HDTenEightyP/NetNews huggingface dataset:
From: toma@cdc910b21.gsfc.nasa.gov (Tom Atwater)
Subject: Re: photons
Originator: toma@zephyr.gsfc.nasa.gov
Organization: NASA Goddard Space Flight Center, Greenbelt, MD
Distribution: na
Date: Wed, 22 Jul 1992 10:42:09 GMT


newsgroups: alt.sci.new-theories
Subject: Re: photons
Summary: 
Expires: 
Followup-To: 
Distribution: na
Organization: NASA Goddard Space Flight Center, Greenbelt, MD
Keywords: 

In article <24756@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
>In article <1992Jul21.132737.21878@nsisrv.gsfc.nasa.gov>, toma@zephyr.gsfc.nasa.gov (Tom Atwater) writes...
>>In article <1992Jul21.074354.31069@watson.ibm.com> jec@pilatus.zurich.ibm.com (Jean Cherbonnier) writes:
>>>How come the gravitation can curb light beams when photons
>>>have no mass ? 
>> 
>>The simple answer is: photons have zero REST mass.
>>This is equivalent to saying that stationary photons do not exist.
>>The moving photon has energy, which is equivalent to mass (E = m c^2).
>>Therefore at least qualitatively it can be seen how gravity, which
>>operates on mass, can affect a photon, which has energy/mass.
>
>This answer is roughly correct, but not how most physicists would 
>describe it.
>
>Photons have no mass.  Period.  In GR, the gravitational force depends on the
>complete energy-momentum tensor, not just the "0-0" component, which is the
>mass.  So a particle with any energy whatsoever is affected by gravity even if
>it has no mass. But the force it experiences is not the same as the one
>a particle at rest but with mass = E/c^2 would have.  It's more complicated
>than that because of the tensorial equations.
>
>"Relativistic mass" is an outdated and troublesome notion, which has gone
>the way of the old Minkowski (imaginary) metric in relativity.  Do you
>really want to say that a photon has a mass that depends on it's wavelength?

In the end, I see this as a question of semantics.
What is mass?
No matter how you answer that question, the mass of something
is equivalent to its energy, whether the energy is kinetic or 'rest mass',
or whatever.
The fundamental quantity is ENERGY, not mass.
All systems with energy (which is to say, all physical systems) are affected
by gravity.

I guess I'm just not a member of {most physicists} (nor do I wish to be considered
such :-) ).

-- 
Tom Atwater

toma@chapman.gsfc.nasa.gov
CompuServe: 72540,1652
From: G.Joly@cs.ucl.ac.uk (Gordon Joly)
Newsgroups: alt.sci.physics.new-theories
Subject: Re: Halley's comet
Date: 21 Jul 92 16:34:47 GMT




So which comet is Giotto going to look at next?


Gordon Joly      Phone  +44 71 387 7050 ext 3703      FAX  +44 71 387 1397
Internet: G.Joly@cs.ucl.ac.uk        UUCP: ...!{uunet,uknet}!ucl-cs!G.Joly
Computer Science, University College London, Gower Street, LONDON WC1E 6BT
Newsgroups: alt.sci.physics.new-theories
From: knapp@spot.Colorado.EDU (David Knapp)
Subject: Re: photons
Organization: University of Colorado, Boulder
Date: Tue, 21 Jul 1992 18:51:14 GMT

In article <1992Jul21.132737.21878@nsisrv.gsfc.nasa.gov> toma@zephyr.gsfc.nasa.gov (Tom Atwater) writes:
>In article <1992Jul21.074354.31069@watson.ibm.com> jec@pilatus.zurich.ibm.com (Jean Cherbonnier) writes:
>>A very naive question from a non-physicist :
>>How come the gravitation can curb light beams when photons
>>have no mass ? 
>
>the very same question I wondered myself, many years ago, before getting
>into physics.
>
>The simple answer is: photons have zero REST mass.
>This is equivalent to saying that stationary photons do not exist.
>The moving photon has energy, which is equivalent to mass (E = m c^2).
>Therefore at least qualitatively it can be seen how gravity, which
>operates on mass, can affect a photon, which has energy/mass.

What about the influence on space-time by massive objects?  My understanding
was that the gravitational lensing could be quite well described using
special relativity.  This is not the case?


-- 
"Oh please, Lord, break the curse on women's hearts that says we don't need 
our men.  Break that independence...Help men to rise up to take positions
of leadership and authority that we might submit to them."  -Toni Denver,
 operation rescue member, as she is quoted in Life Magazine, July 1992
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: alt.sci.physics.new-theories
Subject: Re: photons
Date: 22 Jul 92 18:57:16 GMT
Reply-To: sichase@csa2.lbl.gov
Distribution: na
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.3-4

In article <1992Jul22.104209.29404@nsisrv.gsfc.nasa.gov>, toma@cdc910b21.gsfc.nasa.gov (Tom Atwater) writes...
> 
>In the end, I see this as a question of semantics.
>What is mass?
>No matter how you answer that question, the mass of something
>is equivalent to its energy, whether the energy is kinetic or 'rest mass',
>or whatever.
>The fundamental quantity is ENERGY, not mass.
>All systems with energy (which is to say, all physical systems) are affected
>by gravity.
> 

No.  Mass is not equivalent to energy.  m^2 = E^2 - p^2 is the correct 
formula.  So mass and energy are intimately related, but one is not equivalent
to the other.  It is more than a matter of semantics.  If you just take
m = E/c^2 to calculate the gravitational pull of an object with energy 
E, you WILL get the wrong result.

And just to pick nits, mass is Lorentz invariant, so is in a certain 
sense more fundamental than energy, which depends upon your reference
frame.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: alt.sci.physics.new-theories
Subject: Re: LaRouche's Physics - Analysis Wanted
From: alan@StarConn.com (Alan Deikman)
Date: 21 Jul 92 21:17:08 GMT
Organization: Starnet-Public Access UNIX--Los Altos, CA  415-949-3133

In article <4946@transfer.stratus.com> tarl@sw.stratus.com (Tarl Neustaedter) writes:
>A couple of comments on the politics of LaRouche, followed by expressions
>of puzzlement on physical arguments.
>
>In article <1992Jul18.215816.6316@usenet.ins.cwru.edu>, aq817@cleveland.Freenet.Edu (Steve Crocker) writes:
>> [LaRouche]
>> He began a 15 year federal prison sentence early in 1989. He was framed on
>> charges of fraudently obtaining loans from supporters, and I believe 
>> conspiracy to obstruct justice.
>
>Framed? Fascinating. His organization certainly practiced fraud on a massive
>scale, affecting a couple of people I know (their credit cards got rung up
>for large charges they did not authorize). The courts ruled that LaRouche
>was part and parcel of the fraud - if you have evidence otherwise, you should
>be presenting it in court.
>

Hah!  Near where I live I read several political posters that have a
picture of the studious Mr. LaRouche and the caption:  "LaRouche for
President:  The one opponent Bush feared enough to put in prison."
You talk to a LaRouche supporter and you find they take it very 
seriously.  Anyway, it reminds me of the tactics that we have seen
in this group defending Dewey Larson's physics: if it ISN'T TRUE,
why are you PERSECUTING ME?

Let's not bring all that up again.


Alan Deikman
============
From: mcline@terapin.com (Matthew Cline)
Newsgroups: alt.sci.physics.new-theories
Subject: Re: Time Travel?
Date: 21 Jul 92 10:33:23 PST
Organization: BBS

>How do they know everybody on earth has the same mitochondrial DNA? No one
teste
>d me or anybody I know. Is this another of these experiments where 10 people
get
> tested and the results get extrapolated wildly.
        I can't seem to find my source on this, but I'm pretty sure that they
used large samples.  My guess would be thousands of samples from around the
world.  Now that I think of it, My source porbably doesn't refer to the sample
size, just the results.  If I can find it, I'll quote whatever numbers it has
in another post.

Matthew Cline
Newsgroups: alt.sci.physics.new-theories
From: silverstein@vxdesy.desy.de
Subject: Re: photons
Organization: (DESY, Hamburg, Germany)
Date: Tue, 21 Jul 1992 14:03:09 GMT

In article <1992Jul21.074354.31069@watson.ibm.com>, jec@pilatus.zurich.ibm.com (Jean Cherbonnier) writes:
> A very naive question from a non-physicist :
> How come the gravitation can curb light beams when photons
> have no mass ? 

Not that naive a question, really. To answer it, I'll have to give you the
day-1 lesson on General Relativity that we physicists all got.

Let's do a thought experiment. suppose you are in a tall building with a very
fast elevator in it, and you can see into it.

There is a guy in the elevator with a flashlight 1 meter above the floor
that fires a short pulse of light in a horizontal direction (in your frame
of reference) at time t=0.

At the time the light is emitted, the elevator is at zero velocity, and 
begins accelerating upward with an acceleration a. (this sounds artificial,
and it is, but I'm trying to make it as simple as possible by removing
unnecessary constant terms).

          ^
          | a
      +-------+
      |       |
      |0      |
   -  |+- ->  |
  1m  |^      |
   -  +-------+

Now, you see the light moving horizontally as the elevator keeps
accelerating upward. But by the time the light beam reaches the other
side of the elevator at time t, the elevator has moved upward, so the
light will hit the far wall closer to the floor. You can easily calculate
the height at which it will hit:
                 2
 h = 1m - 1/2 a t   (describes a parabolic trajectory)

Now, the guy in the elevator also sees the light beam hit the wall lower than
where he aimed, and will also see that the light followed a parabolic
trajectory.

At this point, we need to accept a postulate by Einstein that an accelerational
reference frame is indistinguishable from a reference frame in a gravitational
field. The guy in the elevator has no way to distinguish whether the
acceleration he feels is due to a large mass beneath him, or an acceleration
of the elevator. Either way, he feels pulled towards the floor, and either way,
he will see the light bend downwards.

This way, we predict that light will be bent by a gravitational field.

This effect is difficult to measure on earth where the gravitational pull is
relatively small, but has been seen, for instance, by measuring the apparent 
positions of stars whose light passes close to the sun. This is done during
solar eclipses, and the stars do appear to shift position in the sky in a way
consistent with GR.
From: me@amiganet.chi.il.us (Corey Sweeney)
Newsgroups: alt.sci.physics.new-theories
Subject: Re: photons
Date: 24 Jul 92 01:11:03 GMT
Organization: Amiga Network Information Systems

In article <1992Jul21.132737.21878@nsisrv.gsfc.nasa.gov>,
toma@zephyr.gsfc.nasa.gov (Tom Atwater) writes:
>In article <1992Jul21.074354.31069@watson.ibm.com> jec@pilatus.zurich.ibm.com
(J
>ean Cherbonnier) writes:
>>A very naive question from a non-physicist :
>>How come the gravitation can curb light beams when photons
>>have no mass ? 
>
>the very same question I wondered myself, many years ago, before getting
>into physics.
>
>The simple answer is: photons have zero REST mass.
>This is equivalent to saying that stationary photons do not exist.
>The moving photon has energy, which is equivalent to mass (E = m c^2).
>Therefore at least qualitatively it can be seen how gravity, which
>operates on mass, can affect a photon, which has energy/mass.
>
>
>-- 
>Tom Atwater
>
>toma@chapman.gsfc.nasa.gov
>CompuServe: 72540,1652


I have to argue with you on that one.  I agree that the photons would curve but
not because of thier non-rest mass but because of the fact that gravitation is
a yanking of space and that distortion redirects all particles regardless of
any properties the same.
Newsgroups: alt.sci.physics.new-theories
From: toma@zephyr.gsfc.nasa.gov (Tom Atwater)
Subject: Re: photons
Organization: NASA Goddard Space Flight Center, Greenbelt, MD
Date: Tue, 21 Jul 1992 13:27:37 GMT

In article <1992Jul21.074354.31069@watson.ibm.com> jec@pilatus.zurich.ibm.com (Jean Cherbonnier) writes:
>A very naive question from a non-physicist :
>How come the gravitation can curb light beams when photons
>have no mass ? 

the very same question I wondered myself, many years ago, before getting
into physics.

The simple answer is: photons have zero REST mass.
This is equivalent to saying that stationary photons do not exist.
The moving photon has energy, which is equivalent to mass (E = m c^2).
Therefore at least qualitatively it can be seen how gravity, which
operates on mass, can affect a photon, which has energy/mass.


-- 
Tom Atwater

toma@chapman.gsfc.nasa.gov
CompuServe: 72540,1652
From: clune@physics.Berkeley.EDU (Tom Clune)
Newsgroups: alt.sci.physics.new-theories
Subject: Re: photons
Date: 22 Jul 1992 18:15:54 GMT
Organization: University of California, Berkeley
Distribution: na
NNTP-Posting-Host: physics.berkeley.edu

I think an important point is being overlooked here in regards
to the original question:  Why do photons get bent by gravity?

General Relativity can be divided cleanly (for the most part) into two parts.

(1)  How does space curve due to matter.

(2)  How do bodies move in the presence of curvature.  (gravity)

The answer to (1) depends on mass/energy density.

However, the answer to (2) makes no reference to mass or energy.
Light does not bend as much due to gravity as other objects, simply
because of its speed.  A cannon ball and  a feather take the same
path in a gravitational system if they have the same intial position
and velocity.  In principle if one could have a zero mass object
that could "go" slower than the speed of light, it could be put onto
the trajectory of the cannon ball.

- Tom
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: alt.sci.physics.new-theories
Subject: Re: Elapsed Time near c
Date: 26 Jul 92 19:34:54 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa2.lbl.gov
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.3-4   

In article <1992Jul26.160729.1@vxdesy.desy.de>, silverstein@vxdesy.desy.de writes...
>> 
> 
>Yes, the gravitational force, like the electromagnetic force, is said to have
>an "infinite" range, which means that its effect is exactly zero only at an
>infinite separation.

That is *not* what "infinite range" means.  The formula which describes
a static force with range R between two point-objects separated by a 
distance r, is 

	F = exp(-r/R)/r^2

from which you can see that:

(1) The force is exactly zero only at infinite separation for all possible
values of range. 

(2) At distances small compared to R, F is dominated by 1/r^2, while
at large separations F is dominated by the decreasing exponential.  For
infinite range, F = 1/r^2 for arbitrary r and never enters the exponentially
decreasing regime.

It is point (2) which distinguishes finite and infinite range forces.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: alt.sci.physics.new-theories
From: jec@pilatus.zurich.ibm.com (Jean Cherbonnier)
Subject: photons
Date: Tue, 21 Jul 92 07:43:54 GMT
Reply-To: jec@pilatus.zurich.ibm.com (Jean Cherbonnier)
Organization: IBM T.J. Watson Research Center

A very naive question from a non-physicist :
How come the gravitation can curb light beams when photons
have no mass ? 

J.Cherbonnier
From: Richard.Mathews@West.Sun.COM (Richard M. Mathews)
Newsgroups: alt.sci.physics.new-theories
Subject: Re: photons
Date: 23 Jul 1992 20:36:07 GMT
Organization: Sun Microsystems, Inc.
NNTP-Posting-Host: astro
Originator: richard@astro.West.Sun.COM

knapp@spot.Colorado.EDU (David Knapp) writes:
>What about the influence on space-time by massive objects?  My understanding
>was that the gravitational lensing could be quite well described using
>special relativity.  This is not the case?

Yes and no.  You can use Special Relativity to calculate the bending of
light, and you will get a non-zero answer.  The trouble is that your answer,
as I recall, will be smaller by a factor of 2 from General Relativity's
answer.  The bending of space in GR really makes a difference.

    Richard M. Mathews			 Freedom for Lithuania
Richard.Mathews@West.Sun.COM		        Laisve!
From: "anthony tekatch" <anthony.tekatch@canrem.com>
Newsgroups: alt.sci.physics.acoustics
Subject: dynamic noise reducer
Date: 29 Jul 92 00:40:34 EST
Reply-To: "anthony tekatch" <anthony.tekatch@canrem.com>
Distribution: alt
Organization: Canada Remote Systems

A few weeks ago we had someone here say that dynamic sound/noise
reduction required some microphones and a digital signal processor then
the signal was inverted 180 degrees to oppose the originating noise.

My question is: why the digital signal processor?

The reason for my question is:

I would like to build a system that would reduce the noise that
arrives at my home from a highway that is about 1/2 mile away.

My idea would be to get two microphones one loudspeaker and some
circuits.

The first mic (A) would be about 40ft from my house and the second mic
(B) would be about 20ft from my house and they would both be in-line
from the highway noise.

The first mic's signal would be fed through a delay line of about 40
milli seconds (thats the time I figured it would take the sound to get
20ft from mic#1 to mic#2) and produce signal A'.

The loudspeaker would be in the direction of the house and located near
mic#2, and connected so that the signal would be 180 degrees from the
incoming highway noise.

A' = delayed signal
B  = signal from second mic
C  = intermediate signal (calculated)
D  = fed to loudspeaker in the direction of the house to
     cancel out the highway noise

The circuits would do the following analog calculations:

A'-B=C
B-C=D


Is this possible or am I missing something?

---
  OLX 2.1 TD  ((((((((((HYPNOTIC))))))(((((((((TAGLINE)))))))))))))))))
--
Canada Remote Systems  - Toronto, Ontario/Detroit, MI
World's Largest PCBOARD System - 416-629-7000/629-7044
Newsgroups: alt.sci.physics.acoustics
From: kpesonen@vipunen.hut.fi (Kari A Pesonen)
Subject: File format, HP 35665A
Originator: kpesonen@vipunen.hut.fi
Keywords: HP 35665A, Time capture buffer, file format
Organization: Helsinki University of Technology
Date: Fri, 24 Jul 1992 15:42:56 GMT

Help, please. 
 
I'm looking for the file format of time capture buffer 
files stored on 3,5" DOS-disks by HP 35665A Dynamic 
Signal Analyser. The user manuals I have refer to the 
HP's "Standard Data Format Utilities User Guide", which 
is not included in HP 35665A documentation. 
 
Kari Pesonen                       Kari.Pesonen@hut.fi
From: ea1205978@ntuvax.ntu.ac.sg
Newsgroups: alt.sci.physics.acoustics
Subject: Active Noise Control Again
Date: 31 Jul 92 02:53:52 GMT
Organization: Nanyang Technological University - Singapore


Thany You so much for the replies sent to my account
when I called for help in the field of :-

	ACTIVE ADAPTIVE ACOUSTIC ATTENUATION
		(ACTIVE NOISE CONTROL)

	Unfortunately, the e-mails to me was accidently
deleted when I was purging files within my account.

	Therefore, I would be most happy if the concerned
party would kindly retransmit the information to my account
and If there is any new ideas or data please do include 
them as well.

	Thany You Very Much.

	******
	NEBULA
	******
Newsgroups: alt.sci.physics.acoustics
From: daniel@redwood.ppc.ubc.ca (Daniel Ouellet)
Subject: Re: dynamic noise reducer
Organization: University of B.C. Pulp & Paper Centre
Distribution: alt
Date: Wed, 29 Jul 1992 15:23:24 GMT

In article <199229.2597.436@dosgate>, "anthony tekatch" <anthony.tekatch@canrem.com> writes:
|> A few weeks ago we had someone here say that dynamic sound/noise
|> reduction required some microphones and a digital signal processor then
|> the signal was inverted 180 degrees to oppose the originating noise.
|> 
|> My question is: why the digital signal processor?

I have heard (a few years ago) of problems with analog components because their
characteristics may vary after some time.

|> 
|> The reason for my question is:
|> 
|> I would like to build a system that would reduce the noise that
|> arrives at my home from a highway that is about 1/2 mile away.
|> 
|> My idea would be to get two microphones one loudspeaker and some
|> circuits.
|> 
|> The first mic (A) would be about 40ft from my house and the second mic
|> (B) would be about 20ft from my house and they would both be in-line
|> from the highway noise.
|> 
|> The first mic's signal would be fed through a delay line of about 40
|> milli seconds (thats the time I figured it would take the sound to get
|> 20ft from mic#1 to mic#2) and produce signal A'.
|> 
|> The loudspeaker would be in the direction of the house and located near
|> mic#2, and connected so that the signal would be 180 degrees from the
|> incoming highway noise.
 [stuff deleted]

First, to get a 'perfect' cancellation over a significant area, you would also need to
recreate the directivity of the noise source with your cancellation signal. Since the
highway is a 1/2 mile away, you are probably hit by something close to a plane wave. I
really doubt that you can recreate one with a single speaker at 20 ft.

Second, have you thought of your neighbours ? The noise that you want to blast in your
speaker may produce a cancellation at a location on your property, but it is likely going to add
to the noise your neighbours get. My guess is that within 24 hours, your going to be explaining
how your system works to a police officer :^) .
 
-- 
---------------------------------------------------------------------
Daniel Ouellet, Research Associate
Pulp and Paper Centre, University of British Columbia
2385 East Mall, Vancouver, BC, Canada V6T 1Z4
Tel:(604)822-8240   Fax:(604)822-8563   Email: daniel@ppc.ubc.ca
From: stella@gandalf.rutgers.edu (Ricky Suave Stella)
Newsgroups: alt.visa.us
Subject: Re: How about alt.visa.can?
Date: 30 Jul 92 16:19:54 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

rlerdorf@netcom.com (Rasmus Lerdorf) writes:


>If you are a permanent resident of Canada or a Canadian citizen, getting
>your spouse a permanent residence status is automatic and is usually done
>in under 3 months.  Canada is also not picky about multiple citizenships
>and I would assume the same would apply to multiple permanent residencies.


First statement kind of true...

Canada accepts double citizenship (not multiple) with some countries, ie
Argentina and recently the US.  It will not accept dual citizenship with
Italy (where you are Italian by blood and not where you are born)

It doesn't allow multiple permanent residencies.  Only one.  And the 
requirements of not loosing it are much tougher than on any other country.
You must be in Canadian territory for at least 180 days of any particualr
year.
 

-- 
---------------------------------------------------------------------------
 Ricardo Stella                                 stella@gandalf.rutgers.edu
 RUCS-US Manager - IML-SERC                     stella@remus.rutgers.edu
 Hill 118 - (908)932-2491        ...suave...    Rutgers University, NJ
From: rlerdorf@netcom.com (Rasmus Lerdorf)
Newsgroups: alt.visa.us
Subject: How about alt.visa.can?
Date: 28 Jul 92 15:37:34 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

Any interest in an alt.visa.canada group?  I'd sure like to see it..

-- 
Rasmus Lerdorf	         _   _   _   _    Nutec North America
Product Manager	        _ _   _ _ _ _     2629 Terminal Blvd.
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Newsgroups: alt.visa.us