Actual photons?

One of the allures of amateur astronomy is to say that we're seeing
the "actual photons" from pick your favorite deep sky object. I was
thinking about this and wondering about the veracity of this
statement. Since most of us use reflectors or refractors with a
diagonal, I was wondering if it is the *same* photon that gets
reflected off of a mirror. Since I am scientifically challenged, I
don't know the answer. I also don't know if the question even makes
sense (is there such a thing as "sameness" in the quantum mechanical
world?).

As far as I know we do not see "actual photons".
Each reflection from the surface means

"actual photon" is absorbed by the surface
"newly generated photon" is radiated off the surface

How many reflections of a photon can we count during "its" trip to our
eyes? Surely many of them. So...

Anyway, I agree, I used to say to my friends "... but I caught that
million_years_old photons!" ;-)

Roman

BigKhat wrote:

One of the allures of amateur astronomy is to say that we're seeing
the "actual photons" from pick your favorite deep sky object. I was
thinking about this and wondering about the veracity of this
statement. Since most of us use reflectors or refractors with a
diagonal, I was wondering if it is the *same* photon that gets
reflected off of a mirror. Since I am scientifically challenged, I
don't know the answer. I also don't know if the question even makes
sense (is there such a thing as "sameness" in the quantum mechanical
world?).

On 3 Sep 2004 12:06:53 -0700, (BigKhat) wrote:

One of the allures of amateur astronomy is to say that we're seeing
the "actual photons" from pick your favorite deep sky object. I was
thinking about this and wondering about the veracity of this
statement. Since most of us use reflectors or refractors with a
diagonal, I was wondering if it is the *same* photon that gets
reflected off of a mirror. Since I am scientifically challenged, I
don't know the answer. I also don't know if the question even makes
sense (is there such a thing as "sameness" in the quantum mechanical
world?).

No, you don't see the actual photons. Refraction, reflection, scattering- these
are all processes that on the quantum level result from photons being absorbed
and re-emitted. This is true even for naked eye observing.

But the stimulus in your brain still follows as a direct result of the
properties of the photons that left the object, so philosophically, I think you
may as well consider that you are seeing the original photons.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

In article , Chris L Peterson
wrote:

On 3 Sep 2004 12:06:53 -0700, (BigKhat) wrote:

One of the allures of amateur astronomy is to say that we're seeing
the "actual photons" from pick your favorite deep sky object. I was
thinking about this and wondering about the veracity of this
statement. Since most of us use reflectors or refractors with a
diagonal, I was wondering if it is the *same* photon that gets
reflected off of a mirror. Since I am scientifically challenged, I
don't know the answer. I also don't know if the question even makes
sense (is there such a thing as "sameness" in the quantum mechanical
world?).

No, you don't see the actual photons. Refraction, reflection, scattering- these
are all processes that on the quantum level result from photons being absorbed
and re-emitted. This is true even for naked eye observing.

But the stimulus in your brain still follows as a direct result of the
properties of the photons that left the object, so philosophically, I think you
may as well consider that you are seeing the original photons.

_______________________________________________ __

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com



Yeah, and talking about photon reflecting and re-emission, all light from
stars (and galaxies) has travelled an additional million light years or so
farther than we commonly think, because of the random walk they take just
escaping from their source in their star's core.

The photon reaction(s) from our Sun which warm our face on a summer's day
is about 5 times older than the earliest Neanderthal, and has transversed
10 times the diameter of our galaxy to reach us.

Defender

The photon reaction(s) from our Sun which warm our face on a summer's =
day
is about 5 times older than the earliest Neanderthal, and has =
transversed
10 times the diameter of our galaxy to reach us.


What??

-Florian

"Florian" wrote in message
...
The photon reaction(s) from our Sun which warm our face on a summer's day
is about 5 times older than the earliest Neanderthal, and has transversed
10 times the diameter of our galaxy to reach us.


What??

-Florian

If I'm not mistaken, (been reading up on this the last few months), The
photon that is created in the heart of our Sun takes a random walk at that
speed of light from the center of the Sun to the outer reaches. This Walk
is taken by going left then right then up and left again and then sideways
and ect.. ect.. Each movement is about an inch or so long before it goes off
in to another direction. This random walk could take up to five million
years before it reaches what could be called the surface of the Sun. At
this point it shoots out and towards us still at the speed of light and
takes eight minutes for that last leg of the journey because the space
between here and there is much less dense and much much cooler.

Lately I've been reading up on the six different quarks. The leptons
and barions, their charges and weights, and ect.. and all though it's
getting easier for me to catch on - it's getting harder to remember the
earlier readings to say what the photons are reacting to to cause them to
change directions in the hot and dense solar center. The bad thing is that
Quantum theories are getting easier for me to understand, a point I never
dreamed I'd reach.
--
Michael A. Barlow

photon that is created in the heart of our Sun takes a random walk at that
speed of light from the center of the Sun to the outer reaches. This Walk
is taken by going left then right

This random walk has to have a bias to it otherwize it would never move
from its initial position.
I wonder if old photos are any different from young photons. For example
are old photons grayer, slower, etc.

HAVRILIAK wrote:
This random walk has to have a bias to it otherwize it would never move
from its initial position.

This is false. A fairly standard result from stochastic processes is
that the mean distance from the starting point of a random walker whose
steps are independent and identically distributed (i.i.d.) is the mean
length of one step times the square root of the number of steps.

I wonder if old photos are any different from young photons. For example
are old photons grayer, slower, etc.

Photons differ only in energy and polarization, as far as I remember.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

HAVRILIAK says...

photon that is created in the heart of our Sun takes a random walk at that
speed of light from the center of the Sun to the outer reaches. This Walk
is taken by going left then right

This random walk has to have a bias to it otherwize it would never move
from its initial position.

That's not true. If a random walk doesn't, on average, get farther
and farther from the starting position as time goes by it isn't a
random walk.

"Michael Barlow" wrote:

If I'm not mistaken, (been reading up on this the last few months), The
photon that is created in the heart of our Sun takes a random walk at that
speed of light from the center of the Sun to the outer reaches. This Walk
is taken by going left then right then up and left again and then sideways
and ect.. ect.. Each movement is about an inch or so long before it goes off
in to another direction. This random walk could take up to five million
years before it reaches what could be called the surface of the Sun. At
this point it shoots out and towards us still at the speed of light and
takes eight minutes for that last leg of the journey because the space
between here and there is much less dense and much much cooler.

Robert Noyes book "The Sun our Star" (Harvard 1982) reckons 10 million
years for the random walk. Most recent sources say 170,000 years. Best
explanation for the difference that I can find is that the convection
zone is thicker than suspected in 1980s.

It is just as well the photons go through some transformations in the
Sun - the photons produced in the core are gamma rays that would do us
no good at all.

--
Martin Frey
http://www.hadastro.org.uk
N 51 02 E 0 47