C[omp]ute

From: "andrew cooke" <andrew@...>

Date: Sun, 19 Feb 2006 09:15:52 -0300 (CLST)

There were some depressingly poor answers to an AskMe question recently. 
The question was - How do local (earth-bound) variations in gravity affect
people?  Are their known variations in people in different regions?

In response to "the variations are small" the poster made the observation
that very small amounts of chemicals can be dangerous.

In my opinion at least three important points were either missed or
presented very poorly:

- The difference between small absolute amounts and small relative
changes.  A small amount of a certain lethal chemical may indeed be
dangerous, but if you are already drinking several pints of a poison, one
extra drop is unlikely to be significant.  This is the case with gravity,
which we all experience already: the amount is changing, but it's a change
in something that is already large.

- The difference between atomic and continuous actors.  A "small amount"
of a chemical might be as small as single molecule, but if that molecule
gets in the wrong place, it could catalyse an important reaction in the
body (catalysts help a reaction along - they are not used up in the
reaction, but simply increase the rate, so a small amount can go a long
way).  In contrast gravity is spread out across the whole body - there's
no known equivalent of a gravity molecule - so it cannot have a powerful
effect in a small region (note that gravitons - gravity particles - have
been postulated, so this argument may be wrong, but even then it probably
remains correct in a
statistical sense, in that each graviton will interact with a different
part of the body, for a brief moment, rather than behaving like a molecule
stuck in one (unluckily dangerous) place for a long time).

- Everyday variations in the environment.  No-one had calculated (when I
last looked) the gravitational effect of living near a large building, or
a bus driving by.  These might be significant and could make any effect
very difficult to measure (and relatively homogenous).

I agree with the people who replied on the original thread that any effect
is unlikely.  But their answers were largely unjustified - their intuition
was probably right, but it's worrying that they either didn't know, or
couldn't be bothered to work out or explain the points above.

And it's ironic that the person asking the question was one of the people
who, indirectly, stopped me contributing to the site.

Andrew