175-199.
2 Peter D. Ward and Donald Brownlee, Rare Earth (New York: Copernicus, 2000).
3 William J. Broad, “Maybe We Are Alone in the Universe After All,” New York Times, (February 8, 2000), 1-4.
4 Michael J. Denton, Nature’s Destiny: How the Laws of Biology Reveal Purpose in the Universe (New York: The Free Press, 1998), 3-4.
5 Joel Achenbach, “Life Beyond Earth,” National Geographic (January, 2000, Special Millennium Issue), 45.
6 Hawking, 124.