Iridium is a very rare substance on Earth, though we find it often in asteroids. If you look at any layer of rock strata that goes down far enough, and therefore back in time far enough, you see a strange line, a thin dark line, marking the end of the age of the dinosaurs.

No matter where you dig on Earth you will find this strange layer loaded with a very rare material. If you dig deeper, you start to find dinosaur bones. The evidence that a big death-mountain from space wiped the dinosaurs and many other animals and plants off of the Earth like crumbs off of a dirty table is strong.

The dinosaurs died because they didn't have a space program. -- Larry Niven

In 2029, this death-mountain will hurl past the Earth. It will come very very close. How close? So close, that some of our communication satellites are higher up. In terms of cosmic distances, this is as close as the blade gets to your skin when you shave.

In the 1990s, every possible telescope we could spare was fixed on Jupiter, as comet Shoemaker Levy-9 slammed into the king of planets. The Earth is loaded with impact craters, but thanks to active geology, most of the clues aren't visible. On dead bodies with no geology, we see craters all over. We see craters within craters. The closer we zoom in, the more craters we see. In fact, the pattern repeats at any scale, almost like a fractal. On other bodies with more active geology, like the ice moon Europa, or the volcanic moon Io, where surfaces are constantly rebuilt, the evidence is of course harder to find.

The point is, impacts do happen. They are inevitable. They have happened and they will happen again. The odds of an impact big enough to end most Earth life are low, only a few times in million years, but they do happen. The odds of you, the reader, dying from an asteroid are somewhere between 1 in 50,000 to 1 in 500,000. Although rare, the huge number of people that would die (including perhaps ALL of us) are so high per impact that stats raise. The chance of dying in a tornado are 1 in 60,000 according to the same article, and the odds of dying in a tsunami are 1 in 500,000.

Cost benefit analyses are calculated which place a monetary-value to human life; how might one look that took the species itself into consideration? And, how expensive is space really? In adjusted dollars, the cost of one of our “expensive” space missions is less than what the old European countries spent on voyages across the ocean. As a percentage of our multi trillion dollar intake, such projects are already relatively cheap. Five million is the cost usually allocated for a the death of human, but if we're calculating all humans, with the possibility of no more humans ever, would our projected cost merely equal 5 million times the number of humans? And what about the rest of the life stuck on this speck with us? Have they no value?

Some estimates say that we'd need a ten year lead-time to do anything about a big death-mountain coming our way. Wouldn't it be wise to have the infrastructure ready so that we could just go tackle this issue, when it next comes our way?

When humans investigated a comet some years back by ramming a projectile in and watching what came out, a few UK articles slammed this exercise. It was “tampering with nature” and such. Yet, this gave us invaluable information. Some death-mountains are actually rubble piles instead of solid objects – utterly crucial information to dealing with this threat in the future.

Of course, there are a plethora of other possible threats, both from space and local that could wipe us out, threats which would be mitigated in terms of their damage to the entire species if we have other places to live.

Certainly by now someone reading this is thinking about all of the Earthly problems we could fix with the kind of money required for a space infrastructure (being able to live in space without resources from Earth, essentially). But when the issue is the entire human race or better schools or more farms, doesn't the entire human race hold some sway? And, why can't we do both? Why is this always presented as an either-or? Another columnist recently mentioned bullies at school and mentioned that before we bother with space, we should address the human condition and make us all co-exist more harmoniously.

But can't we address bullies and prepare kids for college both at the same time? Is one issue contingent on the other, in other words? Would anyone suggest shutting down the education system until bullies were re-programmed or removed? Was England a perfect society when the Pilgrims came? What makes anyone think that we will ever solve all of our problems, and, why must space wait for these problems to be solved?

The survival of the species has to trump the suffering of even the many, even if we assume that one problem has to be solved at the expense of another, or that these problems stack up in some linear way.

Let's not let this little bit from Terry Jacks apply to human kind:

We had joy we had fun

We had seasons in the sun

But the stars we could reach

Were just starfish on the beach

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