interactions among themselves, one of them will flip itself out of the band between Mars and Jupiter. It will generally head sunward– that means that it comes toward us. It only takes one, and in two minutes the whole planet will be uninhabitable. Maybe a few of us will survive. Perhaps a couple of people up in Denver will be able to hang on.
The last time it happened something five miles wide landed north off of present-day Yucatan. It left a hundred mile wide hole, and kicked up a tidal wave that, when it passed where Kansas City is today, was five hundred feet high. Denver would have escaped the tidal wave, but the world was totally changed in a matter of minutes.
We can prevent this from happening if we put enough attention towards it, and take our physicists off of things like quarks, which most of us are not too concerned about. We were worried that the Russians would get there first, and make a super bomb that we wouldn’t be able to make. Now that’s over, so let’s put an umbrella of protection over our culture– so that we have a million years or so to ponder what our options are. Who are we? That sort of thing.
David: Do you think it’s possible to blow up an asteroid that’s headed towards us before it strikes the Earth?
Kary: I think so. The next time one of them is about to land here, whether we’ve prepared for it or not, we’ll probably try to do that. There have been a couple of movies where people make an emergency attempt to, and there have been technical papers written about it; but we shouldn’t wait until one is almost here. We need to be watching them. There are now about seventy-five catalogued Earth-orbit-crossing asteroids. Astronomers are watching their orbits, but every now and then a new one appears, or someone suddenly discovers a new comet. Comets and asteroids both have that very unpredictable aspect. Some amateur astronomer in Arizona will suddenly see something, and say, Jesus, that’s heading right towards us. It’s going to be here in a month.
I think the problem is that when our physicists think of something fundamental, they assume that it is either the tiniest little thing, or the hugest. It’s either the whole universe, or it’s a vibrating string 10-45 meters wide or something like a quark that has absolutely no volume. It’s more romantic, I guess, to talk about and study those sorts of things. I love it, but it’s not as practical as studying and understanding the solar system. There are dangers to us right here.
If you look at the surface of the moon, where weather has not been destroying the evidence of impacts, what do you see? The whole place is full of holes. Mars is the same way. There are all kinds of craters around, because things have been smashing into them. We watched eight or nine almost earth-size objects crash into Jupiter in 1994. They left huge holes, bigger than the earth. Any one of those impacts would have destroyed us.
We need to have space stations. We need to get away from here, and have people up there ready to defend us. This is not a fanciful idea. There’s more evidence for this than for anything else that’s dangerous to us. That’s the way our civilization is going to end, when something big smashes into this planet. We’re going to get to watch it on CNN, and we’re going to be helpless.
David: Do you think that the human species is going to survive the next hundred years, and if so, how do you envision humanity’s future evolution?
Kary: I think the probability is good that we’re going to exist for a whole longer than that, but exactly what the conditions will be, I have absolutely no idea. I see a lot of science fiction movies that I think are probable, and they’re all different. I’m kind of an optimist. I don’t think it’s going to get terribly worse.
David: It’s just that the human species has reached a point in its evolution where it has the potential to drive itself into extinction.
Kary: I am optimistic that we won’t do it. That optimism does not arise from evidence, it’s just my feeling that we won’t. We’ve had the ability to wipe ourselves out for quite a while now.
David: Do you see any teleology in nature, or think that there is any direction in evolution? Or do you think it’s purely a random process?
Kary: My feeling about evolution is that it seems to have a teleology, but it doesn’t really. It’s just the operation of selection on random changes, as far as I can tell. I accept that theory as being the way evolution works.
I think there is so much more in existence besides matter, energy and time. Nineteenth Century physics had those in an orderly arrangement, but it is too weird to be just that. There are other things going on, so evolution might not actually be without some kind of presupposed or predestined direction. But I think it’s possible that it all happens through random changes.
There’s a book by Richard Dawkins called Climbing Mount Improbable that I like. I think that the evolutionary mechanism makes it possible for very bizarre things to evolve in very slow steps. In his book Dawkins talks about the fact that you don’t go straight up the face of Mount Improbable. (Mount Improbable being the end, or the present state of being, of some particular species.) You always go in little steps, back and forth, crisscrossing, finding the trails.
If you look at any one of the little steps leading to something as improbable as the human eye, it doesn’t seem like such a magical thing. In fact, if random steps aren’t the mechanism whereby very complex things like those form, then the next possible choice is somebody did it. Then you have to figure out, well, where did that somebody come from? The beauty of evolution is it says it can happen anywhere and it will get really freaky. (laughter)
You don’t have to know who or why. The laws of evolution say that if you have random chances of species undergoing changes, then the ones which are best fit to reproduce in the environment they find themselves in will survive and continually create weirder and weirder things. You’ll end up with giraffes, elephants, crocodiles, and people.
David: I’m sure you’re aware that there’s evidence that E. Coli bacteria don’t always mutate randomly–that there’s actually a response to the environment with regard to how their genetic mutations occur, so as to be more adaptive. How do you account for that?
Kary: There’s something like that in E. Coli and several other organisms. With the passage of a particular kind of retro-virus through several different species, there are certain DNA changes that happen that are actually not random. But if you look for the mechanism of those, you’d find that those mechanisms themselves are in place probably due to random things. In other words, the fact that you can change your DNA in a way that’s not random, does not mean that most of evolution doesn’t occur due to random changes.
I think it’s not an unlikely hypothesis that we’re here simply because we survived, and there were changes all along that were random. It doesn’t take any more than that, because time is so long. Four billion years means a lot of generations, and little tiny changes at every stage of the way, selected by whatever was there, the environment at the time, could very likely produce things like this. Nobody’s ever shown that experimentally. There is really no experimental evidence for Darwinian evolution ever creating a new species.
David: I guess it might take awhile to run the experiment. (laughter)
Kary: Yes, it takes time. But there are processes that help us to understand this. For instance, there are a lot of PCR-based permutation experiments, where you try to make a whole bunch of different kinds of the same molecule–millions and millions of variations of it. You select for the one that has a property that you like, and then you take that one and do the same thing to it. You can increase the ability of, say, some RNA species that you’re making, or some protein that you’re finally making from it, to bind to some specific protein receptors, thousands of fold that way– just doing it randomly.
You just reproduce the thing over and over in a way that will make little mistakes. Then you pick the best one, and do the same thing to it. Then pick the best one from that bunch and do it again. Eventually you end up with something that’s almost qualitatively different, something that has a property that you’ve been selecting for which is so much greater than the thing you started with. You can almost say this is a different species of molecule.