In article , (Gregory L. Hansen) writes:
In article ,
Laurel Amberdine wrote:
On 6 Jul 2003 17:43:30 -0700, Edward Green wrote:
"Steve Harris" wrote in message
...

If there's no change in photon energy to first order, then
obviously that's a breaking of Carnot's law to first order,
since Carnot requires an decrease in photon temperature
(photon energy) for work to be extracted.

True, I snipped context and all, but I love the way "to first order"
sometimes takes on a meaning all of its own -- as if it meant
something without even specifying "with respect to X".

Ignorance time: people are saying "to first (second, zeroth) order" etc,
quite often lately. What does it mean, anyway?

If you have some function f(x), perhaps an unknown that you're trying to
solve equations of motion to find, it's often possible to approximate it
and wind up with a polynomial expansion. So you might get

f(x) ~= a + bx + cx^2 + ...

First order would be linear in x, second order would be quadratic in x,
etc.

In this particular discussion, I don't think "first order" really means
anything, it's just something that people are saying.

Actually, it does mean just what it is supposed to. First order in
delta_p (momentum transfer).

Mati Meron | "When you argue with a fool,
| chances are he is doing just the same"