Dimensional analysis yields an understanding of the power density of the
Sun. All of the power generated within the Sun is radiated from the
photosphere, whose area scales as the radius of the Sun, which scales as
4*Pi*R^2 while the volume scales as 4/3*Pi*R^3. Hence, the power density of
the Sun per unit volume or per unit mass, scales as 3/R. From a human
perspective, since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal. In fact, when the Sun is active, the
power density of the Sun is less than that of the human body:

http://en.wikipedia.org/wiki/Sun

The power density of the Sun per unit mass could go from infinitesimal of
zero and we would not notice, because we are mortal.

On Feb 23, 10:23*pm, "kiloVolts"
mant...@4u3t7s0s5A6s1e7F3G6rH3h5d4q3a3s2aX7A2D5y6 j1z.com wrote:
Dimensional analysis yields an understanding of the power density of the
Sun. All of the power generated within the Sun is radiated from the
photosphere, whose area scales as the radius of the Sun, which scales as
4*Pi*R^2 while the volume scales as 4/3*Pi*R^3. Hence, the power density of
the Sun per unit volume or per unit mass, scales as 3/R. From a human
perspective, since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal. In fact, when the Sun is active, the
power density of the Sun is less than that of the human body:

WRONG


The core is the only location in the Sun that produces an appreciable
amount of heat via fusion: the rest of the star is heated by energy
that is transferred outward from the core. All of the energy produced
by fusion in the core must travel through many successive layers to
the solar photosphere before it escapes into space as sunlight or
kinetic energy of particles.

So FUSION occurs at the Core not at the surface.

Bye
Sanny

Talk with Physics Computer: http://www.GetClub.com

"Sanny" wrote

So FUSION occurs at the Core not at the surface.

You are a ****ing idiot. No one said that fusion occurs at the surface of
the Sun. Go back and read the post again. What high school did you graduate
from?

"Sanny" wrote

So FUSION occurs at the Core not at the surface.

You are a ****ing idiot. No one said that fusion occurs at the surface of
the Sun. Go back and read the post again. What high school did you
graduate from?


Sanny reads at a grade three level:

From:

http://en.wikipedia.org/wiki/Sun

"About 3.4×1038 protons (hydrogen nuclei) are converted into helium nuclei
every second (out of ~8.9×1056 total amount of free protons in the Sun),
releasing energy at the matter-energy conversion rate of 4.26 million metric
tons per second, 383 yottawatts (3.83×1026 W) or 9.15×1010 megatons of TNT
per second. This actually corresponds to a surprisingly low rate of energy
production in the Sun's core-about 0.3 W/m3 (watts per cubic meter). This is
less power than generated by a candle. Power density is about 6 µW/kg of
matter. For comparison, the human body produces heat at approximately the
rate 1.2 W/kg, roughly a million times greater per unit mass."

The power density of the Sun per unit mass is six orders of magnitude less
that the power density of the human body. If the power density of the Sun
were to go from infinitesimally infinitesimal to zero, we would not notice,
because we are mortal.

"kiloVolts" mantrap@4u3t7s0s5A6s1e7F3G6rH3h5d4q3a3s2aX7A2D5y6 j1z.com wrote
in message ...
Dimensional analysis yields an understanding of the power density of the
Sun. All of the power generated within the Sun is radiated from the
photosphere, whose area scales as the radius of the Sun, which scales as
4*Pi*R^2 while the volume scales as 4/3*Pi*R^3. Hence, the power density
of the Sun per unit volume or per unit mass, scales as 3/R. From a human
perspective, since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal. In fact, when the Sun is active,
the power density of the Sun is less than that of the human body:

http://en.wikipedia.org/wiki/Sun

The power density of the Sun per unit mass could go from infinitesimal of
zero and we would not notice, because we are mortal.

a) Solar power is 3.8 E26 watts.
b) surface area is 6.1 E18 square meters.

a/b is 62 E6 watts per square meter, thats 62 megawatts per square meter.

Adult human has around 1 square meter of surface area, therefore about 100
watts per square meter.

On Feb 23, 8:23*am, "kiloVolts"
mant...@4u3t7s0s5A6s1e7F3G6rH3h5d4q3a3s2aX7A2D5y6 j1z.com wrote:
Dimensional analysis yields an understanding of the power density of the
Sun. All of the power generated within the Sun is radiated from the
photosphere, whose area scales as the radius of the Sun, which scales as
4*Pi*R^2 while the volume scales as 4/3*Pi*R^3. Hence, the power density of
the Sun per unit volume or per unit mass, scales as 3/R. From a human
perspective, since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal. In fact, when the Sun is active, the
power density of the Sun is less than that of the human body:

The solar constant at Earth's orbit is 1380W/m^2. Integrate over the
whole volume enclosed by a 1 AU sphere and tell me again how
infintesimal the power output is.


http://en.wikipedia.org/wiki/Sun

The power density of the Sun per unit mass could go from infinitesimal of
zero and we would not notice, because we are mortal.

On Mon, 23 Feb 2009 09:23:32 -0800, "kiloVolts"
mantrap@4u3t7s0s5A6s1e7F3G6rH3h5d4q3a3s2aX7A2D5y6 j1z.com wrote:

Dimensional analysis

Which you completely avoid using any knowledge of, in the rest of your
post. Making me wonder if you have EVER attempted to use dimensional
analysis of any kind for any purpose, at all.

I doubt you can provide a few good examples of why it is of any use,
of your own creation and where I cannot find the exact example
provided on the web, already, nearly quoted verbatim from you.

yields an understanding of the power density of the Sun.

Not really. In fact, I have no idea why you imagine so. And the rest
of your post doesn't use dimensional analysis for any purpose. So it
appears you are just bandying phrases about which you are completely
and totally clueless.

All of the power generated within the Sun is radiated from the
photosphere, whose area scales as the radius of the Sun, which scales as
4*Pi*R^2 while the volume scales as 4/3*Pi*R^3.

So, let's see. You are able to quote basic gemoetry equations. Well,
at least you can do the same thing that a 12 year old can do.

Hence, the power density of
the Sun per unit volume or per unit mass, scales as 3/R.

You mean you just discovered the idea of dividing the area of a sphere
by its volume? Wow.

Well, this may be a good time to let you know that if you do this for
other geometric shapes found in 3D rectilinear manifolds, that you
will find a sphere presents a minimal surface area to volume ratio.

I'm glad you are learning some geometry.

From a human perspective,

Since you are decidedly inhuman, I can't say why you'd try and speak
for the us.

since the radius of the Sun R, is almost infinite,

Yes, you being like the Hottentotts and other primitive tribes of
yesteryear, find that anything more than 3 is "many" or "uncountable."
So it all looks like "infinite" to you, I'm sure.

the power density per unit mass is infinitesimal.

If only you were actually capable of putting two numbers together into
a fraction and understanding even that much alone, you might come to a
different conclusion.

Sadly, you are so uneducationed and incompetent that we can't even
expect you to manage this tiny ratio in your feeble mind. Too bad.

Besides making the logical mistake of conflating volume with mass, you
got this all wrong.

In fact, when the Sun is active,

Hehe. And I'm sure you feel that when the sun sets at night, that it
is no longer active. Oh, well. Much, much work to do educating you.

the power density of the Sun

There is that phrase you don't understand, again.

is less than that of the human body:

http://en.wikipedia.org/wiki/Sun

Well, at least you can find "Sun" on wiki. I could wonder, at times.

The power density of the Sun per unit mass could go from infinitesimal of
zero

Your educational state actually predates early Greek culture. Zeno
would know better.

and we would not notice,

I see. And so you conclude the sun doesn't matter. Well, at least we
don't have to argue with you about the sun causing global warming.

because we are mortal.

Yes, your powerful, decisive point. Everything else you wrote flows
inevitably from this one, sole, important fact that you've noticed.
"We are mortal, therefore the sun cannot be noticed."

Sometimes, I just stare and marvel at how you might have come to be.
Then I realize you are the old Eliza program with web crawling added
and it all makes sense, again.

Jon

--
Religion makes its living by first wounding children and then
tending their injuries.

kiloVolts wrote:
[snip]

since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal.
[snip rest]

Learn some math. Core power generation is 0.3 W/m^3 within about 10%
of the sun's total volume of 1.412×10^27 m³

(0.3 W/m^3)(0.1)(1.412×10^27 m^3) = 4.24x10^25 watts

That is nowhere near either zero or infinity (even the small one).
Number check: solar constant at 1 AU = 1368 W/m^2

(1368 W/m^2)(4)(pi)[1.496x10^11 m/AU)]^2 = 3.85x10^26 watts

Consistent within a factor of 9. Good enough.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

"bw" wrote in message
...

"kiloVolts" mantrap@4u3t7s0s5A6s1e7F3G6rH3h5d4q3a3s2aX7A2D5y6 j1z.com
wrote in message ...
Dimensional analysis yields an understanding of the power density of the
Sun. All of the power generated within the Sun is radiated from the
photosphere, whose area scales as the radius of the Sun, which scales as
4*Pi*R^2 while the volume scales as 4/3*Pi*R^3. Hence, the power density
of the Sun per unit volume or per unit mass, scales as 3/R. From a human
perspective, since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal. In fact, when the Sun is active,
the power density of the Sun is less than that of the human body:

http://en.wikipedia.org/wiki/Sun

The power density of the Sun per unit mass could go from infinitesimal of
zero and we would not notice, because we are mortal.

a) Solar power is 3.8 E26 watts.
b) surface area is 6.1 E18 square meters.

a/b is 62 E6 watts per square meter, thats 62 megawatts per square meter.

Adult human has around 1 square meter of surface area, therefore about 100
watts per square meter.



Duh.

Duh.

"Eric Gisse" wrote in message
...
On Feb 23, 8:23 am, "kiloVolts"
mant...@4u3t7s0s5A6s1e7F3G6rH3h5d4q3a3s2aX7A2D5y6 j1z.com wrote:
Dimensional analysis yields an understanding of the power density of the
Sun. All of the power generated within the Sun is radiated from the
photosphere, whose area scales as the radius of the Sun, which scales as
4*Pi*R^2 while the volume scales as 4/3*Pi*R^3. Hence, the power density
of
the Sun per unit volume or per unit mass, scales as 3/R. From a human
perspective, since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal. In fact, when the Sun is active,
the
power density of the Sun is less than that of the human body:

The solar constant at Earth's orbit is 1380W/m^2. Integrate over the
whole volume enclosed by a 1 AU sphere and tell me again how
infintesimal the power output is.


http://en.wikipedia.org/wiki/Sun

The power density of the Sun per unit mass could go from infinitesimal of
zero and we would not notice, because we are mortal.