Chapter 52
Like a Thief in the Night (cont)

More than just Kilroy was here

Let us return to our scenario:

1. we know that our late twentieth-century, post-industrial civilization is about to be destroyed by an inescapable cosmic or geological cataclysm;
2. we know - because our science is pretty good - that the destruction is going to be near-total;
3. mobilizing massive technological resources, we put our best minds to work to ensure that at least a remnant of our species will survive the catastrophe, and that the core of our scientific, medical, astronomical, geographical, architectural and mathematical knowledge will be preserved;
4. we are of course aware how slim are our chances of succeeding on both counts; nevertheless, galvanized by the prospect of extinction, we make an almighty effort to build the Arks or Vars or strong enclosures in which the chosen survivors can be protected, and we focus our considerable ingenuity on ways to transmit the essence of the knowledge we have accumulated during the 5000 years of our recorded history.

We start by preparing for the worst. We assume that there will be survivors but that they will be blasted back into the Stone Age by the cataclysm. Realizing that it may take ten or twelve thousand years for a civilization as advanced as our own to rise again like a phoenix from the ashes, one of our top priorities is to find a way to communicate with that postulated future civilization. At the least we would want to say to them: KILROY WAS HERE! and to be sure they got the message no matter what language they spoke or what ethical, religious, ideological, metaphysical or philosophical leanings their society might exhibit.

I'm sure we'd want to say more than just 'Kilroy was here'. We'd want, for example, to tell them - those distant grandchildren of ours - when we had lived in relation to their time.

How would we do that? How would we express, say, AD 2012 of the Christian era in a language universal enough to be worked out and understood twelve thousand years hence by a civilization that would know nothing of the Christian or of any of the other eras by which we express chronology?

One obvious solution would be to make use of the beautiful predictability of the earth's axial precession, which has the effect of slowly and regularly altering the declination of the entire star-field in relation to a viewer at a fixed point, and which equally slowly and regularly revolves equinoctial point in relation to the twelve zodiacal constellations. From the predictability of this motion it follows that if we can find a way to declare: WE LIVED WHEN THE VERNAL EQUINOX WAS IN THE CONSTELLATION OF PISCES we will provide a means of specifying our epoch to within a single 2160-year period in every grand precessional cycle of 25,920 years.

The only drawback to this scheme would evident if a civilization equivalent to our own failed to arise within 12,000 or even 20,000 years of the cataclysm, but took much longer - perhaps as much as 30,000 years. In that case, a monument or calendrical device declaring 'lived when the vernal equinox was in the constellation of Pisces' would no longer be unambiguous. If discovered by a high culture flourishing at the very beginning of a future Age of Sagittarius for example it could be read as meaning 'we lived 4320 years before your time' - that is, two full precessional 'months' prior to the Sagittarian Age (the 2160-year 'months' of Aquarius and Capricorn). But it could also mean 'We lived 30,240 years before your time', that is those two 'months' plus the full previous precessional cycle of 25,920 years. The Sagittarian archaeologists would not only have to use their wits to work out the meaning of the message (i.e. WE LIVED WHEN THE VERNAL EQUINOX WAS IN PISCES), but would need to decide from other clues which Age of Pisces we had lived in: the most recent, or the one in the previous precessional cycle, or perhaps even the cycle before that.

Geology would naturally be of assistance in making such broad judgements ...