Initial precision matters - both at closest and furthest imaginable distances

Michael Marshall

Imagine altering the human genome by aiming a radiation ray at an individual hydrogen bond in an individual gene on a single human chromosome, to produce a mutation.

Sounds wacky, but that was what was seriously proposed as the way of the future by science cheerleaders (sorry -journalists) in the first half of the twentieth century.

A laser perhaps.

Even the tiniest miss-aiming of the tiny laser beam at the incredibly tiny chromosome would result in zapping the wrong  hydrogen bond or even the wrong gene, producing heavens knows what.

All this would be done over the shortest imaginable distances  and aiming at a hydrogen bond about 40 trillionths of a metre in size - so any shifting of the laser beam angle at all to the left or right would spell disaster.

Now imagine we want to send a signal to a likely looking livable planet circling the nearest suitable star to us after the Sun itself.

This would be Alpha-Centauri, about 40 trillion kilometres away.

This distance is a thousand trillion trillion times further away, so our laser beam might seem to have more latitude to be off to the left or the right in its aiming.

In fact, it would probably work out to be pretty much the same margin of error - ie none.

If you remember your high school geometry, two lines that appear to be perfectly parallel but are in fact just ever so slightly off ,will eventually arrive at entirely different galaxies.

We humans can never get the precision we crave if we let physicists do the job - they simply aren't up for it.

That laser beam in an odd sort of way is heading out on a ballistic flight - in the sense that it works by 'fire and forget' - once aimed we humans do nothing to correct its path  even when we see the need.

The same way we 'fire and forget' artillery guns, after setting them by tables drawn up by Newtonian physicists and mathematicians .

No aiming device is ever 100% accurate and no flight path can ever calculation for the changing nature of the forces affecting the projectile's travel.

Only some sort of pilot can correct for inflight changes and errors.

By trial and error - the way all science and all human activity works best .

If we could only get scientists to admit it ....