On Sep 8, 2:10=A0pm, verulam
yahoo.com> wrote:> Lorentz,
> I do agree with most of your comments on this thread but, in some
> respects, I think you miss the most salient points.
I didn't miss the salient points. I may have gotten off topic as
far as this evolution fourm is concerned.
> In short, trying to understand the origin of life is not the same as
> trying to devise a perpetual motion machine. Had Jarek's proposal
> really been correct, I suggest mirrors and vacuum tubes might still be
> detectable as inherited components in today's organisms.
>
> The essential point, so it seems to me, about the origin of life is to
> indentify a primordial source of free energy that could have been used
> by *organic chemistry* to trigger evolution.
Jarek's original question didn't concern the origin of life (which
would be off topic here anyway) but concerned an issue in evolution.
He conjectured that an organism could have evolved which could extract
energy from the thermal infrared (IR) background. He suggested
something like photosynthesis, but for small energy photons. He
suggested such organisms could cycle the thermal energy between their
metabolic needs and the thermal energy that surrounds it.
I was addressing the point that energy can't be extracted from
thermal energy unless there was a temperature difference, and that the
thermal energy gets used up. I have no doubt an organism could evolve
that used the short wavelength end of the IR spectrum. However, the
idea of extracting usable energy from the thermal background violates
the laws of thermodynamics.
He made the completely valid point that no one has come up with a
general proof that the fundamental laws of physics lead to the
validity of thermodynamics. He presented the scenario with the mirrors
to prove that the second law could be violated in what he thought was
a pretty obvious way. He also provided conjectures concerning enzymes
that may be able to violate the laws of thermodynamics. I was pointing
out that the examples he provided do not actually violate the laws of
thermodynamics. Starting from some fairly fundamental laws (e.g.,
quantum mechanics, electrodynamics) one can show that the laws of
thermodynamics really are valid for these simple cases.
Apparently, I did catch some of his point. He has posted some
inquiries in some physics forums, where he asked whether it is
possible to violate the laws of thermodynamics. Perhaps the discussion
should stay in these other forums.
> There was no connection made between the posibility of such
> Orgel listed prebiotic energy sources and pointed out that thermal
> energy was largest such source. Because it was the largest energy
> source, I have argued that thermal free energy could have been
> harvested by chemical oscillations induced by daily or yearly
> oscillations in the earth's surface temperature. These, of course,
> would be caused by the earth's spin or orbit.
The origin of life, according to thermodyanmics, must have been
coupled in some way to a temperature difference. You are hypothesizing
the source of the temperature difference. I think you are speculating
that the chemical is at one temperature, and its temperature is
lagging behind season temperature changes in its environment. So the
gradient between the external temperature of a chemical substance and
the environment outside the region with the substance drives the
reaction.
Scientists who believe in deep vents think it is a geothermal
gradient of temperature. Other people think it is the sun which of
course is at a much higher temperature than the earths surface. Every
theory has a different temperature gradient. An origin of life that is
not associated with any temperature gradient would violate
thermodynamics.
> In sum, I do not think we need to invoke breaches in the laws of
> thermodynamics in order to understand the origin of life. Neither do I
> think we need to propose the existence of entities which no longer
> exist, at least as representative components, in extant living
> systems.
There is some validity to Jareks question of whether organisms
could exist that use IR in photosynthesis. If there was a thermal
gradient or temperature difference of some sort, maybe a biological
"thermocouple" could evolve. I was looking at his mirror motor to see
if energy could be extracted from a very small temperature difference.
Toward the very end of the life of his motor, when almost all the
photon energy has been changed to kinetic energy in the mirrors, there
is still a very slow transition from thermal to kinetic energy. In
analogy, maybe a very slow organism could extracting energy from IR
provided that it was in a thermal gradient. However, at zero
temperature difference I propose that extracting energy from IR won't
help the organism. It would emit IR at the same rate it absorbs IR,
and could never feed itself.
Do you think an organism could evolve to extract energy from low
temperature IR emission? Perhaps you know some examples!
>
> Sincerely
>
> John Hewitt
>
> On Sep 6, 10:04=3DA0pm, Lorentz
yahoo.com> wrote:
>
>
>>> On Sep 5, 1:01=3D3DA0am, r norman
_comcast.net> wrote:
>> =3DA0 =3DA0That is not a problem with his analysis, although it can be =a
>> complication. We can analyze the problem under the ideal conditions of
>> mirrors of zero thickness with a zero small specific heat. This would
>> be a limiting condition of course. However, there is no physical law
>> that a priori forbids this limiting condition.
>> =3DA0 =3DA0 The important thing in this limit is that the mirrors would=
not
>> contain a significant amount of internal energy compared to the
>> electromagnetic radiation in the vacuum. Therefore, the only energy
>> these mirrors could carry is kinetic energy. The amount of "heat
>> energy" stored by the mirrors would be insignificant compared to the
>> kinetic energy of the mirrors.
>> =3DA0 =3DA0 =3DA0In a real experiment, the mirrors could be made extrem=
ely thin
>> with substrates made of a heat insulator. The internal energy of the
>> mirrors would be a real-world complication. I think an experiment can
>> be designed where the energy stored by the mirrors could be
>> compensated.
>> =3DA0 =3DA0 =3DA0 As I stated, the real problem with his "thought exper=
iment" i=3D
> s
>> that with the interpretation of thermodynamic laws. The two mirrors
>> and piston in the experiment are merely components of the heat engine.
>> The flow of heat is moving from one heat reservoir (spatial volume
>> initially between the two) to another heat reservoir (the spatial
>> volume outside the two mirrors.
>> =3DA0 =3DA0 Interpreting it this way requires really close attention to=
the
>> formal statements of thermodynamic law. Loose derivative statements
>> can't substitute for formal analysis. The meaning of each separate
>> word has to be analyzed closely.
>> =3DA0 =3DA0 =3DA0It is really easy for someone to to make the mistake o=
f thinki=3D
> ng
>> he figured out how to beat the laws of thermodynamics. Wouldn't it be
>> great if one of the people on this forum really does figure it out!
>> However, validation of the achievement requires a really accurate
>> understanding of the formal theory. I really hope I am teaching
>> someone somewhere science when I critique posts like this.
>> =3DA0 =3DA0 =3DA0A really good journal where problems like this are ana=
lyzed al=3D
> l
>> the time is "Journal of American Physics."
>
>
