"Pioneer anomalous acceleration" and Cassini

"Asimov" schrieb im Newsbeitrag ...
If there was a recoil then a source such as an electron would be losing
or gaining mass simply by a change in temperature. This hasn't been
reported yet.
Do electrons have a temperature?
I thought they only have a speed.

Lots of Greetings!
Volker

"Asimov" wrote in message
...
"Jim Greenfield" bravely wrote to "All" (05 Nov 03 21:28:55)
--- on the heady topic of " "Pioneer anomalous acceleration" and
Cassini"

JG From: (Jim Greenfield)
JG Subject: "Pioneer anomalous acceleration" and Cassini
JG Organization: http://groups.google.com
JG Xref: aeinews sci.astro:7536

JG "Asimov" wrote in
JG message . .. "Jim
JG Greenfield" bravely wrote to "All" (04 Nov 03 23:57:09) --- on the
JG heady topic of " "Pioneer anomalous acceleration" and Cassini"
JG From: (Jim Greenfield)
The question was settled years ago. There *is* definitive anomalous
acceleration in pioneer and the voyagers. No theoretical explanation
has
yet been settled on.

JG Finally gathered the courage to tentatively suggest that when
photons
JG are emmitted, they give a 'recoil' against the source. If radiation
JG from within the craft is directed in a particular direction, a
thrust
JG might occur. (I thought that this would be so insignificant as to be
JG immesurable and undetectable, but maybe not)
JG What would happen to a high-power laser carefully suspended- any
JG chance of detecting an observable thrust counter to beam
direction???

Saying a photon is "emitted" is a bit of a misnomer. I'd rather say a
photon is released or let go. The momentum recoil is in the photon.
That momentum is what results in radiation pressure on the receiving
end. A photon is not so much emitted as the rest of the universe leaves
it behind in time since after all the photon sees zero time elapsed.
Anyways for whatever it's worth, photons interact with spacetime and in
a sense it is spacetime that moves not the photon. The photon is just a
little bit of history or information left behind and telling what the
universe was doing at that instant.

JG I am not interested in the photon after it leaves its source, but in
JG its EFFECT on that source- as in the recoil of my rifle against my
JG shoulder.
JG George and Lupus seem to think there is a counter-push on the source
JG caused by beam emmission, but you claim all energy is retained in the
JG photon (correct?)

If there was a recoil then a source such as an electron would be losing
or gaining mass simply by a change in temperature. This hasn't been
reported yet.

"Asimov" wrote in message
...
"Jim Greenfield" bravely wrote to "All" (05 Nov 03 21:28:55)

JG George and Lupus seem to think there is a counter-push on the source
JG caused by beam emmission, but you claim all energy is retained in the
JG photon (correct?)

If there was a recoil then a source such as an electron would be losing
or gaining mass simply by a change in temperature. This hasn't been
reported yet.

I have no idea what you mean. I suggest you look at Compton
scattering regarding electrons.

There is a recoil because momentum is conserved. The energy of
a photon is E=hv and the momentum is p=E/c so the same momentum
must be imparted to the emitting object but in the opposite
direction.

Force F=dp/dt and power P is dE/dt so F=P/c. For Pioneer the power
is 8W so the force is 2.67*10^-8 N. The mass is about 240kg so
the acceleration is 1.10*10^-10 m/s^2 or 1.10*10^-8 cm/s^2 as you
will find it stated in Table II in the paper by Anderson et al,
or see eqn (33) in section VIII, A.

http://www.arxiv.org/abs/gr-qc/0104064

George

"kurtan" wrote in message
news:T7Lpb.851$%W3.1296@amstwist00...
Perhaps some of you clever guys could care to bestow an opinion on
findings
at www.estfound.org/pioneer.htm . Is it go again for "Tired Light"
redshift?

No. If the craft was at a fixed distance, the shift from
Tired Light would be constant. Doppler gives a constant
shift for constant velocity. What is measured is an
apparent acceleration hence it is the rate of change of
the frequency shift.

Since the shift depends on distance, the rate of change
of the shift must depend on the speed of the craft. That
speed doesn't even appear in their equations.

In fact the shift produced by Tired Light is about four
orders of magnitude less than the Pioneer anomaly.

George

"George Dishman" wrote in message ...
"Asimov" wrote in message
...
"Jim Greenfield" bravely wrote to "All" (05 Nov 03 21:28:55)

JG George and Lupus seem to think there is a counter-push on the source
JG caused by beam emmission, but you claim all energy is retained in the
JG photon (correct?)

If there was a recoil then a source such as an electron would be losing
or gaining mass simply by a change in temperature. This hasn't been
reported yet.

I have no idea what you mean. I suggest you look at Compton
scattering regarding electrons.

There is a recoil because momentum is conserved. The energy of
a photon is E=hv and the momentum is p=E/c so the same momentum
must be imparted to the emitting object but in the opposite
direction.

Force F=dp/dt and power P is dE/dt so F=P/c. For Pioneer the power
is 8W so the force is 2.67*10^-8 N. The mass is about 240kg so
the acceleration is 1.10*10^-10 m/s^2 or 1.10*10^-8 cm/s^2 as you
will find it stated in Table II in the paper by Anderson et al,
or see eqn (33) in section VIII, A.

http://www.arxiv.org/abs/gr-qc/0104064



Thanks George. I find the idea of the transfer of matter from atom -
electron
- photon - "somewhere in the universe" an interesting issue. Now
can I have a set of scales sensitive enough to measure the weight
difference as a (sealed) battery runs down?

Jim G

"Jim Greenfield" wrote in message
om...
"George Dishman" wrote in message
...

There is a recoil because momentum is conserved. The energy of
a photon is E=hv and the momentum is p=E/c so the same momentum
must be imparted to the emitting object but in the opposite
direction.

Force F=dp/dt and power P is dE/dt so F=P/c. For Pioneer the power
is 8W so the force is 2.67*10^-8 N. The mass is about 240kg so
the acceleration is 1.10*10^-10 m/s^2 or 1.10*10^-8 cm/s^2 as you
will find it stated in Table II in the paper by Anderson et al,
or see eqn (33) in section VIII, A.

http://www.arxiv.org/abs/gr-qc/0104064



Thanks George.

OK, if you have any lingering doubts, just remember:
solar sails work ;-)

I find the idea of the transfer of matter from atom -
electron
- photon - "somewhere in the universe" an interesting issue.

If we get into SR, it will make the relationship between
energy and mass clearer, and move you on to the next set
of interesting questions ;-)

Now
can I have a set of scales sensitive enough to measure the weight
difference as a (sealed) battery runs down?

That might be tricky, but the Sun loses about 4 million tons
per second this way. We still can't measure it though, but
we can measure the difference between the sum of an electron
and a proton versus the mass of a hydrogen atom.

George

In message , George Dishman
writes

OK, if you have any lingering doubts, just remember:
solar sails work ;-)

Not according to Thomas Gold!
--
Rabbit arithmetic - 1 plus 1 equals 10
Remove spam and invalid from address to reply.

"George Dishman" wrote in message ...
"Jim Greenfield" wrote in message
om...
"George Dishman" wrote in message
...

There is a recoil because momentum is conserved. The energy of
a photon is E=hv and the momentum is p=E/c so the same momentum
must be imparted to the emitting object but in the opposite
direction.

Force F=dp/dt and power P is dE/dt so F=P/c. For Pioneer the power
is 8W so the force is 2.67*10^-8 N. The mass is about 240kg so
the acceleration is 1.10*10^-10 m/s^2 or 1.10*10^-8 cm/s^2 as you
will find it stated in Table II in the paper by Anderson et al,
or see eqn (33) in section VIII, A.

http://www.arxiv.org/abs/gr-qc/0104064



Thanks George.

OK, if you have any lingering doubts, just remember:
solar sails work ;-)

Since I read of laser "tractors" pushing beads, I never doubted that
they would (so long as there is a net "push" in one direction)

I find the idea of the transfer of matter from atom -
electron
- photon - "somewhere in the universe" an interesting issue.

If we get into SR, it will make the relationship between
energy and mass clearer, and move you on to the next set
of interesting questions ;-)

Now
can I have a set of scales sensitive enough to measure the weight
difference as a (sealed) battery runs down?

That might be tricky, but the Sun loses about 4 million tons
per second this way. We still can't measure it though, but
we can measure the difference between the sum of an electron
and a proton versus the mass of a hydrogen atom.

George

Off to the shed to design a rocket which collects inter-stellar
hydrogen, runs it through a reactor to convert to EMR, and sends
(most) of the radiation out the "back". Not much accelleration, but
outside the solar system??

Jim

In message , Jim
Greenfield writes

Off to the shed to design a rocket which collects inter-stellar
hydrogen, runs it through a reactor to convert to EMR, and sends
(most) of the radiation out the "back". Not much accelleration, but
outside the solar system??

A Busssard ramjet, as you may already know. Doesn't work, for all sorts
of reasons.
--
Rabbit arithmetic - 1 plus 1 equals 10
Remove spam and invalid from address to reply.

In article ,
Jonathan Silverlight writes:
A Busssard ramjet, as you may already know. Doesn't work, for all sorts
of reasons.

Hard to build, no doubt, but "doesn't work?" Why not? Are you
thinking of the mythical "ramjet speed limit?"

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
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