»  National Review Online

June 20th, 2003

  The End Is at Hand

Our Final Hour
        by Sir Martin Rees


As NRO's designated pessimist, I feel it is incumbent on me to seek out news items, points of view, books and movies that will make your flesh creep. Well, I have found a real doozy: Sir Martin Rees's new book Our Final Hour. In Britain the book sells under the title Our Final Century, which expresses its theme a bit more precisely. Sir Martin doesn't think that we — the human race — are going to make it alive through to 12/31/2099, and he has given a bookful of reasons for his opinion.

Sir Martin's two strongest points are:

There is not much doubt that he is right. On the first point, for instance, he notes that we can now create physical situations and processes that do not occur in the natural universe at all. He cites the gravitational wave detector at Stanford University. It contains a metal bar weighing over a ton, cooled to within a tiny fraction of a degree of absolute zero (minus 459° Fahrenheit).

Unless there are extraterrestrial intelligences conducting similar experiments somewhere, this is easily the coldest large object in the universe. The midwinter night-time surface of Pluto is not that cold; inter-galactic space is not that cold; nothing in nature is that cold, because the "background radiation" left over from the Big Bang keeps the universe simmering at a steady 3 degrees above absolute zero. The entire universe resembles the interior of a microwave oven; the Stanford experimenters have shielded their equipment from that background radiation by very ingenious means.

[The Stanford experiment is not, by the way, anything like the last word in coldness. Eric Cornell and Carl Wieman at the University of Colorado got down to 20 billionths of a degree above absolute zero, thereby creating an entirely new state of matter called a Bose-Einstein condensate. Said Cornell: "This state could never have existed naturally anywhere in the universe. So the sample in our lab is the only chunk of this stuff in the universe, unless it is in a lab in some other solar system."]

Messing with the fundamentals of physics could have very dramatic consequences indeed. At the time of the first nuclear explosions in 1945, some of the physicists involved wondered if they might ignite a chain reaction that would destroy Earth's atmosphere. A quick back-of-the-envelope calculation seemed reassuring, so they went ahead with the Trinity test.

It is now clear that there was no possibility of worldwide conflagration from Trinity; but issues of this sort are now coming up with accelerating frequency, and there is a chance that sooner or later we shall get one of them wrong. The whole point of a scientific experiment, after all, is to find out what will happen if … There is no knowing in advance. If there were, the experiment would have no point.

The kinds of experiments we shall soon be conducting might, according to perfectly respectable theories, have very dire results indeed. One possibility is the swift reduction of our planet to a sphere of super-dense "strange matter" about a hundred yards across. Another is the annihilation of spacetime itself — though since the sphere of annihilation could expand only at the speed of light, it would take a few billion years to swallow up the whole universe.

On the second of those bullet points I started with, let me introduce you to New Zealand handyman Bruce Simpson, who is building a cruise missile in his garage. He claims he can do the whole thing for less than NZ$5,000 (about $2,900), using off-the-shelf parts he buys mostly via the internet.

It is the same in biology. Back in the 1990s the Japanese cult called Aum Shinrikyo tried unsuccessfully to track down the ebola virus in Africa. Nowadays, according to Sir Martin, they could assemble it in a home lab, using mail-order ingredients and information available on the internet. That's the "advance" in just ten years; the 21st century has 97 still to go. See his point? Sir Martin:

I staked one thousand dollars on a bet: "That by the year 2020 an instance of bioerror or bioterror will have killed a million people." Of course, I fervently hope to lose this bet. But I honestly do not expect to …

The new science of extremely tiny machines, what is called "nanotechnology," might also ring down the curtain on our little show. One scenario was thought up back in the 1980s by Eric Drexler, who wrote the first book on nanotech. This is the "gray goo" catastrophe. Tiny omnivorous self-replicating machines could spread exponentially, chewing their way through the entire biosphere in a matter of days, leaving the earth's surface stripped of all life.

Is your flesh creeping yet? It probably should be. Sir Martin Rees is not a crank or a weaver of fringe speculations, not a Velikovsky or a von Daniken. He is one of the most eminent theoretical astrophysicists of our time, a Professor at Cambridge University and currently Britain's Astronomer Royal. He writes in level tones — the book is actually rather dull — and does his best to argue the probabilities.

He also gives good coverage of a corollary question that arises from all this doom-mongering: Does it matter if the human race comes to an end? This is connected with another large question, perhaps the largest of all: Are we the only intelligent creatures in the universe?

We do not know the answer to this tremendous question, though there are heuristic arguments both for and against.

Our own intellectual history suggests that we are probably not alone. Everything we once thought unique and central about our situation has been "dethroned" by the advance of knowledge. No, the Sun does not revolve around the Earth. The Earth revolves around the Sun, with a lot of other rocky debris. No, the Sun itself is not particularly important, just one rather average star among tens of billions in an "island universe." No, even that "island universe" is not unique or extraordinary, merely one of billions like it. No, we do not stand high above the animal kingdom. We are part of it, and arose from it. No, our mental states are not, or at best not entirely, the product of our wills acting upon a divine spark of ineffable transcendence. They can be changed completely by the ingestion of pharmaceutical compounds. Even our consciousness itself is in retreat before the onslaughts of the neuroscientists. It would be surprising, after all that dethroning, if we turned out to be the only intelligent species in the cosmos.

It might, none the less, be so. Presumably any intelligent species would have mastered the radio spectrum, as we have, and thrown out distinctive radio waves across interstellar space, as we are doing. No such waves have been detected after decades of searching. Presumably a species just a few hundred years more advanced than us in technology would have embarked on engineering projects, like the Dyson sphere, that would be visible across the gulfs of interstellar space. We don't see any.

Presumably any sufficiently advanced species would spread itself out among the stars. We have not been visited in any obvious way, and it is hard to see the point of anyone crossing the galaxy to visit us in some non-obvious way. Nor is it likely that we are just ahead of everyone else. There are stars billions of years older than the Sun. If intelligent life developed on their planets, there ought to be civilizations in relation to whom we are, developmentally, at the level of plankton.

If we are indeed alone, it may be that once any species attains a certain level of technological sophistication it is certain to destroy itself by one of the processes sketched above, or some other process no-one has though of yet, or good old-fashioned nuclear annihilation. Or it may be that life is so extraordinary that its existence on our own planet is a huge stroke of luck, never repeated elsewhere.

Sir Martin tries to end his book on an optimistic note, suggesting that before the nasty stuff on Earth comes down, we may have propagated ourselves into outer space, or evolved into something smart enough to avert the horrors. (One of his sub-theses is that human or human-machine evolution may be about to speed up dramatically.)

The post-human potential is so immense that not even the most misanthropic amongst us would countenance its being foreclosed by human actions.

The author must spend his time among very cheerful people. I don't think I am an especially egregious case of misanthropy, yet I am certainly ready to countenance that foreclosure. Human extinction doesn't seem improbable to me.

If we are already fooling with the very fabric of space-time, sooner or later we shall tear it. If hobbyists are building cruise missiles in their garages, fifty years on they might very well be kitting them out with thermonuclear warheads. If the DNA of the ebola virus has been reduced to a long string of digits on a website somewhere, it can only be a matter of time before some Tim McVeigh or Osama bin Laden lets it loose in Yankee Stadium. Yep, we're done for. The game is up.

I can't even see that religion offers much of an antidote to this stuff. Would a loving God who cares about humanity allow us to be reduced to gray goo by a swarm of dust-speck-sized robots? I don't see why not. We are an old and tired species, and all too well-informed about our own history — about the things He has allowed.

The cold, distant God of the deists might have decided that we were one of his failed experiments, that there are more hopeful things going on in the Virgo supercluster. He might even be tired of our entire cosmos — which, according to some current theories, may be just one among trillions — and be ready to trash the whole shebang and start again. Even the personal God of my own faith might, for his own unfathomable purposes, decide that he's had enough of our vanity and folly.

Sir Martin Rees has laid out a host of convincing arguments for believing that these are the Last Times. I can't see any good reasons, theological or otherwise, for thinking that he is wrong.